Updated Shader Changes (markdown)

Shader-Changes.md

@@ -1,3 +1,5 @@
+Shaders are special programs ran by the GPU. The Source SDK allows modders to modify or add shaders to the engine, as many mods have done.
+
 Mapbase modifies the shaders in various ways, but these changes aren't meant to improve graphical quality as much as they're meant to fix bugs or "improve the mapping experience".
 
 Before we actually get into what these changes are, we need to talk about the caveat of modifying existing shaders:
@@ -14,9 +16,15 @@ You could potentially get away with using the original shaders if you don't need
 
 ---
 
-# Actual Shader Changes
+---
 
-**These are the changes Mapbase makes with its custom shaders:**
+The majority of Mapbase's large-scale shader changes come from other projects or are based off of other versions of the engine, so they've been split into two categories for changes made by other people and changes made specifically for Mapbase.
+
+---
+
+## "Third Party" shader changes
+
+Other people's work from other people's projects that have been gathered into Mapbase.
 
 ---
 ### Insolence's Alien Swarm/C17:EP1 projected textures
@@ -27,7 +35,11 @@ Mapbase uses a combination of Alien Swarm, City 17: Episode One, and G-String pr
 
 ---
 ### Downfall's Alien Swarm radial fog
-Mapbase uses Half-Life 2: Downfall's implementation of Alien Swarm's radial fog, as opposed to Half-Life 2's planar fog. This means fog is calculated radially and doesn't change as you rotate the camera and prevents players from being able to see past fog by looking a the edges of their screens. This feature was highly requested.
+Mapbase uses Half-Life 2: Downfall's implementation of Alien Swarm's radial fog.
+
+Radial fog was implemented in Source at some point before Alien Swarm, possibly in L4D2 or something, but Half-Life 2 still uses "planar" fog, which is calculated as a plane and changes as you rotate the camera. You could often see past it by rotating the camera and looking at the edge of your screen.
+
+HL2: Downfall implements radial fog in Source 2013, which Mapbase uses and also extends to other shaders. This means fog is calculated radially and doesn't change as you rotate the camera, unlike planar fog.
 
 <p align="left">
 <img src="https://i.imgur.com/bOC9iZu.png" width="512"/>
@@ -37,15 +49,26 @@ Using white fog in the example picture was probably a bad idea.
 
 ---
 ### C17:EP1's phong on LightmappedGeneric
-Mapbase uses City 17: Episode One's LightmappedGeneric/WorldVertexTransition fog, ported from Insolence's repository.
+Mapbase uses City 17: Episode One's LightmappedGeneric/WorldVertexTransition phong, implemented from Insolence's repository.
 
-(todo: figure out what it looks like)
+This was ported with the projected texture changes when Mapbase gleaned shader stuff from the Insolence repo. It was ported because the FXC files were being copied directly instead of cherry-picking individual code changes. (there was a very large number of changes, they were brand-new files, I was still learning how to mod shaders, etc.) There was also some mild demand for them. Again, even though I got this from the Insolence repo, the code was almost entirely from City 17: Episode One and you could find more information on their ModDB page. (todo: link)
+
+(todo: also figure out what it looks like for an in-Mapbase screenshot)
 
 ---
 ### Alien Swarm ropes (SplineRope)
-Mapbase uses Alien Swarm ropes from Half-Life 2: Downfall, including both the SplineRope shader and keyframe_rope itself. This looks and runs better, apparently.
+Mapbase uses Alien Swarm ropes from Half-Life 2: Downfall, including both the SplineRope shader and the changes to move/keyframe_rope itself.
 
-(todo: figure out the details)
+The circumstances behind this being added are similar to that of the "brush phong" above, but I didn't know whether this was required for the radial fog changes to work at the time. I still don't know many of the differences, although it does seem to look better.
+
+(todo: figure out more details)
+
+---
+---
+
+## Mapbase's own shader changes
+
+Shader changes created specifically for Mapbase, mostly by Blixibon.
 
 ---
 ### $blendmodulatetexture fixes