32 lines
1.8 KiB
Markdown
32 lines
1.8 KiB
Markdown
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---
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title: "Shader Module"
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date: 2021-01-26T17:41:14-08:00
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weight: 4
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---
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Shaders are, to perhaps oversimplify a bit, the procedures that are used in rendering. A shader is a parallel program that your GPU will run thousands or tens of thousands of times simultaneously to process your data.
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Explaining everything about shaders is beyond the scope of this documentation and there are plenty of resources for learning shader programming out there, so I will stick to a simple explanation and you can take it from there.
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Vertex shaders are programs that transform vertex data. A vertex shader runs once per vertex and outputs some vertex-related data.
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The graphics pipeline "rasterizes" your vertex data to produce pixel data, and this pixel data is then further transformed by your pixel, or "fragment" shader.
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We'll talk more about this when we get to graphics pipelines. For now, let's explain how to create a MoonWorks shader module.
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MoonWorks shader modules expect input in a format called "SPIR-V bytecode." Unlike the bad old days where you were locked into whatever shader language your engine required, SPIR-V is an intermediate representation. That means it can compile from higher level shader languages like GLSL or HLSL. Personally I prefer GLSL, but you can use any shader language you want that outputs SPIR-V!
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To compile a GLSL shader into SPIR-V, you can use the [glslangValidator](https://github.com/KhronosGroup/glslang) program like this:
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```sh
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glslangValidator -V myCoolShader.frag -o myCoolShaderFrag.spv
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```
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This will output a file named "myCoolShaderFrag.spv". Now we can put that shader module into MoonWorks.
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```cs
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var myShaderModule = new ShaderModule(GraphicsDevice, "myCoolShaderFrag.spv");
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```
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Shader modules don't do anything on their own - you use them as part of a graphics pipeline. We'll get into that later.
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