glGenerateMipmap take a very long load time compare to NVIDIA 9800GT
I am working on OpenGL 3.2 forward compatible profile thus the only auto generation of mipmap I can use is glGenerateMipmap.
glGenTextures(1,textureID); glBindTexture(GL_TEXTURE_2D,*textureID); if(colorDepth == 32){ glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8,width,height,0, GL_RGBA, GL_UNSIGNED_BYTE,pixelData); } else if(colerDepth == 24){ glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB8,width,height,0, GL_RGB, GL_UNSIGNED_BYTE,pixelData); }
There are two problem
1.the time take to generate mipmap is very long it take 30 second to generate mipmap of 13 of 2048 * 2048 24bit texture , compare to my GF 9800GT which only take 2~3 second.
2.the quality of mipmap is bad even when viewing upclose,It look like the driver choose some lowres mipmap instead of hires one (very noticable when using mipmap on normalmap/bumpmap texture).
Please someone with knowledge about working with ATI/AMD GPU help me on this,since without any mipmap texture/bumpmap effect will look very shimmering when view from distance.
My system is windows xp ,AMD athlonx2 64bit 250 CPU, ATIHD4670 with 10.3 driver
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER,GL_LINEAR); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER,GL_LINEAR_MIPMAP_LINEAR); glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAX_ANISOTROPY_EXT,16);
glHint(GL_GENERATE_MIPMAP_HINT,GL_NICEST); //change this to FASTEST didnt help loding time
glGenerateMipmap(GL_TEXTURE_2D);
