gpu plugin: add fog

Co-authored-by: logarithm <allan.palmu@gmail.com>

runelite-client/src/main/resources/net/runelite/client/plugins/gpu/frag.glsl

@@ -28,10 +28,12 @@ uniform sampler2DArray textures;
 uniform vec2 textureOffsets[64];
 uniform float brightness;
 uniform float smoothBanding;
+uniform vec4 fogColor;
 
 in vec4 Color;
 in float fHsl;
 in vec4 fUv;
+in float fogAmount;
 
 out vec4 FragColor;
 
@@ -54,8 +56,9 @@ void main() {
     vec4 textureColor = texture(textures, vec3(animatedUv, n));
     vec4 textureColorBrightness = pow(textureColor, vec4(brightness, brightness, brightness, 1.0f));
 
-    FragColor = textureColorBrightness * smoothColor;
-  } else {
-    FragColor = smoothColor;
+    smoothColor = textureColorBrightness * smoothColor;
   }
+
+  vec3 mixedColor = mix(smoothColor.rgb, fogColor.rgb, fogAmount);
+  FragColor = vec4(mixedColor, smoothColor.a);
 }

runelite-client/src/main/resources/net/runelite/client/plugins/gpu/geom.glsl

@@ -49,10 +49,12 @@ in ivec3 vPosition[];
 in vec4 vColor[];
 in float vHsl[];
 in vec4 vUv[];
+in float vFogAmount[];
 
 out vec4 Color;
 out float fHsl;
 out vec4 fUv;
+out float fogAmount;
 
 #include to_screen.glsl
 
@@ -71,6 +73,7 @@ void main() {
   Color = vColor[0];
   fHsl = vHsl[0];
   fUv = vUv[0];
+  fogAmount = vFogAmount[0];
   gl_Position  = projectionMatrix * tmp;
   EmitVertex();
 
@@ -78,6 +81,7 @@ void main() {
   Color = vColor[1];
   fHsl = vHsl[1];
   fUv = vUv[1];
+  fogAmount = vFogAmount[1];
   gl_Position  = projectionMatrix * tmp;
   EmitVertex();
 
@@ -85,6 +89,7 @@ void main() {
   Color = vColor[2];
   fHsl = vHsl[2];
   fUv = vUv[2];
+  fogAmount = vFogAmount[2];
   gl_Position  = projectionMatrix * tmp;
   EmitVertex();
 

runelite-client/src/main/resources/net/runelite/client/plugins/gpu/vert.glsl

@@ -25,18 +25,43 @@
 
 #version 330
 
+#define TILE_SIZE 128
+
+#define FOG_SCENE_EDGE_MIN TILE_SIZE
+#define FOG_SCENE_EDGE_MAX (103 * TILE_SIZE)
+
 layout (location = 0) in ivec4 VertexPosition;
 layout (location = 1) in vec4 uv;
 
+layout(std140) uniform uniforms {
+  int cameraYaw;
+  int cameraPitch;
+  int centerX;
+  int centerY;
+  int zoom;
+  int cameraX;
+  int cameraY;
+  int cameraZ;
+  ivec2 sinCosTable[2048];
+};
+
 uniform float brightness;
+uniform int useFog;
+uniform int fogDepth;
+uniform int drawDistance;
 
 out ivec3 vPosition;
 out vec4 vColor;
 out float vHsl;
 out vec4 vUv;
+out float vFogAmount;
 
 #include hsl_to_rgb.glsl
 
+float fogFactorLinear(const float dist, const float start, const float end) {
+  return 1.0 - clamp((dist - start) / (end - start), 0.0, 1.0);
+}
+
 void main()
 {
   ivec3 vertex = VertexPosition.xyz;
@@ -50,4 +75,14 @@ void main()
   vColor = vec4(rgb, 1.f - a);
   vHsl = float(hsl);
   vUv = uv;
+
+  int fogWest = max(FOG_SCENE_EDGE_MIN, cameraX - drawDistance);
+  int fogEast = min(FOG_SCENE_EDGE_MAX, cameraX + drawDistance - TILE_SIZE);
+  int fogSouth = max(FOG_SCENE_EDGE_MIN, cameraZ - drawDistance);
+  int fogNorth = min(FOG_SCENE_EDGE_MAX, cameraZ + drawDistance - TILE_SIZE);
+
+  // Calculate distance from the scene edge
+  float fogDistance = min(min(vertex.x - fogWest, fogEast - vertex.x), min(vertex.z - fogSouth, fogNorth - vertex.z));
+
+  vFogAmount = fogFactorLinear(fogDistance, 0, fogDepth * TILE_SIZE) * useFog;
 }