Impostors: baking script now auto-scales bounds

2 files changed, 60 insertions, 37 deletions

diff --git a/Scripts/Impostors.cs b/Scripts/Impostors.cs
index 1214b8f..e77be4e 100755
--- a/Scripts/Impostors.cs
+++ b/Scripts/Impostors.cs
@@ -7,7 +7,7 @@ using System.IO;
 public class Impostors : MonoBehaviour
 {
   [Header("Bounding Sphere")]
-  public float sphere_radius_ = 1f;
+  public float radiusScale = 1f;
 
   [Header("Grid Settings")]
   [Range(2, 20)] public int gridResolution = 5;
@@ -27,9 +27,23 @@ public class Impostors : MonoBehaviour
   private Material impostorMaterial;
 
   public bool HasImpostor => impostorObject != null;
-  private float Radius => sphere_radius_ * Mathf.Max(transform.lossyScale.x, transform.lossyScale.y, transform.lossyScale.z);
   private string OutputFolder => GetOutputFolder();
 
+  Bounds GetCombinedBounds()
+  {
+    Renderer[] allRenderers = originalMesh.GetComponentsInChildren<Renderer>(true);
+    Renderer[] renderers = System.Array.FindAll(allRenderers, r => r.gameObject != impostorObject);
+    Bounds bounds = renderers[0].bounds;
+    for (int i = 1; i < renderers.Length; i++)
+      bounds.Encapsulate(renderers[i].bounds);
+    return bounds;
+  }
+
+  float GetBoundingSphereRadius()
+  {
+    return GetCombinedBounds().extents.magnitude * radiusScale;
+  }
+
   void OnEnable() => Camera.onPreRender += UpdateMainCameraPos;
   void OnDisable() => Camera.onPreRender -= UpdateMainCameraPos;
 
@@ -41,8 +55,14 @@ public class Impostors : MonoBehaviour
 
   void OnDrawGizmos()
   {
+    if (originalMesh == null) return;
+
+    Bounds bounds = GetCombinedBounds();
+    Vector3 center = bounds.center;
+    float radius = GetBoundingSphereRadius();
+
     Gizmos.color = Color.cyan;
-    Gizmos.DrawWireSphere(transform.position, Radius);
+    Gizmos.DrawWireSphere(center, radius);
 
     if (Application.isEditor && gridResolution > 0)
     {
@@ -51,9 +71,9 @@ public class Impostors : MonoBehaviour
       {
         for (int x = 0; x < gridResolution; x++)
         {
-          Vector3 worldPos = transform.position + PlaneToHemiOctahedron(x, y) * (Radius + nearClippingDistance);
-          Gizmos.DrawSphere(worldPos, Radius * 0.05f);
-          Gizmos.DrawLine(worldPos, transform.position);
+          Vector3 worldPos = center + PlaneToHemiOctahedron(x, y) * (radius + nearClippingDistance);
+          Gizmos.DrawSphere(worldPos, radius * 0.05f);
+          Gizmos.DrawLine(worldPos, center);
         }
       }
     }
@@ -110,23 +130,27 @@ public class Impostors : MonoBehaviour
     cameras = new Camera[gridResolution * gridResolution];
     int idx = 0;
 
+    Bounds bounds = GetCombinedBounds();
+    Vector3 center = bounds.center;
+    float radius = GetBoundingSphereRadius();
+
     for (int y = 0; y < gridResolution; y++)
     {
       for (int x = 0; x < gridResolution; x++)
       {
         Vector3 localDir = PlaneToHemiOctahedron(x, y);
-        Vector3 worldPos = transform.position + (transform.rotation * localDir) * (Radius + nearClippingDistance);
+        Vector3 worldPos = center + (transform.rotation * localDir) * (radius + nearClippingDistance);
 
         GameObject camObj = new GameObject($"Camera_{x}_{y}");
         camObj.transform.SetParent(parent.transform, false);
         camObj.transform.position = worldPos;
-        camObj.transform.LookAt(transform.position, transform.up);
+        camObj.transform.LookAt(center, transform.up);
 
         Camera cam = camObj.AddComponent<Camera>();
         cam.orthographic = true;
-        cam.orthographicSize = Radius;
+        cam.orthographicSize = radius;
         cam.nearClipPlane = nearClippingDistance;
-        cam.farClipPlane = Radius * 2f + nearClippingDistance;
+        cam.farClipPlane = radius * 2f + nearClippingDistance;
         cam.cullingMask = cullingMask;
         cam.clearFlags = renderSkybox ? CameraClearFlags.Skybox : CameraClearFlags.SolidColor;
         cam.backgroundColor = Color.clear;
@@ -250,7 +274,7 @@ public class Impostors : MonoBehaviour
   public void BakeTexture()
   {
     SetRenderersEnabled(true);
-    if (cameras == null || cameras.Length != gridResolution * gridResolution || cameras[0] == null) CreateCameras();
+    CreateCameras();
 
     Shader depthBlitShader = Shader.Find("Hidden/yum_food/DepthBlit");
     if (depthBlitShader == null) { Debug.LogError("DepthBlit shader not found"); return; }
@@ -539,14 +563,17 @@ public class Impostors : MonoBehaviour
       Shader shader = Shader.Find("yum_food/3ner");
       if (shader == null) { Debug.LogError("Shader not found"); return; }
 
+      Bounds bounds = GetCombinedBounds();
+      float radius = GetBoundingSphereRadius();
+
       impostorMaterial = new Material(shader);
       impostorMaterial.enableInstancing = true;
       for (int i = 0; i < textures.Length; i++)
         impostorMaterial.SetTexture(exportSettings[i].materialProp, textures[i]);
       impostorMaterial.SetInt("_Impostors_Grid_Resolution", gridResolution);
-      impostorMaterial.SetFloat("_Impostors_Sphere_Radius", sphere_radius_);
+      impostorMaterial.SetFloat("_Impostors_Sphere_Radius", radius);
       impostorMaterial.SetFloat("_Impostors_Near_Clip", nearClippingDistance);
-      impostorMaterial.SetFloat("_Impostors_Far_Clip", sphere_radius_ * 2f + nearClippingDistance);
+      impostorMaterial.SetFloat("_Impostors_Far_Clip", radius * 2f + nearClippingDistance);
       impostorMaterial.SetFloat("_ZTest", (float)UnityEngine.Rendering.CompareFunction.LessEqual);
       impostorMaterial.SetFloat("_Impostors_Enabled", 1);
       impostorMaterial.SetFloat("_Impostors_Parallax", 1);
@@ -555,8 +582,9 @@ public class Impostors : MonoBehaviour
 
       impostorObject = GameObject.CreatePrimitive(PrimitiveType.Quad);
       impostorObject.name = "Impostor";
-      impostorObject.transform.SetParent(transform, false);
-      impostorObject.transform.localScale = Vector3.one * sphere_radius_ * 2.0f;
+      impostorObject.transform.position = bounds.center;
+      impostorObject.transform.localScale = Vector3.one * radius * 2.0f;
+      impostorObject.transform.SetParent(transform, true);
       DestroyImmediate(impostorObject.GetComponent<Collider>());
       impostorObject.GetComponent<MeshRenderer>().sharedMaterial = impostorMaterial;
 
@@ -584,7 +612,11 @@ public class Impostors : MonoBehaviour
     if (originalMesh == null) return;
     foreach (Renderer r in originalMesh.GetComponentsInChildren<Renderer>(true))
       r.enabled = enabled;
-    if (impostorObject != null) impostorObject.SetActive(!enabled);
+    if (impostorObject != null)
+    {
+      Renderer impostorRenderer = impostorObject.GetComponent<Renderer>();
+      if (impostorRenderer != null) impostorRenderer.enabled = !enabled;
+    }
   }
 }
 
diff --git a/impostor.cginc b/impostor.cginc
index fe08b67..14fee5b 100755
--- a/impostor.cginc
+++ b/impostor.cginc
@@ -89,24 +89,22 @@ ImpostorSample SampleImpostorCell(float2 cell, float2 uvInCell, float invGridRes
     return s;
 }
 
-float2 ImpostorParallaxOffset(float3 planeX, float3 planeY, float3 planeN, float3 pivotToCamOS, float encodedDepth, float rcpObjScale, float objRadiusScaled, float objNearScaled) {
+float2 ImpostorParallaxOffset(float3 planeX, float3 planeY, float3 planeN, float3 pivotToCamOS, float encodedDepth) {
     float2 camXY = float2(dot(pivotToCamOS, planeX), dot(pivotToCamOS, planeY));
     float camZ = dot(pivotToCamOS, planeN);
     camZ = (abs(camZ) < 1e-4) ? (camZ < 0 ? -1e-4 : 1e-4) : camZ;
 
     float worldSpaceDepth = lerp(_Impostors_Near_Clip, _Impostors_Far_Clip, encodedDepth);
-    float depth01 = (worldSpaceDepth - objNearScaled) * objRadiusScaled;
+    float depth01 = (worldSpaceDepth - _Impostors_Near_Clip) / (2.0 * _Impostors_Sphere_Radius);
     float height = 0.5 - depth01;
 
     return (camXY / camZ) * height;
 }
 
-float3 ReconstructObjectOffset(float3 planeX, float3 planeY, float3 planeN, float2 uv, float encodedDepth, float rcpObjScale, float objRadius, float objNear) {
-    float objFar = _Impostors_Far_Clip * rcpObjScale;
-
-    float2 offsetXY = (0.5 - uv) * (2.0 * objRadius);
-    float objectSpaceDepth = lerp(objNear, objFar, encodedDepth);
-    float offsetZ = (objRadius + objNear) - objectSpaceDepth;
+float3 ReconstructObjectOffset(float3 planeX, float3 planeY, float3 planeN, float2 uv, float encodedDepth) {
+    float2 offsetXY = (0.5 - uv) * (2.0 * _Impostors_Sphere_Radius);
+    float worldSpaceDepth = lerp(_Impostors_Near_Clip, _Impostors_Far_Clip, encodedDepth);
+    float offsetZ = (_Impostors_Sphere_Radius + _Impostors_Near_Clip) - worldSpaceDepth;
 
     return offsetXY.x * planeX + offsetXY.y * planeY + offsetZ * planeN;
 }
@@ -212,21 +210,14 @@ ImpostorResult impostor_frag(float3 worldPos) {
         return result;
     }
 
-    // Pre-compute scale values once for both parallax and reconstruction
-    float objScale = max(2.0 * _Impostors_Sphere_Radius, 1e-4);
-    float rcpObjScale = rcp(objScale);
-    float objRadius = _Impostors_Sphere_Radius * rcpObjScale;
-    float objRadiusScaled = rcp(2.0 * objRadius);
-    float objNearScaled = _Impostors_Near_Clip * rcpObjScale;
-
     float2 parallaxOffset0 = 0, parallaxOffset1 = 0, parallaxOffset2 = 0;
     bool needsParallaxResample = false;
 
     [branch]
     if (parallaxStrength > 0.001) {
-        parallaxOffset0 = ImpostorParallaxOffset(planeX0, planeY0, planeN0, pivotToCamOS, depthBlended, rcpObjScale, objRadiusScaled, objNearScaled) * parallaxStrength;
-        parallaxOffset1 = ImpostorParallaxOffset(planeX1, planeY1, planeN1, pivotToCamOS, depthBlended, rcpObjScale, objRadiusScaled, objNearScaled) * parallaxStrength;
-        parallaxOffset2 = ImpostorParallaxOffset(planeX2, planeY2, planeN2, pivotToCamOS, depthBlended, rcpObjScale, objRadiusScaled, objNearScaled) * parallaxStrength;
+        parallaxOffset0 = ImpostorParallaxOffset(planeX0, planeY0, planeN0, pivotToCamOS, depthBlended) * parallaxStrength;
+        parallaxOffset1 = ImpostorParallaxOffset(planeX1, planeY1, planeN1, pivotToCamOS, depthBlended) * parallaxStrength;
+        parallaxOffset2 = ImpostorParallaxOffset(planeX2, planeY2, planeN2, pivotToCamOS, depthBlended) * parallaxStrength;
 
         float maxOffsetSq = max(max(dot(parallaxOffset0, parallaxOffset0), dot(parallaxOffset1, parallaxOffset1)), dot(parallaxOffset2, parallaxOffset2));
         needsParallaxResample = maxOffsetSq > 0.00005;
@@ -275,9 +266,9 @@ ImpostorResult impostor_frag(float3 worldPos) {
     result.smoothness = blended.metallicGloss.g;
 
 #if defined(_IMPOSTORS_DEPTH)
-    float3 offset0 = ReconstructObjectOffset(planeX0, planeY0, planeN0, finalUv0, depth0, rcpObjScale, objRadius, objNearScaled);
-    float3 offset1 = ReconstructObjectOffset(planeX1, planeY1, planeN1, finalUv1, depth1, rcpObjScale, objRadius, objNearScaled);
-    float3 offset2 = ReconstructObjectOffset(planeX2, planeY2, planeN2, finalUv2, depth2, rcpObjScale, objRadius, objNearScaled);
+    float3 offset0 = ReconstructObjectOffset(planeX0, planeY0, planeN0, finalUv0, depth0);
+    float3 offset1 = ReconstructObjectOffset(planeX1, planeY1, planeN1, finalUv1, depth1);
+    float3 offset2 = ReconstructObjectOffset(planeX2, planeY2, planeN2, finalUv2, depth2);
     result.objPos = offset0 * bw.x + offset1 * bw.y + offset2 * bw.z;
 #endif