5

An easy way to parallelize a path tracer is to have different threads (or machines!) work on different parts of the image. For instance, you could break the image into a 20x20 grid and have each thread grab a tile, render it, and try to grab another tile. A way I like to divy out this work is to use an atomic integer. Each thread atomically increments the ...


3

Rasterization is sometimes used for primary rays. However, it limits greatly what you can do - depth of field, motion blur, participating media, refraction, only basic camera models, no adaptive or custom sampling, etc.


2

The issue is, that you considered that the rays coming from the camera to be the light carrying rays. Instead, the rays bounce off the surface, and return to the light source (which you have decided to position at the camera). This means that your light direction is not $\pmb{d}$ but rather $-\pmb{d}$, then $\cos\theta = - \pmb{d} \cdot \pmb{n}$, provided ...


1

There are renderes that do this. Most notably Pixars Renderman prefers to work this way. Hybrid renderers can work in other ways too... It used to be that hybrid renderers like this were quite common, they still are somewhat in software only implementations. They are slowly being replaced though by a new breed of trace only renderes though. Mostly the ...


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