The ppixels sampler2D uniform – not widely documented – gives access to the previously rendered frame and can be useful to implement iterative effects or simulations (like the Conway’s game of life included in the examples). All the uniforms that I will list below can be added to any type of shader, but if a shader is set to render a scene without lights but it declares a lighting uniform, then that uniform will not be initialized.Īny shaders in Processing can declare the following basic uniform and attribute variables:Ī couple of convenience aliases: modelview can be used instead of modelviewMatrix, transform instead of transformMatrix, and vertex for position. By rendering state, I simply mean if lights and/or textures are being used in the scene. The important thing to keep in mind when coding a shader to use in a Processing sketch is the rendering state at the moment when the shader will be invoked by Processing. However, the renderer became a little “smarter” in regards to this shader selection process, and so these defines are not longer required (although you can keep them around in the shader code). The type can be indicated by #define line, such asĪnd was used by the OpenGL renderer to pick the right shader to use depending on the specific combination of stroke, lights, and textures at each specific point along the rendering of the sketch’s output. This notion of “shader type” it only matters to Processing, and is not part of the GLSL language. With the recent release of Processing 2.1.2, I could say (with very high certainty) that the shader API in Processing 2 reached a “stable status” and won’t go through any further changes.Ī distinction that was introduced early on in the shader architecture of Processing 2 was that of color, light, texture, texlight, point and line shaders.
PMOUSE PROCESSING FULL
The reference section in the Processing website, the PShader tutorial, and the built-in examples are all up-to-date, but the last full listing of all the uniform and attribute variables was mentioned in an older post in this blog, and has gone a bit out of date since then. Since that time, the shader API – defined not only by the new functions in the Processing language to load and run shaders in a sketch, but also by the set of uniform and attribute variables inside a shader that Processing automatically initializes with the geometry coming from the sketch – has gone some minor changes and tweaks. Among those, a new OpenGL renderer with GLSL shader support. Processing 2.0 was released almost a year ago, and introduced many exciting improvements in several areas.
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