我想在片段着色器中绘制深度缓冲区,我这样做:
顶点着色器:
varying vec4 position_;
gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex;
position_ = gl_ModelViewProjectionMatrix * gl_Vertex;
片元着色器:
float depth = ((position_.z / position_.w) + 1.0) * 0.5;
gl_FragColor = vec4(depth, depth, depth, 1.0);
但是我打印出来的都是白色,我做错了什么?