John Carmack(@ID_AA_Carmack):Whenever I see a decorative mirror ball, I think about the old-school OpenGL GL_SPHERE_MAP texgen option, and light probes for realistic lighting of synthetic renderings for merging with photos. Long before cube maps were an option, sphere maps allowed a form of shiny surface rendering, but only from a limited viewpoint — you couldn’t walk all the way around a shiny object. For light probes, you could take multiple photos with different exposure times to capture a true many-orders-of-magnitude high dynamic range composite image for realistic image based lighting of everything from direct sunlight to subtle shadowed region indirect lighting.

2026.10.06 19:07

Whenever I see a decorative mirror ball, I think about the old-school OpenGL GL_SPHERE_MAP texgen option, and light probes for realistic lighting of synthetic renderings for merging with photos. Long before cube maps were an option, sphere maps allowed a form of shiny surface rendering, but only from a limited viewpoint — you couldn’t walk all the way around a shiny object. For light probes, you could take multiple photos with different exposure times to capture a true many-orders-of-magnitude high dynamic range composite image for realistic image based lighting of everything from direct sunlight to subtle shadowed region indirect lighting.