使用法线贴图渲染会导致依赖于旋转的光照
Rendering using normal maps causes rotation-dependent lighting
当物体没有从原点旋转时，法线贴图看起来很棒，聚光灯和平行光也能工作，但是当我在原地旋转物体时，它会变暗然后再次变亮，就在顶面上.
我正在使用多维数据集进行测试。我使用几何着色器来可视化我计算出的法线（在乘以 TBN 矩阵之后），它们似乎位于正确的位置。如果我把法线贴图从等式中去掉，那么光照就很好了。
这里是计算 TBN 的地方：
void calculateTBN()
{
//get the normal matrix
mat3 model = mat3(transpose(inverse(mat3(transform))));
vec3 T = normalize(vec3(model * tangent.xyz ));
vec3 N = normalize(vec3(model * normal ));
vec3 B = cross(N, T);
mat3 TBN = mat3( T , B , N);
outputVertex.TBN =TBN;
}
并对法线进行采样和变换：
vec3 calculateNormal()
{
//Sort the input so that the normal is between 1 and minus 1 instead of 0 and 1
vec3 input = texture2D(normalMap, inputFragment.textureCoord).xyz;
input = 2.0 * input - vec3(1.0, 1.0, 1.0);
vec3 newNormal = normalize(inputFragment.TBN* input);
return newNormal;
}
我的光照在世界中space（据我所知，它考虑了变换矩阵但不考虑相机或投影矩阵）
我确实尝试了将 TBN 作为逆（或转置）传递然后将每个向量与法线相乘的技术。那有同样的效果。无论如何，我宁愿在世界 space 工作，因为显然这对延迟照明更好？或者我听说过。
如果您想查看任何照明代码等，我会添加它，但我认为没有必要，因为它与此不同。
编辑::
根据要求，这里是顶点和片段着色器的一部分
#version 330
uniform mat4 T; // Translation matrix
uniform mat4 S; // Scale matrix
uniform mat4 R; // Rotation matrix
uniform mat4 camera; // camera matrix
uniform vec4 posRelParent; // the position relative to the parent
// Input vertex packet
layout (location = 0) in vec4 position;
layout (location = 2) in vec3 normal;
layout (location = 3) in vec4 tangent;
layout (location = 4) in vec4 bitangent;
layout (location = 8) in vec2 textureCoord;
// Output vertex packet
out packet {
vec2 textureCoord;
vec3 normal;
vec3 vert;
mat3 TBN;
vec3 tangent;
vec3 bitangent;
vec3 normalTBN;
} outputVertex;
mat4 transform;
mat3 TBN;
void calculateTBN()
{
//get the model matrix, the transform of the object with scaling and transform removeds
mat3 model = mat3(transpose(inverse(transform)));
vec3 T = normalize(model*tangent.xyz);
vec3 N = normalize(model*normal);
//I used to retrieve the bitangents by crossing the normal and tangent but now they are calculated independently
vec3 B = normalize(model*bitangent.xyz);
TBN = mat3( T , B , N);
outputVertex.TBN = TBN;
//Pass though TBN vectors for colour debugging in the fragment shader
outputVertex.tangent = T;
outputVertex.bitangent = B;
outputVertex.normalTBN = N;
}
void main(void) {
outputVertex.textureCoord = textureCoord;
// Setup local variable pos in case we want to modify it (since position is constant)
vec4 pos = vec4(position.x, position.y, position.z, 1.0) + posRelParent;
//Work out the transform matrix
transform = T * R * S;
//Work out the normal for lighting
mat3 normalMat = transpose(inverse(mat3(transform)));
outputVertex.normal = normalize(normalMat* normal);
calculateTBN();
outputVertex.vert =(transform* pos).xyz;
//Work out the final pos of the vertex
gl_Position = camera * transform * pos;
}
片段的光照向量：
vec3 applyLight(Light thisLight, vec3 baseColor, vec3 surfacePos, vec3 surfaceToCamera)
{
float attenuation = 1.0f;
vec3 lightPos = (thisLight.finalLightMatrix*thisLight.position).xyz;
vec3 surfaceToLight;
vec3 coneDir = normalize(thisLight.coneDirection);
if (thisLight.position.w == 0.0f)
{
//Directional Light (all rays same angle, use position as direction)
surfaceToLight = normalize( (thisLight.position).xyz);
attenuation = 1.0f;
}
else
{
//Point light
surfaceToLight = normalize(lightPos - surfacePos);
float distanceToLight = length(lightPos - surfacePos);
attenuation = 1.0 / (1.0f + thisLight.attenuation * pow(distanceToLight, 2));
//Work out the Cone restrictions
float lightToSurfaceAngle = degrees(acos(dot(-surfaceToLight, normalize(coneDir))));
if (lightToSurfaceAngle > thisLight.coneAngle)
{
attenuation = 0.0;
}
}
}
这也是碎片着色器的主要部分：
void main(void) {
//get the base colour from the texture
vec4 tempFragColor = texture2D(textureImage, inputFragment.textureCoord).rgba;
//Support for objects with and without a normal map
if (useNormalMap == 1)
{
calcedNormal = calculateNormal();
}
else
{
calcedNormal = inputFragment.normal;
}
vec3 surfaceToCamera = normalize((cameraPos_World) - (inputFragment.vert));
vec3 tempColour = vec3(0.0, 0.0, 0.0);
for (int count = 0; count < numLights; count++)
{
tempColour += applyLight(allLights[count], tempFragColor.xyz, inputFragment.vert, surfaceToCamera);
}
vec3 gamma = vec3(1.0 / 2.2);
fragmentColour = vec4(pow(tempColour,gamma), tempFragColor.a);
//fragmentColour = vec4(calcedNormal, 1);
}
编辑 2：
几何着色器用于通过 TBN 矩阵可视化 "sampled" 法线，如下所示：
void GenerateLineAtVertex(int index)
{
vec3 testSampledNormal = vec3(0, 0, 1);
vec3 bitangent = cross(gs_in[index].normal, gs_in[index].tangent);
mat3 TBN = mat3(gs_in[index].tangent, bitangent, gs_in[index].normal);
testSampledNormal = TBN * testSampledNormal;
gl_Position = gl_in[index].gl_Position;
EmitVertex();
gl_Position =
gl_in[index].gl_Position
+ vec4(testSampledNormal, 0.0) * MAGNITUDE;
EmitVertex();
EndPrimitive();
}
而且是顶点着色器
void main(void) {
// Setup local variable pos in case we want to modify it (since position is constant)
vec4 pos = vec4(position.x, position.y, position.z, 1.0);
mat4 transform = T* R * S;
// Apply transformation to pos and store result in gl_Position
gl_Position = projection* camera* transform * pos;
mat3 normalMatrix = mat3(transpose(inverse(camera * transform)));
vs_out.tangent = normalize(vec3(projection * vec4(normalMatrix * tangent.xyz, 0.0)));
vs_out.normal = normalize(vec3(projection * vec4(normalMatrix * normal , 0.0)));
}
这是可视化的 TBN 向量。点上的小角度是由于我如何应用投影矩阵的问题，而不是实际向量中的错误。红线只是显示了我在纹理上绘制的箭头所在的位置，从那个角度看它们不是很清楚。仅此而已。
问题解决了！
实际上与上面的代码无关，尽管感谢所有帮助过的人。
我使用我自己的纹理加载器导入纹理，它默认使用非伽马校正的 32 位 SRGB 颜色。我将它切换为 24 位和 RGB 颜色，它立即工作。典型的开发者问题....
当物体没有从原点旋转时，法线贴图看起来很棒，聚光灯和平行光也能工作，但是当我在原地旋转物体时，它会变暗然后再次变亮，就在顶面上.
我正在使用多维数据集进行测试。我使用几何着色器来可视化我计算出的法线（在乘以 TBN 矩阵之后），它们似乎位于正确的位置。如果我把法线贴图从等式中去掉，那么光照就很好了。
这里是计算 TBN 的地方：
void calculateTBN()
{
//get the normal matrix
mat3 model = mat3(transpose(inverse(mat3(transform))));
vec3 T = normalize(vec3(model * tangent.xyz ));
vec3 N = normalize(vec3(model * normal ));
vec3 B = cross(N, T);
mat3 TBN = mat3( T , B , N);
outputVertex.TBN =TBN;
}
并对法线进行采样和变换：
vec3 calculateNormal()
{
//Sort the input so that the normal is between 1 and minus 1 instead of 0 and 1
vec3 input = texture2D(normalMap, inputFragment.textureCoord).xyz;
input = 2.0 * input - vec3(1.0, 1.0, 1.0);
vec3 newNormal = normalize(inputFragment.TBN* input);
return newNormal;
}
我的光照在世界中space（据我所知，它考虑了变换矩阵但不考虑相机或投影矩阵）
我确实尝试了将 TBN 作为逆（或转置）传递然后将每个向量与法线相乘的技术。那有同样的效果。无论如何，我宁愿在世界 space 工作，因为显然这对延迟照明更好？或者我听说过。
如果您想查看任何照明代码等，我会添加它，但我认为没有必要，因为它与此不同。
编辑:: 根据要求，这里是顶点和片段着色器的一部分
#version 330
uniform mat4 T; // Translation matrix
uniform mat4 S; // Scale matrix
uniform mat4 R; // Rotation matrix
uniform mat4 camera; // camera matrix
uniform vec4 posRelParent; // the position relative to the parent
// Input vertex packet
layout (location = 0) in vec4 position;
layout (location = 2) in vec3 normal;
layout (location = 3) in vec4 tangent;
layout (location = 4) in vec4 bitangent;
layout (location = 8) in vec2 textureCoord;
// Output vertex packet
out packet {
vec2 textureCoord;
vec3 normal;
vec3 vert;
mat3 TBN;
vec3 tangent;
vec3 bitangent;
vec3 normalTBN;
} outputVertex;
mat4 transform;
mat3 TBN;
void calculateTBN()
{
//get the model matrix, the transform of the object with scaling and transform removeds
mat3 model = mat3(transpose(inverse(transform)));
vec3 T = normalize(model*tangent.xyz);
vec3 N = normalize(model*normal);
//I used to retrieve the bitangents by crossing the normal and tangent but now they are calculated independently
vec3 B = normalize(model*bitangent.xyz);
TBN = mat3( T , B , N);
outputVertex.TBN = TBN;
//Pass though TBN vectors for colour debugging in the fragment shader
outputVertex.tangent = T;
outputVertex.bitangent = B;
outputVertex.normalTBN = N;
}
void main(void) {
outputVertex.textureCoord = textureCoord;
// Setup local variable pos in case we want to modify it (since position is constant)
vec4 pos = vec4(position.x, position.y, position.z, 1.0) + posRelParent;
//Work out the transform matrix
transform = T * R * S;
//Work out the normal for lighting
mat3 normalMat = transpose(inverse(mat3(transform)));
outputVertex.normal = normalize(normalMat* normal);
calculateTBN();
outputVertex.vert =(transform* pos).xyz;
//Work out the final pos of the vertex
gl_Position = camera * transform * pos;
}
片段的光照向量：
vec3 applyLight(Light thisLight, vec3 baseColor, vec3 surfacePos, vec3 surfaceToCamera)
{
float attenuation = 1.0f;
vec3 lightPos = (thisLight.finalLightMatrix*thisLight.position).xyz;
vec3 surfaceToLight;
vec3 coneDir = normalize(thisLight.coneDirection);
if (thisLight.position.w == 0.0f)
{
//Directional Light (all rays same angle, use position as direction)
surfaceToLight = normalize( (thisLight.position).xyz);
attenuation = 1.0f;
}
else
{
//Point light
surfaceToLight = normalize(lightPos - surfacePos);
float distanceToLight = length(lightPos - surfacePos);
attenuation = 1.0 / (1.0f + thisLight.attenuation * pow(distanceToLight, 2));
//Work out the Cone restrictions
float lightToSurfaceAngle = degrees(acos(dot(-surfaceToLight, normalize(coneDir))));
if (lightToSurfaceAngle > thisLight.coneAngle)
{
attenuation = 0.0;
}
}
}
这也是碎片着色器的主要部分：
void main(void) {
//get the base colour from the texture
vec4 tempFragColor = texture2D(textureImage, inputFragment.textureCoord).rgba;
//Support for objects with and without a normal map
if (useNormalMap == 1)
{
calcedNormal = calculateNormal();
}
else
{
calcedNormal = inputFragment.normal;
}
vec3 surfaceToCamera = normalize((cameraPos_World) - (inputFragment.vert));
vec3 tempColour = vec3(0.0, 0.0, 0.0);
for (int count = 0; count < numLights; count++)
{
tempColour += applyLight(allLights[count], tempFragColor.xyz, inputFragment.vert, surfaceToCamera);
}
vec3 gamma = vec3(1.0 / 2.2);
fragmentColour = vec4(pow(tempColour,gamma), tempFragColor.a);
//fragmentColour = vec4(calcedNormal, 1);
}
编辑 2：
几何着色器用于通过 TBN 矩阵可视化 "sampled" 法线，如下所示：
void GenerateLineAtVertex(int index)
{
vec3 testSampledNormal = vec3(0, 0, 1);
vec3 bitangent = cross(gs_in[index].normal, gs_in[index].tangent);
mat3 TBN = mat3(gs_in[index].tangent, bitangent, gs_in[index].normal);
testSampledNormal = TBN * testSampledNormal;
gl_Position = gl_in[index].gl_Position;
EmitVertex();
gl_Position =
gl_in[index].gl_Position
+ vec4(testSampledNormal, 0.0) * MAGNITUDE;
EmitVertex();
EndPrimitive();
}
而且是顶点着色器
void main(void) {
// Setup local variable pos in case we want to modify it (since position is constant)
vec4 pos = vec4(position.x, position.y, position.z, 1.0);
mat4 transform = T* R * S;
// Apply transformation to pos and store result in gl_Position
gl_Position = projection* camera* transform * pos;
mat3 normalMatrix = mat3(transpose(inverse(camera * transform)));
vs_out.tangent = normalize(vec3(projection * vec4(normalMatrix * tangent.xyz, 0.0)));
vs_out.normal = normalize(vec3(projection * vec4(normalMatrix * normal , 0.0)));
}
这是可视化的 TBN 向量。点上的小角度是由于我如何应用投影矩阵的问题，而不是实际向量中的错误。红线只是显示了我在纹理上绘制的箭头所在的位置，从那个角度看它们不是很清楚。仅此而已。
问题解决了！ 实际上与上面的代码无关，尽管感谢所有帮助过的人。
我使用我自己的纹理加载器导入纹理，它默认使用非伽马校正的 32 位 SRGB 颜色。我将它切换为 24 位和 RGB 颜色，它立即工作。典型的开发者问题....