OpenGL-Shader-Changes.md

@@ -15,7 +15,7 @@ Prepares the shader system for use. Compiles the fallback shader. Returns false
 
 - `void LoadShader(int slot, char *code, hwdshaderstage_t stage)`
 
-Loads shader source code from the null-terminated string `code` into `slot`. Slots start from 1, the first slot 0 is reserved for the fallback shader. `stage` is either fragment or vertex. (Perhaps in the future the rest of the stages could be added)
+Loads shader source code from the null-terminated string `code` into `slot`. Valid slots are from 0 to `HWR_MAXSHADERS`. `stage` is either `HWD_SHADERSTAGE_VERTEX` or `HWD_SHADERSTAGE_FRAGMENT`. The memory in `code` belongs to the backend now. Any previous shader code in `slot` and `stage` is freed from memory. (Perhaps in the far future the rest of the stages could be added)
 
 - `boolean CompileShader(int slot)`
 
@@ -37,6 +37,28 @@ The fixed function pipeline is used for draw calls instead of shaders. (used for
 
 Sets certain values that are given to shader uniform variables. (currently only level time)
 
+hw_shaders.c
+------------
+
+Each geometry type has a "shader target", which contains references to the vanilla and custom shaders used for that geometry. `HWR_GetShaderFromTarget` is used to get the shader that should currently be used for that target.
+
+```
+enum
+{
+	SHADER_FLOOR,
+	SHADER_WALL,
+	SHADER_SPRITE,
+	SHADER_MODEL,
+	SHADER_WATER,
+	SHADER_FOG,
+	SHADER_SKY,
+
+	NUMSHADERTARGETS,
+};
+```
+
+Custom shader loading functions from `hw_main.c` are adapted and moved to `hw_shaders.c`.
+
 The shader "pre-preprocessor"
 -----------------------------