Early depth and float depth texture

Any body got early depth test working with a float texture (GL_DEPTH_COMPONENT_32F_NV) attached to an FBO on G80/G92 ?

I have tried it in my application and I can’t get it to work, whereas it works well with GL_DEPTH24_STENCIL8_EXT.
I use 169.21 on a G92 under windows XP.

Thank you

Here’s what the guidelines say:

  • Clearing z is close to free and enables early z-cull optimizations

  • Don’t create triangles with holes in them (that is, avoid alpha test or texkill)

  • Don’t modify depth (that is, allow the GPU to use the interpolated depth

But since it works for GL_DEPTH24_STENCIL8_EXT I don’t think it’s an issue.

Perhaps it’s because the Z-buffer uses a lossless compression for GL_DEPTH24_STENCIL8_EXT to save bandwidth which has a good mapping for the early-Z while the 32F format is not compressed.