gpu plugin: add fog

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

runelite-client/src/main/java/net/runelite/client/plugins/gpu/GpuPlugin.java

@@ -215,6 +215,10 @@ public class GpuPlugin extends Plugin implements DrawCallbacks
 	private int centerY;
 
 	// Uniforms
+	private int uniUseFog;
+	private int uniFogColor;
+	private int uniFogDepth;
+	private int uniDrawDistance;
 	private int uniProjectionMatrix;
 	private int uniBrightness;
 	private int uniTex;
@@ -506,6 +510,10 @@ public class GpuPlugin extends Plugin implements DrawCallbacks
 		uniProjectionMatrix = gl.glGetUniformLocation(glProgram, "projectionMatrix");
 		uniBrightness = gl.glGetUniformLocation(glProgram, "brightness");
 		uniSmoothBanding = gl.glGetUniformLocation(glProgram, "smoothBanding");
+		uniUseFog = gl.glGetUniformLocation(glProgram, "useFog");
+		uniFogColor = gl.glGetUniformLocation(glProgram, "fogColor");
+		uniFogDepth = gl.glGetUniformLocation(glProgram, "fogDepth");
+		uniDrawDistance = gl.glGetUniformLocation(glProgram, "drawDistance");
 
 		uniTex = gl.glGetUniformLocation(glUiProgram, "tex");
 		uniTextures = gl.glGetUniformLocation(glProgram, "textures");
@@ -723,7 +731,6 @@ public class GpuPlugin extends Plugin implements DrawCallbacks
 		scene.setDrawDistance(drawDistance);
 	}
 
-
 	public void drawScenePaint(int orientation, int pitchSin, int pitchCos, int yawSin, int yawCos, int x, int y, int z,
 							SceneTilePaint paint, int tileZ, int tileX, int tileY,
 							int zoom, int centerX, int centerY)
@@ -1016,6 +1023,13 @@ public class GpuPlugin extends Plugin implements DrawCallbacks
 
 			gl.glUseProgram(glProgram);
 
+			final int drawDistance = Math.max(0, Math.min(MAX_DISTANCE, config.drawDistance()));
+			final int fogDepth = config.fogDepth();
+			gl.glUniform1i(uniUseFog, fogDepth > 0 ? 1 : 0);
+			gl.glUniform4f(uniFogColor, (sky >> 16 & 0xFF) / 255f, (sky >> 8 & 0xFF) / 255f, (sky & 0xFF) / 255f, 1f);
+			gl.glUniform1i(uniFogDepth, fogDepth);
+			gl.glUniform1i(uniDrawDistance, drawDistance * Perspective.LOCAL_TILE_SIZE);
+
 			// Brightness happens to also be stored in the texture provider, so we use that
 			gl.glUniform1f(uniBrightness, (float) textureProvider.getBrightness());
 			gl.glUniform1f(uniSmoothBanding, config.smoothBanding() ? 0f : 1f);

runelite-client/src/main/java/net/runelite/client/plugins/gpu/GpuPluginConfig.java

@@ -64,4 +64,15 @@ public interface GpuPluginConfig extends Config
 	{
 		return AntiAliasingMode.DISABLED;
 	}
+
+	@ConfigItem(
+		keyName = "fogDepth",
+		name = "Fog depth",
+		description = "Distance from the scene edge the fog starts",
+		position = 4
+	)
+	default int fogDepth()
+	{
+		return 0;
+	}
 }

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;
 }