#149 Improve SSR Shader

Assets/BuiltIn/Shader/SSR/GLSL/LibSSR.glsl

@@ -1,63 +1,71 @@
-#define RAY_LENGTH 32.0
+// References
+// https://github.com/MonkeyFirst/Urho3D_SSR_Shader/blob/master/bin/CoreData/Shaders/GLSL/SSR.glsl
+vec2 binarySearch(vec3 dir, vec3 rayPosition)
+{
+	vec4 projectedCoord;
+
+	for(int i = 16; i > 0; --i)
+	{
+		projectedCoord = uProjection * vec4(rayPosition.xyz, 1.0);
+		projectedCoord.xy = projectedCoord.xy / projectedCoord.w;
+		projectedCoord.xy = 0.5 * projectedCoord.xy + vec2(0.5, 0.5);
+
+		vec4 testPosition = texture(uTexPosition, projectedCoord.xy);
+		float dDepth = rayPosition.z - testPosition.w;
+
+		dir *= 0.5;
+		if(dDepth > 0.0)
+			rayPosition -= dir;
+		else
+			rayPosition += dir;
+	}
+
+	return projectedCoord.xy;
+}
 
-vec3 SSR(const vec3 baseColor, const vec3 position, const vec3 reflection, const float roughness)
-{	
+vec3 SSR(const vec3 baseColor, const vec4 position, const vec3 reflection, const float roughness)
+{
 	vec4 projectedCoord;
 
-	vec3 beginPosition;
-	vec3 endPosition;
+	// convert to view space
+	vec3 rayPosition = (uView * vec4(position.xyz, 1.0)).xyz;
+	vec3 viewReflection = normalize((uView * vec4(reflection, 0.0)).xyz);
 
-	vec3 rayPosition = position;
-	vec4 viewPosition;
-
-	vec3 dir = reflection * RAY_LENGTH;
+	// step 0.5m
+	vec3 dir = viewReflection * 0.5;
 
 	float mipLevel = roughness * 5.0;
+	vec2 ssrUV;
 
 	// ray test
 	for (int i = 32; i > 0; --i)
 	{
-		// begin ray
-		beginPosition = rayPosition;
-
-		// end ray
-		endPosition = rayPosition + dir;
-
-		// mid ray
-		rayPosition += dir * 0.5;
+		rayPosition += dir;
 
 		// convert 3d position to 2d texture coord
-		projectedCoord = uViewProjection * vec4(rayPosition.xyz, 1.0);
+		projectedCoord = uProjection * vec4(rayPosition.xyz, 1.0);
 		projectedCoord.xy = projectedCoord.xy / projectedCoord.w;
-		projectedCoord.xy = 0.5 * projectedCoord.xy + vec2(0.5, 0.5);
+		ssrUV = 0.5 * projectedCoord.xy + vec2(0.5, 0.5);
 
-		vec3 testPosition = texture(uTexPosition, projectedCoord.xy).xyz;
+		vec4 testPosition = texture(uTexPosition, ssrUV);
 
-		vec3 d1 = testPosition - beginPosition;
-		float lengthSQ1 = d1.x*d1.x + d1.y*d1.y + d1.z*d1.z;
-
-		vec3 d2 = testPosition - endPosition;
-		float lengthSQ2 = d2.x*d2.x + d2.y*d2.y + d2.z*d2.z;
-
-		// beginPosition is nearer
-		if (lengthSQ1 < lengthSQ2)
+		float depthDiff = rayPosition.z - testPosition.w;
+		if(depthDiff >= 0.0)
 		{
-			rayPosition = beginPosition;
+			ssrUV = binarySearch(dir, rayPosition);
+			break;
 		}
-
-		// binary search test
-		dir *= 0.5;
 	}
 
 	// z clip when camera look down
 	float z = (uView * vec4(reflection, 0.0)).z;
 	z = clamp(z, 0.0, 1.0);
 
 	// convert 3d position to 2d texture coord
-	vec3 color = textureLod(uTexLastFrame, projectedCoord.xy, 0).rgb;
+	vec3 color = textureLod(uTexLastFrame, ssrUV, mipLevel).rgb;
 
 	// edge factor
-	vec2 dCoords = smoothstep(vec2(0.0, 0.0), vec2(0.5, 0.5), abs(vec2(0.5, 0.5) - projectedCoord.xy));
+	vec2 dCoords = smoothstep(vec2(0.0, 0.0), vec2(0.5, 0.5), abs(vec2(0.5, 0.5) - ssrUV));
 	float screenEdgefactor = clamp(1.0 - (dCoords.x + dCoords.y), 0.0, 1.0);
 
 	return mix(baseColor * 0.8, color, screenEdgefactor * z);

Assets/BuiltIn/Shader/SSR/HLSL/LibSSR.hlsl

@@ -1,65 +1,78 @@
-#define RAY_LENGTH 32.0
+// References
+// https://github.com/MonkeyFirst/Urho3D_SSR_Shader/blob/master/bin/CoreData/Shaders/GLSL/SSR.glsl
 
-float3 SSR(const float3 baseColor, const float3 position, const float3 reflection, const float roughness)
+float2 binarySearch(float3 dir, float3 rayPosition)
+{
+	float4 projectedCoord;
+
+	[unroll]
+	for(int i = 16; i > 0; --i)
+	{
+		projectedCoord = mul(float4(rayPosition.xyz, 1.0), uProjection);
+		projectedCoord.xy = projectedCoord.xy / projectedCoord.w;
+		projectedCoord.xy = float2(0.5, -0.5) * projectedCoord.xy + float2(0.5, 0.5);
+
+		float4 testPosition = uTexPosition.Sample(uTexPositionSampler, projectedCoord.xy);
+		float dDepth = rayPosition.z - testPosition.w;
+
+		dir *= 0.5;
+		if(dDepth > 0.0)
+			rayPosition -= dir;
+		else
+			rayPosition += dir;
+	}
+
+	return projectedCoord.xy;
+}
+
+float3 SSR(const float3 baseColor, const float4 position, const float3 reflection, const float roughness)
 {	
 	float4 projectedCoord;
 
-	float3 beginPosition;
-	float3 endPosition;
+	// convert to view space
+	float3 rayPosition = mul(float4(position.xyz, 1.0), uView).xyz;
+	float3 viewReflection = normalize(mul(float4(reflection, 0.0), uView).xyz);
 
-	float3 rayPosition = position;
-	float4 viewPosition;
-
-	float3 dir = reflection * RAY_LENGTH;
+	// step 0.5m
+	float3 dir = viewReflection * 0.5;
 
 	float mipLevel = roughness * 5.0;
-
-	// ray test
+	float2 ssrUV;
+
+	// RayMarch test
+	[unroll]
 	for (int i = 32; i > 0; --i)
 	{
-		// begin ray
-		beginPosition = rayPosition;
+		rayPosition += dir;
 
-		// end ray
-		endPosition = rayPosition + dir;
-
-		// mid ray
-		rayPosition += dir * 0.5;
-
-		// convert 3d position to 2d texture coord		
-		projectedCoord = mul(float4(rayPosition.xyz, 1.0), uViewProjection);
+		// convert 3d position to 2d texture coord
+		projectedCoord = mul(float4(rayPosition.xyz, 1.0), uProjection);
 		projectedCoord.xy = projectedCoord.xy / projectedCoord.w;
-		projectedCoord.xy = float2(0.5, -0.5) * projectedCoord.xy + float2(0.5, 0.5);
 
-		float3 testPosition = uTexPosition.Sample(uTexPositionSampler, projectedCoord.xy).xyz;
+		ssrUV = float2(0.5, -0.5) * projectedCoord.xy + float2(0.5, 0.5);
+		float4 testPosition = uTexPosition.Sample(uTexPositionSampler, ssrUV);
 
-		float3 d1 = testPosition - beginPosition;
-		float lengthSQ1 = d1.x*d1.x + d1.y*d1.y + d1.z*d1.z;
-
-		float3 d2 = testPosition - endPosition;
-		float lengthSQ2 = d2.x*d2.x + d2.y*d2.y + d2.z*d2.z;
-
-		// beginPosition is nearer
-		if (lengthSQ1 < lengthSQ2)
+		float depthDiff = rayPosition.z - testPosition.w;
+		if(depthDiff >= 0.0)
 		{
-			rayPosition = beginPosition;
+			ssrUV = binarySearch(dir, rayPosition);
+			break;
 		}
-
-		// binary search test
-		dir *= 0.5;
 	}
 
 	// z clip when camera look down
 	float z = mul(float4(reflection, 0.0), uView).z;
 	z = clamp(z, 0.0, 1.0);
 
 	// convert 3d position to 2d texture coord	
-	float3 color = uTexLastFrame.SampleLevel(uTexLastFrameSampler, projectedCoord.xy, 0).rgb;
+	float3 color = uTexLastFrame.SampleLevel(uTexLastFrameSampler, ssrUV, mipLevel).rgb;
 
 	// edge factor
-	float2 dCoords = smoothstep(float2(0.0, 0.0), float2(0.5, 0.5), abs(float2(0.5, 0.5) - projectedCoord.xy));
+	float2 dCoords = smoothstep(float2(0.0, 0.0), float2(0.5, 0.5), abs(float2(0.5, 0.5) - ssrUV));
 	float screenEdgefactor = clamp(1.0 - (dCoords.x + dCoords.y), 0.0, 1.0);
 
 	return lerp(baseColor * 0.8, color, screenEdgefactor * z);
+
+	// test
 	// return float3(screenEdgefactor * z, screenEdgefactor * z, screenEdgefactor * z);
 }

Assets/BuiltIn/Shader/SpecularGlossiness/Lighting/GLSL/LibSG.glsl

@@ -10,7 +10,7 @@ vec3 SG(
 	const vec3 baseColor,
 	const float spec,
 	const float gloss,
-	const vec3 position,
+	const vec4 position,
 	const vec3 worldViewDir,
 	const vec3 worldLightDir,
 	const vec3 worldNormal,

Assets/BuiltIn/Shader/SpecularGlossiness/Lighting/GLSL/SGDirectionalLightBakeFS.glsl

@@ -84,7 +84,7 @@ vec3 SG(
 	const vec3 baseColor,
 	const float spec,
 	const float gloss,
-	const vec3 position,
+	const vec4 position,
 	const vec3 worldViewDir,
 	const vec3 worldLightDir,
 	const vec3 worldNormal,
@@ -155,7 +155,7 @@ void main(void)
 		albedo,
 		data.r,
 		data.g,
-		position,
+		posdepth,
 		viewDir,
 		uLightDirection.xyz,
 		normal,

Assets/BuiltIn/Shader/SpecularGlossiness/Lighting/GLSL/SGDirectionalLightFS.d.glsl

@@ -23,6 +23,7 @@ uniform mat4 uShadowMatrix[3];
 #if defined(ENABLE_SSR)
 uniform mat4 uViewProjection;
 uniform mat4 uView;
+uniform mat4 uProjection;
 #endif
 
 in vec2 varTexCoord0;
@@ -82,7 +83,7 @@ void main(void)
 		albedo,
 		data.r,
 		data.g,
-		position,
+		posdepth,
 		viewDir,
 		uLightDirection.xyz,
 		normal,

Assets/BuiltIn/Shader/SpecularGlossiness/Lighting/GLSL/SGDirectionalLightFS.glsl

@@ -18,6 +18,7 @@ uniform vec3 uShadowDistance;
 uniform mat4 uShadowMatrix[3];
 uniform mat4 uViewProjection;
 uniform mat4 uView;
+uniform mat4 uProjection;
 in vec2 varTexCoord0;
 out vec4 FragColor;
 vec2 rand(vec2 co){
@@ -73,38 +74,50 @@ float solveMetallic(vec3 diffuse, vec3 specular, float oneMinusSpecularStrength)
 	float D = b * b - 4.0 * a * c;
 	return clamp((-b + sqrt(D)) / (2.0 * a), 0.0, 1.0);
 }
-vec3 SSR(const vec3 baseColor, const vec3 position, const vec3 reflection, const float roughness)
+vec2 binarySearch(vec3 dir, vec3 rayPosition)
 {
 	vec4 projectedCoord;
-	vec3 beginPosition;
-	vec3 endPosition;
-	vec3 rayPosition = position;
-	vec4 viewPosition;
-	vec3 dir = reflection * 32.0;
+	for(int i = 16; i > 0; --i)
+	{
+		projectedCoord = uProjection * vec4(rayPosition.xyz, 1.0);
+		projectedCoord.xy = projectedCoord.xy / projectedCoord.w;
+		projectedCoord.xy = 0.5 * projectedCoord.xy + vec2(0.5, 0.5);
+		vec4 testPosition = texture(uTexPosition, projectedCoord.xy);
+		float dDepth = rayPosition.z - testPosition.w;
+		dir *= 0.5;
+		if(dDepth > 0.0)
+			rayPosition -= dir;
+		else
+			rayPosition += dir;
+	}
+	return projectedCoord.xy;
+}
+vec3 SSR(const vec3 baseColor, const vec4 position, const vec3 reflection, const float roughness)
+{
+	vec4 projectedCoord;
+	vec3 rayPosition = (uView * vec4(position.xyz, 1.0)).xyz;
+	vec3 viewReflection = normalize((uView * vec4(reflection, 0.0)).xyz);
+	vec3 dir = viewReflection * 0.5;
 	float mipLevel = roughness * 5.0;
+	vec2 ssrUV;
 	for (int i = 32; i > 0; --i)
 	{
-		beginPosition = rayPosition;
-		endPosition = rayPosition + dir;
-		rayPosition += dir * 0.5;
-		projectedCoord = uViewProjection * vec4(rayPosition.xyz, 1.0);
+		rayPosition += dir;
+		projectedCoord = uProjection * vec4(rayPosition.xyz, 1.0);
 		projectedCoord.xy = projectedCoord.xy / projectedCoord.w;
-		projectedCoord.xy = 0.5 * projectedCoord.xy + vec2(0.5, 0.5);
-		vec3 testPosition = texture(uTexPosition, projectedCoord.xy).xyz;
-		vec3 d1 = testPosition - beginPosition;
-		float lengthSQ1 = d1.x*d1.x + d1.y*d1.y + d1.z*d1.z;
-		vec3 d2 = testPosition - endPosition;
-		float lengthSQ2 = d2.x*d2.x + d2.y*d2.y + d2.z*d2.z;
-		if (lengthSQ1 < lengthSQ2)
+		ssrUV = 0.5 * projectedCoord.xy + vec2(0.5, 0.5);
+		vec4 testPosition = texture(uTexPosition, ssrUV);
+		float depthDiff = rayPosition.z - testPosition.w;
+		if(depthDiff >= 0.0)
 		{
-			rayPosition = beginPosition;
+			ssrUV = binarySearch(dir, rayPosition);
+			break;
 		}
-		dir *= 0.5;
 	}
 	float z = (uView * vec4(reflection, 0.0)).z;
 	z = clamp(z, 0.0, 1.0);
-	vec3 color = textureLod(uTexLastFrame, projectedCoord.xy, 0).rgb;
-	vec2 dCoords = smoothstep(vec2(0.0, 0.0), vec2(0.5, 0.5), abs(vec2(0.5, 0.5) - projectedCoord.xy));
+	vec3 color = textureLod(uTexLastFrame, ssrUV, mipLevel).rgb;
+	vec2 dCoords = smoothstep(vec2(0.0, 0.0), vec2(0.5, 0.5), abs(vec2(0.5, 0.5) - ssrUV));
 	float screenEdgefactor = clamp(1.0 - (dCoords.x + dCoords.y), 0.0, 1.0);
 	return mix(baseColor * 0.8, color, screenEdgefactor * z);
 }
@@ -122,7 +135,7 @@ vec3 SG(
 	const vec3 baseColor,
 	const float spec,
 	const float gloss,
-	const vec3 position,
+	const vec4 position,
 	const vec3 worldViewDir,
 	const vec3 worldLightDir,
 	const vec3 worldNormal,
@@ -188,7 +201,7 @@ void main(void)
 		albedo,
 		data.r,
 		data.g,
-		position,
+		posdepth,
 		viewDir,
 		uLightDirection.xyz,
 		normal,

Assets/BuiltIn/Shader/SpecularGlossiness/Lighting/HLSL/LibSG.hlsl

@@ -10,7 +10,7 @@ float3 SG(
 	const float3 baseColor,
 	const float spec,
 	const float gloss,
-	const float3 position,
+	const float4 position,
 	const float3 worldViewDir,
 	const float3 worldLightDir,
 	const float3 worldNormal,

Assets/BuiltIn/Shader/SpecularGlossiness/Lighting/HLSL/SGDirectionalLightBakeFS.hlsl

@@ -95,7 +95,7 @@ float3 SG(
 	const float3 baseColor,
 	const float spec,
 	const float gloss,
-	const float3 position,
+	const float4 position,
 	const float3 worldViewDir,
 	const float3 worldLightDir,
 	const float3 worldNormal,
@@ -166,7 +166,7 @@ float4 main(PS_INPUT input) : SV_TARGET
 		albedo,
 		data.r,
 		data.g,
-		position,
+		posdepth,
 		viewDir,
 		uLightDirection.xyz,
 		normal,