shader-programming

1# Shader programming (cross-engine)
2 
3Shaders are small programs that run **per vertex** and **per pixel** on the GPU.
4The concepts — the pipeline, coordinate spaces, UVs, and how common effects are
5built — port across engines; only the language dialect and built-in variable
6names change. This skill teaches those portable fundamentals in GLSL with HLSL
7equivalents; use `godot-shaders` (or Unity/Unreal material docs) for the exact
8engine syntax and built-ins.
9 
10## When to use
11 
12- Use to understand or write vertex/fragment shaders and to reason about UVs,
13  coordinate spaces, and the GPU pipeline.
14- Use to build common effects: tint/recolor, scrolling textures, dissolve,
15  outlines, fresnel/rim light, vignette, color grading.
16- Use to translate a shader concept between GLSL and HLSL, or between engines.
17 
18**When *not* to use:** for an engine's exact shader language and built-ins, use
19`godot-shaders` (Godot shading language) or the engine's material docs. For full
20particle VFX systems, see `unreal-niagara`. For post-process *stacks*, defer to
21the engine's renderer settings.
22 
23## Core workflow
24 
251. **Know which stage you're in.** The **vertex** shader transforms each vertex
26   into clip space and passes data (UVs, normals) onward; the **fragment/pixel**
27   shader runs per rasterized pixel and outputs a color. Most game effects live
28   in the fragment stage.
292. **Track coordinate spaces.** Positions move model → world → view → clip space;
30…