Forum Discussion
Lens distortion model for DirectX raytracing based rendering?
I'm interested in experimenting with VR rendering using DirectX raytracing where the Rift lens distortion could be directly corrected in the ray generation shader rather than rendering an undistorted...
volgaksoy said:
Hi Matt,
We currently do not expose the distortion profile to VR apps. Tracing primary rays won't be a good fit for raytracing with current hardware (even Turing).
Well, it can be a good fit and I even did this 2013 with DK1 and DK2 - you seem to have a very limited idea of what raytracing is. You can use raytracing for example on geometric surfaces with 1000fps even on a GTX8800 in a simple shader. Raytracing does not have to be slow, if your scene is simple enough it can be much faster than a scanline approach!
Still you would need the distortion for primary rays. It would be stupid to calculate a linear scanline picture to a texture first and then calculate the distortion from that framebuffer. Scanline detour will pick from a frambuffer-texture and will end up blurring with interpolation. To reduce blur a much bigger texture would be needed then, just to drop most of the sample information.
With raytracing you are f.e. capable of directly picking the samples from a texture of a quad without any unnecessary drawing of triangles to a texture first, then picking some of the samples from the scanline-framebuffer. Each ray would be used and have a perfect fit in the simulated scene.
This is much faster with raytracing than a detour via scanline, that's why internal quad layers are calculated like this in the OVR-API! Why don't you want to give these capabilitys to developers and decide whats best for them instead?