Props: remove studio diagnostics; document the prop tint path

Drop the temporary DrawModel/SetColor logs now that the prop tint works, and
document the IStudioRender hook layout, the short model-name format used for
prop detection, the SetColor-before-DrawModel ordering, and why prop
materials cannot be tinted directly.

2 files changed, 21 insertions, 25 deletions

diff --git a/CONTEXT.md b/CONTEXT.md
index 5eca9f8..2199be6 100644
--- a/CONTEXT.md
+++ b/CONTEXT.md
@@ -329,11 +329,27 @@ vocabulary / decisions.
   already-loaded `materialsystem.so` and walk every material with
   `FirstMaterial` / `NextMaterial` / `GetMaterial`.
 - `IMaterial::ColorModulate(r,g,b)` is applied to materials whose
-  `GetTextureGroupName()` is `World textures` (sky names excluded), to
-  `SkyBox textures` (or names containing `sky`), and to prop materials whose
-  name starts with `models/props` (static props and prop_physics share those
-  model materials; NPC/player/weapon materials are excluded). Lightmaps are
-  not touched.
+  `GetTextureGroupName()` is `World textures` (sky names excluded) and to
+  `SkyBox textures` (or names containing `sky`). Lightmaps are not touched.
+- Props are NOT tinted through their materials: VertexLitGeneric materials get
+  their colour modulation from `IStudioRender`, which the engine sets per
+  model draw (white), so the material var is overridden. `src/studio.cpp`
+  hooks the `VStudioRender025` interface object instead:
+  `SetColorModulation`/`SetAlphaModulation` (slots 27/28), `DrawModel` (29),
+  `DrawModelStaticProp` (30) and `DrawModelArray` (46), all checked against
+  `CStudioRenderContext`'s vtable in `studiorender.so`.
+  `DrawModel` checks `DrawModelInfo_t::m_pStudioHdr->name`; note the name is
+  the short form with Windows separators (`props_junk\wood_crate002a.mdl`,
+  no `models/` prefix), so prop detection matches `props/`, `props\` and
+  `props_` after stripping `models/` (excluding `props_skybox`). For a prop it
+  sets the prop colour right before calling the original draw; setting the
+  colour from a flag inside the draw does not work because the engine calls
+  `SetColorModulation(1,1,1)` *before* `DrawModel`.
+  Do not force `SetAlphaModulation` there: the earlier attempt produced
+  error-material props and a material-system crash.
+- `prop_tint_update()` also writes `m_clrRender` on prop entities (dynamic
+  props) as a secondary path; the netvar resolver rejects offset 0 (an
+  embedded-table false positive) and only accepts 0x20..0x2000.
 - Slot map (2013 SDK layout, registered under `VMaterialSystem080`):
   `IMaterialSystem` 73/74/75/76/77 = First/Next/Invalid/Get/GetNumMaterials;
   `IMaterial` 0/1/28 = GetName/GetTextureGroupName/ColorModulate.
diff --git a/src/studio.cpp b/src/studio.cpp
index c4c3cfb..485b4fb 100644
--- a/src/studio.cpp
+++ b/src/studio.cpp
@@ -40,8 +40,6 @@ bool g_installed = false;
 int g_prop_depth = 0;
 int g_static_calls = 0;
 int g_static_props = 0;
-int g_model_logs = 0;
-int g_array_logs = 0;
 
 bool prop_tint_on() {
   return feature_active(FEAT_WORLD_TINT) && g_tint_prop_on;
@@ -89,15 +87,7 @@ bool is_prop_model(const char *name) {
          strncmp(name, "props_", 6) == 0;
 }
 
-int g_color_logs = 0;
-
 void hook_set_color(void *self, const float *color) {
-  if (g_color_logs < 10) {
-    g_color_logs++;
-    logf("studio: SetColorModulation depth=%d color=%.2f,%.2f,%.2f",
-         g_prop_depth, color ? color[0] : 0.0f, color ? color[1] : 0.0f,
-         color ? color[2] : 0.0f);
-  }
   if (g_prop_depth > 0 && prop_tint_on()) {
     float c[4];
     prop_color(c);
@@ -120,11 +110,6 @@ void hook_draw_model(void *self, void *results, void *info, void *bone,
                      void *flex, void *flex_delayed, int flags) {
   const char *model = info_model_name(info);
   bool prop = prop_tint_on() && is_prop_model(model);
-  if (g_model_logs < 10) {
-    g_model_logs++;
-    logf("studio: DrawModel model=\"%s\" prop=%d", model ? model : "?",
-         (int)prop);
-  }
   if (prop) {
     float c[4];
     prop_color(c);
@@ -140,11 +125,6 @@ void hook_draw_array(void *self, void *info, int count, void *instances,
                      int stride, int flags) {
   const char *model = info_model_name(info);
   bool prop = prop_tint_on() && is_prop_model(model);
-  if (g_array_logs < 10) {
-    g_array_logs++;
-    logf("studio: DrawModelArray count=%d model=\"%s\" prop=%d", count,
-         model ? model : "?", (int)prop);
-  }
   if (prop)
     g_prop_depth++;
   g_orig_draw_array(self, info, count, instances, stride, flags);