   Paraboloid mapping interpolation issue
  Hi all,I know that tessellation and interpolation issues in paraboloid mapping were discussed many times, but I still did not find correct answer that could help me.Following are some screenshots from my application (shadowmap texture and tessellation preview). Red "circle" shows some corner in the scene.When I move camera a bit forward, interpolation issue appears (see red "rectangle"). The biggest problem appears on some parts that are not well tessellated, i.e. "blue object" should be placed on greenly highlighted part (see right part of third pic)I wrote my application according to Jason's article (thank you Jason, good work!!!). The only difference is that I use GLSL shaders.Could you please help me or give me some hints??? Thank you so much.   
Quote:Original post by navy1983Hi all,I know that tessellation and interpolation issues in paraboloid mapping were discussed many times, but I still did not find correct answer that could help me....Could you please help me or give me some hints??? yes, we can help you for sure. But what's your particular question?If you know about tesselation and interpolation issues, you know everything special about parabolid maps and the linear interpolated triangles in your curved space obviously look wrong, you do everything right and the result is expected to be that and tesselation is the only thing that would help you, like you probably know.so what's your question?;  I wanted to know if there is another way how to do the paraboloid mapping correctly, except for tessellation.I'm not experienced enough in writing shaders and I was thinking there might be some tricks that could solve my problem. Probably not ... :(   ;  Remove all t-junktionsthat won't solve all problems, but it will just reduce the amount of artefact.there is probably no other way than to tesselate to solve most issues.   ;  There is no simple solution that I'm aware of.  You could try doing a manual interpolation of the positions for each vertex in the pixel shader, and only output the fragment if it should be, but this will only work part of the time.Have you considered using HW tessellation to overcome the issue?   ;  Yes, I have. But I still have not found any reasonable how-tos for enabling HW tessellation.   ;  I know you mentioned usin GLSL, but I have at least some shader examples for hull and domain shaders in my engine that you could use.  I would assume that it is nearly identical to GLSL, but at least it would be a good starting point...  (see link below to get the engine code).   