我正在按照本教程创建带有环境映射的天空盒/立方体贴图。我在理解顶点着色器中的计算时遇到了一些麻烦:
#version 330 core
layout (location = 0) in vec3 position;
layout (location = 1) in vec3 normal;
out vec3 Normal;
out vec3 Position;
uniform mat4 model;
uniform mat4 view;
uniform mat4 projection;
void main()
{
gl_Position = projection * view * model * vec4(position, 1.0f);
Normal = mat3(transpose(inverse(model))) * normal;
Position = vec3(model * vec4(position, 1.0f));
}
在这里,作者是在计算法线之前将其传递给片段着色器以计算反射纹理:
Normal = mat3(transpose(inverse(model))) * normal;
我的问题是,这个计算究竟是做什么的?为什么在与法线相乘之前必须计算模型矩阵的逆矩阵的转置?