Development Journal of a Raytracer

Example image for Ward Shader (Image is linked to bigger version).

I have changed the scene a bit and now am sure that I have a bug somewhere. But first the positive thing, the specular highlights are very nice, they are really quite different depending on material. The floor and the three blocks have the Ward Shader, the rest is Phong. The left block is "rolled brass", the one in the middle is "enamel finished metal" and the right one is "white ceramic tiles", the floor is "varnished plywood" (per the Ward paper). I didn't bother to give the blocks a color, they are just white and the floor has a simple checker texture.

The left block also seems to show a bit of the ceiling (only visible very faintly in full image). But those rings on the floor are very strange. They seem to be reflections of the bright spots on the ceiling (where the point lights are, they are 20cm beneath the ceiling, 3.3m above the floor). I can't tell, if it would be correct to see only a rather thin, bright line, but I see no reason for them not being full circles. It seems, that only the left half is visible. I guess I have to have another look at the Ward BRDF Shader.