GLSL聚光投影体积
GLSL spotlight projection volume
在我的开源项目中，我使用 Qt3D 设置了一个延迟渲染管道。到目前为止一切顺利，但现在我想通过添加聚光灯投影体积来向前推进。 （例如现场好像有烟）
像这样：
我正在使用的片段着色器在问题的最后。
我已经读到对于每个片段我应该从光线位置进行光线行进并找到与圆锥体的交叉点，但我不知道如何将其转化为 GLSL。
我可以使用来自 GBuffer 的深度图（从相机的角度）轻松添加制服，但我不知道这是否有帮助。
由于我的 GLSL 知识非常有限，请用实际代码回复，不要冗长的数学解释，我无法 understand/translate 成代码。请耐心等待我。
uniform sampler2D color;
uniform sampler2D position;
uniform sampler2D normal;
uniform vec2 winSize;
out vec4 fragColor;
const int MAX_LIGHTS = 102;
const int TYPE_POINT = 0;
const int TYPE_DIRECTIONAL = 1;
const int TYPE_SPOT = 2;
struct Light {
int type;
vec3 position;
vec3 color;
float intensity;
vec3 direction;
float constantAttenuation;
float linearAttenuation;
float quadraticAttenuation;
float cutOffAngle;
};
uniform Light lightsArray[MAX_LIGHTS];
uniform int lightsNumber;
void main()
{
vec2 texCoord = gl_FragCoord.xy / winSize;
vec4 col = texture(color, texCoord);
vec3 pos = texture(position, texCoord).xyz;
vec3 norm = texture(normal, texCoord).xyz;
vec3 lightColor = vec3(0.0);
vec3 s;
float att;
for (int i = 0; i < lightsNumber; ++i) {
att = 1.0;
if ( lightsArray[i].type != TYPE_DIRECTIONAL ) {
s = lightsArray[i].position - pos;
if (lightsArray[i].constantAttenuation != 0.0
|| lightsArray[i].linearAttenuation != 0.0
|| lightsArray[i].quadraticAttenuation != 0.0) {
float dist = length(s);
att = 1.0 / (lightsArray[i].constantAttenuation + lightsArray[i].linearAttenuation * dist + lightsArray[i].quadraticAttenuation * dist * dist);
}
s = normalize( s );
if ( lightsArray[i].type == TYPE_SPOT ) {
if ( degrees(acos(dot(-s, normalize(lightsArray[i].direction))) ) > lightsArray[i].cutOffAngle)
att = 0.0;
}
} else {
s = normalize(-lightsArray[i].direction);
}
float diffuse = max( dot( s, norm ), 0.0 );
lightColor += att * lightsArray[i].intensity * diffuse * lightsArray[i].color;
}
fragColor = vec4(col.rgb * lightColor, col.a);
}
这是聚光灯在上面的原始着色器中的样子：
[编辑 - 已解决]感谢 Rabbid76 出色的回答和宝贵的支持
这是查看圆锥投影的修改代码：
#version 140
uniform sampler2D color;
uniform sampler2D position;
uniform sampler2D normal;
uniform vec2 winSize;
out vec4 fragColor;
const int MAX_LIGHTS = 102;
const int TYPE_POINT = 0;
const int TYPE_DIRECTIONAL = 1;
const int TYPE_SPOT = 2;
struct Light {
int type;
vec3 position;
vec3 color;
float intensity;
vec3 direction;
float constantAttenuation;
float linearAttenuation;
float quadraticAttenuation;
float cutOffAngle;
};
uniform Light lightsArray[MAX_LIGHTS];
uniform int lightsNumber;
uniform mat4 inverseViewMatrix; // defined by camera position, camera target and up vector
void main()
{
vec2 texCoord = gl_FragCoord.xy / winSize;
vec4 col = texture(color, texCoord);
vec3 pos = texture(position, texCoord).xyz;
vec3 norm = texture(normal, texCoord).xyz;
vec3 lightColor = vec3(0.0);
vec3 s;
// calculate unprojected fragment position on near plane and line of sight relative to view
float nearZ = -1.0;
vec3 nearPos = vec3( (texCoord.x - 0.5) * winSize.x / winSize.y, texCoord.y - 0.5, nearZ ); // 1.0 is camera near
vec3 los = normalize( nearPos );
// ray definition
vec3 O = vec3( inverseViewMatrix * vec4( 0.0, 0.0, 0.0, 1.0 ) ); // translation part of the camera matrix, which is equal to the camera position
vec3 D = (length(pos) > 0.0) ? normalize(pos - O) : (mat3(inverseViewMatrix) * los);
for (int i = 0; i < lightsNumber; ++i)
{
float att = 1.0;
if ( lightsArray[i].type == TYPE_DIRECTIONAL )
{
s = normalize( -lightsArray[i].direction );
}
else
{
s = lightsArray[i].position - pos;
if (lightsArray[i].type != TYPE_SPOT
&& (lightsArray[i].constantAttenuation != 0.0
|| lightsArray[i].linearAttenuation != 0.0
|| lightsArray[i].quadraticAttenuation != 0.0))
{
float dist = length(s);
att = 1.0 / (lightsArray[i].constantAttenuation + lightsArray[i].linearAttenuation * dist + lightsArray[i].quadraticAttenuation * dist * dist);
}
s = normalize( s );
if ( lightsArray[i].type == TYPE_SPOT )
{
// cone definition
vec3 C = lightsArray[i].position;
vec3 V = normalize(lightsArray[i].direction);
float cosTh = cos( radians(lightsArray[i].cutOffAngle) );
// ray - cone intersection
vec3 CO = O - C;
float DdotV = dot( D, V );
float COdotV = dot( CO, V );
float a = DdotV * DdotV - cosTh * cosTh;
float b = 2.0 * (DdotV * COdotV - dot( D, CO ) * cosTh * cosTh);
float c = COdotV * COdotV - dot( CO, CO ) * cosTh * cosTh;
float det = b * b - 4.0 * a * c;
// find intersection
float isIsect = 0.0;
vec3 isectP = vec3(0.0);
if ( det >= 0.0 )
{
vec3 P1 = O + (-b - sqrt(det)) / (2.0 * a) * D;
vec3 P2 = O + (-b + sqrt(det)) / (2.0 * a) * D;
float isect1 = step( 0.0, dot(normalize(P1 - C), V) );
float isect2 = step( 0.0, dot(normalize(P2 - C), V) );
if ( isect1 < 0.5 )
{
P1 = P2;
isect1 = isect2;
}
if ( isect2 < 0.5 )
{
P2 = P1;
isect2 = isect1;
}
isectP = (length(P1 - O) < length(P2 - O)) ? P1 : P2;
isIsect = mix( isect2, 1.0, isect1 );
if ( length(pos) != 0.0 && length(isectP - O) > length(pos - O))
isIsect = 0.0;
}
float dist = length( isectP - C.xyz );
float limit = degrees(acos(dot(-s, normalize(lightsArray[i].direction))) );
if (isIsect > 0 || limit <= lightsArray[i].cutOffAngle)
{
att = 1.0 / dot( vec3( 1.0, dist, dist * dist ),
vec3(lightsArray[i].constantAttenuation,
lightsArray[i].linearAttenuation,
lightsArray[i].quadraticAttenuation) );
}
else
att = 0.0;
}
}
float diffuse = max( dot( s, norm ), 0.0 );
lightColor += att * lightsArray[i].intensity * diffuse * lightsArray[i].color;
}
fragColor = vec4(col.rgb * lightColor, col.a);
}
传递给着色器的制服是：
qml: lightsArray[0].type = 0
qml: lightsArray[0].position = QVector3D(0, 10, 0)
qml: lightsArray[0].color = #ffffff
qml: lightsArray[0].intensity = 0.8
qml: lightsArray[0].constantAttenuation = 1
qml: lightsArray[0].linearAttenuation = 0
qml: lightsArray[0].quadraticAttenuation = 0
qml: lightsArray[1].type = 2
qml: lightsArray[1].position = QVector3D(0, 3, 0)
qml: lightsArray[1].color = #008000
qml: lightsArray[1].intensity = 0.5
qml: lightsArray[1].constantAttenuation = 2
qml: lightsArray[1].linearAttenuation = 0
qml: lightsArray[1].quadraticAttenuation = 0
qml: lightsArray[1].direction = QVector3D(-0.573576, -0.819152, 0)
qml: lightsArray[1].cutOffAngle = 15
qml: lightsNumber = 2
截图：
对于聚光灯的光锥的原始可视化，您必须做视线与光锥的交点。
以下算法在透视视图中工作，并且计算是在视图（眼睛）空间中完成的。该算法不关心场景的几何形状，不做任何深度测试或阴影测试，它只是光锥的叠加可视化。
透视图中的视线可以用一个点和一个方向来定义。由于计算是在view(eye)space中进行的，所以点就是view(视锥体的原点)也就是vec3(0.0).
方向就很容易确定了, 通过视线与相机平截头体的近平面的交点。如果片段的投影 XY 坐标在归一化设备坐标中已知（左下角点为 (-1,-1) 右上角点为 (1,1)，则可以轻松计算出这一点，请参阅 [= 的答案20=]问题）。
float aspect = .....; // ratio of the view port (widht/length)
float fov = .....; // filed of view angle in radians (angle of the camera frustum on the Y-axis)
vec2 ndcPos = .....; // fragment position in NDC space from (-1,-1) to (1,1)
vec3 tanFov = tan( fov * 0.5 );
vec3 los = normalize( vec3( ndcPos.x * aspect * tanFov, ndcPos.y * tanFov, -1.0 ) );
光锥是由光源的原点、光源指向的方向、光锥的全角来定义的。位置和方向必须在视图 space 上。角度必须以弧度为单位设置。
vec3 vLightPos = .....; // position of the light source in view space
vec3 vLightDir = .....; // direction of the light in view space
float coneAngle = .....; // full angle of the light cone in radians
如何计算射线和圆锥的交点可以在 Whosebug 问题 and in the following paper: Intersection of a ray and a cone 的答案中找到。
下面的代码计算了上面定义的射线和圆锥体的交点。结果点存储在isectP中。类型float的变量isIsect如果有交集则设置为1.0，否则设置为0.0.
// ray definition
vec3 O = vec3(0.0);
vec3 D = los;
// cone definition
vec3 C = vLightPos;
vec3 V = vLightDir;
float cosTh = cos( coneAngle * 0.5 );
// ray - cone intersection
vec3 CO = O - C;
float DdotV = dot( D, V );
float COdotV = dot( CO, V );
float a = DdotV*DdotV - cosTh*cosTh;
float b = 2.0 * (DdotV*COdotV - dot( D, CO )*cosTh*cosTh);
float c = COdotV*COdotV - dot( CO, CO )*cosTh*cosTh;
float det = b*b - 4.0*a*c;
// find intersection
float isIsect = 0.0;
vec3 isectP = vec3(0.0);
if ( det >= 0.0 )
{
vec3 P1 = O + (-b-sqrt(det))/(2.0*a) * D;
vec3 P2 = O + (-b+sqrt(det))/(2.0*a) * D;
float isect1 = step( 0.0, dot(normalize(P1-C), V) );
float isect2 = step( 0.0, dot(normalize(P2-C), V) );
P1 = mix( P2, P1, isect1 );
isectP = P2.z < 0.0 && P2.z > P1.z ? P2 : P1;
isIsect = mix( isect2, 1.0, isect1 ) * step( isectP.z, 0.0 );
}
有关完整的 GLSL 代码，请参阅以下 WebGL 示例：
(function loadscene() {
var sliderScale = 100.0
var gl, canvas, vp_size, camera, progDraw, progLightCone, bufTorus = {}, bufQuad = {}, drawFB;
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;
var cutOffAngle = document.getElementById( "cutOffAngle" ).value;
// setup view projection and model
vp_size = [canvas.width, canvas.height];
var prjMat = camera.Perspective();
var viewMat = camera.LookAt();
var modelMat = IdentM44();
modelMat = RotateAxis( modelMat, CalcAng( deltaMS, 13.0 ), 0 );
modelMat = RotateAxis( modelMat, CalcAng( deltaMS, 17.0 ), 1 );
var lightPos = [0.95, 0.95, -1.0];
var lightDir = [-1.0, -1.0, -3.0];
var lightCutOffAngleRad = cutOffAngle * Math.PI / 180.0;
var lightAtt = [0.7, 0.1, 0.5];
drawFB.Bind( true );
gl.enable( gl.DEPTH_TEST );
gl.clearColor( 0.0, 0.0, 0.0, 1.0 );
gl.clear( gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT );
ShProg.Use( progDraw );
ShProg.SetM44( progDraw, "u_projectionMat44", prjMat );
ShProg.SetM44( progDraw, "u_viewMat44", viewMat );
ShProg.SetF3( progDraw, "u_light.position", lightPos );
ShProg.SetF3( progDraw, "u_light.direction", lightDir );
ShProg.SetF1( progDraw, "u_light.ambient", ambient );
ShProg.SetF1( progDraw, "u_light.diffuse", diffuse );
ShProg.SetF1( progDraw, "u_light.specular", specular );
ShProg.SetF1( progDraw, "u_light.shininess", shininess );
ShProg.SetF3( progDraw, "u_light.attenuation", lightAtt );
ShProg.SetF1( progDraw, "u_light.cutOffAngle", lightCutOffAngleRad );
ShProg.SetM44( progDraw, "u_modelMat44", modelMat );
bufObj = bufTorus;
gl.enableVertexAttribArray( progDraw.inPos );
gl.enableVertexAttribArray( progDraw.inNV );
gl.enableVertexAttribArray( progDraw.inCol );
gl.bindBuffer( gl.ARRAY_BUFFER, bufObj.pos );
gl.vertexAttribPointer( progDraw.inPos, 3, gl.FLOAT, false, 0, 0 );
gl.bindBuffer( gl.ARRAY_BUFFER, bufObj.nv );
gl.vertexAttribPointer( progDraw.inNV, 3, gl.FLOAT, false, 0, 0 );
gl.bindBuffer( gl.ARRAY_BUFFER, bufObj.col );
gl.vertexAttribPointer( progDraw.inCol, 3, gl.FLOAT, false, 0, 0 );
gl.bindBuffer( gl.ELEMENT_ARRAY_BUFFER, bufObj.inx );
gl.drawElements( gl.TRIANGLES, bufObj.inxLen, gl.UNSIGNED_SHORT, 0 );
gl.disableVertexAttribArray( progDraw.pos );
gl.disableVertexAttribArray( progDraw.nv );
gl.disableVertexAttribArray( progDraw.col );
drawFB.Release( true );
gl.viewport( 0, 0, canvas.width, canvas.height );
var texUnitDraw = 2;
drawFB.BindTexture( texUnitDraw );
ShProg.Use( progLightCone );
ShProg.SetI1( progLightCone, "u_colorAttachment0", texUnitDraw );
ShProg.SetF2( progLightCone, "u_depthRange", [ camera.near, camera.far ] );
ShProg.SetF2( progLightCone, "u_vp", camera.vp );
ShProg.SetF1( progLightCone, "u_fov", camera.fov_y * Math.PI / 180.0 );
ShProg.SetF3( progLightCone, "u_light.position", lightPos );
ShProg.SetF3( progLightCone, "u_light.direction", lightDir );
ShProg.SetF3( progLightCone, "u_light.attenuation", lightAtt );
ShProg.SetF1( progLightCone, "u_light.cutOffAngle", lightCutOffAngleRad );
gl.enableVertexAttribArray( progLightCone.inPos );
gl.bindBuffer( gl.ARRAY_BUFFER, bufQuad.pos );
gl.vertexAttribPointer( progLightCone.inPos, 2, gl.FLOAT, false, 0, 0 );
gl.bindBuffer( gl.ELEMENT_ARRAY_BUFFER, bufQuad.inx );
gl.drawElements( gl.TRIANGLES, bufQuad.inxLen, gl.UNSIGNED_SHORT, 0 );
gl.disableVertexAttribArray( progLightCone.inPos );
requestAnimationFrame(render);
}
function initScene() {
canvas = document.getElementById( "glow-canvas");
vp_size = [canvas.width, canvas.height];
gl = canvas.getContext( "experimental-webgl" );
if ( !gl )
return;
document.getElementById( "ambient" ).value = 0.25 * sliderScale;
document.getElementById( "diffuse" ).value = 1.0 * sliderScale;
document.getElementById( "specular" ).value = 1.0 * sliderScale;
document.getElementById( "shininess" ).value = 10.0;
document.getElementById( "cutOffAngle" ).value = 30.0;
progDraw = ShProg.Create(
[ { source : "draw-shader-vs", stage : gl.VERTEX_SHADER },
{ source : "draw-shader-fs", stage : gl.FRAGMENT_SHADER }
] );
progDraw.inPos = ShProg.AttrI( progDraw, "inPos" );
progDraw.inNV = ShProg.AttrI( progDraw, "inNV" );
progDraw.inCol = ShProg.AttrI( progDraw, "inCol" );
if ( progDraw == 0 )
return;
progLightCone = ShProg.Create(
[ { source : "light-cone-shader-vs", stage : gl.VERTEX_SHADER },
{ source : "light-cone-shader-fs", stage : gl.FRAGMENT_SHADER }
] );
progLightCone.inPos = ShProg.AttrI( progDraw, "inPos" );
if ( progDraw == 0 )
return;
var circum_size = 32, tube_size = 32;
var rad_circum = 1.5;
var rad_tube = 0.8;
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.pos = gl.createBuffer();
gl.bindBuffer( gl.ARRAY_BUFFER, bufTorus.pos );
gl.bufferData( gl.ARRAY_BUFFER, new Float32Array( torus_pts ), gl.STATIC_DRAW );
bufTorus.nv = gl.createBuffer();
gl.bindBuffer( gl.ARRAY_BUFFER, bufTorus.nv );
gl.bufferData( gl.ARRAY_BUFFER, new Float32Array( torus_nv ), gl.STATIC_DRAW );
bufTorus.col = gl.createBuffer();
gl.bindBuffer( gl.ARRAY_BUFFER, bufTorus.col );
gl.bufferData( gl.ARRAY_BUFFER, new Float32Array( torus_col ), gl.STATIC_DRAW );
bufTorus.inx = gl.createBuffer();
gl.bindBuffer( gl.ELEMENT_ARRAY_BUFFER, bufTorus.inx );
gl.bufferData( gl.ELEMENT_ARRAY_BUFFER, new Uint16Array( torus_inx ), gl.STATIC_DRAW );
bufTorus.inxLen = torus_inx.length;
bufQuad.pos = gl.createBuffer();
gl.bindBuffer( gl.ARRAY_BUFFER, bufQuad.pos );
gl.bufferData( gl.ARRAY_BUFFER, new Float32Array( [ -1.0, -1.0, 1.0, -1.0, 1.0, 1.0, -1.0, 1.0 ] ), gl.STATIC_DRAW );
bufQuad.inx = gl.createBuffer();
gl.bindBuffer( gl.ELEMENT_ARRAY_BUFFER, bufQuad.inx );
gl.bufferData( gl.ELEMENT_ARRAY_BUFFER, new Uint16Array( [ 0, 1, 2, 0, 2, 3 ] ), gl.STATIC_DRAW );
bufQuad.inxLen = 6;
camera = new Camera( [0, 4, 0.0], [0, 0, 0], [0, 0, 1], 90, vp_size, 0.5, 100 );
window.onresize = resize;
resize();
requestAnimationFrame(render);
}
function resize() {
//vp_size = [gl.drawingBufferWidth, gl.drawingBufferHeight];
vp_size = [window.innerWidth, window.innerHeight]
//vp_size = [256, 256]
canvas.width = vp_size[0];
canvas.height = vp_size[1];
var fbsize = Math.max(vp_size[0], vp_size[1]);
fbsize = 1 << 31 - Math.clz32(fbsize); // nearest power of 2
var fb_rect = [fbsize, fbsize];
drawFB = FrameBuffer.Create( fb_rect );
}
function Fract( val ) {
return val - Math.trunc( val );
}
function CalcAng( deltaMS, intervall ) {
return Fract( deltaMS / (1000*intervall) ) * 2.0 * Math.PI;
}
function CalcMove( deltaMS, intervall, range ) {
var pos = self.Fract( deltaMS / (1000*intervall) ) * 2.0
var pos = pos < 1.0 ? pos : (2.0-pos)
return range[0] + (range[1] - range[0]) * pos;
}
function IdentM44() { 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 = matA.slice(0);
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 ];
}
Camera = function( pos, target, up, fov_y, vp, near, far ) {
this.Time = function() { return Date.now(); }
this.pos = pos;
this.target = target;
this.up = up;
this.fov_y = fov_y;
this.vp = vp;
this.near = near;
this.far = far;
this.orbit_mat = this.current_orbit_mat = this.model_mat = this.current_model_mat = IdentM44();
this.mouse_drag = this.auto_spin = false;
this.auto_rotate = true;
this.mouse_start = [0, 0];
this.mouse_drag_axis = [0, 0, 0];
this.mouse_drag_angle = 0;
this.mouse_drag_time = 0;
this.drag_start_T = this.rotate_start_T = this.Time();
this.Ortho = function() {
var fn = this.far + this.near;
var f_n = this.far - this.near;
var w = this.vp[0];
var h = this.vp[1];
return [
2/w, 0, 0, 0,
0, 2/h, 0, 0,
0, 0, -2/f_n, 0,
0, 0, -fn/f_n, 1 ];
};
this.Perspective = function() {
var n = this.near;
var f = this.far;
var fn = f + n;
var f_n = f - n;
var r = this.vp[0] / this.vp[1];
var t = 1 / Math.tan( Math.PI * this.fov_y / 360 );
return [
t/r, 0, 0, 0,
0, t, 0, 0,
0, 0, -fn/f_n, -1,
0, 0, -2*f*n/f_n, 0 ];
};
this.LookAt = function() {
var mz = Normalize( [ this.pos[0]-this.target[0], this.pos[1]-this.target[1], this.pos[2]-this.target[2] ] );
var mx = Normalize( Cross( this.up, mz ) );
var my = Normalize( Cross( mz, mx ) );
var tx = Dot( mx, this.pos );
var ty = Dot( my, this.pos );
var tz = Dot( [-mz[0], -mz[1], -mz[2]], this.pos );
return [mx[0], my[0], mz[0], 0, mx[1], my[1], mz[1], 0, mx[2], my[2], mz[2], 0, tx, ty, tz, 1];
};
}
var FrameBuffer = {};
FrameBuffer.Create = function( vp, texturePlan ) {
var texPlan = texturePlan ? new Uint8Array( texturePlan ) : null;
var fb = gl.createFramebuffer();
fb.width = vp[0];
fb.height = vp[1];
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 );
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.viewport( 0, 0, this.width, this.height );
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;
}
var ShProg = {};
ShProg.Create = function( shaderList ) {
var shaderObjs = [];
for ( var i_sh = 0; i_sh < shaderList.length; ++ i_sh ) {
var shderObj = this.Compile( shaderList[i_sh].source, shaderList[i_sh].stage );
if ( shderObj == 0 )
return 0;
shaderObjs.push( shderObj );
}
var progObj = this.Link( shaderObjs )
if ( progObj != 0 ) {
progObj.attrInx = {};
var noOfAttributes = gl.getProgramParameter( progObj, gl.ACTIVE_ATTRIBUTES );
for ( var i_n = 0; i_n < noOfAttributes; ++ i_n ) {
var name = gl.getActiveAttrib( progObj, i_n ).name;
progObj.attrInx[name] = gl.getAttribLocation( progObj, name );
}
progObj.uniLoc = {};
var noOfUniforms = gl.getProgramParameter( progObj, gl.ACTIVE_UNIFORMS );
for ( var i_n = 0; i_n < noOfUniforms; ++ i_n ) {
var name = gl.getActiveUniform( progObj, i_n ).name;
progObj.uniLoc[name] = gl.getUniformLocation( progObj, name );
}
}
return progObj;
}
ShProg.AttrI = function( progObj, name ) { return progObj.attrInx[name]; }
ShProg.UniformL = function( progObj, name ) { return progObj.uniLoc[name]; }
ShProg.Use = function( progObj ) { gl.useProgram( progObj ); }
ShProg.SetI1 = function( progObj, name, val ) { if(progObj.uniLoc[name]) gl.uniform1i( progObj.uniLoc[name], val ); }
ShProg.SetF1 = function( progObj, name, val ) { if(progObj.uniLoc[name]) gl.uniform1f( progObj.uniLoc[name], val ); }
ShProg.SetF2 = function( progObj, name, arr ) { if(progObj.uniLoc[name]) gl.uniform2fv( progObj.uniLoc[name], arr ); }
ShProg.SetF3 = function( progObj, name, arr ) { if(progObj.uniLoc[name]) gl.uniform3fv( progObj.uniLoc[name], arr ); }
ShProg.SetF4 = function( progObj, name, arr ) { if(progObj.uniLoc[name]) gl.uniform4fv( progObj.uniLoc[name], arr ); }
ShProg.SetM44 = function( progObj, name, mat ) { if(progObj.uniLoc[name]) gl.uniformMatrix4fv( progObj.uniLoc[name], false, mat ); }
ShProg.Compile = function( source, shaderStage ) {
var shaderScript = document.getElementById(source);
if (shaderScript) {
source = "";
var node = shaderScript.firstChild;
while (node) {
if (node.nodeType == 3) source += node.textContent;
node = node.nextSibling;
}
}
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 : 0;
}
ShProg.Link = 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 : 0;
}
initScene();
})();
html,body { margin: 0; overflow: hidden; }
#gui { position : absolute; top : 0; left : 0; }
<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 clip_space_pos;
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;
gl_Position = u_projectionMat44 * viewPos;
}
</script>
<script id="draw-shader-fs" type="x-shader/x-fragment">
precision mediump float;
varying vec3 vertPos;
varying vec3 vertNV;
varying vec3 vertCol;
struct Light {
vec3 position;
vec3 direction;
float ambient;
float diffuse;
float specular;
float shininess;
vec3 attenuation;
float cutOffAngle;
};
uniform Light u_light;
void main()
{
vec3 color = vertCol;
vec3 lightCol = u_light.ambient * color;
vec3 normalV = normalize( vertNV );
vec3 lightV = normalize( u_light.position - vertPos );
float lightD = length( u_light.position - vertPos );
float cosL = dot( normalize( u_light.direction ), -lightV );
float inCone = step( cos( u_light.cutOffAngle * 0.5 ), cosL );
float att = 1.0 / dot( vec3( 1.0, lightD, lightD*lightD ), u_light.attenuation );
float NdotL = max( 0.0, dot( normalV, lightV ) );
lightCol += NdotL * u_light.diffuse * color * inCone * att;
vec3 eyeV = normalize( -vertPos );
vec3 halfV = normalize( eyeV + lightV );
float NdotH = max( 0.0, dot( normalV, halfV ) );
float kSpecular = ( u_light.shininess + 2.0 ) * pow( NdotH, u_light.shininess ) / ( 2.0 * 3.14159265 );
lightCol += kSpecular * u_light.specular * color * inCone * att;
gl_FragColor = vec4( lightCol.rgb, 1.0 );
}
</script>
<script id="light-cone-shader-vs" type="x-shader/x-vertex">
precision mediump float;
attribute vec2 inPos;
varying vec2 vertPos;
void main()
{
vertPos.xy = inPos.xy;
gl_Position = vec4( inPos, 0.0, 1.0 );
}
</script>
<script id="light-cone-shader-fs" type="x-shader/x-fragment">
precision mediump float;
varying vec2 vertPos;
uniform sampler2D u_colorAttachment0;
uniform vec2 u_depthRange;
uniform vec2 u_vp;
uniform float u_fov;
struct Light {
vec3 position;
vec3 direction;
float ambient;
float diffuse;
float specular;
float shininess;
vec3 attenuation;
float cutOffAngle;
};
uniform Light u_light;
void main()
{
vec4 texCol = texture2D( u_colorAttachment0, vertPos.st * 0.5 + 0.5 );
vec3 vLightPos = u_light.position;
vec3 vLightDir = normalize( u_light.direction );
float tanFOV = tan(u_fov*0.5);
vec3 nearPos = vec3( vertPos.x * u_vp.x/u_vp.y * tanFOV, vertPos.y * tanFOV, -1.0 );
//vec2 texCoord = gl_FragCoord.xy / u_vp;
//vec3 nearPos = vec3( (texCoord.x-0.5) * u_vp.x/u_vp.y, texCoord.y-0.5, -u_depthRange.x );
vec3 los = normalize( nearPos );
// ray definition
vec3 O = vec3(0.0);
vec3 D = los;
// cone definition
vec3 C = vLightPos;
vec3 V = vLightDir;
float cosTh = cos( u_light.cutOffAngle * 0.5 );
// ray - cone intersection
vec3 CO = O - C;
float DdotV = dot( D, V );
float COdotV = dot( CO, V );
float a = DdotV*DdotV - cosTh*cosTh;
float b = 2.0 * (DdotV*COdotV - dot( D, CO )*cosTh*cosTh);
float c = COdotV*COdotV - dot( CO, CO )*cosTh*cosTh;
float det = b*b - 4.0*a*c;
// find intersection
float isIsect = 0.0;
vec3 isectP = vec3(0.0);
if ( det >= 0.0 )
{
vec3 P1 = O + (-b-sqrt(det))/(2.0*a) * D;
vec3 P2 = O + (-b+sqrt(det))/(2.0*a) * D;
float isect1 = step( 0.0, dot(normalize(P1-C), V) );
float isect2 = step( 0.0, dot(normalize(P2-C), V) );
if ( isect1 < 0.5 )
{
P1 = P2;
isect1 = isect2;
}
if ( isect2 < 0.5 )
{
P2 = P1;
isect2 = isect1;
}
isectP = ( P1.z > -u_depthRange.x || (P2.z < -u_depthRange.x && P1.z < P2.z ) ) ? P2 : P1;
isIsect = mix( isect2, 1.0, isect1 ) * step( isectP.z, -u_depthRange.x );
}
float dist = length( isectP - vLightPos.xyz );
float att = 1.0 / dot( vec3( 1.0, dist, dist*dist ), u_light.attenuation );
gl_FragColor = vec4( mix( texCol.rgb, vec3(1.0, 1.0, 1.0), isIsect * att * 0.5 ), 1.0 );
}
</script>
<div><form id="gui" name="inputs">
<table>
<tr> <td> <font color=#40f040>ambient</font> </td>
<td> <input type="range" id="ambient" min="0" max="100" value="0"/></td> </tr>
<tr> <td> <font color=#40f040>diffuse</font> </td>
<td> <input type="range" id="diffuse" min="0" max="100" value="0"/></td> </tr>
<tr> <td> <font color=#40f040>specular</font> </td>
<td> <input type="range" id="specular" min="0" max="100" value="0"/></td> </tr>
<tr> <td> <font color=#40f040>shininess</font> </td>
<td> <input type="range" id="shininess" min="1" max="100" value="0"/></td> </tr>
<tr> <td> <font color=#40f040>cut off angle</font> </td>
<td> <input type="range" id="cutOffAngle" min="1" max="180" value="0"/></td> </tr>
</table>
</form>
</div>
<canvas id="glow-canvas" style="border: none;"></canvas>
在我的开源项目中，我使用 Qt3D 设置了一个延迟渲染管道。到目前为止一切顺利，但现在我想通过添加聚光灯投影体积来向前推进。 （例如现场好像有烟） 像这样：
我正在使用的片段着色器在问题的最后。 我已经读到对于每个片段我应该从光线位置进行光线行进并找到与圆锥体的交叉点，但我不知道如何将其转化为 GLSL。 我可以使用来自 GBuffer 的深度图（从相机的角度）轻松添加制服，但我不知道这是否有帮助。
由于我的 GLSL 知识非常有限，请用实际代码回复，不要冗长的数学解释，我无法 understand/translate 成代码。请耐心等待我。
uniform sampler2D color;
uniform sampler2D position;
uniform sampler2D normal;
uniform vec2 winSize;
out vec4 fragColor;
const int MAX_LIGHTS = 102;
const int TYPE_POINT = 0;
const int TYPE_DIRECTIONAL = 1;
const int TYPE_SPOT = 2;
struct Light {
int type;
vec3 position;
vec3 color;
float intensity;
vec3 direction;
float constantAttenuation;
float linearAttenuation;
float quadraticAttenuation;
float cutOffAngle;
};
uniform Light lightsArray[MAX_LIGHTS];
uniform int lightsNumber;
void main()
{
vec2 texCoord = gl_FragCoord.xy / winSize;
vec4 col = texture(color, texCoord);
vec3 pos = texture(position, texCoord).xyz;
vec3 norm = texture(normal, texCoord).xyz;
vec3 lightColor = vec3(0.0);
vec3 s;
float att;
for (int i = 0; i < lightsNumber; ++i) {
att = 1.0;
if ( lightsArray[i].type != TYPE_DIRECTIONAL ) {
s = lightsArray[i].position - pos;
if (lightsArray[i].constantAttenuation != 0.0
|| lightsArray[i].linearAttenuation != 0.0
|| lightsArray[i].quadraticAttenuation != 0.0) {
float dist = length(s);
att = 1.0 / (lightsArray[i].constantAttenuation + lightsArray[i].linearAttenuation * dist + lightsArray[i].quadraticAttenuation * dist * dist);
}
s = normalize( s );
if ( lightsArray[i].type == TYPE_SPOT ) {
if ( degrees(acos(dot(-s, normalize(lightsArray[i].direction))) ) > lightsArray[i].cutOffAngle)
att = 0.0;
}
} else {
s = normalize(-lightsArray[i].direction);
}
float diffuse = max( dot( s, norm ), 0.0 );
lightColor += att * lightsArray[i].intensity * diffuse * lightsArray[i].color;
}
fragColor = vec4(col.rgb * lightColor, col.a);
}
这是聚光灯在上面的原始着色器中的样子：
[编辑 - 已解决]感谢 Rabbid76 出色的回答和宝贵的支持
这是查看圆锥投影的修改代码：
#version 140
uniform sampler2D color;
uniform sampler2D position;
uniform sampler2D normal;
uniform vec2 winSize;
out vec4 fragColor;
const int MAX_LIGHTS = 102;
const int TYPE_POINT = 0;
const int TYPE_DIRECTIONAL = 1;
const int TYPE_SPOT = 2;
struct Light {
int type;
vec3 position;
vec3 color;
float intensity;
vec3 direction;
float constantAttenuation;
float linearAttenuation;
float quadraticAttenuation;
float cutOffAngle;
};
uniform Light lightsArray[MAX_LIGHTS];
uniform int lightsNumber;
uniform mat4 inverseViewMatrix; // defined by camera position, camera target and up vector
void main()
{
vec2 texCoord = gl_FragCoord.xy / winSize;
vec4 col = texture(color, texCoord);
vec3 pos = texture(position, texCoord).xyz;
vec3 norm = texture(normal, texCoord).xyz;
vec3 lightColor = vec3(0.0);
vec3 s;
// calculate unprojected fragment position on near plane and line of sight relative to view
float nearZ = -1.0;
vec3 nearPos = vec3( (texCoord.x - 0.5) * winSize.x / winSize.y, texCoord.y - 0.5, nearZ ); // 1.0 is camera near
vec3 los = normalize( nearPos );
// ray definition
vec3 O = vec3( inverseViewMatrix * vec4( 0.0, 0.0, 0.0, 1.0 ) ); // translation part of the camera matrix, which is equal to the camera position
vec3 D = (length(pos) > 0.0) ? normalize(pos - O) : (mat3(inverseViewMatrix) * los);
for (int i = 0; i < lightsNumber; ++i)
{
float att = 1.0;
if ( lightsArray[i].type == TYPE_DIRECTIONAL )
{
s = normalize( -lightsArray[i].direction );
}
else
{
s = lightsArray[i].position - pos;
if (lightsArray[i].type != TYPE_SPOT
&& (lightsArray[i].constantAttenuation != 0.0
|| lightsArray[i].linearAttenuation != 0.0
|| lightsArray[i].quadraticAttenuation != 0.0))
{
float dist = length(s);
att = 1.0 / (lightsArray[i].constantAttenuation + lightsArray[i].linearAttenuation * dist + lightsArray[i].quadraticAttenuation * dist * dist);
}
s = normalize( s );
if ( lightsArray[i].type == TYPE_SPOT )
{
// cone definition
vec3 C = lightsArray[i].position;
vec3 V = normalize(lightsArray[i].direction);
float cosTh = cos( radians(lightsArray[i].cutOffAngle) );
// ray - cone intersection
vec3 CO = O - C;
float DdotV = dot( D, V );
float COdotV = dot( CO, V );
float a = DdotV * DdotV - cosTh * cosTh;
float b = 2.0 * (DdotV * COdotV - dot( D, CO ) * cosTh * cosTh);
float c = COdotV * COdotV - dot( CO, CO ) * cosTh * cosTh;
float det = b * b - 4.0 * a * c;
// find intersection
float isIsect = 0.0;
vec3 isectP = vec3(0.0);
if ( det >= 0.0 )
{
vec3 P1 = O + (-b - sqrt(det)) / (2.0 * a) * D;
vec3 P2 = O + (-b + sqrt(det)) / (2.0 * a) * D;
float isect1 = step( 0.0, dot(normalize(P1 - C), V) );
float isect2 = step( 0.0, dot(normalize(P2 - C), V) );
if ( isect1 < 0.5 )
{
P1 = P2;
isect1 = isect2;
}
if ( isect2 < 0.5 )
{
P2 = P1;
isect2 = isect1;
}
isectP = (length(P1 - O) < length(P2 - O)) ? P1 : P2;
isIsect = mix( isect2, 1.0, isect1 );
if ( length(pos) != 0.0 && length(isectP - O) > length(pos - O))
isIsect = 0.0;
}
float dist = length( isectP - C.xyz );
float limit = degrees(acos(dot(-s, normalize(lightsArray[i].direction))) );
if (isIsect > 0 || limit <= lightsArray[i].cutOffAngle)
{
att = 1.0 / dot( vec3( 1.0, dist, dist * dist ),
vec3(lightsArray[i].constantAttenuation,
lightsArray[i].linearAttenuation,
lightsArray[i].quadraticAttenuation) );
}
else
att = 0.0;
}
}
float diffuse = max( dot( s, norm ), 0.0 );
lightColor += att * lightsArray[i].intensity * diffuse * lightsArray[i].color;
}
fragColor = vec4(col.rgb * lightColor, col.a);
}
传递给着色器的制服是：
qml: lightsArray[0].type = 0
qml: lightsArray[0].position = QVector3D(0, 10, 0)
qml: lightsArray[0].color = #ffffff
qml: lightsArray[0].intensity = 0.8
qml: lightsArray[0].constantAttenuation = 1
qml: lightsArray[0].linearAttenuation = 0
qml: lightsArray[0].quadraticAttenuation = 0
qml: lightsArray[1].type = 2
qml: lightsArray[1].position = QVector3D(0, 3, 0)
qml: lightsArray[1].color = #008000
qml: lightsArray[1].intensity = 0.5
qml: lightsArray[1].constantAttenuation = 2
qml: lightsArray[1].linearAttenuation = 0
qml: lightsArray[1].quadraticAttenuation = 0
qml: lightsArray[1].direction = QVector3D(-0.573576, -0.819152, 0)
qml: lightsArray[1].cutOffAngle = 15
qml: lightsNumber = 2
截图：
对于聚光灯的光锥的原始可视化，您必须做视线与光锥的交点。
以下算法在透视视图中工作，并且计算是在视图（眼睛）空间中完成的。该算法不关心场景的几何形状，不做任何深度测试或阴影测试，它只是光锥的叠加可视化。
透视图中的视线可以用一个点和一个方向来定义。由于计算是在view(eye)space中进行的，所以点就是view(视锥体的原点)也就是vec3(0.0).
方向就很容易确定了, 通过视线与相机平截头体的近平面的交点。如果片段的投影 XY 坐标在归一化设备坐标中已知（左下角点为 (-1,-1) 右上角点为 (1,1)，则可以轻松计算出这一点，请参阅 [= 的答案20=]问题）。
float aspect = .....; // ratio of the view port (widht/length)
float fov = .....; // filed of view angle in radians (angle of the camera frustum on the Y-axis)
vec2 ndcPos = .....; // fragment position in NDC space from (-1,-1) to (1,1)
vec3 tanFov = tan( fov * 0.5 );
vec3 los = normalize( vec3( ndcPos.x * aspect * tanFov, ndcPos.y * tanFov, -1.0 ) );
光锥是由光源的原点、光源指向的方向、光锥的全角来定义的。位置和方向必须在视图 space 上。角度必须以弧度为单位设置。
vec3 vLightPos = .....; // position of the light source in view space
vec3 vLightDir = .....; // direction of the light in view space
float coneAngle = .....; // full angle of the light cone in radians
如何计算射线和圆锥的交点可以在 Whosebug 问题
下面的代码计算了上面定义的射线和圆锥体的交点。结果点存储在isectP中。类型float的变量isIsect如果有交集则设置为1.0，否则设置为0.0.
// ray definition
vec3 O = vec3(0.0);
vec3 D = los;
// cone definition
vec3 C = vLightPos;
vec3 V = vLightDir;
float cosTh = cos( coneAngle * 0.5 );
// ray - cone intersection
vec3 CO = O - C;
float DdotV = dot( D, V );
float COdotV = dot( CO, V );
float a = DdotV*DdotV - cosTh*cosTh;
float b = 2.0 * (DdotV*COdotV - dot( D, CO )*cosTh*cosTh);
float c = COdotV*COdotV - dot( CO, CO )*cosTh*cosTh;
float det = b*b - 4.0*a*c;
// find intersection
float isIsect = 0.0;
vec3 isectP = vec3(0.0);
if ( det >= 0.0 )
{
vec3 P1 = O + (-b-sqrt(det))/(2.0*a) * D;
vec3 P2 = O + (-b+sqrt(det))/(2.0*a) * D;
float isect1 = step( 0.0, dot(normalize(P1-C), V) );
float isect2 = step( 0.0, dot(normalize(P2-C), V) );
P1 = mix( P2, P1, isect1 );
isectP = P2.z < 0.0 && P2.z > P1.z ? P2 : P1;
isIsect = mix( isect2, 1.0, isect1 ) * step( isectP.z, 0.0 );
}
有关完整的 GLSL 代码，请参阅以下 WebGL 示例：
(function loadscene() {
var sliderScale = 100.0
var gl, canvas, vp_size, camera, progDraw, progLightCone, bufTorus = {}, bufQuad = {}, drawFB;
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;
var cutOffAngle = document.getElementById( "cutOffAngle" ).value;
// setup view projection and model
vp_size = [canvas.width, canvas.height];
var prjMat = camera.Perspective();
var viewMat = camera.LookAt();
var modelMat = IdentM44();
modelMat = RotateAxis( modelMat, CalcAng( deltaMS, 13.0 ), 0 );
modelMat = RotateAxis( modelMat, CalcAng( deltaMS, 17.0 ), 1 );
var lightPos = [0.95, 0.95, -1.0];
var lightDir = [-1.0, -1.0, -3.0];
var lightCutOffAngleRad = cutOffAngle * Math.PI / 180.0;
var lightAtt = [0.7, 0.1, 0.5];
drawFB.Bind( true );
gl.enable( gl.DEPTH_TEST );
gl.clearColor( 0.0, 0.0, 0.0, 1.0 );
gl.clear( gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT );
ShProg.Use( progDraw );
ShProg.SetM44( progDraw, "u_projectionMat44", prjMat );
ShProg.SetM44( progDraw, "u_viewMat44", viewMat );
ShProg.SetF3( progDraw, "u_light.position", lightPos );
ShProg.SetF3( progDraw, "u_light.direction", lightDir );
ShProg.SetF1( progDraw, "u_light.ambient", ambient );
ShProg.SetF1( progDraw, "u_light.diffuse", diffuse );
ShProg.SetF1( progDraw, "u_light.specular", specular );
ShProg.SetF1( progDraw, "u_light.shininess", shininess );
ShProg.SetF3( progDraw, "u_light.attenuation", lightAtt );
ShProg.SetF1( progDraw, "u_light.cutOffAngle", lightCutOffAngleRad );
ShProg.SetM44( progDraw, "u_modelMat44", modelMat );
bufObj = bufTorus;
gl.enableVertexAttribArray( progDraw.inPos );
gl.enableVertexAttribArray( progDraw.inNV );
gl.enableVertexAttribArray( progDraw.inCol );
gl.bindBuffer( gl.ARRAY_BUFFER, bufObj.pos );
gl.vertexAttribPointer( progDraw.inPos, 3, gl.FLOAT, false, 0, 0 );
gl.bindBuffer( gl.ARRAY_BUFFER, bufObj.nv );
gl.vertexAttribPointer( progDraw.inNV, 3, gl.FLOAT, false, 0, 0 );
gl.bindBuffer( gl.ARRAY_BUFFER, bufObj.col );
gl.vertexAttribPointer( progDraw.inCol, 3, gl.FLOAT, false, 0, 0 );
gl.bindBuffer( gl.ELEMENT_ARRAY_BUFFER, bufObj.inx );
gl.drawElements( gl.TRIANGLES, bufObj.inxLen, gl.UNSIGNED_SHORT, 0 );
gl.disableVertexAttribArray( progDraw.pos );
gl.disableVertexAttribArray( progDraw.nv );
gl.disableVertexAttribArray( progDraw.col );
drawFB.Release( true );
gl.viewport( 0, 0, canvas.width, canvas.height );
var texUnitDraw = 2;
drawFB.BindTexture( texUnitDraw );
ShProg.Use( progLightCone );
ShProg.SetI1( progLightCone, "u_colorAttachment0", texUnitDraw );
ShProg.SetF2( progLightCone, "u_depthRange", [ camera.near, camera.far ] );
ShProg.SetF2( progLightCone, "u_vp", camera.vp );
ShProg.SetF1( progLightCone, "u_fov", camera.fov_y * Math.PI / 180.0 );
ShProg.SetF3( progLightCone, "u_light.position", lightPos );
ShProg.SetF3( progLightCone, "u_light.direction", lightDir );
ShProg.SetF3( progLightCone, "u_light.attenuation", lightAtt );
ShProg.SetF1( progLightCone, "u_light.cutOffAngle", lightCutOffAngleRad );
gl.enableVertexAttribArray( progLightCone.inPos );
gl.bindBuffer( gl.ARRAY_BUFFER, bufQuad.pos );
gl.vertexAttribPointer( progLightCone.inPos, 2, gl.FLOAT, false, 0, 0 );
gl.bindBuffer( gl.ELEMENT_ARRAY_BUFFER, bufQuad.inx );
gl.drawElements( gl.TRIANGLES, bufQuad.inxLen, gl.UNSIGNED_SHORT, 0 );
gl.disableVertexAttribArray( progLightCone.inPos );
requestAnimationFrame(render);
}
function initScene() {
canvas = document.getElementById( "glow-canvas");
vp_size = [canvas.width, canvas.height];
gl = canvas.getContext( "experimental-webgl" );
if ( !gl )
return;
document.getElementById( "ambient" ).value = 0.25 * sliderScale;
document.getElementById( "diffuse" ).value = 1.0 * sliderScale;
document.getElementById( "specular" ).value = 1.0 * sliderScale;
document.getElementById( "shininess" ).value = 10.0;
document.getElementById( "cutOffAngle" ).value = 30.0;
progDraw = ShProg.Create(
[ { source : "draw-shader-vs", stage : gl.VERTEX_SHADER },
{ source : "draw-shader-fs", stage : gl.FRAGMENT_SHADER }
] );
progDraw.inPos = ShProg.AttrI( progDraw, "inPos" );
progDraw.inNV = ShProg.AttrI( progDraw, "inNV" );
progDraw.inCol = ShProg.AttrI( progDraw, "inCol" );
if ( progDraw == 0 )
return;
progLightCone = ShProg.Create(
[ { source : "light-cone-shader-vs", stage : gl.VERTEX_SHADER },
{ source : "light-cone-shader-fs", stage : gl.FRAGMENT_SHADER }
] );
progLightCone.inPos = ShProg.AttrI( progDraw, "inPos" );
if ( progDraw == 0 )
return;
var circum_size = 32, tube_size = 32;
var rad_circum = 1.5;
var rad_tube = 0.8;
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.pos = gl.createBuffer();
gl.bindBuffer( gl.ARRAY_BUFFER, bufTorus.pos );
gl.bufferData( gl.ARRAY_BUFFER, new Float32Array( torus_pts ), gl.STATIC_DRAW );
bufTorus.nv = gl.createBuffer();
gl.bindBuffer( gl.ARRAY_BUFFER, bufTorus.nv );
gl.bufferData( gl.ARRAY_BUFFER, new Float32Array( torus_nv ), gl.STATIC_DRAW );
bufTorus.col = gl.createBuffer();
gl.bindBuffer( gl.ARRAY_BUFFER, bufTorus.col );
gl.bufferData( gl.ARRAY_BUFFER, new Float32Array( torus_col ), gl.STATIC_DRAW );
bufTorus.inx = gl.createBuffer();
gl.bindBuffer( gl.ELEMENT_ARRAY_BUFFER, bufTorus.inx );
gl.bufferData( gl.ELEMENT_ARRAY_BUFFER, new Uint16Array( torus_inx ), gl.STATIC_DRAW );
bufTorus.inxLen = torus_inx.length;
bufQuad.pos = gl.createBuffer();
gl.bindBuffer( gl.ARRAY_BUFFER, bufQuad.pos );
gl.bufferData( gl.ARRAY_BUFFER, new Float32Array( [ -1.0, -1.0, 1.0, -1.0, 1.0, 1.0, -1.0, 1.0 ] ), gl.STATIC_DRAW );
bufQuad.inx = gl.createBuffer();
gl.bindBuffer( gl.ELEMENT_ARRAY_BUFFER, bufQuad.inx );
gl.bufferData( gl.ELEMENT_ARRAY_BUFFER, new Uint16Array( [ 0, 1, 2, 0, 2, 3 ] ), gl.STATIC_DRAW );
bufQuad.inxLen = 6;
camera = new Camera( [0, 4, 0.0], [0, 0, 0], [0, 0, 1], 90, vp_size, 0.5, 100 );
window.onresize = resize;
resize();
requestAnimationFrame(render);
}
function resize() {
//vp_size = [gl.drawingBufferWidth, gl.drawingBufferHeight];
vp_size = [window.innerWidth, window.innerHeight]
//vp_size = [256, 256]
canvas.width = vp_size[0];
canvas.height = vp_size[1];
var fbsize = Math.max(vp_size[0], vp_size[1]);
fbsize = 1 << 31 - Math.clz32(fbsize); // nearest power of 2
var fb_rect = [fbsize, fbsize];
drawFB = FrameBuffer.Create( fb_rect );
}
function Fract( val ) {
return val - Math.trunc( val );
}
function CalcAng( deltaMS, intervall ) {
return Fract( deltaMS / (1000*intervall) ) * 2.0 * Math.PI;
}
function CalcMove( deltaMS, intervall, range ) {
var pos = self.Fract( deltaMS / (1000*intervall) ) * 2.0
var pos = pos < 1.0 ? pos : (2.0-pos)
return range[0] + (range[1] - range[0]) * pos;
}
function IdentM44() { 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 = matA.slice(0);
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 ];
}
Camera = function( pos, target, up, fov_y, vp, near, far ) {
this.Time = function() { return Date.now(); }
this.pos = pos;
this.target = target;
this.up = up;
this.fov_y = fov_y;
this.vp = vp;
this.near = near;
this.far = far;
this.orbit_mat = this.current_orbit_mat = this.model_mat = this.current_model_mat = IdentM44();
this.mouse_drag = this.auto_spin = false;
this.auto_rotate = true;
this.mouse_start = [0, 0];
this.mouse_drag_axis = [0, 0, 0];
this.mouse_drag_angle = 0;
this.mouse_drag_time = 0;
this.drag_start_T = this.rotate_start_T = this.Time();
this.Ortho = function() {
var fn = this.far + this.near;
var f_n = this.far - this.near;
var w = this.vp[0];
var h = this.vp[1];
return [
2/w, 0, 0, 0,
0, 2/h, 0, 0,
0, 0, -2/f_n, 0,
0, 0, -fn/f_n, 1 ];
};
this.Perspective = function() {
var n = this.near;
var f = this.far;
var fn = f + n;
var f_n = f - n;
var r = this.vp[0] / this.vp[1];
var t = 1 / Math.tan( Math.PI * this.fov_y / 360 );
return [
t/r, 0, 0, 0,
0, t, 0, 0,
0, 0, -fn/f_n, -1,
0, 0, -2*f*n/f_n, 0 ];
};
this.LookAt = function() {
var mz = Normalize( [ this.pos[0]-this.target[0], this.pos[1]-this.target[1], this.pos[2]-this.target[2] ] );
var mx = Normalize( Cross( this.up, mz ) );
var my = Normalize( Cross( mz, mx ) );
var tx = Dot( mx, this.pos );
var ty = Dot( my, this.pos );
var tz = Dot( [-mz[0], -mz[1], -mz[2]], this.pos );
return [mx[0], my[0], mz[0], 0, mx[1], my[1], mz[1], 0, mx[2], my[2], mz[2], 0, tx, ty, tz, 1];
};
}
var FrameBuffer = {};
FrameBuffer.Create = function( vp, texturePlan ) {
var texPlan = texturePlan ? new Uint8Array( texturePlan ) : null;
var fb = gl.createFramebuffer();
fb.width = vp[0];
fb.height = vp[1];
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 );
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.viewport( 0, 0, this.width, this.height );
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;
}
var ShProg = {};
ShProg.Create = function( shaderList ) {
var shaderObjs = [];
for ( var i_sh = 0; i_sh < shaderList.length; ++ i_sh ) {
var shderObj = this.Compile( shaderList[i_sh].source, shaderList[i_sh].stage );
if ( shderObj == 0 )
return 0;
shaderObjs.push( shderObj );
}
var progObj = this.Link( shaderObjs )
if ( progObj != 0 ) {
progObj.attrInx = {};
var noOfAttributes = gl.getProgramParameter( progObj, gl.ACTIVE_ATTRIBUTES );
for ( var i_n = 0; i_n < noOfAttributes; ++ i_n ) {
var name = gl.getActiveAttrib( progObj, i_n ).name;
progObj.attrInx[name] = gl.getAttribLocation( progObj, name );
}
progObj.uniLoc = {};
var noOfUniforms = gl.getProgramParameter( progObj, gl.ACTIVE_UNIFORMS );
for ( var i_n = 0; i_n < noOfUniforms; ++ i_n ) {
var name = gl.getActiveUniform( progObj, i_n ).name;
progObj.uniLoc[name] = gl.getUniformLocation( progObj, name );
}
}
return progObj;
}
ShProg.AttrI = function( progObj, name ) { return progObj.attrInx[name]; }
ShProg.UniformL = function( progObj, name ) { return progObj.uniLoc[name]; }
ShProg.Use = function( progObj ) { gl.useProgram( progObj ); }
ShProg.SetI1 = function( progObj, name, val ) { if(progObj.uniLoc[name]) gl.uniform1i( progObj.uniLoc[name], val ); }
ShProg.SetF1 = function( progObj, name, val ) { if(progObj.uniLoc[name]) gl.uniform1f( progObj.uniLoc[name], val ); }
ShProg.SetF2 = function( progObj, name, arr ) { if(progObj.uniLoc[name]) gl.uniform2fv( progObj.uniLoc[name], arr ); }
ShProg.SetF3 = function( progObj, name, arr ) { if(progObj.uniLoc[name]) gl.uniform3fv( progObj.uniLoc[name], arr ); }
ShProg.SetF4 = function( progObj, name, arr ) { if(progObj.uniLoc[name]) gl.uniform4fv( progObj.uniLoc[name], arr ); }
ShProg.SetM44 = function( progObj, name, mat ) { if(progObj.uniLoc[name]) gl.uniformMatrix4fv( progObj.uniLoc[name], false, mat ); }
ShProg.Compile = function( source, shaderStage ) {
var shaderScript = document.getElementById(source);
if (shaderScript) {
source = "";
var node = shaderScript.firstChild;
while (node) {
if (node.nodeType == 3) source += node.textContent;
node = node.nextSibling;
}
}
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 : 0;
}
ShProg.Link = 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 : 0;
}
initScene();
})();
html,body { margin: 0; overflow: hidden; }
#gui { position : absolute; top : 0; left : 0; }
<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 clip_space_pos;
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;
gl_Position = u_projectionMat44 * viewPos;
}
</script>
<script id="draw-shader-fs" type="x-shader/x-fragment">
precision mediump float;
varying vec3 vertPos;
varying vec3 vertNV;
varying vec3 vertCol;
struct Light {
vec3 position;
vec3 direction;
float ambient;
float diffuse;
float specular;
float shininess;
vec3 attenuation;
float cutOffAngle;
};
uniform Light u_light;
void main()
{
vec3 color = vertCol;
vec3 lightCol = u_light.ambient * color;
vec3 normalV = normalize( vertNV );
vec3 lightV = normalize( u_light.position - vertPos );
float lightD = length( u_light.position - vertPos );
float cosL = dot( normalize( u_light.direction ), -lightV );
float inCone = step( cos( u_light.cutOffAngle * 0.5 ), cosL );
float att = 1.0 / dot( vec3( 1.0, lightD, lightD*lightD ), u_light.attenuation );
float NdotL = max( 0.0, dot( normalV, lightV ) );
lightCol += NdotL * u_light.diffuse * color * inCone * att;
vec3 eyeV = normalize( -vertPos );
vec3 halfV = normalize( eyeV + lightV );
float NdotH = max( 0.0, dot( normalV, halfV ) );
float kSpecular = ( u_light.shininess + 2.0 ) * pow( NdotH, u_light.shininess ) / ( 2.0 * 3.14159265 );
lightCol += kSpecular * u_light.specular * color * inCone * att;
gl_FragColor = vec4( lightCol.rgb, 1.0 );
}
</script>
<script id="light-cone-shader-vs" type="x-shader/x-vertex">
precision mediump float;
attribute vec2 inPos;
varying vec2 vertPos;
void main()
{
vertPos.xy = inPos.xy;
gl_Position = vec4( inPos, 0.0, 1.0 );
}
</script>
<script id="light-cone-shader-fs" type="x-shader/x-fragment">
precision mediump float;
varying vec2 vertPos;
uniform sampler2D u_colorAttachment0;
uniform vec2 u_depthRange;
uniform vec2 u_vp;
uniform float u_fov;
struct Light {
vec3 position;
vec3 direction;
float ambient;
float diffuse;
float specular;
float shininess;
vec3 attenuation;
float cutOffAngle;
};
uniform Light u_light;
void main()
{
vec4 texCol = texture2D( u_colorAttachment0, vertPos.st * 0.5 + 0.5 );
vec3 vLightPos = u_light.position;
vec3 vLightDir = normalize( u_light.direction );
float tanFOV = tan(u_fov*0.5);
vec3 nearPos = vec3( vertPos.x * u_vp.x/u_vp.y * tanFOV, vertPos.y * tanFOV, -1.0 );
//vec2 texCoord = gl_FragCoord.xy / u_vp;
//vec3 nearPos = vec3( (texCoord.x-0.5) * u_vp.x/u_vp.y, texCoord.y-0.5, -u_depthRange.x );
vec3 los = normalize( nearPos );
// ray definition
vec3 O = vec3(0.0);
vec3 D = los;
// cone definition
vec3 C = vLightPos;
vec3 V = vLightDir;
float cosTh = cos( u_light.cutOffAngle * 0.5 );
// ray - cone intersection
vec3 CO = O - C;
float DdotV = dot( D, V );
float COdotV = dot( CO, V );
float a = DdotV*DdotV - cosTh*cosTh;
float b = 2.0 * (DdotV*COdotV - dot( D, CO )*cosTh*cosTh);
float c = COdotV*COdotV - dot( CO, CO )*cosTh*cosTh;
float det = b*b - 4.0*a*c;
// find intersection
float isIsect = 0.0;
vec3 isectP = vec3(0.0);
if ( det >= 0.0 )
{
vec3 P1 = O + (-b-sqrt(det))/(2.0*a) * D;
vec3 P2 = O + (-b+sqrt(det))/(2.0*a) * D;
float isect1 = step( 0.0, dot(normalize(P1-C), V) );
float isect2 = step( 0.0, dot(normalize(P2-C), V) );
if ( isect1 < 0.5 )
{
P1 = P2;
isect1 = isect2;
}
if ( isect2 < 0.5 )
{
P2 = P1;
isect2 = isect1;
}
isectP = ( P1.z > -u_depthRange.x || (P2.z < -u_depthRange.x && P1.z < P2.z ) ) ? P2 : P1;
isIsect = mix( isect2, 1.0, isect1 ) * step( isectP.z, -u_depthRange.x );
}
float dist = length( isectP - vLightPos.xyz );
float att = 1.0 / dot( vec3( 1.0, dist, dist*dist ), u_light.attenuation );
gl_FragColor = vec4( mix( texCol.rgb, vec3(1.0, 1.0, 1.0), isIsect * att * 0.5 ), 1.0 );
}
</script>
<div><form id="gui" name="inputs">
<table>
<tr> <td> <font color=#40f040>ambient</font> </td>
<td> <input type="range" id="ambient" min="0" max="100" value="0"/></td> </tr>
<tr> <td> <font color=#40f040>diffuse</font> </td>
<td> <input type="range" id="diffuse" min="0" max="100" value="0"/></td> </tr>
<tr> <td> <font color=#40f040>specular</font> </td>
<td> <input type="range" id="specular" min="0" max="100" value="0"/></td> </tr>
<tr> <td> <font color=#40f040>shininess</font> </td>
<td> <input type="range" id="shininess" min="1" max="100" value="0"/></td> </tr>
<tr> <td> <font color=#40f040>cut off angle</font> </td>
<td> <input type="range" id="cutOffAngle" min="1" max="180" value="0"/></td> </tr>
</table>
</form>
</div>
<canvas id="glow-canvas" style="border: none;"></canvas>