add parallax support

Author: ook3D

CodeWalker.Shaders/BasicPS.hlsl

@@ -3,15 +3,43 @@
 
 float4 main(VS_OUTPUT input) : SV_TARGET
 {
+    // Calculate parallax offset if height mapping is enabled
+    float2 parallaxTexOffset = float2(0, 0);
+    float parallaxSelfShadow = 1.0;
+    if (EnableHeightMap && RenderMode == 0)
+    {
+        float3 viewDir = -normalize(input.CamRelPos); // Negate to get direction FROM surface TO camera
+        float3 norm0 = normalize(input.Normal);
+        float3 tang0 = normalize(input.Tangent.xyz);
+        float3 bitang0 = normalize(input.Bitangent.xyz);
+        parallaxTexOffset = ParallaxOffset(
+            Heightmap, TextureSS, input.Texcoord0,
+            viewDir, norm0, tang0, bitang0,
+            heightScale, heightBias);
+
+        // Parallax self-shadow, transform light dir to tangent space and trace
+        float3 tanLightDir;
+        tanLightDir.x = dot(tang0, GlobalLights.LightDir.xyz);
+        tanLightDir.y = dot(bitang0, GlobalLights.LightDir.xyz);
+        tanLightDir.z = dot(norm0, GlobalLights.LightDir.xyz);
+        float shadowAmount = TraceSelfShadow(Heightmap, TextureSS,
+            input.Texcoord0 + parallaxTexOffset,
+            tanLightDir, 1.0, heightScale);
+        parallaxSelfShadow = 1.0 - shadowAmount * PARALLAX_SELF_SHADOW_AMOUNT;
+    }
+
+    // Apply parallax offset to base texture coordinates
+    float2 texc0 = input.Texcoord0 + parallaxTexOffset;
+
     float4 c = float4(0.5, 0.5, 0.5, 1);
     if (RenderMode == 0) c = float4(1, 1, 1, 1);
     if (EnableTexture > 0)
     {
-        float2 texc = input.Texcoord0;
+        float2 texc = texc0;
         if (RenderMode >= 5)
         {
-            if (RenderSamplerCoord == 2) texc = input.Texcoord1;
-            else if (RenderSamplerCoord == 3) texc = input.Texcoord2;
+            if (RenderSamplerCoord == 2) texc = input.Texcoord1 + parallaxTexOffset;
+            else if (RenderSamplerCoord == 3) texc = input.Texcoord2 + parallaxTexOffset;
         }
 
         c = Colourmap.Sample(TextureSS, texc);
@@ -80,8 +108,8 @@ float4 main(VS_OUTPUT input) : SV_TARGET
     if (RenderMode == 0)
     {
 
-        float4 nv = Bumpmap.Sample(TextureSS, input.Texcoord0);  //sample r1.xyzw, v2.xyxx, t3.xyzw, s3  (BumpSampler)
-        float4 sv = Specmap.Sample(TextureSS, input.Texcoord0);  //sample r2.xyzw, v2.xyxx, t4.xyzw, s4  (SpecSampler)
+        float4 nv = Bumpmap.Sample(TextureSS, texc0);  //sample r1.xyzw, v2.xyxx, t3.xyzw, s3  (BumpSampler)
+        float4 sv = Specmap.Sample(TextureSS, texc0);  //sample r2.xyzw, v2.xyxx, t4.xyzw, s4  (SpecSampler)
 
 
         float2 nmv = nv.xy;
@@ -92,7 +120,7 @@ float4 main(VS_OUTPUT input) : SV_TARGET
             if (EnableDetailMap)
             {
                 //detail normalmapp
-                r0.xy = input.Texcoord0 * detailSettings.zw;    //mul r0.xy, v2.xyxx, detailSettings.zwzz
+                r0.xy = texc0 * detailSettings.zw;    //mul r0.xy, v2.xyxx, detailSettings.zwzz
                 r0.zw = r0.xy * 3.17;       //mul r0.zw, r0.xxxy, l(0.000000, 0.000000, 3.170000, 3.170000)
                 r0.xy = Detailmap.Sample(TextureSS, r0.xy).xy - 0.5;    //sample r1.xyzw, r0.xyxx, t2.xyzw, s2  (DetailSampler)    //mad r0.xy, r1.xyxx, l(2.000000, 2.000000, 0.000000, 0.000000), l(-1.000000, -1.000000, 0.000000, 0.000000)
                 r0.zw = Detailmap.Sample(TextureSS, r0.zw).xy - 0.5;    //sample r1.xyzw, r0.zwzz, t2.xyzw, s2  (DetailSampler)    //mad r0.zw, r1.xxxy, l(0.000000, 0.000000, 2.000000, 2.000000), l(0.000000, 0.000000, -1.000000, -1.000000) //r0.zw = r0.zw*0.5;          //mul r0.zw, r0.zzzw, l(0.000000, 0.000000, 0.500000, 0.500000)
@@ -161,7 +189,7 @@ float4 main(VS_OUTPUT input) : SV_TARGET
 
     float4 fc = c;
 
-    c.rgb = FullLighting(c.rgb, spec, norm, input.Colour0, GlobalLights, EnableShadows, input.Shadows.x, input.LightShadow);
+    c.rgb = FullLighting(c.rgb, spec, norm, input.Colour0, GlobalLights, EnableShadows, input.Shadows.x, input.LightShadow, parallaxSelfShadow);
 
 
     if (IsEmissive==1)

CodeWalker.Shaders/BasicPS.hlsli

@@ -6,6 +6,7 @@ Texture2D<float4> Specmap : register(t3);
 Texture2D<float4> Detailmap : register(t4);
 Texture2D<float4> Colourmap2 : register(t5);
 Texture2D<float4> TintPalette : register(t6);
+Texture2D<float4> Heightmap : register(t7);
 SamplerState TextureSS : register(s0);
 
 
@@ -39,6 +40,10 @@ cbuffer PSGeomVars : register(b2)
     float wetnessMultiplier;
     uint SpecOnly;
 	float4 TextureAlphaMask;
+    uint EnableHeightMap;
+    float heightScale;
+    float heightBias;
+    float Pad0;
 }
 
 

CodeWalker.Shaders/BasicPS_Deferred.hlsl

@@ -3,17 +3,32 @@
 
 PS_OUTPUT main(VS_OUTPUT input)
 {
+    // Calculate parallax offset if height mapping is enabled
+    float2 parallaxTexOffset = float2(0, 0);
+    if (EnableHeightMap && RenderMode == 0)
+    {
+        float3 viewDir = -normalize(input.CamRelPos); // Negate to get direction FROM surface TO camera
+        parallaxTexOffset = ParallaxOffset(
+            Heightmap, TextureSS, input.Texcoord0,
+            viewDir, normalize(input.Normal),
+            normalize(input.Tangent.xyz), normalize(input.Bitangent.xyz),
+            heightScale, heightBias);
+    }
+
+    // Apply parallax offset to base texture coordinates
+    float2 texc0 = input.Texcoord0 + parallaxTexOffset;
+
     float4 c = float4(0.5, 0.5, 0.5, 1);
     if (RenderMode == 0) c = float4(1, 1, 1, 1);
     if (EnableTexture > 0)
     {
-        float2 texc = input.Texcoord0;
+        float2 texc = texc0;
         if (RenderMode >= 5)
         {
             if (RenderSamplerCoord == 2)
-                texc = input.Texcoord1;
+                texc = input.Texcoord1 + parallaxTexOffset;
             else if (RenderSamplerCoord == 3)
-                texc = input.Texcoord2;
+                texc = input.Texcoord2 + parallaxTexOffset;
         }
 
         c = Colourmap.Sample(TextureSS, texc);
@@ -85,8 +100,8 @@ PS_OUTPUT main(VS_OUTPUT input)
     if (RenderMode == 0)
     {
 
-        float4 nv = Bumpmap.Sample(TextureSS, input.Texcoord0);
-        float4 sv = Specmap.Sample(TextureSS, input.Texcoord0);
+        float4 nv = Bumpmap.Sample(TextureSS, texc0);
+        float4 sv = Specmap.Sample(TextureSS, texc0);
 
 
         float2 nmv = nv.xy;
@@ -97,7 +112,7 @@ PS_OUTPUT main(VS_OUTPUT input)
             if (EnableDetailMap)
             {
                 //detail normalmapp
-                r0.xy = input.Texcoord0 * detailSettings.zw;
+                r0.xy = texc0 * detailSettings.zw;
                 r0.zw = r0.xy * 3.17;
                 r0.xy = Detailmap.Sample(TextureSS, r0.xy).xy - 0.5;
                 r0.zw = Detailmap.Sample(TextureSS, r0.zw).xy - 0.5;

CodeWalker.Shaders/Common.hlsli

@@ -119,6 +119,163 @@ float3 NormalMap(float2 nmv, float bumpinezz, float3 norm, float3 tang, float3 b
 }
 
 
+// POM constants
+#define POM_MIN_STEPS 3
+#define POM_MAX_STEPS 16
+#define POM_VDOTN_BLEND_FACTOR 0.25f
+#define POM_HEIGHT_SCALE 0.1f          // Global parallax strength multiplier (1.0 = full, 0.5 = half)
+
+// Distance-based POM fade constants (reduces noise at steep angles/distance)
+#define POM_DISTANCE_START 5.0f    // Distance where fade begins
+#define POM_DISTANCE_END 50.0f     // Distance where POM is fully disabled
+
+// Binary search refinement for more precise intersection (reduces ring artifacts at close range)
+#define POM_BINARY_SEARCH_STEPS 5   // Number of binary search iterations after linear search
+#define POM_CLOSE_DISTANCE 2.0f     // Distance threshold for close-range step boost
+#define POM_CLOSE_STEP_MULTIPLIER 2.0f  // Step multiplier when very close to surface
+
+// Distance fade lookup table (5 control points for smooth non-linear falloff)
+// Based on GTA V pomWeights table
+#define NUM_POM_CTRL_POINTS 5
+static const float pomWeights[NUM_POM_CTRL_POINTS] = {
+    1.0f,   // Full quality at close range
+    0.9f,
+    0.5f,   // 50% at mid distance
+    0.1f,
+    0.0f    // Disabled at far distance
+};
+
+// Compute smooth distance-based fade for POM steps
+float ComputePOMDistanceFade(float distanceBlend)
+{
+    if (distanceBlend >= 1.0f)
+        return 0.0f;
+
+    // Find the nearest control points and interpolate
+    int startPoint = clamp(int(distanceBlend * (NUM_POM_CTRL_POINTS - 1)), 0, NUM_POM_CTRL_POINTS - 2);
+    int endPoint = startPoint + 1;
+
+    float t = distanceBlend * (NUM_POM_CTRL_POINTS - 1) - float(startPoint);
+    return lerp(pomWeights[startPoint], pomWeights[endPoint], t);
+}
+
+// Performs relief mapping by tracing through the height field
+float TraceHeight(Texture2D<float4> heightMapSampler, SamplerState samplerState, float2 texCoords, float2 direction, float2 bias, int maxNumberOfSteps)
+{
+    if (maxNumberOfSteps == 0)
+    {
+        return 0.0f;
+    }
+
+    float heightStep = 1.0f / float(maxNumberOfSteps);
+    float2 offsetPerStep = direction * heightStep;
+
+    float currentBound = 1.0f;
+    float previousBound = currentBound;
+
+    float2 texCoordOffset = bias;
+
+    // Use derivatives for proper mip selection to avoid aliasing
+    float2 ddx0 = ddx(texCoords.xy);
+    float2 ddy0 = ddy(texCoords.xy);
+
+    float currentHeight = heightMapSampler.SampleGrad(samplerState, texCoords.xy, ddx0, ddy0).r + 1e-6f;
+    float previousHeight = currentHeight;
+
+    [unroll(POM_MAX_STEPS)]
+    for (int s = 0; s < maxNumberOfSteps; ++s)
+    {
+        if (currentHeight < currentBound)
+        {
+            previousBound = currentBound;
+            previousHeight = currentHeight;
+
+            currentBound -= heightStep;
+            texCoordOffset += offsetPerStep;
+            currentHeight = heightMapSampler.SampleGrad(samplerState, texCoords + texCoordOffset, ddx0, ddy0).r;
+        }
+        else
+        {
+            break;
+        }
+    }
+
+    // Interpolate between the two points to find a more precise height
+    float currentDelta = currentBound - currentHeight;
+    float previousDelta = previousBound - previousHeight;
+    float denominator = previousDelta - currentDelta;
+
+    float finalHeight = currentHeight;
+
+    if (denominator > 0)
+    {
+        finalHeight = ((currentBound * previousDelta) - (previousBound * currentDelta)) / denominator;
+    }
+
+    return clamp(finalHeight, 0.0, 1.0f);
+}
+
+// Parallax self-shadow: traces through heightmap in light direction to find occlusion
+// Returns shadow factor (0 = fully lit, 1 = fully in shadow)
+float TraceSelfShadow(Texture2D<float4> heightMapSampler, SamplerState samplerState, float2 texCoords, float3 tanLightDir, float edgeWeight, float hScale)
+{
+    float2 inXY = (tanLightDir.xy * hScale * edgeWeight) / max(tanLightDir.z, 0.01f);
+
+    // Sample base height at current (displaced) position
+    float sh0 = heightMapSampler.SampleLevel(samplerState, texCoords, 0).r;
+
+    // Trace 7 samples along light direction with increasing weight for closer occlusion
+    float shA = (heightMapSampler.SampleLevel(samplerState, texCoords + inXY * 0.88, 0).r - sh0 - 0.88) *  1;
+    float sh9 = (heightMapSampler.SampleLevel(samplerState, texCoords + inXY * 0.77, 0).r - sh0 - 0.77) *  2;
+    float sh8 = (heightMapSampler.SampleLevel(samplerState, texCoords + inXY * 0.66, 0).r - sh0 - 0.66) *  4;
+    float sh7 = (heightMapSampler.SampleLevel(samplerState, texCoords + inXY * 0.55, 0).r - sh0 - 0.55) *  6;
+    float sh6 = (heightMapSampler.SampleLevel(samplerState, texCoords + inXY * 0.44, 0).r - sh0 - 0.44) *  8;
+    float sh5 = (heightMapSampler.SampleLevel(samplerState, texCoords + inXY * 0.33, 0).r - sh0 - 0.33) * 10;
+    float sh4 = (heightMapSampler.SampleLevel(samplerState, texCoords + inXY * 0.22, 0).r - sh0 - 0.22) * 12;
+
+    float finalHeight = max(max(max(max(max(max(shA, sh9), sh8), sh7), sh6), sh5), sh4);
+    return saturate(finalHeight);
+}
+
+#define PARALLAX_SELF_SHADOW_AMOUNT 0.95f
+
+// Calculate parallax texture coordinate offset
+float2 ParallaxOffset(Texture2D<float4> heightMapSampler, SamplerState samplerState, float2 texCoords,
+                       float3 viewDir, float3 normal, float3 tangent, float3 bitangent,
+                       float inHeightScale, float inHeightBias)
+{
+    // Transform view direction to tangent space
+    float3 tanEyePos;
+    tanEyePos.x = dot(tangent.xyz, viewDir.xyz);
+    tanEyePos.y = dot(bitangent.xyz, viewDir.xyz);
+    tanEyePos.z = dot(normal.xyz, viewDir.xyz);
+    tanEyePos = normalize(tanEyePos);
+
+    // Clamp Z to avoid division issues at grazing angles
+    float zLimit = 0.1f;
+    float clampedZ = max(zLimit, tanEyePos.z);
+
+    // Calculate view-dependent step count for quality/performance balance
+    float VdotN = abs(dot(normalize(viewDir.xyz), normalize(normal.xyz)));
+    float numberOfSteps = lerp(POM_MAX_STEPS, POM_MIN_STEPS, VdotN);
+
+    // Apply global scale based on view angle for smooth falloff
+    float globalScale = saturate(numberOfSteps - 1.0f) * saturate(VdotN / POM_VDOTN_BLEND_FACTOR);
+
+    // Calculate max parallax offset and bias offset
+    float2 maxParallaxOffset = (-tanEyePos.xy / clampedZ) * inHeightScale * globalScale;
+    float2 heightBiasOffset = (tanEyePos.xy / clampedZ) * inHeightBias * globalScale;
+
+    // Trace through height field
+    float height = TraceHeight(heightMapSampler, samplerState, texCoords, maxParallaxOffset, heightBiasOffset, (int)numberOfSteps);
+
+    // Calculate final texture coordinate offset
+    float2 texCoordOffset = heightBiasOffset + (maxParallaxOffset * (1.0f - height));
+
+    return texCoordOffset;
+}
+
+
 
 
 float3 BasicLighting(float4 lightcolour, float4 ambcolour, float pclit)

CodeWalker.Shaders/Shadowmap.hlsli

@@ -225,7 +225,7 @@ float ShadowAmount(float4 shadowcoord, float shadowdepth)//, inout float4 colour
 
 
 
-float3 FullLighting(float3 diff, float3 spec, float3 norm, float4 vc0, uniform ShaderGlobalLightParams globalLights, uint enableShadows, float shadowdepth, float4 shadowcoord)
+float3 FullLighting(float3 diff, float3 spec, float3 norm, float4 vc0, uniform ShaderGlobalLightParams globalLights, uint enableShadows, float shadowdepth, float4 shadowcoord, float selfShadow = 1.0)
 {
     float lf = saturate(dot(norm, globalLights.LightDir.xyz));
 
@@ -241,6 +241,9 @@ float3 FullLighting(float3 diff, float3 spec, float3 norm, float4 vc0, uniform S
         }
     }
 
+    // Apply parallax self-shadow to cascade shadow
+    shadowlit *= selfShadow;
+
     lf *= shadowlit;
 
     float3 speclit = spec*shadowlit;