Question

I sometimes disable depth buffer writing via glDepthMask(GL_FALSE) during the rendering of a frame. That works perfectly fine on some GPUs (like the Motorola Droid’s PowerVR), but on the HTC EVO with the Adreno GPU for example, I end up with the frame buffer being complete garbage (I see traces of the meshes I rendered somewhere, but the entire screen is mostly trashed).

If I force glDepthMask to be true the entire time, everything works fine.

I need glDepthMask to be off during parts of the alpha rendering. What can cause the framebuffer to get destroyed by turning the depth writing off?

Answer 1

The problem was that glDepthMask needs to be true when calling glClearDepth. This apparently only applies to Adreno GPUs, not to PowerVR GPUs.