我正在学习 Phong 着色并得到一些混淆:
- Phong着色中光的位置坐标是什么?(模型空间、模型视图或其他什么?)
- 据此:http ://www.ozone3d.net/tutorials/glsl_lighting_phong_p2.php :
顶点着色器是:
varying vec3 normal, lightDir, eyeVec;
void main()
{
normal = gl_NormalMatrix * gl_Normal;
vec3 vVertex = vec3(gl_ModelViewMatrix * gl_Vertex);
lightDir = vec3(gl_LightSource[0].position.xyz - vVertex);
eyeVec = -vVertex;
gl_Position = ftransform();
}
为什么 eyeVec = -vVertex?