A terrain rendering approach (part 1)

There are several methods to create and display a terrain, in real-time. In this post, I will explain the approach I followed on the demo I’m writing for my work at Igalia. Some work is still in progress.

The terrain had to meet the following requirements:

  • its size should be arbitrary
  • parts outside the viewer’s field of view should be culled

Continue reading A terrain rendering approach (part 1)

Debugging graphics code using replacement shaders (Linux, Mesa)

Sometimes, when working with the mesa drivers, modifying or replacing a shader might be extremely useful for debugging. Mesa allows users to replace their shaders at runtime without having to change the original code by providing these environment variables:

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Creating cube map images from HDR panoramas on GNU/Linux

As part of my work for Igalia I wanted to do some environment mapping. I was able to find plenty of high quality .hdr images online but I couldn’t find any (OSS) tool to convert them to cubemap images. Then, Nuclear (John Tsiombikas) gave me the solution: he wrote a minimal tool that does the job quickly and produces high quality cube maps.

So, here’s a short “how to” create cubemaps on Linux using his “cubemapper” program in combination with other OSS tools:

Continue reading Creating cube map images from HDR panoramas on GNU/Linux

Morphing test

So far, I hadn’t try to morph 3D objects to other 3D objects and I thought it’s something tricky to do. Today, I realized how simple and easy it is when I wrote this small test:

If you carefully choose the 3D models to have the same number of polygons, and to meet a few topological requirements, then you only need to interpolate the values of the meshes’ vectors, normals (and materials, textures, whatever you need) and draw the intermediate mesh every time. As interpolation parameter you can choose the values of a positive function that varies from 0 to 1 and backwards (I used (sin(msecs/factor) + 1)/2) to have that continuously changing effect. And that’s all! 😀

The test is here: https://bitbucket.org/eleni-hikiko/morphing and it includes an obj with a scene with 3 meshes that meet the morphing requirements  (I only used the first two meshes here).