Impostors: continue work on depth, getting closer

5 files changed, 44 insertions, 27 deletions

diff --git a/3ner.cginc b/3ner.cginc
index ab80a8d..18c23ee 100644
--- a/3ner.cginc
+++ b/3ner.cginc
@@ -258,7 +258,7 @@ float4 frag(v2f i, uint facing : SV_IsFrontFace
 #endif
     ) : SV_Target {
   UNITY_SETUP_INSTANCE_ID(i);
-#if defined(SHADOW_CASTER_PASS)
+#if defined(SHADOW_CASTER_PASS) && !(_IMPOSTORS)
   return 0;
 #endif
 
@@ -281,18 +281,9 @@ float4 frag(v2f i, uint facing : SV_IsFrontFace
   i.normal = pbr.normal;
   i.objPos = pbr.objPos;
   propagateObjPos(i);
+
   float4 imp_clip_pos = UnityObjectToClipPos(i.objPos);
   depth = imp_clip_pos.z / imp_clip_pos.w;
-  if (false) {
-    depth *= 100;
-    depth *= depth;
-    depth *= depth;
-    depth *= 100;
-    return float4(depth, depth, depth, 1);
-  }
-  if (false) {
-    return float4(i.objPos, 1);
-  }
 #endif
 
 #if defined(_DEBUG_VIEW_UNLIT)
@@ -304,7 +295,6 @@ float4 frag(v2f i, uint facing : SV_IsFrontFace
 #elif defined(_DEBUG_VIEW_DEPTH)
   float2 screen_uv = i.pos.xy / _ScreenParams.xy;
   float depth = SAMPLE_DEPTH_TEXTURE(_CameraDepthTexture, screen_uv);
-  depth = 1.0f - depth;
   depth *= 100;
   depth *= depth;
   depth *= depth;
@@ -323,4 +313,3 @@ float4 frag(v2f i, uint facing : SV_IsFrontFace
 }
 
 #endif  // __3NER_INC
-
diff --git a/DepthBlit.shader b/DepthBlit.shader
index 4094fe5..b2a512f 100644
--- a/DepthBlit.shader
+++ b/DepthBlit.shader
@@ -20,7 +20,7 @@ Shader "Hidden/yum_food/DepthBlit"
 
             #include "UnityCG.cginc"
 
-            sampler2D _DepthTex;
+            UNITY_DECLARE_DEPTH_TEXTURE(_DepthTex);
             float _Near;
             float _Far;
 
@@ -41,7 +41,14 @@ Shader "Hidden/yum_food/DepthBlit"
             float4 frag(v2f i) : SV_Target
             {
                 // 0 = near clip plane, 1 = far clip plane.
-                return tex2D(_DepthTex, i.uv).r;
+                float rawDepth = SAMPLE_DEPTH_TEXTURE(_DepthTex, i.uv);
+                // Unity uses reversed-Z on most platforms: 1 at near, 0 at far.
+                // Flip to get linear 0-1 (0=near, 1=far) for orthographic cameras.
+                #if defined(UNITY_REVERSED_Z)
+                    return 1.0 - rawDepth;
+                #else
+                    return rawDepth;
+                #endif
             }
             ENDCG
         }
diff --git a/Scripts/Impostors.cs b/Scripts/Impostors.cs
index e1447b6..9769aa1 100644
--- a/Scripts/Impostors.cs
+++ b/Scripts/Impostors.cs
@@ -298,17 +298,25 @@ public class Impostors : MonoBehaviour
     Color[] origAlpha = preserveAlpha ? (Color[])alpha.Clone() : null;
     Color[] buffer = (Color[])pixels.Clone();
 
+    bool[] filled = new bool[pixels.Length];
+    for (int i = 0; i < pixels.Length; i++)
+      filled[i] = alpha[i].a > 0.01f;
+    bool[] filledNext = new bool[filled.Length];
+
     int[] dx = { -1, 1, 0, 0 };
     int[] dy = { 0, 0, -1, 1 };
 
     for (int iter = 0; iter < iterations; iter++)
     {
+      System.Array.Copy(pixels, buffer, pixels.Length);
+      System.Array.Copy(filled, filledNext, filled.Length);
+
       for (int y = 0; y < h; y++)
       {
         for (int x = 0; x < w; x++)
         {
           int i = y * w + x;
-          if (alpha[i].a > 0.01f) continue;
+          if (filled[i]) continue;
 
           Color sum = Color.clear;
           int count = 0;
@@ -317,7 +325,7 @@ public class Impostors : MonoBehaviour
             int nx = x + dx[d], ny = y + dy[d];
             if (nx < 0 || nx >= w || ny < 0 || ny >= h) continue;
             int ni = ny * w + nx;
-            if (alpha[ni].a > 0.01f || (iter > 0 && pixels[ni].a > 0))
+            if (filled[ni])
             {
               sum += pixels[ni];
               count++;
@@ -327,10 +335,12 @@ public class Impostors : MonoBehaviour
           {
             buffer[i] = sum / count;
             buffer[i].a = 1;
+            filledNext[i] = true;
           }
         }
       }
-      var tmp = pixels; pixels = buffer; buffer = tmp;
+      var tmpFilled = filled; filled = filledNext; filledNext = tmpFilled;
+      var tmpPixels = pixels; pixels = buffer; buffer = tmpPixels;
     }
 
     if (preserveAlpha)
@@ -488,6 +498,7 @@ public class Impostors : MonoBehaviour
       impostorMaterial.SetFloat("_Impostors_Sphere_Radius", sphere_radius_);
       impostorMaterial.SetFloat("_Impostors_Near_Clip", nearClippingDistance);
       impostorMaterial.SetFloat("_Impostors_Far_Clip", sphere_radius_ * 2f + nearClippingDistance);
+      impostorMaterial.SetFloat("_ZTest", (float)UnityEngine.Rendering.CompareFunction.LessEqual);
       impostorMaterial.SetFloat("_Impostors_Enabled", 1);
       impostorMaterial.SetFloat("_Impostors_Parallax", 1);
       impostorMaterial.SetFloat("_Cull", (float)UnityEngine.Rendering.CullMode.Front);
diff --git a/impostor.cginc b/impostor.cginc
index 184a8fe..e84f9db 100644
--- a/impostor.cginc
+++ b/impostor.cginc
@@ -67,9 +67,9 @@ float2 VirtualPlaneUV(float3 frameDir, float3 pivotToCam, float3 vertexToCam) {
 
 #if defined(_IMPOSTORS)
 
-// Decode linear 0-1 depth (0=near clip, 1=far clip) to world space distance from camera
+// Decode linear 0-1 depth (0=near clip, 1=far clip) to world space distance from camera.
 float DecodeImpostorDepth(float linearDepth) {
-    return _Impostors_Near_Clip + linearDepth * 2.0f * _Impostors_Sphere_Radius;
+    return lerp(_Impostors_Near_Clip, _Impostors_Far_Clip, linearDepth);
 }
 
 float2 ClampUvInCell(float2 uv) {
@@ -90,6 +90,8 @@ struct ImpostorResult {
     float metallic;
     float smoothness;
     float3 objPos;
+    // TODO rm
+    float debug;
 };
 
 float SampleImpostorDepthCell(float2 cell, float2 uvInCell, float gridRes) {
@@ -133,9 +135,13 @@ float2 ImpostorParallaxOffsetForFrame(float3 frameDir, float3 pivotToCamOS, floa
     float camZ = dot(pivotToCamOS, planeN);
     camZ = (abs(camZ) < 1e-4) ? (camZ < 0 ? -1e-4 : 1e-4) : camZ;
 
-    // Decode depth to world space, then normalize to [0,1] range
+    // Convert world-space depth to object space to match scaled impostor.
+    float objScale = max(2.0 * _Impostors_Sphere_Radius, 1e-4);
+    float objRadius = _Impostors_Sphere_Radius / objScale;
+    float objNear = _Impostors_Near_Clip / objScale;
     float worldSpaceDepth = DecodeImpostorDepth(encodedDepth);
-    float depth01 = (worldSpaceDepth - _Impostors_Near_Clip) / (2.0 * _Impostors_Sphere_Radius);
+    float objectSpaceDepth = worldSpaceDepth / objScale;
+    float depth01 = (objectSpaceDepth - objNear) / (2.0 * objRadius);
     // Convert to signed "height" where nearer pixels shift more (matches typical bump-offset convention).
     float zSurface = (depth01 - 0.5);
     float2 planeCoord = 0.5 - uvBase;
@@ -150,12 +156,14 @@ float3 ReconstructObjectOffsetFromFrame(float3 frameDir, float2 uv, float encode
     float3 planeX, planeY, planeN;
     FrameBasis(frameDir, planeX, planeY, planeN);
 
-    // UV offset from center, scaled to world units (baking camera spans [-Radius, Radius])
-    float2 offsetXY = (0.5 - uv) * 2.0 * _Impostors_Sphere_Radius;
+    float objScale = max(2.0f * _Impostors_Sphere_Radius, 1e-4);
+    float objRadius = _Impostors_Sphere_Radius / objScale;
+    float objNear = _Impostors_Near_Clip / objScale;
+    float objFar = _Impostors_Far_Clip / objScale;
 
-    // Decode depth to world space, convert to offset from center along view direction
-    float worldSpaceDepth = DecodeImpostorDepth(encodedDepth);
-    float offsetZ = (_Impostors_Sphere_Radius + _Impostors_Near_Clip) - worldSpaceDepth;
+    float2 offsetXY = (0.5f - uv) * 2.0f * objRadius;
+    float objectSpaceDepth = lerp(objNear, objFar, encodedDepth);
+    float offsetZ = (objRadius + objNear) - objectSpaceDepth;
 
     return offsetXY.x * planeX + offsetXY.y * planeY + offsetZ * planeN;
 }
diff --git a/pbr.cginc b/pbr.cginc
index 2aa6be7..076cf65 100644
--- a/pbr.cginc
+++ b/pbr.cginc
@@ -26,6 +26,7 @@ struct Pbr {
 #endif
 #if defined(_IMPOSTORS)
   float3 objPos;
+  float debug;  // TODO rm
 #endif
 };
 
@@ -170,6 +171,7 @@ Pbr getPbr(v2f i) {
   pbr.smoothness = imp.smoothness;
   pbr.metallic = imp.metallic;
   pbr.objPos = imp.objPos;
+  pbr.debug = imp.debug;
 #else
   pbr.albedo = _MainTex.Sample(aniso16_trilinear_repeat_s, uv_parallax * _MainTex_ST.xy + _MainTex_ST.zw);
   pbr.albedo *= _Color;