From cc8b06d1e40116161a50aa0c6ea6fa572a5b2367 Mon Sep 17 00:00:00 2001
From: Kelsi <kelsihates2fa@gmail.com>
Date: Thu, 19 Feb 2026 18:19:52 -0800
Subject: [PATCH] Fix black background on lamp/lantern/torch glow effects

Three-part fix for glow textures showing opaque black rectangles instead
of being transparent:

1. Pass blend mode to fragment shader via uBlendMode uniform. For additive
   blend modes (3=Add, 6=BlendAdd), discard near-black fragments (maxRGB
   < 0.1) since they contribute nothing visually but render as dark
   rectangles against sky/terrain.

2. Expand colorKeyBlack texture keyword detection to include "lamp",
   "lantern", "glow", "flare", "brazier", "campfire", "bonfire" in
   addition to the existing "candle", "flame", "fire", "torch".

3. Expand flameLikeModel detection for glow sprite conversion to include
   "brazier", "campfire", "bonfire". Also compute glow centers for
   colorKeyBlack batches (not just blendMode >= 3) so glow sprites
   position correctly for all flame-like objects.
---
 src/rendering/m2_renderer.cpp | 31 ++++++++++++++++++++++++++-----
 1 file changed, 26 insertions(+), 5 deletions(-)

diff --git a/src/rendering/m2_renderer.cpp b/src/rendering/m2_renderer.cpp
index 73b4c24f..f11a298f 100644
--- a/src/rendering/m2_renderer.cpp
+++ b/src/rendering/m2_renderer.cpp
@@ -327,6 +327,7 @@ bool M2Renderer::initialize(pipeline::AssetManager* assets) {
         uniform bool uAlphaTest;
         uniform bool uColorKeyBlack;
         uniform bool uUnlit;
+        uniform int uBlendMode;
         uniform float uFadeAlpha;
 
         uniform vec3 uFogColor;
@@ -353,10 +354,18 @@ bool M2Renderer::initialize(pipeline::AssetManager* assets) {
             if (uAlphaTest && texColor.a < 0.5) {
                 discard;
             }
-            if (uAlphaTest && max(texColor.r, max(texColor.g, texColor.b)) < 0.06) {
+            float maxRgb = max(texColor.r, max(texColor.g, texColor.b));
+            if (uAlphaTest && maxRgb < 0.06) {
                 discard;
             }
-            if (uColorKeyBlack && max(texColor.r, max(texColor.g, texColor.b)) < 0.08) {
+            if (uColorKeyBlack && maxRgb < 0.08) {
+                discard;
+            }
+            // Additive blend modes (3=Add, 6=BlendAdd): near-black fragments
+            // contribute nothing visually (add ~0 to framebuffer) but show as
+            // dark rectangles against sky/terrain. Discard them.
+            // Skip Mod(4)/Mod2x(5) since near-black is intentional for those.
+            if ((uBlendMode == 3 || uBlendMode == 6) && maxRgb < 0.1) {
                 discard;
             }
 
@@ -1210,7 +1219,7 @@ bool M2Renderer::loadModel(const pipeline::M2Model& model, uint32_t modelId) {
             bgpu.batchOpacity = texFailed ? 0.0f : 1.0f;
 
             // Compute batch center and radius for glow sprite positioning
-            if (bgpu.blendMode >= 3 && batch.indexCount > 0) {
+            if ((bgpu.blendMode >= 3 || bgpu.colorKeyBlack) && batch.indexCount > 0) {
                 glm::vec3 sum(0.0f);
                 uint32_t counted = 0;
                 for (uint32_t j = batch.indexStart; j < batch.indexStart + batch.indexCount; j++) {
@@ -1891,6 +1900,7 @@ void M2Renderer::render(const Camera& camera, const glm::mat4& view, const glm::
     glActiveTexture(GL_TEXTURE0);
     shader->setUniform("uTexture", 0);  // Texture unit 0, set once per frame
     shader->setUniform("uColorKeyBlack", false);
+    shader->setUniform("uBlendMode", 0);
 
     // Performance counters
     uint32_t boneMatrixUploads = 0;
@@ -1984,7 +1994,10 @@ void M2Renderer::render(const Camera& camera, const glm::mat4& view, const glm::
             (modelKeyLower.find("torch") != std::string::npos) ||
             (modelKeyLower.find("candle") != std::string::npos) ||
             (modelKeyLower.find("flame") != std::string::npos) ||
-            (modelKeyLower.find("fire") != std::string::npos);
+            (modelKeyLower.find("fire") != std::string::npos) ||
+            (modelKeyLower.find("brazier") != std::string::npos) ||
+            (modelKeyLower.find("campfire") != std::string::npos) ||
+            (modelKeyLower.find("bonfire") != std::string::npos);
 
         for (const auto& batch : model.batches) {
             if (batch.indexCount == 0) continue;
@@ -2078,6 +2091,7 @@ void M2Renderer::render(const Camera& camera, const glm::mat4& view, const glm::
                         break;
                 }
                 lastBlendMode = batch.blendMode;
+                shader->setUniform("uBlendMode", static_cast<int>(batch.blendMode));
             } else {
                 // Still need to know if batch is transparent for depth mask logic
                 batchTransparent = (batch.blendMode >= 2);
@@ -2899,7 +2913,14 @@ GLuint M2Renderer::loadTexture(const std::string& path, uint32_t texFlags) {
         containsToken(key, "candle") ||
         containsToken(key, "flame") ||
         containsToken(key, "fire") ||
-        containsToken(key, "torch");
+        containsToken(key, "torch") ||
+        containsToken(key, "lamp") ||
+        containsToken(key, "lantern") ||
+        containsToken(key, "glow") ||
+        containsToken(key, "flare") ||
+        containsToken(key, "brazier") ||
+        containsToken(key, "campfire") ||
+        containsToken(key, "bonfire");
 
     // Load BLP texture
     pipeline::BLPImage blp = assetManager->loadTexture(key);