From dcdfc1fcf1142dcf29ba6caa4c317f3bf9fdec81 Mon Sep 17 00:00:00 2001
From: Zane van Iperen <zane@zanevaniperen.com>
Date: Wed, 2 Oct 2024 00:08:01 +0900
Subject: [PATCH] drivers/glrend: fix light accumulation

---
 drivers/glrend/brender.common.glsl | 25 +++++++++++--------------
 drivers/glrend/brender.frag.glsl   | 27 +++++++++++----------------
 drivers/glrend/brender.vert.glsl   |  9 ++++-----
 3 files changed, 26 insertions(+), 35 deletions(-)

diff --git a/drivers/glrend/brender.common.glsl b/drivers/glrend/brender.common.glsl
index 244ccd02..722cd750 100644
--- a/drivers/glrend/brender.common.glsl
+++ b/drivers/glrend/brender.common.glsl
@@ -203,24 +203,21 @@ vec3 lightingColourSpotAtten(in vec4 p, in vec4 n, in br_light alp)
 
 
 
-vec4 fragmainXX(in vec4 position, in vec4 normal, out bool directLightExists)
+vec4 accumulateLights(in vec4 position, in vec4 normal)
 {
-//#if DEBUG_DISABLE_LIGHTS
-    //return surface_colour;
-//#endif
+#if DEBUG_DISABLE_LIGHTS
+    return vec4(1);
+#endif
 
     if (num_lights == 0u || unlit != 0u) {
-        return surface_colour;
+        return vec4(1);
     }
 
     vec4 normalDirection = normal;
 
-    vec3 _colour = surface_colour.xyz;
-
     /* This is shit, but this is the way the engine does it */
     vec3 lightColour = vec3(0.0);
-    vec3 directLightColour = vec3(0.0);
-    directLightExists = false;
+    bool directLightExists = false;
 
     for (uint i = 0u; i < num_lights; ++i) {
 #if !DEBUG_DISABLE_LIGHT_AMBIENT
@@ -232,7 +229,7 @@ vec4 fragmainXX(in vec4 position, in vec4 normal, out bool directLightExists)
         if (lights[i].position.w == 0) {
 #if !DEBUG_DISABLE_LIGHT_DIRECTIONAL
             directLightExists = true;
-            directLightColour += lightingColourDirect(position, normalDirection, lights[i]);
+            lightColour += lightingColourDirect(position, normalDirection, lights[i]);
 #endif
         } else {
             if (lights[i].spot_angles == vec2(0.0, 0.0)) {
@@ -256,9 +253,9 @@ vec4 fragmainXX(in vec4 position, in vec4 normal, out bool directLightExists)
         }
     }
 
-    lightColour += directLightColour;
-    lightColour *= _colour;
+    if (!directLightExists && num_lights > 0u && unlit == 0u) {
+        lightColour += clear_colour.rgb;
+    }
 
-    lightColour = clamp(lightColour, 0.0, 1.0);
-    return vec4(lightColour, surface_colour.a);
+    return vec4(clamp(lightColour, 0.0, 1.0), 1);
 }
diff --git a/drivers/glrend/brender.frag.glsl b/drivers/glrend/brender.frag.glsl
index 73322c76..917897f5 100644
--- a/drivers/glrend/brender.frag.glsl
+++ b/drivers/glrend/brender.frag.glsl
@@ -7,6 +7,7 @@ in vec4 position;
 in vec2 uv;
 in vec4 normal;
 in vec4 colour;
+in vec4 vertexLight;
 
 in vec3 rawPosition;
 in vec3 rawNormal;
@@ -119,39 +120,33 @@ void main()
         discard;
 
 #if ENABLE_PHONG
-    vec4 lightColour;
-
-    bool directLightExists = false;
-    lightColour = fragmainXX(position, normal, directLightExists);
-    if (!directLightExists && num_lights > 0u && unlit == 0u) {
-        lightColour += vec4(clear_colour.rgb, 0.0);
-    }
+    vec4 fragmentLight = accumulateLights(position, normal);
 #else
-    vec4 lightColour = vec4(0, 0, 0, 0);
+    vec4 fragmentLight = vec4(1);
 #endif
 
-    vec4 surfaceColour = (surface_colour * texColour);
-    vec3 fragColour = vec3((colour.rgb + lightColour.rgb) * texColour.rgb);
+    vec4 surfaceColour = (surface_colour * texColour * vertexLight);
+    vec4 fragColour = surfaceColour * fragmentLight;
 
     /* Perform gamma correction */
 #if ENABLE_GAMMA_CORRECTION
-    fragColour = pow(fragColour, vec3(1.0 / 1.2));
-    // fragColour = adjustContrast(fragColour, 0.1);
-    // fragColour = adjustExposure(fragColour, 2.0);
+    fragColour.rgb = pow(fragColour.rgb, vec3(1.0 / 1.2));
+    // fragColour.rgb = adjustContrast(fragColour.rgb, 0.1);
+    // fragColour.rgb = adjustExposure(fragColour.rgb, 2.0);
 #endif
 
 #if ENABLE_SIMULATE_8BIT_COLOUR
-    fragColour = floor(fragColour.rgb * vec3(15.0)) / vec3(15.0);
+    fragColour.rgb = floor(fragColour.rgb * vec3(15.0)) / vec3(15.0);
 #endif
 #if ENABLE_SIMULATE_16BIT_COLOUR
     float r = floor(fragColour.r * 31.0) / 31.0;
     float g = floor(fragColour.g * 63.0) / 63.0;
     float b = floor(fragColour.b * 31.0) / 31.0;
-    fragColour = vec3(r, g, b);
+    fragColour.rgb = vec3(r, g, b);
 #endif
 
     /* The actual surface colour. */
-    mainColour = vec4(fragColour, surfaceColour.a);
+    mainColour = fragColour;
 
     return;
 }
diff --git a/drivers/glrend/brender.vert.glsl b/drivers/glrend/brender.vert.glsl
index 28ac3b28..3f265221 100644
--- a/drivers/glrend/brender.vert.glsl
+++ b/drivers/glrend/brender.vert.glsl
@@ -11,6 +11,7 @@ out vec4 position;
 out vec4 normal;
 out vec2 uv;
 out vec4 colour;
+out vec4 vertexLight;
 
 out vec3 rawPosition;
 out vec3 rawNormal;
@@ -33,14 +34,12 @@ void main()
     position = model_view * pos;
     normal = vec4(normalize(mat3(normal_matrix) * aNormal), 0);
     uv = aUV;
+    colour = aColour;
 
 #if ENABLE_GOURAUD
-    bool directLightExists = false;
-    colour = aColour + fragmainXX(position, normal, directLightExists);
-    if (!directLightExists && num_lights > 0u && unlit == 0u)
-        colour += vec4(clear_colour.rgb, 0.0);
+    vertexLight = accumulateLights(position, normal);
 #else
-    colour = aColour;
+    vertexLight = vec4(1);
 #endif
 
     rawPosition = aPosition;