Environment map conversion procedure using generic pixel-to-ray and ray-to-pixel primitives. You need this equirectangular environment map image: latlong.ppm. The output is a spherical mirror ball image spherical.ppm that you can also use in the former OpenGL(R) reflection mapping program-Environment map conversion procedure using generic pixel-to-ray and ray-to-pixel primitives. You need this equirectangular environment map image: latlong.ppm. The output is a spherical mirror ball image spherical.ppm that you can also use in the former OpenGL (R) reflection mapping program