I simply draw something into a render target, and use it as an normal texture. It's always working greate to me with my nvidia video card. But today I found my program ran terribly slow (less than 5 fps) on a intel card.
After running an analyse I found glGenerateMipmapEXT is the trouble maker, it costs most of the cpu time. Here's how I bind a RT texture:
glBindTexture(GL_TEXTURE_2D, m_textureID);<br> glGenerateMipmapEXT(GL_TEXTURE_2D);
without glGenerateMipmapEXT the texture is nothing but pure white pic. Something wrong with my RTT?