OpenGL ES3 阴影贴图问题
OpenGL ES3 Shadow map problems
我在 Android 的 C++ 项目上工作，使用 OpenGL ES3，所以我尝试用定向光实现阴影贴图，我很了解这个理论，但我从未成功渲染它。
首先，我创建了包含深度图的帧缓冲区：
glGenFramebuffers(1, &depthMapFBO);
glBindFramebuffer(GL_FRAMEBUFFER, depthMapFBO);
glGenTextures(1, &depthMap);
glBindTexture(GL_TEXTURE_2D, depthMap);
glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT, SHADOW_WIDTH, SHADOW_HEIGHT, 0, GL_DEPTH_COMPONENT, GL_FLOAT, 0);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_TEXTURE_2D, depthMap, 0);
glDrawBuffers(1, GL_NONE);
glReadBuffer(GL_NONE);
glBindTexture(GL_TEXTURE_2D, 0);
glBindFramebuffer(GL_FRAMEBUFFER, 0);
然后我创建了一个编译深度着色器的着色器程序，如下所示：
#version 300 es
precision mediump float;
layout (location = 0) in vec3 position;
layout (location = 4) in ivec4 BoneIDs;
layout (location = 5) in vec4 Weights;
const int MAX_BONES = 100;
uniform mat4 lightSpaceMatrix;
uniform mat4 model;
uniform bool skinned;
uniform mat4 gBones[MAX_BONES];
void main(){
vec4 nPos;
if(skinned){
mat4 BoneTransform = gBones[BoneIDs[0]] * Weights[0];
BoneTransform += gBones[BoneIDs[1]] * Weights[1];
BoneTransform += gBones[BoneIDs[2]] * Weights[2];
BoneTransform += gBones[BoneIDs[3]] * Weights[3];
nPos=BoneTransform * vec4(position, 1.0);
}
else
nPos = vec4(position, 1.0);
vec4 p=model * nPos;
gl_Position = lightSpaceMatrix * p;
}
并使用此着色器程序和灯光 space 矩阵绘制场景，使用以下内容：
glCullFace(GL_FRONT);
double delta = GetCurrentTime() - firstFrame;
glm::mat4 camInv = glm::inverse(camera->getViewMatrix());
glm::mat4 lightSpaceProjection = glm::ortho(-40.0f, 40.0f, -40.0f, 40.0f, -1.0f, 100.0f);
glm::mat4 lightSpaceView = glm::lookAt(sun->direction, glm::vec3(0, 0, 0), glm::vec3(0, 1, 0));
lightSpaceMatrix = lightSpaceProjection * (lightSpaceView*camInv) ;
glViewport(0, 0, SHADOW_WIDTH, SHADOW_HEIGHT);
glBindFramebuffer(GL_FRAMEBUFFER, depthMapFBO);
glClear(GL_DEPTH_BUFFER_BIT);
directDepthShader.use();
glUniformMatrix4fv(glGetUniformLocation(directDepthShader.getProgramID(), "lightSpaceMatrix"), 1, GL_FALSE, glm::value_ptr(lightSpaceMatrix));
for (mesh_it it = castShadowMeshes.begin(); it != castShadowMeshes.end(); it++) {
it->get()->renderDepth(directDepthShader, delta);
}
glCullFace(GL_BACK);
glBindFramebuffer(GL_FRAMEBUFFER, 0);
最后，我使用常规着色器程序渲染场景，并使用以下代码将深度图绑定到 shadowMap 制服：
glViewport(0, 0, width, height);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
phongShader.use();
if (sun != nullptr)
if (sun->castShadow)
glUniformMatrix4fv(glGetUniformLocation(phongShader.getProgramID(), "lightSpaceMatrix"), 1, GL_FALSE, glm::value_ptr(lightSpaceMatrix));
this->setLightsUniforms(phongShader);
this->setViewUniforms(phongShader);
for (mesh_it it = phongMeshes.begin(); it != phongMeshes.end(); it++) {
if (it->get()->hasNormalMap) {
glUniform1i(glGetUniformLocation(phongShader.getProgramID(), "has_normal_map"), 1);
if (directlights.size() > 0) {
for (dlight_it it = this->directlights.begin(); it != this->directlights.end(); ++it) {
GLuint directLightPosLoc = glGetUniformLocation(phongShader.getProgramID(), (const GLchar*) ("directLightPos[" + ToString((*it)->index) + "]").c_str());
glUniform3f(directLightPosLoc, (*it)->direction.x, (*it)->direction.y, (*it)->direction.z);
}
}
if (pointlights.size() > 0) {
for (plight_it it = this->pointlights.begin(); it != this->pointlights.end(); ++it) {
GLuint pointLightPosLoc = glGetUniformLocation(phongShader.getProgramID(), (const GLchar*) ("pointLightPos[" + ToString((*it)->index) + "]").c_str());
glUniform3f(pointLightPosLoc, (*it)->position.x, (*it)->position.y, (*it)->position.z);
}
}
if (spotlights.size() > 0) {
for (slight_it it = this->spotlights.begin(); it != this->spotlights.end(); ++it) {
GLuint spotLightPosLoc = glGetUniformLocation(phongShader.getProgramID(), (const GLchar*) ("spotLightPos[" + ToString((*it)->index) + "]").c_str());
glUniform3f(spotLightPosLoc, (*it)->position.x, (*it)->position.y, (*it)->position.z);
}
}
}
double first = GetCurrentTime() - firstFrame;
it->get()->textures = 0;
if (sun != nullptr)
if (sun->castShadow) {
glUniform1i(glGetUniformLocation(phongShader.getProgramID(), "shadowMap"), it->get()->textures);
glActiveTexture(GL_TEXTURE0 + it->get()->textures);
glBindTexture(GL_TEXTURE_2D, depthMap);
it->get()->textures++;
}
it->get()->Render(phongShader, first, deltaTime);
glBindTexture(GL_TEXTURE_2D, 0);
}
最终着色器顶点和片段如下：
顶点：
#version 300 es
precision mediump float;
#define NR_DIRECT_LIGHTS 0
#define NR_POINT_LIGHTS 0
#define NR_SPOT_LIGHTS 0
layout (location = 0) in vec3 position;
layout (location = 1) in vec3 normal;
layout (location = 2) in vec2 texCoord;
layout (location = 3) in vec3 tangent;
layout (location = 4) in ivec4 BoneIDs;
layout (location = 5) in vec4 Weights;
const int MAX_BONES = 100;
out vec2 TexCoords;
out vec3 Normal;
out vec3 tDirectLightPos[NR_DIRECT_LIGHTS];
out vec3 tPointLightPos[NR_POINT_LIGHTS];
out vec3 tSpotLightPos[NR_SPOT_LIGHTS];
out vec3 tViewPos;
out vec3 tFragPos;
out vec4 FragPosLightSpace;
// conditions //
uniform bool has_normal_map;
uniform bool skinned;
//
uniform mat4 model;
uniform mat4 view;
uniform mat4 projection;
uniform vec3 viewPos;
uniform mat4 lightSpaceMatrix;
uniform mat4 gBones[MAX_BONES];
uniform vec3 directLightPos[NR_DIRECT_LIGHTS];
uniform vec3 pointLightPos[NR_POINT_LIGHTS];
uniform vec3 spotLightPos[NR_SPOT_LIGHTS];
void main(){
TexCoords = texCoord;
vec4 nPos;
vec3 N=transpose(inverse(mat3(model))) * normal;
if(skinned){
mat4 BoneTransform = gBones[BoneIDs[0]] * Weights[0];
BoneTransform += gBones[BoneIDs[1]] * Weights[1];
BoneTransform += gBones[BoneIDs[2]] * Weights[2];
BoneTransform += gBones[BoneIDs[3]] * Weights[3];
nPos=BoneTransform * vec4(position, 1.0);
Normal=(BoneTransform*vec4(N,0.0)).xyz;
}
else{
nPos = vec4(position, 1.0);
Normal=N;
}
gl_Position = projection*view * model * nPos;
vec3 FragPos = vec3(model * nPos);
if(has_normal_map){
mat3 normalMatrix = transpose(inverse(mat3(model)));
vec3 T = normalize(normalMatrix * tangent);
vec3 N = normalize(N);
T = normalize(T - dot(T, N) * N);
vec3 B = cross(N,T);
if (dot(cross(N, T), B) < 0.0)
T = T * -1.0;
mat3 TBN = transpose(mat3(T, B, N));
tViewPos=TBN*viewPos;
tFragPos=TBN*FragPos;
for(int i = 0; i < NR_DIRECT_LIGHTS-2; i++)
tDirectLightPos[i]=TBN*directLightPos[i];
for(int i = 0; i < NR_POINT_LIGHTS-2; i++)
tPointLightPos[i]=TBN*pointLightPos[i];
for(int i = 0; i < NR_SPOT_LIGHTS-2; i++)
tSpotLightPos[i]=TBN*spotLightPos[i];
}
else{
tViewPos=viewPos;
tFragPos=FragPos;
}
FragPosLightSpace = lightSpaceMatrix * vec4(FragPos,1.0);
}
片段：
#version 300 es
precision mediump float;
#define NR_DIRECT_LIGHTS 0
#define NR_POINT_LIGHTS 0
#define NR_SPOT_LIGHTS 0
out vec4 glFragColor;
vec2 poissonDisk[4] = vec2[](
vec2( -0.94201624, -0.39906216 ),
vec2( 0.94558609, -0.76890725 ),
vec2( -0.094184101, -0.92938870 ),
vec2( 0.34495938, 0.29387760 )
);
struct SpotLight{
vec3 position;
vec3 direction;
vec3 color;
float constant;
float linear;
float quadratic;
float cutoff;
float outerCutOff;
float intensity;
int castShadow;
};
struct PointLight{
vec3 position;
vec3 color;
float constant;
float linear;
float quadratic;
float intensity;
};
struct DirectLight {
vec3 direction;
vec3 color;
float intensity;
int castShadow;
};
in vec2 TexCoords;
in vec3 Normal;
in vec4 FragPosLightSpace;
in vec3 tDirectLightPos[NR_DIRECT_LIGHTS];
in vec3 tPointLightPos[NR_POINT_LIGHTS];
in vec3 tSpotLightPos[NR_SPOT_LIGHTS];
in vec3 tViewPos;
in vec3 tFragPos;
uniform bool Has_normal_map;
uniform sampler2D mat_diffuse;
uniform sampler2D mat_specular;
uniform sampler2D mat_normal;
uniform sampler2D shadowMap;
uniform vec3 matDiffuse;
uniform vec3 matSpecular;
uniform float shininess;
uniform float far_plane;
uniform DirectLight directLights[NR_DIRECT_LIGHTS];
uniform PointLight pointLights[NR_POINT_LIGHTS];
uniform SpotLight spotLights[NR_SPOT_LIGHTS];
vec3 calcDirectLight(DirectLight,vec3,vec3,vec3,vec3);
vec3 calcPointLight(PointLight,vec3,vec3,vec3,vec3);
vec3 calcSpotLight(SpotLight,vec3,vec3,vec3,vec3);
float directShadowCalculation();
void main(){
vec3 normal;
if(Has_normal_map){
normal=texture(mat_normal, TexCoords).rgb;
normal = normalize(normal * 2.0 - 1.0); // this normal is in tangent space
}
else
normal=normalize(Normal);
vec3 diffColor= matDiffuse+vec3(texture(mat_diffuse, TexCoords));
vec3 specColor= matSpecular+vec3(texture(mat_specular,TexCoords));
vec3 result;
result=vec3(0.0);
for(int i = 0; i < NR_DIRECT_LIGHTS-2; i++)
result += calcDirectLight(directLights[i],normal,tDirectLightPos[i],diffColor,specColor);
for(int i = 0; i < NR_POINT_LIGHTS-2; i++)
result += calcPointLight(pointLights[i],normal,tPointLightPos[i],vec3(0.0,0.2,0.4),specColor);
for(int i = 0; i < NR_SPOT_LIGHTS-2; i++)
result += calcSpotLight(spotLights[i],normal,tSpotLightPos[i],diffColor,specColor);
vec4 color =vec4(result,1.0);
float gamma = 2.2;
color.rgb = pow(color.rgb, vec3(1.0/gamma));
vec4 ambient=vec4(0.2,0.2,0.2,1.0)*vec4(diffColor,1.0);
glFragColor=ambient+color;
}
vec3 calcDirectLight(DirectLight light,vec3 norm,vec3 tLightPos,vec3 diffColor,vec3 specColor){
vec3 lightDir ;
if(Has_normal_map)
lightDir= normalize(tLightPos);
else
lightDir = normalize(light.direction);
float diff = max(dot(lightDir,norm), 0.0);
vec3 diffuse = light.color * diff *diffColor;
vec3 viewDir = normalize(tViewPos- tFragPos);
vec3 halfwayDir = normalize(lightDir + viewDir);
float spec = pow(max(dot(norm, halfwayDir), 0.0), 32.0);
vec3 specular = shininess* spec *specColor* light.color;
vec3 result;
if(light.castShadow==1){
float shadow = directShadowCalculation();
result =light.intensity* ( shadow* (diffuse + specular));
}
else
result =light.intensity* (diffuse + specular);
return result;
}
vec3 calcPointLight(PointLight light,vec3 norm,vec3 tLightPos,vec3 diffColor,vec3 specColor){
vec3 lightDir ;
if(Has_normal_map)
lightDir= normalize(tLightPos-tFragPos);
else
lightDir = normalize(light.position - tFragPos);
float diff = max(dot(lightDir,norm), 0.0);
vec3 diffuse = light.color * diff * diffColor;
vec3 viewDir = normalize(tViewPos- tFragPos);
vec3 halfwayDir = normalize(lightDir + viewDir);
float spec = pow(max(dot(norm, halfwayDir), 0.0), 16.0);
vec3 specular =shininess* specColor * spec * light.color;
vec3 result;
float distance = length(light.position - tFragPos);
float attenuation = 1.0f / (light.constant + light.linear * distance +light.quadratic * (distance * distance));
diffuse *= attenuation;
specular *= attenuation;
result=light.intensity*(diffuse+specular);
return result;
}
vec3 calcSpotLight(SpotLight light,vec3 norm,vec3 tLightPos,vec3 diffColor,vec3 specColor){
vec3 lightDir ;
if(Has_normal_map)
lightDir= normalize(tLightPos-tFragPos);
else
lightDir = normalize(light.position - tFragPos);
float diff = max(dot(lightDir,norm), 0.0);
vec3 diffuse = light.color * diff * diffColor;
vec3 viewDir = normalize(tViewPos- tFragPos);
float spec =0.0;
vec3 halfwayDir = normalize(lightDir + viewDir);
spec = pow(max(dot(norm, halfwayDir), 0.0), 16.0);
vec3 specular = shininess* light.color * spec * specColor;
// Spotlight (soft edges)
float theta = dot(lightDir, normalize(-light.direction));
float epsilon = (light.cutoff - light.outerCutOff);
float intensity = clamp((theta - light.outerCutOff) / epsilon, 0.0, 1.0);
diffuse *= intensity;
specular *= intensity;
// Attenuation
float distance = length(light.position - tFragPos);
float attenuation = 1.0f / (light.constant + light.linear * distance + light.quadratic * (distance * distance));
diffuse *= attenuation;
specular *= attenuation;
vec3 result = intensity*(diffuse+specular);
return result;
}
float directShadowCalculation(){
vec3 projCoords = FragPosLightSpace.xyz / FragPosLightSpace.w;
projCoords = projCoords * 0.5 + 0.5;
float shadow = 1.0;
for (int i=0;i<4;i++){
if ( texture( shadowMap, -projCoords.xy + poissonDisk[i]/700.0 ).z < -projCoords.z ){
shadow-=0.2;
}
}
if(projCoords.z > 1.0)
shadow = 0.0;
return shadow;
}
对不起所有的代码，但我不知道问题出在哪里，花了一周的时间搜索和调试没有任何进展。
编辑
1- 灯光位置矢量为 (-3.5f, 8.0f, 1.0f)
2- 我将 directShadowCalculation() 更改为：
float directShadowCalculation(){
vec3 projCoords = FragPosLightSpace.xyz / FragPosLightSpace.w;
projCoords = projCoords * 0.5 + 0.5;
float shadow = 1.0;
for (int i=0;i<4;i++){
if ( texture( shadowMap, projCoords.xy + poissonDisk[i]/700.0 ).z < projCoords.z ){
shadow-=0.2;
}
}
if(projCoords.z > 1.0)
shadow = 0.0;
return shadow;
}
这是结果
如果您必须将视图 space 坐标转换为光源的局部 space，则必须在执行此操作时设置 lightSpaceMatrix:
lightSpaceMatrix = lightSpaceProjection * (lightSpaceView*camInv)
因为，您必须通过 camInv 从视图 space 转换到世界 space。然后你必须转换世界 space 坐标，从光源 (lightSpaceView) 看到。最后你必须投影它 lightSpaceProjection.
但是你直接从世界坐标转换到光源的局部space，在vertex shader中：
FragPosLightSpace = lightSpaceMatrix * vec4(FragPos,1.0);
因此，您必须像这样设置 lightSpaceMatrix：
lightSpaceMatrix = lightSpaceProjection * lightSpaceView
投影矩阵描述了从场景的 3D 点到视口的 2D 点的映射。它从视图（眼睛）space 转换为剪辑 space，剪辑中的坐标 space 通过除以 转换为归一化设备坐标（NDC） ]w 剪辑坐标的分量。 NDC 的范围是 (-1,-1,-1) 到 (1,1,1)。
这与正交投影或透视投影无关。
将投影片段位置 (light space) 除以其 w 分量后，projCoords 的范围为 (-1, - 1, -1) 到 (1, 1, 1)。
projCoords = projCoords * 0.5 + 0.5;将XY坐标转换为纹理坐标，将Z坐标转换为[0, 1]范围内的深度值。
vec3 projCoords = FragPosLightSpace.xyz / FragPosLightSpace.w;
projCoords = projCoords * 0.5 + 0.5;
阴影测试中的反转没有意义，因为纹理的内容也应该是 [0,1] 范围内的深度值。
影子测试应该看起来像这样：
if ( texture( shadowMap, projCoords.xy ).z < projCoords.z )
{
....
}
如果sun->direction是朝向太阳的方向，那么lightSpaceView就得这样设置：
glm::mat4 lightSpaceView = glm::lookAt(sun->direction, glm::vec3(0, 0, 0), glm::vec3(0, 1, 0));
但是，如果sun->direction是太阳照射的方向，那么lightSpaceView就得这样设置：
glm::mat4 lightSpaceView = glm::lookAt(-sun->direction, glm::vec3(0, 0, 0), glm::vec3(0, 1, 0));
由于您对光使用正交投影并且光的原点space矩阵靠近世界的原点space，所以光投影的近平面应该远在光的背面 space。否则，在生成光深度图时，距离太阳近的物体将被光投影的近平面裁剪。
glm::mat4 lightSpaceProjection = glm::ortho(-40.0f, 40.0f, -40.0f, 40.0f, -100.0f, 100.0f);
由于光照计算是在视图 space 中完成的，因此您必须将光照位置从世界 space 转换到视图 space:
GLuint directLightPosLoc = glGetUniformLocation(phongShader.getProgramID(), (const GLchar*) ("directLightPos[" + ToString((*it)->index) + "]").c_str());
glm::vec3 dir = glm::mat3(camera->getViewMatrix()) * (*it)->direction;
glUniform3fv( directLightPosLoc, 1, &dir[0] );
GLuint pointLightPosLoc = glGetUniformLocation(phongShader.getProgramID(), (const GLchar*) ("pointLightPos[" + ToString((*it)->index) + "]").c_str());
glm::vec4 pos = camera->getViewMatrix( * glm::vec4((*it)->position.x, (*it)->position.y, (*it)->position.z, 1.0);
glUniform3fv( directLightPosLoc, 1, &pos[0] );
GLuint spotLightPosLoc = glGetUniformLocation(phongShader.getProgramID(), (const GLchar*) ("spotLightPos[" + ToString((*it)->index) + "]").c_str());
glm::vec4 pos = camera->getViewMatrix( * glm::vec4((*it)->position.x, (*it)->position.y, (*it)->position.z, 1.0);
glUniform3fv( spotLightPosLoc, 1, &pos[0] );
查看演示该算法的 WebGL 示例：
(function loadscene() {
var sliderScale = 100.0
var gl;
var progShadow;
var progDraw;
var shadowFB;
var bufTorus;
var bufGround;
var canvas;
var vp_size;
var fb_size;
function render(deltaMS){
var ambient = document.getElementById( "ambient" ).value / sliderScale;
var diffuse = document.getElementById( "diffuse" ).value / sliderScale;
var specular = document.getElementById( "specular" ).value / sliderScale;
var shininess = document.getElementById( "shininess" ).value;
canvas = document.getElementById( "scene-canvas" );
var lightPos = [-3.0, 0.0, 2.0];
var lightAnimationMat = RotateAxis( IdentityMat44(), CalcAng( deltaMS, 20.0 ), 2 );
lightPos = Transform( lightPos, lightAnimationMat );
var lightDir = [ -lightPos[0], -lightPos[1], -lightPos[2] ];
var light = Camera.Create( lightPos, [0, 0, 0], [0, 0, 1], 110, [ 5.0, 5.0 ], -20.0, 20.0 );
var camera = Camera.Create( [0, 2.5, 2], [0, 0, 0], [0, 0, 1], 110, [vp_size[0], vp_size[1]], 0.5, 100.0 );
var lightPrjMat = Camera.Ortho( light );
var lightViewMat = Camera.LookAt( light );
var prjMat = Camera.Perspective( camera );
var viewMat = Camera.LookAt( camera );
var modelMat = IdentityMat44();
modelMat = RotateAxis( modelMat, CalcAng( deltaMS, 13.0 ), 0 );
modelMat = RotateAxis( modelMat, CalcAng( deltaMS, 17.0 ), 1 );
groundModelMat = IdentityMat44();
var viewLightDir = TransformVec( lightDir, viewMat );
gl.viewport( 0, 0, fb_size[0], fb_size[1] );
gl.enable( gl.DEPTH_TEST );
shadowFB.Bind( true );
ShaderProgram.Use( progShadow );
ShaderProgram.SetUniformM44( progShadow, "u_projectionMat44", lightPrjMat );
ShaderProgram.SetUniformM44( progShadow, "u_viewMat44", lightViewMat );
ShaderProgram.SetUniformM44( progShadow, "u_modelMat44", modelMat );
ShaderProgram.SetUniformF2( progShadow, "u_depthRange", [light.near, light.far] );
VertexBuffer.Draw( bufTorus );
gl.viewport( 0, 0, vp_size[0], vp_size[1] );
shadowFB.Release( true );
shadowFB.BindTexture( 1 );
ShaderProgram.Use( progDraw );
ShaderProgram.SetUniformM44( progDraw, "u_projectionMat44", prjMat );
ShaderProgram.SetUniformM44( progDraw, "u_viewMat44", viewMat );
ShaderProgram.SetUniformM44( progDraw, "u_lightProjectionMat44", lightPrjMat );
ShaderProgram.SetUniformM44( progDraw, "u_lightViewMat44", lightViewMat );
ShaderProgram.SetUniformM44( progDraw, "u_modelMat44", modelMat );
ShaderProgram.SetUniformI1( progDraw, "u_depthSampler", 1 );
ShaderProgram.SetUniformF3( progDraw, "u_lightDir", viewLightDir )
ShaderProgram.SetUniformF1( progDraw, "u_ambient", ambient )
ShaderProgram.SetUniformF1( progDraw, "u_diffuse", diffuse )
ShaderProgram.SetUniformF1( progDraw, "u_specular", specular )
ShaderProgram.SetUniformF1( progDraw, "u_shininess", shininess )
VertexBuffer.Draw( bufTorus );
ShaderProgram.SetUniformM44( progDraw, "u_modelMat44", groundModelMat );
VertexBuffer.Draw( bufGround );
requestAnimationFrame(render);
}
function nearestPow2( aSize ){
return Math.pow( 2, Math.round( Math.log( aSize ) / Math.log( 2 ) ) );
}
function resize() {
//vp_size = [gl.drawingBufferWidth, gl.drawingBufferHeight];
vp_size = [window.innerWidth, window.innerHeight]
canvas.width = vp_size[0];
canvas.height = vp_size[1];
var size = Math.max(256, Math.max(vp_size[0], vp_size[1]));
size = nearestPow2(size/2);
fb_size = [size, size]
shadowFB = FrameBuffer.Create( fb_size );
}
function initScene() {
document.getElementById( "ambient" ).value = 0.2 * sliderScale;
document.getElementById( "diffuse" ).value = 0.7 * sliderScale;
document.getElementById( "specular" ).value = 0.5 * sliderScale;
document.getElementById( "shininess" ).value = 8.0;
canvas = document.getElementById( "scene-canvas");
vp_size = [canvas.width, canvas.height];
gl = canvas.getContext( "experimental-webgl" );
if ( !gl )
return;
progShadow = ShaderProgram.Create(
[ { source : "shadow-shader-vs", stage : gl.VERTEX_SHADER },
{ source : "shadow-shader-fs", stage : gl.FRAGMENT_SHADER }
] );
if (!progShadow.progObj)
return null;
progShadow.inPos = ShaderProgram.AttributeIndex( progShadow, "inPos" );
progShadow.inNV = ShaderProgram.AttributeIndex( progShadow, "inNV" );
progShadow.inCol = ShaderProgram.AttributeIndex( progShadow, "inCol" );
progDraw = ShaderProgram.Create(
[ { source : "draw-shader-vs", stage : gl.VERTEX_SHADER },
{ source : "draw-shader-fs", stage : gl.FRAGMENT_SHADER }
] );
if (!progDraw.progObj)
return null;
progDraw.inPos = ShaderProgram.AttributeIndex( progDraw, "inPos" );
progDraw.inNV = ShaderProgram.AttributeIndex( progDraw, "inNV" );
progDraw.inCol = ShaderProgram.AttributeIndex( progDraw, "inCol" );
// create torus
var circum_size = 32, tube_size = 32;
var rad_circum = 1.0;
var rad_tube = 0.5;
var torus_pts = [];
var torus_nv = [];
var torus_col = [];
var torus_inx = [];
var col = [1, 0.5, 0.0];
for ( var i_c = 0; i_c < circum_size; ++ i_c ) {
var center = [
Math.cos(2 * Math.PI * i_c / circum_size),
Math.sin(2 * Math.PI * i_c / circum_size) ]
for ( var i_t = 0; i_t < tube_size; ++ i_t ) {
var tubeX = Math.cos(2 * Math.PI * i_t / tube_size)
var tubeY = Math.sin(2 * Math.PI * i_t / tube_size)
var pt = [
center[0] * ( rad_circum + tubeX * rad_tube ),
center[1] * ( rad_circum + tubeX * rad_tube ),
tubeY * rad_tube ]
var nv = [ pt[0] - center[0] * rad_tube, pt[1] - center[1] * rad_tube, tubeY * rad_tube ]
torus_pts.push( pt[0], pt[1], pt[2] );
torus_nv.push( nv[0], nv[1], nv[2] );
torus_col.push( col[0], col[1], col[2] );
var i_cn = (i_c+1) % circum_size
var i_tn = (i_t+1) % tube_size
var i_c0 = i_c * tube_size;
var i_c1 = i_cn * tube_size;
torus_inx.push( i_c0+i_t, i_c0+i_tn, i_c1+i_t, i_c0+i_tn, i_c1+i_t, i_c1+i_tn )
}
}
bufTorus = VertexBuffer.Create(
[ { data : torus_pts, attrSize : 3, attrLoc : progDraw.inPos },
{ data : torus_nv, attrSize : 3, attrLoc : progDraw.inNV },
{ data : torus_col, attrSize : 3, attrLoc : progDraw.inCol } ],
torus_inx
);
var g_l = 8.0;
var g_h = -2.5;
var g_c = [ 0.8, 0.6, 0.8 ];
bufGround = VertexBuffer.Create(
[ { data : [ -g_l, -g_l, g_h, g_l, -g_l, g_h, g_l, g_l, g_h, -g_l, g_l, g_h ], attrSize : 3, attrLoc : progDraw.inPos },
{ data : [ 0.0, 0.0, 1.0, 0.0, 0.0, 1.0, 0.0, 0.0, 1.0, 0.0, 0.0, 1.0 ], attrSize : 3, attrLoc : progDraw.inNV },
{ data : [ g_c[0], g_c[1], g_c[2], g_c[0], g_c[1], g_c[2], g_c[0], g_c[1], g_c[2], g_c[0], g_c[1], g_c[2] ], attrSize : 3, attrLoc : progDraw.inCol } ],
[ 0, 1, 2, 0, 2, 3 ]
);
window.onresize = resize;
resize();
requestAnimationFrame(render);
}
var startTime;
function Fract( val ) {
return val - Math.trunc( val );
}
function CalcAng( deltaTime, intervall ) {
return Fract( deltaTime / (1000*intervall) ) * 2.0 * Math.PI;
}
function IdentityMat44() { return [1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1]; }
function RotateAxis(matA, angRad, axis) {
var aMap = [ [1, 2], [2, 0], [0, 1] ];
var a0 = aMap[axis][0], a1 = aMap[axis][1];
var sinAng = Math.sin(angRad), cosAng = Math.cos(angRad);
var matB = IdentityMat44();
for ( var i = 0; i < 16; ++ i ) matB[i] = matA[i];
for ( var i = 0; i < 3; ++ i ) {
matB[a0*4+i] = matA[a0*4+i] * cosAng + matA[a1*4+i] * sinAng;
matB[a1*4+i] = matA[a0*4+i] * -sinAng + matA[a1*4+i] * cosAng;
}
return matB;
}
function Cross( a, b ) { return [ a[1] * b[2] - a[2] * b[1], a[2] * b[0] - a[0] * b[2], a[0] * b[1] - a[1] * b[0], 0.0 ]; }
function Dot( a, b ) { return a[0]*b[0] + a[1]*b[1] + a[2]*b[2]; }
function Normalize( v ) {
var len = Math.sqrt( v[0] * v[0] + v[1] * v[1] + v[2] * v[2] );
return [ v[0] / len, v[1] / len, v[2] / len ];
}
Transform = function(vec, mat) {
return [
vec[0] * mat[0*4+0] + vec[1] * mat[1*4+0] + vec[2] * mat[2*4+0] + mat[3*4+0],
vec[0] * mat[0*4+1] + vec[1] * mat[1*4+1] + vec[2] * mat[2*4+1] + mat[3*4+1],
vec[0] * mat[0*4+2] + vec[1] * mat[1*4+2] + vec[2] * mat[2*4+2] + mat[3*4+2],
vec[0] * mat[0*4+3] + vec[1] * mat[1*4+3] + vec[2] * mat[2*4+3] + mat[3*4+3] ]
if ( h[3] == 0.0 )
return [0, 0, 0]
return [ h[0]/h[3], h[1]/h[3], h[2]/h[3] ];
}
TransformVec = function(vec, mat) {
return [
vec[0] * mat[0*4+0] + vec[1] * mat[1*4+0] + vec[2] * mat[2*4+0],
vec[0] * mat[0*4+1] + vec[1] * mat[1*4+1] + vec[2] * mat[2*4+1],
vec[0] * mat[0*4+2] + vec[1] * mat[1*4+2] + vec[2] * mat[2*4+2] ]
}
var Camera = {};
Camera.Create = function( pos, target, up, fov_y, vp, near, far ) {
var camera = {};
camera.pos = pos;
camera.target = target;
camera.up = up;
camera.fov_y = fov_y;
camera.vp = vp;
camera.near = near;
camera.far = far;
return camera;
}
Camera.Ortho = function( camera ) {
var fn = camera.far + camera.near;
var f_n = camera.far - camera.near;
var w = camera.vp[0];
var h = camera.vp[1];
var m = IdentityMat44();
m[0] = 2 / w; m[1] = 0; m[2] = 0; m[3] = 0;
m[4] = 0; m[5] = 2 / h; m[6] = 0; m[7] = 0;
m[8] = 0; m[9] = 0; m[10] = -2 / f_n; m[11] = 0;
m[12] = 0; m[13] = 0; m[14] = -fn / f_n; m[15] = 1;
return m;
}
Camera.Perspective = function( camera ) {
var fn = camera.far + camera.near;
var f_n = camera.far - camera.near;
var r = camera.vp[0] / camera.vp[1];
var t = 1 / Math.tan( Math.PI * camera.fov_y / 360 );
var m = IdentityMat44();
m[0] = t/r; m[1] = 0; m[2] = 0; m[3] = 0;
m[4] = 0; m[5] = t; m[6] = 0; m[7] = 0;
m[8] = 0; m[9] = 0; m[10] = -fn / f_n; m[11] = -1;
m[12] = 0; m[13] = 0; m[14] = -2 * camera.far * camera.near / f_n; m[15] = 0;
return m;
}
Camera.LookAt = function( camera ) {
var mz = Normalize( [ camera.pos[0]-camera.target[0], camera.pos[1]-camera.target[1], camera.pos[2]-camera.target[2] ] );
var mx = Normalize( Cross( camera.up, mz ) );
var my = Normalize( Cross( mz, mx ) );
var tx = Dot( mx, camera.pos );
var ty = Dot( my, camera.pos );
var tz = Dot( [-mz[0], -mz[1], -mz[2]], camera.pos );
var m = IdentityMat44();
m[0] = mx[0]; m[1] = my[0]; m[2] = mz[0]; m[3] = 0;
m[4] = mx[1]; m[5] = my[1]; m[6] = mz[1]; m[7] = 0;
m[8] = mx[2]; m[9] = my[2]; m[10] = mz[2]; m[11] = 0;
m[12] = tx; m[13] = ty; m[14] = tz; m[15] = 1;
return m;
}
var ShaderProgram = {};
ShaderProgram.Create = function (shaderList) {
var shaderObjs = [];
for (var i_sh = 0; i_sh < shaderList.length; ++i_sh) {
var shderObj = this.CompileShader(shaderList[i_sh].source, shaderList[i_sh].stage);
if (shderObj == 0)
return 0;
shaderObjs.push(shderObj);
}
var prog = {}
prog.progObj = this.LinkProgram(shaderObjs)
if (prog.progObj) {
prog.attribIndex = {};
var noOfAttributes = gl.getProgramParameter(prog.progObj, gl.ACTIVE_ATTRIBUTES);
for (var i_n = 0; i_n < noOfAttributes; ++i_n) {
var name = gl.getActiveAttrib(prog.progObj, i_n).name;
prog.attribIndex[name] = gl.getAttribLocation(prog.progObj, name);
}
prog.unifomLocation = {};
var noOfUniforms = gl.getProgramParameter(prog.progObj, gl.ACTIVE_UNIFORMS);
for (var i_n = 0; i_n < noOfUniforms; ++i_n) {
var name = gl.getActiveUniform(prog.progObj, i_n).name;
prog.unifomLocation[name] = gl.getUniformLocation(prog.progObj, name);
}
}
return prog;
}
ShaderProgram.AttributeIndex = function (prog, name) { return prog.attribIndex[name]; }
ShaderProgram.UniformLocation = function (prog, name) { return prog.unifomLocation[name]; }
ShaderProgram.Use = function (prog) { gl.useProgram(prog.progObj); }
ShaderProgram.SetUniformI1 = function (prog, name, val) { if (prog.unifomLocation[name]) gl.uniform1i(prog.unifomLocation[name], val); }
ShaderProgram.SetUniformF1 = function (prog, name, val) { if (prog.unifomLocation[name]) gl.uniform1f(prog.unifomLocation[name], val); }
ShaderProgram.SetUniformF2 = function (prog, name, arr) { if (prog.unifomLocation[name]) gl.uniform2fv(prog.unifomLocation[name], arr); }
ShaderProgram.SetUniformF3 = function (prog, name, arr) { if (prog.unifomLocation[name]) gl.uniform3fv(prog.unifomLocation[name], arr); }
ShaderProgram.SetUniformF4 = function (prog, name, arr) { if (prog.unifomLocation[name]) gl.uniform4fv(prog.unifomLocation[name], arr); }
ShaderProgram.SetUniformM33 = function (prog, name, mat) { if (prog.unifomLocation[name]) gl.uniformMatrix3fv(prog.unifomLocation[name], false, mat); }
ShaderProgram.SetUniformM44 = function (prog, name, mat) { if (prog.unifomLocation[name]) gl.uniformMatrix4fv(prog.unifomLocation[name], false, mat); }
ShaderProgram.CompileShader = function (source, shaderStage) {
var shaderScript = document.getElementById(source);
if (shaderScript)
source = shaderScript.text;
var shaderObj = gl.createShader(shaderStage);
gl.shaderSource(shaderObj, source);
gl.compileShader(shaderObj);
var status = gl.getShaderParameter(shaderObj, gl.COMPILE_STATUS);
if (!status) alert(gl.getShaderInfoLog(shaderObj));
return status ? shaderObj : null;
}
ShaderProgram.LinkProgram = function (shaderObjs) {
var prog = gl.createProgram();
for (var i_sh = 0; i_sh < shaderObjs.length; ++i_sh)
gl.attachShader(prog, shaderObjs[i_sh]);
gl.linkProgram(prog);
status = gl.getProgramParameter(prog, gl.LINK_STATUS);
if (!status) alert("Could not initialise shaders");
gl.useProgram(null);
return status ? prog : null;
}
var VertexBuffer = {};
VertexBuffer.Create = function( attributes, indices ) {
var buffer = {};
buffer.buf = [];
buffer.attr = []
for ( var i = 0; i < attributes.length; ++ i ) {
buffer.buf.push( gl.createBuffer() );
buffer.attr.push( { size : attributes[i].attrSize, loc : attributes[i].attrLoc } );
gl.bindBuffer( gl.ARRAY_BUFFER, buffer.buf[i] );
gl.bufferData( gl.ARRAY_BUFFER, new Float32Array( attributes[i].data ), gl.STATIC_DRAW );
}
buffer.inx = gl.createBuffer();
gl.bindBuffer( gl.ELEMENT_ARRAY_BUFFER, buffer.inx );
gl.bufferData( gl.ELEMENT_ARRAY_BUFFER, new Uint16Array( indices ), gl.STATIC_DRAW );
buffer.inxLen = indices.length;
gl.bindBuffer( gl.ARRAY_BUFFER, null );
gl.bindBuffer( gl.ELEMENT_ARRAY_BUFFER, null );
return buffer;
}
VertexBuffer.Draw = function( bufObj ) {
for ( var i = 0; i < bufObj.buf.length; ++ i ) {
gl.bindBuffer( gl.ARRAY_BUFFER, bufObj.buf[i] );
gl.vertexAttribPointer( bufObj.attr[i].loc, bufObj.attr[i].size, gl.FLOAT, false, 0, 0 );
gl.enableVertexAttribArray( bufObj.attr[i].loc );
}
gl.bindBuffer( gl.ELEMENT_ARRAY_BUFFER, bufObj.inx );
gl.drawElements( gl.TRIANGLES, bufObj.inxLen, gl.UNSIGNED_SHORT, 0 );
for ( var i = 0; i < bufObj.buf.length; ++ i )
gl.disableVertexAttribArray( bufObj.attr[i].loc );
gl.bindBuffer( gl.ARRAY_BUFFER, null );
gl.bindBuffer( gl.ELEMENT_ARRAY_BUFFER, null );
}
var FrameBuffer = {};
FrameBuffer.Create = function( vp, texturePlan ) {
var texPlan = texturePlan ? new Uint8Array( texturePlan ) : null;
var fb = gl.createFramebuffer();
var fbsize = Math.max(vp[0], vp[1]);
fbsize = 1 << 31 - Math.clz32(fbsize); // nearest power of 2
fb.width = fbsize;
fb.height = fbsize;
gl.bindFramebuffer( gl.FRAMEBUFFER, fb );
fb.color0_texture = gl.createTexture();
gl.bindTexture( gl.TEXTURE_2D, fb.color0_texture );
gl.texImage2D( gl.TEXTURE_2D, 0, gl.RGBA, fb.width, fb.height, 0, gl.RGBA, gl.UNSIGNED_BYTE, texPlan );
gl.texParameteri( gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST );
gl.texParameteri( gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST );
gl.texParameteri( gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE );
gl.texParameteri( gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE );
fb.renderbuffer = gl.createRenderbuffer();
gl.bindRenderbuffer( gl.RENDERBUFFER, fb.renderbuffer );
gl.renderbufferStorage( gl.RENDERBUFFER, gl.DEPTH_COMPONENT16, fb.width, fb.height );
gl.framebufferTexture2D( gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D, fb.color0_texture, 0 );
gl.framebufferRenderbuffer( gl.FRAMEBUFFER, gl.DEPTH_ATTACHMENT, gl.RENDERBUFFER, fb.renderbuffer );
gl.bindTexture( gl.TEXTURE_2D, null );
gl.bindRenderbuffer( gl.RENDERBUFFER, null );
gl.bindFramebuffer( gl.FRAMEBUFFER, null );
fb.Bind = function( clear ) {
gl.bindFramebuffer( gl.FRAMEBUFFER, this );
if ( clear ) {
gl.clearColor( 0.0, 0.0, 0.0, 1.0 );
gl.clear( gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT );
}
};
fb.Release = function( clear ) {
gl.bindFramebuffer( gl.FRAMEBUFFER, null );
if ( clear ) {
gl.clearColor( 0.0, 0.0, 0.0, 1.0 );
gl.clear( gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT );
}
};
fb.BindTexture = function( textureUnit ) {
gl.activeTexture( gl.TEXTURE0 + textureUnit );
gl.bindTexture( gl.TEXTURE_2D, this.color0_texture );
};
return fb;
}
initScene();
})();
html,body {
height: 100%;
width: 100%;
margin: 0;
overflow: hidden;
}
#gui {
position : absolute;
top : 0;
left : 0;
}
<script id="shadow-shader-vs" type="x-shader/x-vertex">
precision mediump float;
attribute vec3 inPos;
attribute vec3 inNV;
attribute vec3 inCol;
varying vec3 vertPos;
varying vec3 vertNV;
varying vec3 vertCol;
varying vec4 vPosPrj;
uniform mat4 u_projectionMat44;
uniform mat4 u_viewMat44;
uniform mat4 u_modelMat44;
void main()
{
vec3 modelNV = mat3( u_modelMat44 ) * normalize( inNV );
vertNV = mat3( u_viewMat44 ) * modelNV;
vertCol = inCol;
vec4 modelPos = u_modelMat44 * vec4( inPos, 1.0 );
vec4 viewPos = u_viewMat44 * modelPos;
vertPos = viewPos.xyz / viewPos.w;
vPosPrj = u_projectionMat44 * viewPos;
gl_Position = vPosPrj;
}
</script>
<script id="shadow-shader-fs" type="x-shader/x-fragment">
precision mediump float;
varying vec3 vertPos;
varying vec3 vertNV;
varying vec3 vertCol;
varying vec4 vPosPrj;
uniform vec2 u_depthRange;
vec3 PackDepth( in float depth )
{
float depthVal = depth * (256.0*256.0*256.0 - 1.0) / (256.0*256.0*256.0);
vec4 encode = fract( depthVal * vec4(1.0, 256.0, 256.0*256.0, 256.0*256.0*256.0) );
return encode.xyz - encode.yzw / 256.0 + 1.0/512.0;
}
void main()
{
float ndc_depth = vPosPrj.z / vPosPrj.w;
float nearZ = u_depthRange.x;
float farZ = u_depthRange.y;
float depth = ndc_depth * 0.5 + 0.5;
gl_FragColor = vec4( PackDepth( depth ).xyz, 1.0 );
}
</script>
<script id="draw-shader-vs" type="x-shader/x-vertex">
precision mediump float;
attribute vec3 inPos;
attribute vec3 inNV;
attribute vec3 inCol;
varying vec3 vertPos;
varying vec3 vertNV;
varying vec3 vertCol;
varying vec4 lightPrj;
varying vec4 vPosPrj;
uniform mat4 u_projectionMat44;
uniform mat4 u_viewMat44;
uniform mat4 u_modelMat44;
uniform mat4 u_lightProjectionMat44;
uniform mat4 u_lightViewMat44;
void main()
{
vec3 modelNV = mat3( u_modelMat44 ) * normalize( inNV );
vertNV = mat3( u_viewMat44 ) * modelNV;
vertCol = inCol;
vec4 modelPos = u_modelMat44 * vec4( inPos, 1.0 );
vec4 lightPos = u_lightViewMat44 * modelPos;
vec4 viewPos = u_viewMat44 * modelPos;
lightPrj = u_lightProjectionMat44 * lightPos;
vertPos = viewPos.xyz / viewPos.w;
vPosPrj = u_projectionMat44 * viewPos;
gl_Position = vPosPrj;
}
</script>
<script id="draw-shader-fs" type="x-shader/x-fragment">
precision mediump float;
varying vec3 vertPos;
varying vec3 vertNV;
varying vec3 vertCol;
varying vec4 lightPrj;
varying vec4 vPosPrj;
uniform sampler2D u_depthSampler;
uniform vec3 u_lightDir;
uniform float u_ambient;
uniform float u_diffuse;
uniform float u_specular;
uniform float u_shininess;
float UnpackDepth( in vec3 pack )
{
float depth = dot( pack, 1.0 / vec3(1.0, 256.0, 256.0*256.0) );
return depth * (256.0*256.0*256.0) / (256.0*256.0*256.0 - 1.0);
}
float Depth( in sampler2D depthSampler, in vec2 texC )
{
vec3 depthVal = texture2D( depthSampler, texC.st ).xyz;
return UnpackDepth( depthVal.rgb );
}
void main()
{
vec3 ndc_light = lightPrj.xyz / lightPrj.w;
vec2 lightTexC = ndc_light.xy * 0.5 + 0.5;
float lightDepth = ndc_light.z * 0.5 + 0.5;
float testDepth = Depth( u_depthSampler, lightTexC );
float shadow = step( lightDepth-0.01, testDepth ) + step( testDepth, 0.0 );
vec3 color = vertCol;
vec3 lightCol = u_ambient * color;
vec3 normalV = normalize( vertNV );
vec3 lightV = normalize( -u_lightDir );
float NdotL = max( 0.0, dot( normalV, lightV ) );
lightCol += shadow * NdotL * u_diffuse * color;
vec3 eyeV = normalize( -vertPos );
vec3 halfV = normalize( eyeV + lightV );
float NdotH = max( 0.0, dot( normalV, halfV ) );
float kSpecular = ( u_shininess + 2.0 ) * pow( NdotH, u_shininess ) / ( 2.0 * 3.14159265 );
lightCol += shadow * kSpecular * u_specular * color;
gl_FragColor = vec4( lightCol.rgb, 1.0 );
}
</script>
<div><form id="gui" name="inputs"><table>
<tr> <td> <font color= #CCF>ambient</font> </td>
<td> <input type="range" id="ambient" min="0" max="100" value="0"/></td> </tr>
<tr> <td> <font color= #CCF>diffuse</font> </td>
<td> <input type="range" id="diffuse" min="0" max="100" value="0"/></td> </tr>
<tr> <td> <font color= #CCF>specular</font> </td>
<td> <input type="range" id="specular" min="0" max="100" value="0"/></td> </tr>
<tr> <td> <font color= #CCF>shininess</font> </td>
<td> <input type="range" id="shininess" min="0" max="100" value="0"/></td> </tr>
</table></form></div>
<canvas id="scene-canvas" style="border: none;" width="512" height="512"></canvas>
另见
- How to render depth linearly in modern OpenGL with gl_FragCoord.z in fragment shader
我在 Android 的 C++ 项目上工作，使用 OpenGL ES3，所以我尝试用定向光实现阴影贴图，我很了解这个理论，但我从未成功渲染它。
glGenFramebuffers(1, &depthMapFBO);
glBindFramebuffer(GL_FRAMEBUFFER, depthMapFBO);
glGenTextures(1, &depthMap);
glBindTexture(GL_TEXTURE_2D, depthMap);
glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT, SHADOW_WIDTH, SHADOW_HEIGHT, 0, GL_DEPTH_COMPONENT, GL_FLOAT, 0);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_TEXTURE_2D, depthMap, 0);
glDrawBuffers(1, GL_NONE);
glReadBuffer(GL_NONE);
glBindTexture(GL_TEXTURE_2D, 0);
glBindFramebuffer(GL_FRAMEBUFFER, 0);
然后我创建了一个编译深度着色器的着色器程序，如下所示：
#version 300 es
precision mediump float;
layout (location = 0) in vec3 position;
layout (location = 4) in ivec4 BoneIDs;
layout (location = 5) in vec4 Weights;
const int MAX_BONES = 100;
uniform mat4 lightSpaceMatrix;
uniform mat4 model;
uniform bool skinned;
uniform mat4 gBones[MAX_BONES];
void main(){
vec4 nPos;
if(skinned){
mat4 BoneTransform = gBones[BoneIDs[0]] * Weights[0];
BoneTransform += gBones[BoneIDs[1]] * Weights[1];
BoneTransform += gBones[BoneIDs[2]] * Weights[2];
BoneTransform += gBones[BoneIDs[3]] * Weights[3];
nPos=BoneTransform * vec4(position, 1.0);
}
else
nPos = vec4(position, 1.0);
vec4 p=model * nPos;
gl_Position = lightSpaceMatrix * p;
}
并使用此着色器程序和灯光 space 矩阵绘制场景，使用以下内容：
glCullFace(GL_FRONT);
double delta = GetCurrentTime() - firstFrame;
glm::mat4 camInv = glm::inverse(camera->getViewMatrix());
glm::mat4 lightSpaceProjection = glm::ortho(-40.0f, 40.0f, -40.0f, 40.0f, -1.0f, 100.0f);
glm::mat4 lightSpaceView = glm::lookAt(sun->direction, glm::vec3(0, 0, 0), glm::vec3(0, 1, 0));
lightSpaceMatrix = lightSpaceProjection * (lightSpaceView*camInv) ;
glViewport(0, 0, SHADOW_WIDTH, SHADOW_HEIGHT);
glBindFramebuffer(GL_FRAMEBUFFER, depthMapFBO);
glClear(GL_DEPTH_BUFFER_BIT);
directDepthShader.use();
glUniformMatrix4fv(glGetUniformLocation(directDepthShader.getProgramID(), "lightSpaceMatrix"), 1, GL_FALSE, glm::value_ptr(lightSpaceMatrix));
for (mesh_it it = castShadowMeshes.begin(); it != castShadowMeshes.end(); it++) {
it->get()->renderDepth(directDepthShader, delta);
}
glCullFace(GL_BACK);
glBindFramebuffer(GL_FRAMEBUFFER, 0);
最后，我使用常规着色器程序渲染场景，并使用以下代码将深度图绑定到 shadowMap 制服：
glViewport(0, 0, width, height);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
phongShader.use();
if (sun != nullptr)
if (sun->castShadow)
glUniformMatrix4fv(glGetUniformLocation(phongShader.getProgramID(), "lightSpaceMatrix"), 1, GL_FALSE, glm::value_ptr(lightSpaceMatrix));
this->setLightsUniforms(phongShader);
this->setViewUniforms(phongShader);
for (mesh_it it = phongMeshes.begin(); it != phongMeshes.end(); it++) {
if (it->get()->hasNormalMap) {
glUniform1i(glGetUniformLocation(phongShader.getProgramID(), "has_normal_map"), 1);
if (directlights.size() > 0) {
for (dlight_it it = this->directlights.begin(); it != this->directlights.end(); ++it) {
GLuint directLightPosLoc = glGetUniformLocation(phongShader.getProgramID(), (const GLchar*) ("directLightPos[" + ToString((*it)->index) + "]").c_str());
glUniform3f(directLightPosLoc, (*it)->direction.x, (*it)->direction.y, (*it)->direction.z);
}
}
if (pointlights.size() > 0) {
for (plight_it it = this->pointlights.begin(); it != this->pointlights.end(); ++it) {
GLuint pointLightPosLoc = glGetUniformLocation(phongShader.getProgramID(), (const GLchar*) ("pointLightPos[" + ToString((*it)->index) + "]").c_str());
glUniform3f(pointLightPosLoc, (*it)->position.x, (*it)->position.y, (*it)->position.z);
}
}
if (spotlights.size() > 0) {
for (slight_it it = this->spotlights.begin(); it != this->spotlights.end(); ++it) {
GLuint spotLightPosLoc = glGetUniformLocation(phongShader.getProgramID(), (const GLchar*) ("spotLightPos[" + ToString((*it)->index) + "]").c_str());
glUniform3f(spotLightPosLoc, (*it)->position.x, (*it)->position.y, (*it)->position.z);
}
}
}
double first = GetCurrentTime() - firstFrame;
it->get()->textures = 0;
if (sun != nullptr)
if (sun->castShadow) {
glUniform1i(glGetUniformLocation(phongShader.getProgramID(), "shadowMap"), it->get()->textures);
glActiveTexture(GL_TEXTURE0 + it->get()->textures);
glBindTexture(GL_TEXTURE_2D, depthMap);
it->get()->textures++;
}
it->get()->Render(phongShader, first, deltaTime);
glBindTexture(GL_TEXTURE_2D, 0);
}
最终着色器顶点和片段如下：
顶点：
#version 300 es
precision mediump float;
#define NR_DIRECT_LIGHTS 0
#define NR_POINT_LIGHTS 0
#define NR_SPOT_LIGHTS 0
layout (location = 0) in vec3 position;
layout (location = 1) in vec3 normal;
layout (location = 2) in vec2 texCoord;
layout (location = 3) in vec3 tangent;
layout (location = 4) in ivec4 BoneIDs;
layout (location = 5) in vec4 Weights;
const int MAX_BONES = 100;
out vec2 TexCoords;
out vec3 Normal;
out vec3 tDirectLightPos[NR_DIRECT_LIGHTS];
out vec3 tPointLightPos[NR_POINT_LIGHTS];
out vec3 tSpotLightPos[NR_SPOT_LIGHTS];
out vec3 tViewPos;
out vec3 tFragPos;
out vec4 FragPosLightSpace;
// conditions //
uniform bool has_normal_map;
uniform bool skinned;
//
uniform mat4 model;
uniform mat4 view;
uniform mat4 projection;
uniform vec3 viewPos;
uniform mat4 lightSpaceMatrix;
uniform mat4 gBones[MAX_BONES];
uniform vec3 directLightPos[NR_DIRECT_LIGHTS];
uniform vec3 pointLightPos[NR_POINT_LIGHTS];
uniform vec3 spotLightPos[NR_SPOT_LIGHTS];
void main(){
TexCoords = texCoord;
vec4 nPos;
vec3 N=transpose(inverse(mat3(model))) * normal;
if(skinned){
mat4 BoneTransform = gBones[BoneIDs[0]] * Weights[0];
BoneTransform += gBones[BoneIDs[1]] * Weights[1];
BoneTransform += gBones[BoneIDs[2]] * Weights[2];
BoneTransform += gBones[BoneIDs[3]] * Weights[3];
nPos=BoneTransform * vec4(position, 1.0);
Normal=(BoneTransform*vec4(N,0.0)).xyz;
}
else{
nPos = vec4(position, 1.0);
Normal=N;
}
gl_Position = projection*view * model * nPos;
vec3 FragPos = vec3(model * nPos);
if(has_normal_map){
mat3 normalMatrix = transpose(inverse(mat3(model)));
vec3 T = normalize(normalMatrix * tangent);
vec3 N = normalize(N);
T = normalize(T - dot(T, N) * N);
vec3 B = cross(N,T);
if (dot(cross(N, T), B) < 0.0)
T = T * -1.0;
mat3 TBN = transpose(mat3(T, B, N));
tViewPos=TBN*viewPos;
tFragPos=TBN*FragPos;
for(int i = 0; i < NR_DIRECT_LIGHTS-2; i++)
tDirectLightPos[i]=TBN*directLightPos[i];
for(int i = 0; i < NR_POINT_LIGHTS-2; i++)
tPointLightPos[i]=TBN*pointLightPos[i];
for(int i = 0; i < NR_SPOT_LIGHTS-2; i++)
tSpotLightPos[i]=TBN*spotLightPos[i];
}
else{
tViewPos=viewPos;
tFragPos=FragPos;
}
FragPosLightSpace = lightSpaceMatrix * vec4(FragPos,1.0);
}
片段：
#version 300 es
precision mediump float;
#define NR_DIRECT_LIGHTS 0
#define NR_POINT_LIGHTS 0
#define NR_SPOT_LIGHTS 0
out vec4 glFragColor;
vec2 poissonDisk[4] = vec2[](
vec2( -0.94201624, -0.39906216 ),
vec2( 0.94558609, -0.76890725 ),
vec2( -0.094184101, -0.92938870 ),
vec2( 0.34495938, 0.29387760 )
);
struct SpotLight{
vec3 position;
vec3 direction;
vec3 color;
float constant;
float linear;
float quadratic;
float cutoff;
float outerCutOff;
float intensity;
int castShadow;
};
struct PointLight{
vec3 position;
vec3 color;
float constant;
float linear;
float quadratic;
float intensity;
};
struct DirectLight {
vec3 direction;
vec3 color;
float intensity;
int castShadow;
};
in vec2 TexCoords;
in vec3 Normal;
in vec4 FragPosLightSpace;
in vec3 tDirectLightPos[NR_DIRECT_LIGHTS];
in vec3 tPointLightPos[NR_POINT_LIGHTS];
in vec3 tSpotLightPos[NR_SPOT_LIGHTS];
in vec3 tViewPos;
in vec3 tFragPos;
uniform bool Has_normal_map;
uniform sampler2D mat_diffuse;
uniform sampler2D mat_specular;
uniform sampler2D mat_normal;
uniform sampler2D shadowMap;
uniform vec3 matDiffuse;
uniform vec3 matSpecular;
uniform float shininess;
uniform float far_plane;
uniform DirectLight directLights[NR_DIRECT_LIGHTS];
uniform PointLight pointLights[NR_POINT_LIGHTS];
uniform SpotLight spotLights[NR_SPOT_LIGHTS];
vec3 calcDirectLight(DirectLight,vec3,vec3,vec3,vec3);
vec3 calcPointLight(PointLight,vec3,vec3,vec3,vec3);
vec3 calcSpotLight(SpotLight,vec3,vec3,vec3,vec3);
float directShadowCalculation();
void main(){
vec3 normal;
if(Has_normal_map){
normal=texture(mat_normal, TexCoords).rgb;
normal = normalize(normal * 2.0 - 1.0); // this normal is in tangent space
}
else
normal=normalize(Normal);
vec3 diffColor= matDiffuse+vec3(texture(mat_diffuse, TexCoords));
vec3 specColor= matSpecular+vec3(texture(mat_specular,TexCoords));
vec3 result;
result=vec3(0.0);
for(int i = 0; i < NR_DIRECT_LIGHTS-2; i++)
result += calcDirectLight(directLights[i],normal,tDirectLightPos[i],diffColor,specColor);
for(int i = 0; i < NR_POINT_LIGHTS-2; i++)
result += calcPointLight(pointLights[i],normal,tPointLightPos[i],vec3(0.0,0.2,0.4),specColor);
for(int i = 0; i < NR_SPOT_LIGHTS-2; i++)
result += calcSpotLight(spotLights[i],normal,tSpotLightPos[i],diffColor,specColor);
vec4 color =vec4(result,1.0);
float gamma = 2.2;
color.rgb = pow(color.rgb, vec3(1.0/gamma));
vec4 ambient=vec4(0.2,0.2,0.2,1.0)*vec4(diffColor,1.0);
glFragColor=ambient+color;
}
vec3 calcDirectLight(DirectLight light,vec3 norm,vec3 tLightPos,vec3 diffColor,vec3 specColor){
vec3 lightDir ;
if(Has_normal_map)
lightDir= normalize(tLightPos);
else
lightDir = normalize(light.direction);
float diff = max(dot(lightDir,norm), 0.0);
vec3 diffuse = light.color * diff *diffColor;
vec3 viewDir = normalize(tViewPos- tFragPos);
vec3 halfwayDir = normalize(lightDir + viewDir);
float spec = pow(max(dot(norm, halfwayDir), 0.0), 32.0);
vec3 specular = shininess* spec *specColor* light.color;
vec3 result;
if(light.castShadow==1){
float shadow = directShadowCalculation();
result =light.intensity* ( shadow* (diffuse + specular));
}
else
result =light.intensity* (diffuse + specular);
return result;
}
vec3 calcPointLight(PointLight light,vec3 norm,vec3 tLightPos,vec3 diffColor,vec3 specColor){
vec3 lightDir ;
if(Has_normal_map)
lightDir= normalize(tLightPos-tFragPos);
else
lightDir = normalize(light.position - tFragPos);
float diff = max(dot(lightDir,norm), 0.0);
vec3 diffuse = light.color * diff * diffColor;
vec3 viewDir = normalize(tViewPos- tFragPos);
vec3 halfwayDir = normalize(lightDir + viewDir);
float spec = pow(max(dot(norm, halfwayDir), 0.0), 16.0);
vec3 specular =shininess* specColor * spec * light.color;
vec3 result;
float distance = length(light.position - tFragPos);
float attenuation = 1.0f / (light.constant + light.linear * distance +light.quadratic * (distance * distance));
diffuse *= attenuation;
specular *= attenuation;
result=light.intensity*(diffuse+specular);
return result;
}
vec3 calcSpotLight(SpotLight light,vec3 norm,vec3 tLightPos,vec3 diffColor,vec3 specColor){
vec3 lightDir ;
if(Has_normal_map)
lightDir= normalize(tLightPos-tFragPos);
else
lightDir = normalize(light.position - tFragPos);
float diff = max(dot(lightDir,norm), 0.0);
vec3 diffuse = light.color * diff * diffColor;
vec3 viewDir = normalize(tViewPos- tFragPos);
float spec =0.0;
vec3 halfwayDir = normalize(lightDir + viewDir);
spec = pow(max(dot(norm, halfwayDir), 0.0), 16.0);
vec3 specular = shininess* light.color * spec * specColor;
// Spotlight (soft edges)
float theta = dot(lightDir, normalize(-light.direction));
float epsilon = (light.cutoff - light.outerCutOff);
float intensity = clamp((theta - light.outerCutOff) / epsilon, 0.0, 1.0);
diffuse *= intensity;
specular *= intensity;
// Attenuation
float distance = length(light.position - tFragPos);
float attenuation = 1.0f / (light.constant + light.linear * distance + light.quadratic * (distance * distance));
diffuse *= attenuation;
specular *= attenuation;
vec3 result = intensity*(diffuse+specular);
return result;
}
float directShadowCalculation(){
vec3 projCoords = FragPosLightSpace.xyz / FragPosLightSpace.w;
projCoords = projCoords * 0.5 + 0.5;
float shadow = 1.0;
for (int i=0;i<4;i++){
if ( texture( shadowMap, -projCoords.xy + poissonDisk[i]/700.0 ).z < -projCoords.z ){
shadow-=0.2;
}
}
if(projCoords.z > 1.0)
shadow = 0.0;
return shadow;
}
对不起所有的代码，但我不知道问题出在哪里，花了一周的时间搜索和调试没有任何进展。
编辑
1- 灯光位置矢量为 (-3.5f, 8.0f, 1.0f)
2- 我将 directShadowCalculation() 更改为：
float directShadowCalculation(){
vec3 projCoords = FragPosLightSpace.xyz / FragPosLightSpace.w;
projCoords = projCoords * 0.5 + 0.5;
float shadow = 1.0;
for (int i=0;i<4;i++){
if ( texture( shadowMap, projCoords.xy + poissonDisk[i]/700.0 ).z < projCoords.z ){
shadow-=0.2;
}
}
if(projCoords.z > 1.0)
shadow = 0.0;
return shadow;
}
这是结果
如果您必须将视图 space 坐标转换为光源的局部 space，则必须在执行此操作时设置 lightSpaceMatrix:
lightSpaceMatrix = lightSpaceProjection * (lightSpaceView*camInv)
因为，您必须通过 camInv 从视图 space 转换到世界 space。然后你必须转换世界 space 坐标，从光源 (lightSpaceView) 看到。最后你必须投影它 lightSpaceProjection.
但是你直接从世界坐标转换到光源的局部space，在vertex shader中：
FragPosLightSpace = lightSpaceMatrix * vec4(FragPos,1.0);
因此，您必须像这样设置 lightSpaceMatrix：
lightSpaceMatrix = lightSpaceProjection * lightSpaceView
投影矩阵描述了从场景的 3D 点到视口的 2D 点的映射。它从视图（眼睛）space 转换为剪辑 space，剪辑中的坐标 space 通过除以 转换为归一化设备坐标（NDC） ]w 剪辑坐标的分量。 NDC 的范围是 (-1,-1,-1) 到 (1,1,1)。
这与正交投影或透视投影无关。
将投影片段位置 (light space) 除以其 w 分量后，projCoords 的范围为 (-1, - 1, -1) 到 (1, 1, 1)。
projCoords = projCoords * 0.5 + 0.5;将XY坐标转换为纹理坐标，将Z坐标转换为[0, 1]范围内的深度值。
vec3 projCoords = FragPosLightSpace.xyz / FragPosLightSpace.w;
projCoords = projCoords * 0.5 + 0.5;
阴影测试中的反转没有意义，因为纹理的内容也应该是 [0,1] 范围内的深度值。
影子测试应该看起来像这样：
if ( texture( shadowMap, projCoords.xy ).z < projCoords.z )
{
....
}
如果sun->direction是朝向太阳的方向，那么lightSpaceView就得这样设置：
glm::mat4 lightSpaceView = glm::lookAt(sun->direction, glm::vec3(0, 0, 0), glm::vec3(0, 1, 0));
但是，如果sun->direction是太阳照射的方向，那么lightSpaceView就得这样设置：
glm::mat4 lightSpaceView = glm::lookAt(-sun->direction, glm::vec3(0, 0, 0), glm::vec3(0, 1, 0));
由于您对光使用正交投影并且光的原点space矩阵靠近世界的原点space，所以光投影的近平面应该远在光的背面 space。否则，在生成光深度图时，距离太阳近的物体将被光投影的近平面裁剪。
glm::mat4 lightSpaceProjection = glm::ortho(-40.0f, 40.0f, -40.0f, 40.0f, -100.0f, 100.0f);
由于光照计算是在视图 space 中完成的，因此您必须将光照位置从世界 space 转换到视图 space:
GLuint directLightPosLoc = glGetUniformLocation(phongShader.getProgramID(), (const GLchar*) ("directLightPos[" + ToString((*it)->index) + "]").c_str());
glm::vec3 dir = glm::mat3(camera->getViewMatrix()) * (*it)->direction;
glUniform3fv( directLightPosLoc, 1, &dir[0] );
GLuint pointLightPosLoc = glGetUniformLocation(phongShader.getProgramID(), (const GLchar*) ("pointLightPos[" + ToString((*it)->index) + "]").c_str());
glm::vec4 pos = camera->getViewMatrix( * glm::vec4((*it)->position.x, (*it)->position.y, (*it)->position.z, 1.0);
glUniform3fv( directLightPosLoc, 1, &pos[0] );
GLuint spotLightPosLoc = glGetUniformLocation(phongShader.getProgramID(), (const GLchar*) ("spotLightPos[" + ToString((*it)->index) + "]").c_str());
glm::vec4 pos = camera->getViewMatrix( * glm::vec4((*it)->position.x, (*it)->position.y, (*it)->position.z, 1.0);
glUniform3fv( spotLightPosLoc, 1, &pos[0] );
查看演示该算法的 WebGL 示例：
(function loadscene() {
var sliderScale = 100.0
var gl;
var progShadow;
var progDraw;
var shadowFB;
var bufTorus;
var bufGround;
var canvas;
var vp_size;
var fb_size;
function render(deltaMS){
var ambient = document.getElementById( "ambient" ).value / sliderScale;
var diffuse = document.getElementById( "diffuse" ).value / sliderScale;
var specular = document.getElementById( "specular" ).value / sliderScale;
var shininess = document.getElementById( "shininess" ).value;
canvas = document.getElementById( "scene-canvas" );
var lightPos = [-3.0, 0.0, 2.0];
var lightAnimationMat = RotateAxis( IdentityMat44(), CalcAng( deltaMS, 20.0 ), 2 );
lightPos = Transform( lightPos, lightAnimationMat );
var lightDir = [ -lightPos[0], -lightPos[1], -lightPos[2] ];
var light = Camera.Create( lightPos, [0, 0, 0], [0, 0, 1], 110, [ 5.0, 5.0 ], -20.0, 20.0 );
var camera = Camera.Create( [0, 2.5, 2], [0, 0, 0], [0, 0, 1], 110, [vp_size[0], vp_size[1]], 0.5, 100.0 );
var lightPrjMat = Camera.Ortho( light );
var lightViewMat = Camera.LookAt( light );
var prjMat = Camera.Perspective( camera );
var viewMat = Camera.LookAt( camera );
var modelMat = IdentityMat44();
modelMat = RotateAxis( modelMat, CalcAng( deltaMS, 13.0 ), 0 );
modelMat = RotateAxis( modelMat, CalcAng( deltaMS, 17.0 ), 1 );
groundModelMat = IdentityMat44();
var viewLightDir = TransformVec( lightDir, viewMat );
gl.viewport( 0, 0, fb_size[0], fb_size[1] );
gl.enable( gl.DEPTH_TEST );
shadowFB.Bind( true );
ShaderProgram.Use( progShadow );
ShaderProgram.SetUniformM44( progShadow, "u_projectionMat44", lightPrjMat );
ShaderProgram.SetUniformM44( progShadow, "u_viewMat44", lightViewMat );
ShaderProgram.SetUniformM44( progShadow, "u_modelMat44", modelMat );
ShaderProgram.SetUniformF2( progShadow, "u_depthRange", [light.near, light.far] );
VertexBuffer.Draw( bufTorus );
gl.viewport( 0, 0, vp_size[0], vp_size[1] );
shadowFB.Release( true );
shadowFB.BindTexture( 1 );
ShaderProgram.Use( progDraw );
ShaderProgram.SetUniformM44( progDraw, "u_projectionMat44", prjMat );
ShaderProgram.SetUniformM44( progDraw, "u_viewMat44", viewMat );
ShaderProgram.SetUniformM44( progDraw, "u_lightProjectionMat44", lightPrjMat );
ShaderProgram.SetUniformM44( progDraw, "u_lightViewMat44", lightViewMat );
ShaderProgram.SetUniformM44( progDraw, "u_modelMat44", modelMat );
ShaderProgram.SetUniformI1( progDraw, "u_depthSampler", 1 );
ShaderProgram.SetUniformF3( progDraw, "u_lightDir", viewLightDir )
ShaderProgram.SetUniformF1( progDraw, "u_ambient", ambient )
ShaderProgram.SetUniformF1( progDraw, "u_diffuse", diffuse )
ShaderProgram.SetUniformF1( progDraw, "u_specular", specular )
ShaderProgram.SetUniformF1( progDraw, "u_shininess", shininess )
VertexBuffer.Draw( bufTorus );
ShaderProgram.SetUniformM44( progDraw, "u_modelMat44", groundModelMat );
VertexBuffer.Draw( bufGround );
requestAnimationFrame(render);
}
function nearestPow2( aSize ){
return Math.pow( 2, Math.round( Math.log( aSize ) / Math.log( 2 ) ) );
}
function resize() {
//vp_size = [gl.drawingBufferWidth, gl.drawingBufferHeight];
vp_size = [window.innerWidth, window.innerHeight]
canvas.width = vp_size[0];
canvas.height = vp_size[1];
var size = Math.max(256, Math.max(vp_size[0], vp_size[1]));
size = nearestPow2(size/2);
fb_size = [size, size]
shadowFB = FrameBuffer.Create( fb_size );
}
function initScene() {
document.getElementById( "ambient" ).value = 0.2 * sliderScale;
document.getElementById( "diffuse" ).value = 0.7 * sliderScale;
document.getElementById( "specular" ).value = 0.5 * sliderScale;
document.getElementById( "shininess" ).value = 8.0;
canvas = document.getElementById( "scene-canvas");
vp_size = [canvas.width, canvas.height];
gl = canvas.getContext( "experimental-webgl" );
if ( !gl )
return;
progShadow = ShaderProgram.Create(
[ { source : "shadow-shader-vs", stage : gl.VERTEX_SHADER },
{ source : "shadow-shader-fs", stage : gl.FRAGMENT_SHADER }
] );
if (!progShadow.progObj)
return null;
progShadow.inPos = ShaderProgram.AttributeIndex( progShadow, "inPos" );
progShadow.inNV = ShaderProgram.AttributeIndex( progShadow, "inNV" );
progShadow.inCol = ShaderProgram.AttributeIndex( progShadow, "inCol" );
progDraw = ShaderProgram.Create(
[ { source : "draw-shader-vs", stage : gl.VERTEX_SHADER },
{ source : "draw-shader-fs", stage : gl.FRAGMENT_SHADER }
] );
if (!progDraw.progObj)
return null;
progDraw.inPos = ShaderProgram.AttributeIndex( progDraw, "inPos" );
progDraw.inNV = ShaderProgram.AttributeIndex( progDraw, "inNV" );
progDraw.inCol = ShaderProgram.AttributeIndex( progDraw, "inCol" );
// create torus
var circum_size = 32, tube_size = 32;
var rad_circum = 1.0;
var rad_tube = 0.5;
var torus_pts = [];
var torus_nv = [];
var torus_col = [];
var torus_inx = [];
var col = [1, 0.5, 0.0];
for ( var i_c = 0; i_c < circum_size; ++ i_c ) {
var center = [
Math.cos(2 * Math.PI * i_c / circum_size),
Math.sin(2 * Math.PI * i_c / circum_size) ]
for ( var i_t = 0; i_t < tube_size; ++ i_t ) {
var tubeX = Math.cos(2 * Math.PI * i_t / tube_size)
var tubeY = Math.sin(2 * Math.PI * i_t / tube_size)
var pt = [
center[0] * ( rad_circum + tubeX * rad_tube ),
center[1] * ( rad_circum + tubeX * rad_tube ),
tubeY * rad_tube ]
var nv = [ pt[0] - center[0] * rad_tube, pt[1] - center[1] * rad_tube, tubeY * rad_tube ]
torus_pts.push( pt[0], pt[1], pt[2] );
torus_nv.push( nv[0], nv[1], nv[2] );
torus_col.push( col[0], col[1], col[2] );
var i_cn = (i_c+1) % circum_size
var i_tn = (i_t+1) % tube_size
var i_c0 = i_c * tube_size;
var i_c1 = i_cn * tube_size;
torus_inx.push( i_c0+i_t, i_c0+i_tn, i_c1+i_t, i_c0+i_tn, i_c1+i_t, i_c1+i_tn )
}
}
bufTorus = VertexBuffer.Create(
[ { data : torus_pts, attrSize : 3, attrLoc : progDraw.inPos },
{ data : torus_nv, attrSize : 3, attrLoc : progDraw.inNV },
{ data : torus_col, attrSize : 3, attrLoc : progDraw.inCol } ],
torus_inx
);
var g_l = 8.0;
var g_h = -2.5;
var g_c = [ 0.8, 0.6, 0.8 ];
bufGround = VertexBuffer.Create(
[ { data : [ -g_l, -g_l, g_h, g_l, -g_l, g_h, g_l, g_l, g_h, -g_l, g_l, g_h ], attrSize : 3, attrLoc : progDraw.inPos },
{ data : [ 0.0, 0.0, 1.0, 0.0, 0.0, 1.0, 0.0, 0.0, 1.0, 0.0, 0.0, 1.0 ], attrSize : 3, attrLoc : progDraw.inNV },
{ data : [ g_c[0], g_c[1], g_c[2], g_c[0], g_c[1], g_c[2], g_c[0], g_c[1], g_c[2], g_c[0], g_c[1], g_c[2] ], attrSize : 3, attrLoc : progDraw.inCol } ],
[ 0, 1, 2, 0, 2, 3 ]
);
window.onresize = resize;
resize();
requestAnimationFrame(render);
}
var startTime;
function Fract( val ) {
return val - Math.trunc( val );
}
function CalcAng( deltaTime, intervall ) {
return Fract( deltaTime / (1000*intervall) ) * 2.0 * Math.PI;
}
function IdentityMat44() { return [1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1]; }
function RotateAxis(matA, angRad, axis) {
var aMap = [ [1, 2], [2, 0], [0, 1] ];
var a0 = aMap[axis][0], a1 = aMap[axis][1];
var sinAng = Math.sin(angRad), cosAng = Math.cos(angRad);
var matB = IdentityMat44();
for ( var i = 0; i < 16; ++ i ) matB[i] = matA[i];
for ( var i = 0; i < 3; ++ i ) {
matB[a0*4+i] = matA[a0*4+i] * cosAng + matA[a1*4+i] * sinAng;
matB[a1*4+i] = matA[a0*4+i] * -sinAng + matA[a1*4+i] * cosAng;
}
return matB;
}
function Cross( a, b ) { return [ a[1] * b[2] - a[2] * b[1], a[2] * b[0] - a[0] * b[2], a[0] * b[1] - a[1] * b[0], 0.0 ]; }
function Dot( a, b ) { return a[0]*b[0] + a[1]*b[1] + a[2]*b[2]; }
function Normalize( v ) {
var len = Math.sqrt( v[0] * v[0] + v[1] * v[1] + v[2] * v[2] );
return [ v[0] / len, v[1] / len, v[2] / len ];
}
Transform = function(vec, mat) {
return [
vec[0] * mat[0*4+0] + vec[1] * mat[1*4+0] + vec[2] * mat[2*4+0] + mat[3*4+0],
vec[0] * mat[0*4+1] + vec[1] * mat[1*4+1] + vec[2] * mat[2*4+1] + mat[3*4+1],
vec[0] * mat[0*4+2] + vec[1] * mat[1*4+2] + vec[2] * mat[2*4+2] + mat[3*4+2],
vec[0] * mat[0*4+3] + vec[1] * mat[1*4+3] + vec[2] * mat[2*4+3] + mat[3*4+3] ]
if ( h[3] == 0.0 )
return [0, 0, 0]
return [ h[0]/h[3], h[1]/h[3], h[2]/h[3] ];
}
TransformVec = function(vec, mat) {
return [
vec[0] * mat[0*4+0] + vec[1] * mat[1*4+0] + vec[2] * mat[2*4+0],
vec[0] * mat[0*4+1] + vec[1] * mat[1*4+1] + vec[2] * mat[2*4+1],
vec[0] * mat[0*4+2] + vec[1] * mat[1*4+2] + vec[2] * mat[2*4+2] ]
}
var Camera = {};
Camera.Create = function( pos, target, up, fov_y, vp, near, far ) {
var camera = {};
camera.pos = pos;
camera.target = target;
camera.up = up;
camera.fov_y = fov_y;
camera.vp = vp;
camera.near = near;
camera.far = far;
return camera;
}
Camera.Ortho = function( camera ) {
var fn = camera.far + camera.near;
var f_n = camera.far - camera.near;
var w = camera.vp[0];
var h = camera.vp[1];
var m = IdentityMat44();
m[0] = 2 / w; m[1] = 0; m[2] = 0; m[3] = 0;
m[4] = 0; m[5] = 2 / h; m[6] = 0; m[7] = 0;
m[8] = 0; m[9] = 0; m[10] = -2 / f_n; m[11] = 0;
m[12] = 0; m[13] = 0; m[14] = -fn / f_n; m[15] = 1;
return m;
}
Camera.Perspective = function( camera ) {
var fn = camera.far + camera.near;
var f_n = camera.far - camera.near;
var r = camera.vp[0] / camera.vp[1];
var t = 1 / Math.tan( Math.PI * camera.fov_y / 360 );
var m = IdentityMat44();
m[0] = t/r; m[1] = 0; m[2] = 0; m[3] = 0;
m[4] = 0; m[5] = t; m[6] = 0; m[7] = 0;
m[8] = 0; m[9] = 0; m[10] = -fn / f_n; m[11] = -1;
m[12] = 0; m[13] = 0; m[14] = -2 * camera.far * camera.near / f_n; m[15] = 0;
return m;
}
Camera.LookAt = function( camera ) {
var mz = Normalize( [ camera.pos[0]-camera.target[0], camera.pos[1]-camera.target[1], camera.pos[2]-camera.target[2] ] );
var mx = Normalize( Cross( camera.up, mz ) );
var my = Normalize( Cross( mz, mx ) );
var tx = Dot( mx, camera.pos );
var ty = Dot( my, camera.pos );
var tz = Dot( [-mz[0], -mz[1], -mz[2]], camera.pos );
var m = IdentityMat44();
m[0] = mx[0]; m[1] = my[0]; m[2] = mz[0]; m[3] = 0;
m[4] = mx[1]; m[5] = my[1]; m[6] = mz[1]; m[7] = 0;
m[8] = mx[2]; m[9] = my[2]; m[10] = mz[2]; m[11] = 0;
m[12] = tx; m[13] = ty; m[14] = tz; m[15] = 1;
return m;
}
var ShaderProgram = {};
ShaderProgram.Create = function (shaderList) {
var shaderObjs = [];
for (var i_sh = 0; i_sh < shaderList.length; ++i_sh) {
var shderObj = this.CompileShader(shaderList[i_sh].source, shaderList[i_sh].stage);
if (shderObj == 0)
return 0;
shaderObjs.push(shderObj);
}
var prog = {}
prog.progObj = this.LinkProgram(shaderObjs)
if (prog.progObj) {
prog.attribIndex = {};
var noOfAttributes = gl.getProgramParameter(prog.progObj, gl.ACTIVE_ATTRIBUTES);
for (var i_n = 0; i_n < noOfAttributes; ++i_n) {
var name = gl.getActiveAttrib(prog.progObj, i_n).name;
prog.attribIndex[name] = gl.getAttribLocation(prog.progObj, name);
}
prog.unifomLocation = {};
var noOfUniforms = gl.getProgramParameter(prog.progObj, gl.ACTIVE_UNIFORMS);
for (var i_n = 0; i_n < noOfUniforms; ++i_n) {
var name = gl.getActiveUniform(prog.progObj, i_n).name;
prog.unifomLocation[name] = gl.getUniformLocation(prog.progObj, name);
}
}
return prog;
}
ShaderProgram.AttributeIndex = function (prog, name) { return prog.attribIndex[name]; }
ShaderProgram.UniformLocation = function (prog, name) { return prog.unifomLocation[name]; }
ShaderProgram.Use = function (prog) { gl.useProgram(prog.progObj); }
ShaderProgram.SetUniformI1 = function (prog, name, val) { if (prog.unifomLocation[name]) gl.uniform1i(prog.unifomLocation[name], val); }
ShaderProgram.SetUniformF1 = function (prog, name, val) { if (prog.unifomLocation[name]) gl.uniform1f(prog.unifomLocation[name], val); }
ShaderProgram.SetUniformF2 = function (prog, name, arr) { if (prog.unifomLocation[name]) gl.uniform2fv(prog.unifomLocation[name], arr); }
ShaderProgram.SetUniformF3 = function (prog, name, arr) { if (prog.unifomLocation[name]) gl.uniform3fv(prog.unifomLocation[name], arr); }
ShaderProgram.SetUniformF4 = function (prog, name, arr) { if (prog.unifomLocation[name]) gl.uniform4fv(prog.unifomLocation[name], arr); }
ShaderProgram.SetUniformM33 = function (prog, name, mat) { if (prog.unifomLocation[name]) gl.uniformMatrix3fv(prog.unifomLocation[name], false, mat); }
ShaderProgram.SetUniformM44 = function (prog, name, mat) { if (prog.unifomLocation[name]) gl.uniformMatrix4fv(prog.unifomLocation[name], false, mat); }
ShaderProgram.CompileShader = function (source, shaderStage) {
var shaderScript = document.getElementById(source);
if (shaderScript)
source = shaderScript.text;
var shaderObj = gl.createShader(shaderStage);
gl.shaderSource(shaderObj, source);
gl.compileShader(shaderObj);
var status = gl.getShaderParameter(shaderObj, gl.COMPILE_STATUS);
if (!status) alert(gl.getShaderInfoLog(shaderObj));
return status ? shaderObj : null;
}
ShaderProgram.LinkProgram = function (shaderObjs) {
var prog = gl.createProgram();
for (var i_sh = 0; i_sh < shaderObjs.length; ++i_sh)
gl.attachShader(prog, shaderObjs[i_sh]);
gl.linkProgram(prog);
status = gl.getProgramParameter(prog, gl.LINK_STATUS);
if (!status) alert("Could not initialise shaders");
gl.useProgram(null);
return status ? prog : null;
}
var VertexBuffer = {};
VertexBuffer.Create = function( attributes, indices ) {
var buffer = {};
buffer.buf = [];
buffer.attr = []
for ( var i = 0; i < attributes.length; ++ i ) {
buffer.buf.push( gl.createBuffer() );
buffer.attr.push( { size : attributes[i].attrSize, loc : attributes[i].attrLoc } );
gl.bindBuffer( gl.ARRAY_BUFFER, buffer.buf[i] );
gl.bufferData( gl.ARRAY_BUFFER, new Float32Array( attributes[i].data ), gl.STATIC_DRAW );
}
buffer.inx = gl.createBuffer();
gl.bindBuffer( gl.ELEMENT_ARRAY_BUFFER, buffer.inx );
gl.bufferData( gl.ELEMENT_ARRAY_BUFFER, new Uint16Array( indices ), gl.STATIC_DRAW );
buffer.inxLen = indices.length;
gl.bindBuffer( gl.ARRAY_BUFFER, null );
gl.bindBuffer( gl.ELEMENT_ARRAY_BUFFER, null );
return buffer;
}
VertexBuffer.Draw = function( bufObj ) {
for ( var i = 0; i < bufObj.buf.length; ++ i ) {
gl.bindBuffer( gl.ARRAY_BUFFER, bufObj.buf[i] );
gl.vertexAttribPointer( bufObj.attr[i].loc, bufObj.attr[i].size, gl.FLOAT, false, 0, 0 );
gl.enableVertexAttribArray( bufObj.attr[i].loc );
}
gl.bindBuffer( gl.ELEMENT_ARRAY_BUFFER, bufObj.inx );
gl.drawElements( gl.TRIANGLES, bufObj.inxLen, gl.UNSIGNED_SHORT, 0 );
for ( var i = 0; i < bufObj.buf.length; ++ i )
gl.disableVertexAttribArray( bufObj.attr[i].loc );
gl.bindBuffer( gl.ARRAY_BUFFER, null );
gl.bindBuffer( gl.ELEMENT_ARRAY_BUFFER, null );
}
var FrameBuffer = {};
FrameBuffer.Create = function( vp, texturePlan ) {
var texPlan = texturePlan ? new Uint8Array( texturePlan ) : null;
var fb = gl.createFramebuffer();
var fbsize = Math.max(vp[0], vp[1]);
fbsize = 1 << 31 - Math.clz32(fbsize); // nearest power of 2
fb.width = fbsize;
fb.height = fbsize;
gl.bindFramebuffer( gl.FRAMEBUFFER, fb );
fb.color0_texture = gl.createTexture();
gl.bindTexture( gl.TEXTURE_2D, fb.color0_texture );
gl.texImage2D( gl.TEXTURE_2D, 0, gl.RGBA, fb.width, fb.height, 0, gl.RGBA, gl.UNSIGNED_BYTE, texPlan );
gl.texParameteri( gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST );
gl.texParameteri( gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST );
gl.texParameteri( gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE );
gl.texParameteri( gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE );
fb.renderbuffer = gl.createRenderbuffer();
gl.bindRenderbuffer( gl.RENDERBUFFER, fb.renderbuffer );
gl.renderbufferStorage( gl.RENDERBUFFER, gl.DEPTH_COMPONENT16, fb.width, fb.height );
gl.framebufferTexture2D( gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0, gl.TEXTURE_2D, fb.color0_texture, 0 );
gl.framebufferRenderbuffer( gl.FRAMEBUFFER, gl.DEPTH_ATTACHMENT, gl.RENDERBUFFER, fb.renderbuffer );
gl.bindTexture( gl.TEXTURE_2D, null );
gl.bindRenderbuffer( gl.RENDERBUFFER, null );
gl.bindFramebuffer( gl.FRAMEBUFFER, null );
fb.Bind = function( clear ) {
gl.bindFramebuffer( gl.FRAMEBUFFER, this );
if ( clear ) {
gl.clearColor( 0.0, 0.0, 0.0, 1.0 );
gl.clear( gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT );
}
};
fb.Release = function( clear ) {
gl.bindFramebuffer( gl.FRAMEBUFFER, null );
if ( clear ) {
gl.clearColor( 0.0, 0.0, 0.0, 1.0 );
gl.clear( gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT );
}
};
fb.BindTexture = function( textureUnit ) {
gl.activeTexture( gl.TEXTURE0 + textureUnit );
gl.bindTexture( gl.TEXTURE_2D, this.color0_texture );
};
return fb;
}
initScene();
})();
html,body {
height: 100%;
width: 100%;
margin: 0;
overflow: hidden;
}
#gui {
position : absolute;
top : 0;
left : 0;
}
<script id="shadow-shader-vs" type="x-shader/x-vertex">
precision mediump float;
attribute vec3 inPos;
attribute vec3 inNV;
attribute vec3 inCol;
varying vec3 vertPos;
varying vec3 vertNV;
varying vec3 vertCol;
varying vec4 vPosPrj;
uniform mat4 u_projectionMat44;
uniform mat4 u_viewMat44;
uniform mat4 u_modelMat44;
void main()
{
vec3 modelNV = mat3( u_modelMat44 ) * normalize( inNV );
vertNV = mat3( u_viewMat44 ) * modelNV;
vertCol = inCol;
vec4 modelPos = u_modelMat44 * vec4( inPos, 1.0 );
vec4 viewPos = u_viewMat44 * modelPos;
vertPos = viewPos.xyz / viewPos.w;
vPosPrj = u_projectionMat44 * viewPos;
gl_Position = vPosPrj;
}
</script>
<script id="shadow-shader-fs" type="x-shader/x-fragment">
precision mediump float;
varying vec3 vertPos;
varying vec3 vertNV;
varying vec3 vertCol;
varying vec4 vPosPrj;
uniform vec2 u_depthRange;
vec3 PackDepth( in float depth )
{
float depthVal = depth * (256.0*256.0*256.0 - 1.0) / (256.0*256.0*256.0);
vec4 encode = fract( depthVal * vec4(1.0, 256.0, 256.0*256.0, 256.0*256.0*256.0) );
return encode.xyz - encode.yzw / 256.0 + 1.0/512.0;
}
void main()
{
float ndc_depth = vPosPrj.z / vPosPrj.w;
float nearZ = u_depthRange.x;
float farZ = u_depthRange.y;
float depth = ndc_depth * 0.5 + 0.5;
gl_FragColor = vec4( PackDepth( depth ).xyz, 1.0 );
}
</script>
<script id="draw-shader-vs" type="x-shader/x-vertex">
precision mediump float;
attribute vec3 inPos;
attribute vec3 inNV;
attribute vec3 inCol;
varying vec3 vertPos;
varying vec3 vertNV;
varying vec3 vertCol;
varying vec4 lightPrj;
varying vec4 vPosPrj;
uniform mat4 u_projectionMat44;
uniform mat4 u_viewMat44;
uniform mat4 u_modelMat44;
uniform mat4 u_lightProjectionMat44;
uniform mat4 u_lightViewMat44;
void main()
{
vec3 modelNV = mat3( u_modelMat44 ) * normalize( inNV );
vertNV = mat3( u_viewMat44 ) * modelNV;
vertCol = inCol;
vec4 modelPos = u_modelMat44 * vec4( inPos, 1.0 );
vec4 lightPos = u_lightViewMat44 * modelPos;
vec4 viewPos = u_viewMat44 * modelPos;
lightPrj = u_lightProjectionMat44 * lightPos;
vertPos = viewPos.xyz / viewPos.w;
vPosPrj = u_projectionMat44 * viewPos;
gl_Position = vPosPrj;
}
</script>
<script id="draw-shader-fs" type="x-shader/x-fragment">
precision mediump float;
varying vec3 vertPos;
varying vec3 vertNV;
varying vec3 vertCol;
varying vec4 lightPrj;
varying vec4 vPosPrj;
uniform sampler2D u_depthSampler;
uniform vec3 u_lightDir;
uniform float u_ambient;
uniform float u_diffuse;
uniform float u_specular;
uniform float u_shininess;
float UnpackDepth( in vec3 pack )
{
float depth = dot( pack, 1.0 / vec3(1.0, 256.0, 256.0*256.0) );
return depth * (256.0*256.0*256.0) / (256.0*256.0*256.0 - 1.0);
}
float Depth( in sampler2D depthSampler, in vec2 texC )
{
vec3 depthVal = texture2D( depthSampler, texC.st ).xyz;
return UnpackDepth( depthVal.rgb );
}
void main()
{
vec3 ndc_light = lightPrj.xyz / lightPrj.w;
vec2 lightTexC = ndc_light.xy * 0.5 + 0.5;
float lightDepth = ndc_light.z * 0.5 + 0.5;
float testDepth = Depth( u_depthSampler, lightTexC );
float shadow = step( lightDepth-0.01, testDepth ) + step( testDepth, 0.0 );
vec3 color = vertCol;
vec3 lightCol = u_ambient * color;
vec3 normalV = normalize( vertNV );
vec3 lightV = normalize( -u_lightDir );
float NdotL = max( 0.0, dot( normalV, lightV ) );
lightCol += shadow * NdotL * u_diffuse * color;
vec3 eyeV = normalize( -vertPos );
vec3 halfV = normalize( eyeV + lightV );
float NdotH = max( 0.0, dot( normalV, halfV ) );
float kSpecular = ( u_shininess + 2.0 ) * pow( NdotH, u_shininess ) / ( 2.0 * 3.14159265 );
lightCol += shadow * kSpecular * u_specular * color;
gl_FragColor = vec4( lightCol.rgb, 1.0 );
}
</script>
<div><form id="gui" name="inputs"><table>
<tr> <td> <font color= #CCF>ambient</font> </td>
<td> <input type="range" id="ambient" min="0" max="100" value="0"/></td> </tr>
<tr> <td> <font color= #CCF>diffuse</font> </td>
<td> <input type="range" id="diffuse" min="0" max="100" value="0"/></td> </tr>
<tr> <td> <font color= #CCF>specular</font> </td>
<td> <input type="range" id="specular" min="0" max="100" value="0"/></td> </tr>
<tr> <td> <font color= #CCF>shininess</font> </td>
<td> <input type="range" id="shininess" min="0" max="100" value="0"/></td> </tr>
</table></form></div>
<canvas id="scene-canvas" style="border: none;" width="512" height="512"></canvas>
另见
- How to render depth linearly in modern OpenGL with gl_FragCoord.z in fragment shader