From fe3430000d1c5eb03a03fb54f17e96b61c044d8d Mon Sep 17 00:00:00 2001
From: Noeri Huisman <8823461+mrxz@users.noreply.github.com>
Date: Tue, 1 Jul 2025 07:26:17 +0200
Subject: [PATCH] Use RenderTarget properties to reduce manual render state
 tracking (#80)

---
 src/PackedSplats.ts | 23 ++++++++---------------
 src/Readback.ts     | 20 ++++++--------------
 2 files changed, 14 insertions(+), 29 deletions(-)

diff --git a/src/PackedSplats.ts b/src/PackedSplats.ts
index ee93abe..456738a 100644
--- a/src/PackedSplats.ts
+++ b/src/PackedSplats.ts
@@ -357,6 +357,7 @@ export class PackedSplats {
     this.target.texture.format = THREE.RGBAIntegerFormat;
     this.target.texture.type = THREE.UnsignedIntType;
     this.target.texture.internalFormat = "RGBA32UI";
+    this.target.scissorTest = true;
     return true;
   }
 
@@ -503,27 +504,21 @@ export class PackedSplats {
 
   private saveRenderState(renderer: THREE.WebGLRenderer) {
     return {
-      xrPresenting: renderer.xr.isPresenting,
+      xrEnabled: renderer.xr.enabled,
       autoClear: renderer.autoClear,
-      scissorTest: renderer.getScissorTest(),
-      pixelRatio: renderer.getPixelRatio(),
     };
   }
 
   private resetRenderState(
     renderer: THREE.WebGLRenderer,
     state: {
-      xrPresenting: boolean;
+      xrEnabled: boolean;
       autoClear: boolean;
-      scissorTest: boolean;
-      pixelRatio: number;
     },
   ) {
     renderer.setRenderTarget(null);
-    renderer.setPixelRatio(state.pixelRatio);
-    renderer.xr.isPresenting = state.xrPresenting;
+    renderer.xr.enabled = state.xrEnabled;
     renderer.autoClear = state.autoClear;
-    renderer.setScissorTest(state.scissorTest);
   }
 
   // Executes a dyno program specified by generator which is any DynoBlock that
@@ -575,17 +570,15 @@ export class PackedSplats {
       );
 
       // Render the desired portion of the layer
-      renderer.setPixelRatio(1);
-      renderer.setRenderTarget(this.target, layer);
-      renderer.xr.isPresenting = false;
-      renderer.autoClear = false;
-      renderer.setScissorTest(true);
-      renderer.setScissor(
+      this.target.scissor.set(
         0,
         layerYStart,
         SPLAT_TEX_WIDTH,
         layerYEnd - layerYStart,
       );
+      renderer.setRenderTarget(this.target, layer);
+      renderer.xr.enabled = false;
+      renderer.autoClear = false;
       renderer.render(PackedSplats.scene, PackedSplats.camera);
 
       base += SPLAT_TEX_WIDTH * (layerYEnd - layerYStart);
diff --git a/src/Readback.ts b/src/Readback.ts
index 67000a9..d56c21c 100644
--- a/src/Readback.ts
+++ b/src/Readback.ts
@@ -84,6 +84,7 @@ export class Readback {
       this.target.texture.format = THREE.RGBAFormat;
       this.target.texture.type = THREE.UnsignedByteType;
       this.target.texture.internalFormat = "RGBA8";
+      this.target.scissorTest = true;
     }
   }
 
@@ -129,27 +130,21 @@ export class Readback {
 
   private saveRenderState(renderer: THREE.WebGLRenderer) {
     return {
-      xrPresenting: renderer.xr.isPresenting,
+      xrEnabled: renderer.xr.enabled,
       autoClear: renderer.autoClear,
-      scissorTest: renderer.getScissorTest(),
-      pixelRatio: renderer.getPixelRatio(),
     };
   }
 
   private resetRenderState(
     renderer: THREE.WebGLRenderer,
     state: {
-      xrPresenting: boolean;
+      xrEnabled: boolean;
       autoClear: boolean;
-      scissorTest: boolean;
-      pixelRatio: number;
     },
   ) {
     renderer.setRenderTarget(null);
-    renderer.setPixelRatio(state.pixelRatio);
-    renderer.xr.isPresenting = state.xrPresenting;
+    renderer.xr.enabled = state.xrEnabled;
     renderer.autoClear = state.autoClear;
-    renderer.setScissorTest(state.scissorTest);
   }
 
   private process({
@@ -182,12 +177,10 @@ export class Readback {
       material.uniforms.targetLayer.value = layer;
 
       // Render the desired portion of the layer
-      renderer.setPixelRatio(1);
+      this.target.scissor.set(0, 0, SPLAT_TEX_WIDTH, layerYEnd);
       renderer.setRenderTarget(this.target, layer);
-      renderer.xr.isPresenting = false;
+      renderer.xr.enabled = false;
       renderer.autoClear = false;
-      renderer.setScissorTest(true);
-      renderer.setScissor(0, 0, SPLAT_TEX_WIDTH, layerYEnd);
       renderer.render(Readback.scene, Readback.camera);
 
       baseIndex += SPLAT_TEX_WIDTH * layerYEnd;
@@ -234,7 +227,6 @@ export class Readback {
         Math.ceil((this.count - layerBase) / SPLAT_TEX_WIDTH),
       );
 
-      renderer.setPixelRatio(1);
       renderer.setRenderTarget(this.target, layer);
 
       // Compute the subarray that this layer of readback corresponds to