From 49df428d95a7c443d418d5b7e2a93af599b54f76 Mon Sep 17 00:00:00 2001
From: salmonik <salmonik@tuta.io>
Date: Wed, 4 Nov 2026 17:51:20 +0100
Subject: Add chams

- Hook IVModelRender::DrawModelExecute (VEngineModel016 slot 19) and force
  models/debug/debugwhite for NPC models, identified by
  ModelRenderInfo_t::entity_index.
- Two passes: MATERIAL_VAR_IGNOREZ through walls, then normal depth, with
  IMaterial::ColorModulate for the configured colour; restore the shared
  material's flag/colour afterwards.
- Material lookup via the IMaterialSystem list, FindMaterial fallback.
- New Chams feature/card with Through walls and colour; [chams] config.
- Remove the temporary ammo/projectile/fuse diagnostics.
---
 src/studio.cpp | 98 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 98 insertions(+)

(limited to 'src/studio.cpp')

diff --git a/src/studio.cpp b/src/studio.cpp
index 23be97f..1b7b77d 100644
--- a/src/studio.cpp
+++ b/src/studio.cpp
@@ -181,8 +181,106 @@ std::string loaded_module_path(const char *needle) {
   return found;
 }
 
+// ---------------------------------------------------------------------------
+// chams: force a flat material on NPC draws
+// ---------------------------------------------------------------------------
+//
+// IVModelRender::DrawModelExecute is called once per model. For NPC entities
+// we force models/debug/debugwhite, optionally with MATERIAL_VAR_IGNOREZ for
+// the through-wall pass, and draw twice. IVModelRender::ForcedMaterialOverride
+// is slot 1; DrawModelExecute is slot 19 in VEngineModel016.
+
+using ModelExecFn = void (*)(void *, const void *, const void *, void *);
+using ForceOverrideFn = void (*)(void *, void *, int);
+
+void *g_modelrender = nullptr;
+ModelExecFn g_orig_model_exec = nullptr;
+ForceOverrideFn g_force_override = nullptr;
+void *g_chams_mat = nullptr;
+bool g_chams_mat_tried = false;
+
+void *chams_material() {
+  if (g_chams_mat_tried)
+    return g_chams_mat;
+  g_chams_mat_tried = true;
+  g_chams_mat = world_find_material("models/debug/debugwhite");
+  if (g_chams_mat)
+    logf("chams: material models/debug/debugwhite = %p", g_chams_mat);
+  else
+    logf("chams: models/debug/debugwhite not found");
+  return g_chams_mat;
+}
+
+void chams_apply(void *mat, bool ignorez) {
+  using ColorFn = void (*)(void *, float, float, float);
+  using FlagFn = void (*)(void *, int, bool);
+  vfunc<ColorFn>(mat, 28)(mat, (float)g_chams_rgb[0] / 255.0f,
+                          (float)g_chams_rgb[1] / 255.0f,
+                          (float)g_chams_rgb[2] / 255.0f);
+  vfunc<FlagFn>(mat, 29)(mat, 1 << 15 /* MATERIAL_VAR_IGNOREZ */, ignorez);
+}
+
+void hkdModelExecute(void *self, const void *state, const void *info,
+                     void *bone) {
+  if (!g_orig_model_exec)
+    return;
+  if (feature_active(FEAT_CHAMS) && info && g_force_override) {
+    // ModelRenderInfo_t::entity_index is at 0x30 on 32-bit.
+    int idx = *(const int *)((const char *)info + 0x30);
+    if (idx > 0 && idx <= 8192 && esp_is_npc_index(idx)) {
+      void *mat = chams_material();
+      if (mat) {
+        if (g_chams_walls) {
+          chams_apply(mat, true);
+          g_force_override(self, mat, 0 /* OVERRIDE_NORMAL */);
+          g_orig_model_exec(self, state, info, bone);
+        }
+        chams_apply(mat, false);
+        g_force_override(self, mat, 0);
+        g_orig_model_exec(self, state, info, bone);
+        g_force_override(self, nullptr, 0);
+        // debugwhite is shared: restore colour and depth behaviour.
+        using ColorFn = void (*)(void *, float, float, float);
+        using FlagFn = void (*)(void *, int, bool);
+        vfunc<FlagFn>(mat, 29)(mat, 1 << 15, false);
+        vfunc<ColorFn>(mat, 28)(mat, 1.0f, 1.0f, 1.0f);
+        return;
+      }
+    }
+  }
+  g_orig_model_exec(self, state, info, bone);
+}
+
 } // namespace
 
+void chams_init() {
+  if (g_modelrender || !g_iface.modelrender) {
+    if (!g_iface.modelrender)
+      logf("chams: VEngineModel016 unavailable");
+    return;
+  }
+  void **vt = *(void ***)g_iface.modelrender;
+  if (!vt) {
+    logf("chams: model render has no vtable");
+    return;
+  }
+  g_force_override = (ForceOverrideFn)vt[1];
+  g_orig_model_exec = (ModelExecFn)vt[19];
+  if (!g_engine.contains((uintptr_t)g_force_override) ||
+      !g_engine.contains((uintptr_t)g_orig_model_exec)) {
+    logf("chams: implausible vtable entries override=%p draw=%p",
+         (void *)g_force_override, (void *)g_orig_model_exec);
+    return;
+  }
+  static void *nvt[32];
+  memcpy(nvt, vt, sizeof(nvt));
+  nvt[19] = (void *)&hkdModelExecute;
+  g_modelrender = g_iface.modelrender;
+  *(void ***)g_modelrender = nvt;
+  logf("chams: IVModelRender %p hooked (draw=%p override=%p)", g_modelrender,
+       (void *)g_orig_model_exec, (void *)g_force_override);
+}
+
 void studio_props_init() {
   if (g_install_tried)
     return;
-- 
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