I would like to use automatic mipmap generation on an nv40 for a floating point texture.
Currently I am crating this texture from a texture rectangle that was created with internal format GL_FLOAT_RGBA16_NV. I then create a new texture 2d of the same exact size of the rectangle and use an internal format of GL_FLOAT_RGBA16_NV or GL_RGBA_FLOAT16_ATI.
It would appear that when I enable the
glTexParameteri(GL_TEXTURE_2D, GL_GENERATE_MIPMAP_SGIS, GL_TRUE);
the copy texture command takes about 2-3 second to copy the image. With mipmap disabled, it only takes a fraction of a second.
I was wondering if
- mipmap generation is not implemented in hardware for 2d floating point textures on nv40
- if not, is there a problem copying from a rectangle to a 2d texture?