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Welcome to the Possumwood wiki pages!
Wiki pages for Possumwood are intended primarilly for tutorials and code examples. Please feel free to contribute!
Unfortunately, this wiki page is not kept up to date with the development of the codebase - it takes a huge amount of effort to write tutorials that takes time from development. Any help would be appreciated!
This tutorial introduces the Lua integration of Possumwood, using a simple example of an addition node.
Introduces basic concepts of GLSL shaders in Possumwood, via a simple setup displaying a rotating car. Its model is loaded from an .obj file, converted to an OpenGL Vertex Buffer Object and displayed using a combination of a vertex and a fragment shader.
A simple GLSL skybox setup, using fragment shader and the background node (based on gluUnProject) to render a background quad with spherically-mapped texture.
Environment map is a simple technique to approximate reflective surfaces in GLSL, without the need of actual raytracing. This tutorial builds on the previous Skybox tutorial, and extends it to make a teapot's material tool like polished metal.
Most implementation of OpenGL 4 remove the ability to influence the width of lines using the classical glLineWidth call. This tutorial describes in detail how to achieve a similar effect (and much more) using a geometry shader, by rendering each line as a camera-facing polygon strip.
Implementation of Curved PN Triangles tessellation technique, presented by Alex Vlachos on GDC 2011. This method tessellates input triangles using solely their vertex positions and normals (independently of the mesh topology) in a geometry shader.
Infinite ground plane, implemented using a single polygon and simple fragment shader "raytracing" against a plane with Y=0.
The Phong reflectance model, and Phong shading are two basic models of light behaviour in computer graphics. This tutorial explains their function, and provides a step-by-step implementation in GLSL, using a single orbiting light as the lightsource.
This tutorial introduces basic concepts of image manipulation in Possumwood, and a simple shader-based OpenGL setup to display a texture in the scene.
Apart from rendering existing images loaded from a file, Possumwood can also generate and edit images using Lua scripting. In this tutorial, we explore a very simple setup which uses Lua and per-pixel expressions to generate an image.