How Quake Wars Met the Ray Tracer

An anonymous reader writes "Intel released the article 'Quake Wars Gets Ray Traced' (PDF) which details the development efforts of the research team that applied a real-time ray tracer to Enemy Territory: Quake Wars. It describes the benefits and challenges of transparency textures with this rendering technology. Further insight is given into what special effects are most costly. Examples of glass and a 3D water implementation are shown. The outlook hints into the area of freely programmable many-core processors, like Intel's upcoming Larrabee, that might be able to handle such a workload." We mentioned the ray-traced Quake Wars last in June; the PDF here delves into the implementation details, rather than just showing a demo, and explains what parts of the game give the most difficulty in going from rasterization to ray-tracing.

Comments

Re:raytracing is VERY established

[TheBracket]

Wolf3D used raycasting, rather than tracing to give a pseudo-3D rendering of what was basically a 2D grid map.

It's pretty clever how it worked, I remember having a LOT of fun cooking up my own similar renderer back in the day (Turbo Pascal with inline asm was fun!). If I remember rightly:
First, the ceiling and floor were drawn in, covering everything (intersecting in the middle, vertically). Then, they took your location on the map, and cast a ray for each row of pixels (320 of them, I believe). This ray went forward until it intersected a wall - and the distance to the wall was measured. It then did a quick calculation (lookup table) to determine the height of the wall at that distance, subtracted half that height from the center of the screen, and plotted a vertical line in the color of the wall. I seem to remember the wall color was retrieved from a small texture and scaled.
That gives surprisingly good results, albeit with no lighting or shading.