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Writing a triangle rasterizer is not that hard. What APIs like OpenGL give you for free (other than a performance boost) is walking all the pixels that are cove

Writing a triangle rasterizer is not that hard. What APIs like OpenGL give you for free (other than a performance boost) is walking all the pixels that are covered by each triangle, and computing the barycentric coordinates for each pixel (and then using these to lerp the vertex data). So that's what you have to replace by a CPU program. I find the much harder part is how to setup the architecture in such a way that the data flows through your shader pipelines without an unbearable amount of boilerplate. 3D APIs don't help with that - if anything they make it harder.

bob1029 5y ago
> Writing a triangle rasterizer is not that hard Certainly. One can write a trivial version in maybe 30 lines of code. Writing a triangle rasterizer that you would want to use in a product that is consumed by another human is hard. Also, it is my experience that none of these things can truly be built in isolation. Depth buffers and acceleration structures crosscut all aspects of a rendering engine. I do agree regarding the 3d APIs though. Writing it yourself in software mode can be easier than learning someone else's mousetrap. This is the path I prefer, even if it is slower at first.