Pre Z缓冲区通过OpenGL？

Question

我怎样才能使用openGL进行Z缓冲预处理.

我试过这个:

glcolormask(0,0,0,0); //disable color buffer

//draw scene

glcolormask(1,1,1,1); //reenable color buffer

//draw scene

//flip buffers

但它不起作用.这样做后我什么都没看到.有什么更好的方法呢？

谢谢

Answer 1

// clear everything
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

// z-prepass
glEnable(GL_DEPTH_TEST);  // We want depth test !
glDepthFunc(GL_LESS);     // We want to get the nearest pixels
glcolormask(0,0,0,0);     // Disable color, it's useless, we only want depth.
glDepthMask(GL_TRUE);     // Ask z writing

draw()

// real render
glEnable(GL_DEPTH_TEST);  // We still want depth test
glDepthFunc(GL_LEQUAL);   // EQUAL should work, too. (Only draw pixels if they are the closest ones)
glcolormask(1,1,1,1);     // We want color this time
glDepthMask(GL_FALSE);    // Writing the z component is useless now, we already have it

draw();