volumetric: Add a height based fog

Warzone2100 · Jan 14, 2024 · 32bf63d · 32bf63d
1 parent 790b8d2
commit 32bf63d
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Showing 3 changed files with 12 additions and 8 deletions.
diff --git a/data/base/shaders/vk/pointlights.glsl b/data/base/shaders/vk/pointlights.glsl
@@ -74,11 +74,12 @@ vec4 iterateOverAllPointLights(
 	return light;
 }
 
-//volumetric
-vec4 volumetricIterateOverAllPointLights(
+// based on equations found here : https://www.shadertoy.com/view/lstfR7
+vec4 volumetricLights(
 	vec2 clipSpaceCoord,
 	vec3 cameraPosition,
-	vec3 WorldFragPos
+	vec3 WorldFragPos,
+	vec3 sunLightColor
 ) {
 	vec3 result = vec3(0);
 	ivec2 bucket = ivec2(WZ_BUCKET_DIMENSION * clipSpaceCoord);
@@ -93,12 +94,15 @@ vec4 volumetricIterateOverAllPointLights(
 #define STEPS 64
 	for (int i = 0; i < STEPS; i++)
 	{
-		vec3 od = fogColor.xyz * length(viewLine / STEPS) / 10000;
+
 		vec3 posOnViewLine = WorldFragPos + viewLine * i / STEPS;
+		// fog is thicker near 0
+		float thickness = exp(-posOnViewLine.y / 300);
 
+		vec3 od = fogColor.xyz * thickness * length(viewLine / STEPS) / 1000;
 
-		float sunLightEnergy = getShadowVisibility(posOnViewLine);
-		vec3 scatteredLight = vec3(sunLightEnergy) * od;
+		float sunLightEnergy = getShadowVisibility(posOnViewLine) ;
+		vec3 scatteredLight = vec3(sunLightEnergy) * sunLightColor * od;
 
 		for (int i = 0; i < bucketOffsetAndSize[bucketId].y; i++)
 		{

diff --git a/data/base/shaders/vk/tcmask_instanced.frag b/data/base/shaders/vk/tcmask_instanced.frag
@@ -375,7 +375,7 @@ void main()
 
 #if 1
 	vec2 clipSpaceCoord = gl_FragCoord.xy / vec2(viewportWidth, viewportHeight);
-	vec4 volumetric = volumetricIterateOverAllPointLights(clipSpaceCoord, cameraPos.xyz, fragPos);
+	vec4 volumetric = volumetricLights(clipSpaceCoord, cameraPos.xyz, fragPos, diffuse.xyz);
 	fragColour.xyz = toneMap(fragColour.xyz * volumetric.a + volumetric.xyz);	
 #else
 	if (fogEnabled > 0)

diff --git a/data/base/shaders/vk/terrain_combined_high.frag b/data/base/shaders/vk/terrain_combined_high.frag
@@ -128,7 +128,7 @@ void main()
 #if 1
 
 	vec2 clipSpaceCoord = gl_FragCoord.xy / vec2(viewportWidth, viewportHeight);	
-	vec4 volumetric = volumetricIterateOverAllPointLights(clipSpaceCoord, cameraPos.xyz, frag.fragPos);
+	vec4 volumetric = volumetricLights(clipSpaceCoord, cameraPos.xyz, frag.fragPos, diffuseLight.xyz);
 	fragColor.xyz = toneMap(fragColor.xyz * volumetric.a + volumetric.xyz);
 #else
 	if (fogEnabled > 0)