Splat Texture (#79)

* Add experimental Splat Texture rendering and examples/splat-texture. Added star.png and heart.png to assets.json and to assets repo. Update examples/depth-of-field to compute from metric aperture size. Added SparkRenderer.renderScale debug parameter. Updated examples/editor: set default highDPI to true, added logFocalDistance, apertureAngle, refactored, grouped into debugFolder, default settings open, preset buttons for nonAA and AA settings.

* Set default highDpi in examples/editor to not(isMobile).

examples.html

@@ -374,6 +374,7 @@
       <a href="/examples/glsl/index.html" class="example-link">GLSL Shaders</a>
       <a href="/examples/debug-color/index.html" class="example-link">Debug Coloring</a>
       <a href="/examples/depth-of-field/index.html" class="example-link">Depth of Field</a>
+      <a href="/examples/splat-texture/index.html" class="example-link">Splat Texture</a>
       <a href="/examples/editor/index.html" class="example-link">Editor</a>
     </div>
     <div class="content">

examples/assets.json

@@ -102,5 +102,13 @@
   "valley.spz": {
     "url": "https://sparkjs.dev/assets/splats/valley.spz",
     "directory": "splats"
+  },
+  "star.png": {
+    "url": "https://sparkjs.dev/assets/images/star.png",
+    "directory": "images"
+  },
+  "heart.png": {
+    "url": "https://sparkjs.dev/assets/images/heart.png",
+    "directory": "images"
   }
 }

examples/depth-of-field/index.html

@@ -38,15 +38,29 @@
     document.body.appendChild(renderer.domElement)
 
     const spark = new SparkRenderer({
-        renderer,
-        apertureAngle: 0.02,
-        focalDistance: 5.0,
+      renderer,
+      apertureAngle: 0.02,
+      focalDistance: 5.0,
     });
     scene.add(spark);
 
+    const apertureSize = {
+      apertureSize: 0.1,
+    };
+    function updateApertureAngle() {
+      if (spark.focalDistance > 0) {
+        spark.apertureAngle = 2 * Math.atan(0.5 * apertureSize.apertureSize / spark.focalDistance);
+      } else {
+        spark.apertureAngle = 0.0;
+      }
+    }
+    updateApertureAngle();
+
     const gui = new GUI({ title: "DoF settings" });
-    gui.add(spark, "focalDistance", 0.1, 15, 0.1);
-    gui.add(spark, "apertureAngle", 0.0, 0.01 * Math.PI, 0.001);
+    gui.add(spark, "focalDistance", 0, 15, 0.01).name("Focal plane dist")
+      .onChange(updateApertureAngle);
+    gui.add(apertureSize, "apertureSize", 0, 0.4, 0.01).name("Aperture size")
+      .onChange(updateApertureAngle);
 
     const splatURL = await getAssetFileURL("valley.spz");
     const background = new SplatMesh({ url: splatURL });

examples/editor/index.html

@@ -68,7 +68,7 @@
     import * as THREE from "three";
     import { OrbitControls } from "three/addons/controls/OrbitControls.js";
     import { GUI } from "lil-gui";
-    import { constructGrid, SparkControls, SparkRenderer, SplatMesh, textSplats, dyno, transcodeSpz, isPcSogs } from "@sparkjsdev/spark";
+    import { constructGrid, SparkControls, SparkRenderer, SplatMesh, textSplats, dyno, transcodeSpz, isMobile, isPcSogs } from "@sparkjsdev/spark";
     import { getAssetFileURL } from "/examples/js/get-asset-url.js";
 
     const scene = new THREE.Scene();
@@ -113,7 +113,7 @@
     const gui = new GUI({
       title: "Settings",
       container: document.getElementById("main-gui")
-    }).close();
+    });
     const secondGui = new GUI({
       title: "Splats",
       container: document.getElementById("second-gui")
@@ -134,7 +134,7 @@
     };
 
     const guiOptions = {
-      highDevicePixel: false,
+      highDevicePixel: !isMobile(),
       stats: false,
       resetOnLoad: true,
       loadOffset: 0,
@@ -462,30 +462,55 @@
         controls.pointerControls.reverseSwipe = value;
       });
 
-    gui.add(guiOptions, "highDevicePixel").name("High DPI").onChange((value) => {
+    function setHighDpi(value) {
       renderer.setPixelRatio(value ? window.devicePixelRatio : 1);
       const width = canvas.clientWidth;
       const height = canvas.clientHeight;
       renderer.setSize(width, height, false);
       console.log("Render size", canvas.width, canvas.height);
+    }
+    setHighDpi(guiOptions.highDevicePixel);
+
+    gui.add(guiOptions, "highDevicePixel").name("High DPI").onChange((value) => {
+      setHighDpi(value);
     });
     gui.add(guiOptions, "stats").name("Show frame stats").onChange((value) => {
       stats.dom.style.display = value ? "block" : "none";
     });
     gui.add(spark.defaultView, "sortRadial").name("Radial sort").listen();
     gui.add(grid, "opacity", 0, 1, 0.01).name("Grid opacity").listen();
+    gui.add({
+      logFocalDistance: 0.0,
+    }, "logFocalDistance", -2, 2, 0.01).name("Ln(Focal distance)").onChange((value) => {
+      spark.focalDistance = Math.exp(value);
+    });
+    gui.add(spark, "apertureAngle", 0, 0.01 * Math.PI, 0.001).name("Aperture angle").listen();
 
+    const debugFolder = gui.addFolder("Debug").close();
     const normalColor = dyno.dynoBool(false);
-    gui.add(normalColor, "value").name("Normal color").onChange(() => updateFrameSplats());
+    debugFolder.add(normalColor, "value").name("Normal color").onChange(() => updateFrameSplats());
 
-    gui.add(spark, "maxStdDev", 0.1, 3.0, 0.01).name("Max Gsplat stddev").listen();
-    gui.add(spark, "falloff", 0, 1, 0.01).name("Gaussian falloff").listen();
-    gui.add(spark, "preBlurAmount", 0, 2, 0.1).name("Blur amount (no AA)");
-    gui.add(spark, "blurAmount", 0, 2, 0.1).name("Blur amount (AA)");
+    debugFolder.add(spark, "maxStdDev", 0.1, 3.0, 0.01).name("Max Gsplat stddev").listen();
+    debugFolder.add(spark, "falloff", 0, 1, 0.01).name("Gaussian falloff").listen();
+    debugFolder.add(spark, "preBlurAmount", 0, 2, 0.1).name("Blur amount (no AA)").listen();
+    debugFolder.add(spark, "blurAmount", 0, 2, 0.1).name("Blur amount (AA)").listen();
+    debugFolder.add({
+      nonAA: () => {
+        spark.preBlurAmount = 0.3;
+        spark.blurAmount = 0.0;
+      },
+    }, "nonAA").name("Non-AA preset");
+    debugFolder.add({
+      AA: () => {
+        spark.preBlurAmount = 0.0;
+        spark.blurAmount = 0.3;
+      },
+    }, "AA").name("AA preset");
+    debugFolder.add(spark, "renderScale", 0.1, 2.0, 0.1).name("Render scale");
 
     const splatsFolder = secondGui.addFolder("Files");
 
-    const editFolder = gui.addFolder("Edit Splats").close();
+    const clipFolder = gui.addFolder("Clip Splats").close();
 
     function updateFrameSplats() {
       frame.children.forEach((child) => {
@@ -502,13 +527,13 @@
     const clipMaxY = dyno.dynoFloat(5);
     const clipMinZ = dyno.dynoFloat(-5);
     const clipMaxZ = dyno.dynoFloat(5);
-    editFolder.add(clipEnable, "value").name("Enable clip").onChange(() => updateFrameSplats());
-    editFolder.add(clipMinX, "value", -5, 5, 0.01).name("Min X").onChange(() => updateFrameSplats());
-    editFolder.add(clipMaxX, "value", -5, 5, 0.01).name("Max X").onChange(() => updateFrameSplats());
-    editFolder.add(clipMinY, "value", -5, 5, 0.01).name("Min Y").onChange(() => updateFrameSplats());
-    editFolder.add(clipMaxY, "value", -5, 5, 0.01).name("Max Y").onChange(() => updateFrameSplats());
-    editFolder.add(clipMinZ, "value", -5, 5, 0.01).name("Min Z").onChange(() => updateFrameSplats());
-    editFolder.add(clipMaxZ, "value", -5, 5, 0.01).name("Max Z").onChange(() => updateFrameSplats());
+    clipFolder.add(clipEnable, "value").name("Enable clip").onChange(() => updateFrameSplats());
+    clipFolder.add(clipMinX, "value", -50, 50, 0.01).name("Min X").onChange(() => updateFrameSplats());
+    clipFolder.add(clipMaxX, "value", -50, 50, 0.01).name("Max X").onChange(() => updateFrameSplats());
+    clipFolder.add(clipMinY, "value", -50, 50, 0.01).name("Min Y").onChange(() => updateFrameSplats());
+    clipFolder.add(clipMaxY, "value", -50, 50, 0.01).name("Max Y").onChange(() => updateFrameSplats());
+    clipFolder.add(clipMinZ, "value", -50, 50, 0.01).name("Min Z").onChange(() => updateFrameSplats());
+    clipFolder.add(clipMaxZ, "value", -50, 50, 0.01).name("Max Z").onChange(() => updateFrameSplats());
 
     function makeWorldModifier(mesh) {
       const context = mesh.context;
@@ -548,7 +573,7 @@
       });
     }
 
-    const writeFolder = secondGui.addFolder("Write Gsplats").close();
+    const exportFolder = secondGui.addFolder("Export Gsplats").close();
     const writeOptions = {
       filename: "gsplats",
       trimOpacity: true,
@@ -591,12 +616,12 @@
         URL.revokeObjectURL(url);
       },
     };
-    writeFolder.add(writeOptions, "filename").name("Filename").listen();
-    writeFolder.add(writeOptions, "trimOpacity").name("Trim low opacity");
-    writeFolder.add(writeOptions, "trimOpacityThreshold").name("Trim opacity <= 0..1");
-    writeFolder.add(writeOptions, "maxSh", 0, 3, 1).name("Max spherical harmonics");
-    writeFolder.add(writeOptions, "fractionalBits", 6, 24, 1).name("Fractional bits");
-    writeFolder.add(writeOptions, "writeSpz").name("Create .spz and download");
+    exportFolder.add(writeOptions, "filename").name("Filename").listen();
+    exportFolder.add(writeOptions, "trimOpacity").name("Trim low opacity");
+    exportFolder.add(writeOptions, "trimOpacityThreshold").name("Trim opacity <= 0..1");
+    exportFolder.add(writeOptions, "maxSh", 0, 3, 1).name("Max spherical harmonics");
+    exportFolder.add(writeOptions, "fractionalBits", 6, 24, 1).name("Fractional bits");
+    exportFolder.add(writeOptions, "writeSpz").name("Create .spz and download");
 
     function makeInstructions() {
       const instructions = textSplats({

examples/splat-texture/index.html

@@ -0,0 +1,166 @@
+<!DOCTYPE html>
+<html>
+
+<head>
+  <meta charset="utf-8">
+  <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+  <title>Spark • Splat Texture</title>
+  <style>
+    body {
+      margin: 0;
+    }
+    canvas {
+      touch-action: none;
+    }
+  </style>
+</head>
+
+<body>
+  <script type="importmap">
+    {
+      "imports": {
+        "three": "/examples/js/vendor/three/build/three.module.js",
+        "lil-gui": "/examples/js/vendor/lil-gui/dist/lil-gui.esm.js",
+        "@sparkjsdev/spark": "/dist/spark.module.js"
+      }
+    }
+  </script>
+  <script type="module">
+    import * as THREE from "three";
+    import { SparkRenderer, SplatMesh, SparkControls } from "@sparkjsdev/spark";
+    import GUI from "lil-gui";
+    import { getAssetFileURL } from "/examples/js/get-asset-url.js";
+
+    const scene = new THREE.Scene();
+    const camera = new THREE.PerspectiveCamera(60, window.innerWidth / window.innerHeight, 0.01, 100);
+    const renderer = new THREE.WebGLRenderer();
+    renderer.setSize(window.innerWidth, window.innerHeight);
+    document.body.appendChild(renderer.domElement)
+
+    function imgToRgba(img) {
+        const canvas = document.createElement("canvas");
+        canvas.width = img.width;
+        canvas.height = img.height;
+        const ctx = canvas.getContext("2d");
+        ctx.drawImage(img, 0, 0);
+        const imageData = ctx.getImageData(0, 0, img.width, img.height);
+        const rgba = new Uint8Array(imageData.data.buffer);
+        return { rgba, width: img.width, height: img.height };
+    }
+
+    const textureLoader = new THREE.TextureLoader();
+    const starUrl = await getAssetFileURL("star.png");
+    const star = imgToRgba((await textureLoader.loadAsync(starUrl)).image);
+    const heartUrl = await getAssetFileURL("heart.png");
+    const heart = imgToRgba((await textureLoader.loadAsync(heartUrl)).image);
+
+    const splatTexLayers = 32;
+    const texData = new Uint8Array(4 * star.width * star.height * splatTexLayers);
+    const texData2 = new Uint8Array(4 * star.width * star.height * splatTexLayers);
+    for (let z = 0; z < splatTexLayers; z++) {
+        const t = z / (splatTexLayers - 1);
+        const starOpacity = Math.max((t - 0.5) / 0.5, 0.0);
+        const heartOpacity = Math.max((0.5 - t) / 0.5, 0.0);
+        const gaussOpacity = Math.max(1 - Math.abs(t - 0.5) / 0.5, 0.0);
+        for (let y = 0; y < star.height; y++) {
+            for (let x = 0; x < star.width; x++) {
+                const inIndex = (y * star.width) + x;
+                const outIndex = ((z * star.height) + y) * star.width + x;
+                const o4 = outIndex * 4;
+                const i4 = inIndex * 4;
+                const deltaX = x / star.width - 0.5;
+                const deltaY = y / star.height - 0.5;
+                const dist = Math.sqrt(deltaX * deltaX + deltaY * deltaY) / 0.5;
+                const inside = (dist < 1.0) ? 255 : 0;
+                let r = t * star.rgba[i4] + (1 - t) * inside;
+                let g = t * star.rgba[i4 + 1] + (1 - t) * inside;
+                let b = t * star.rgba[i4 + 2] + (1 - t) * inside;
+                let a = t * star.rgba[i4 + 3] + (1 - t) * inside;
+                texData[o4] = Math.max(0, Math.min(255, Math.round(r)));
+                texData[o4 + 1] = Math.max(0, Math.min(255, Math.round(g)));
+                texData[o4 + 2] = Math.max(0, Math.min(255, Math.round(b)));
+                texData[o4 + 3] = Math.max(0, Math.min(255, Math.round(a)));
+
+                r = starOpacity * star.rgba[i4] + heartOpacity * heart.rgba[i4] + inside * gaussOpacity;
+                g = starOpacity * star.rgba[i4 + 1] + heartOpacity * heart.rgba[i4 + 1] + inside * gaussOpacity;
+                b = starOpacity * star.rgba[i4 + 2] + heartOpacity * heart.rgba[i4 + 2] + inside * gaussOpacity;
+                a = starOpacity * star.rgba[i4 + 3] + heartOpacity * heart.rgba[i4 + 3] + inside * gaussOpacity;
+                texData2[o4] = Math.max(0, Math.min(255, Math.round(r)));
+                texData2[o4 + 1] = Math.max(0, Math.min(255, Math.round(g)));
+                texData2[o4 + 2] = Math.max(0, Math.min(255, Math.round(b)));
+                texData2[o4 + 3] = Math.max(0, Math.min(255, Math.round(a)));
+            }
+        }
+    }
+    const texture = new THREE.Data3DTexture(texData, star.width, star.height, splatTexLayers);
+    texture.needsUpdate = true;
+    const texture2 = new THREE.Data3DTexture(texData2, star.width, star.height, splatTexLayers);
+    texture2.needsUpdate = true;
+
+    const spark = new SparkRenderer({
+        renderer,
+        maxStdDev: 1.0,
+        focalDistance: 0,
+    });
+    const splatTexture = {
+        enable: true,
+        texture: texture,
+        near: 1.0,
+        far: 15,
+        mid: 5,
+    };
+    spark.splatTexture = splatTexture;
+    scene.add(spark);
+
+    const gui = new GUI({ title: "DoF settings" });
+    const selectedTexture = {
+        selection: "texture",
+    };
+    gui.add(selectedTexture, "selection", ["none", "texture", "texture2"]).name("Splat texture").onChange(() => {
+        splatTexture.enable = true;
+        if (selectedTexture.selection === "texture") {
+            splatTexture.texture = texture;
+        } else if (selectedTexture.selection === "texture2") {
+            splatTexture.texture = texture2;
+        } else {
+            splatTexture.enable = false;
+        }
+    });
+    gui.add(spark, "maxStdDev", 0.1, 3, 0.1);
+    gui.add(spark, "falloff", 0, 1, 0.01).name("Gaussian falloff");
+
+    const apertureSize = {
+        apertureSize: 0.1,
+    };
+    function updateApertureAngle() {
+        splatTexture.mid = spark.focalDistance;
+        splatTexture.near = spark.focalDistance / 5.0;
+        splatTexture.far = spark.focalDistance * 5.0;
+        if (spark.focalDistance > 0) {
+            spark.apertureAngle = 2 * Math.atan(0.5 * apertureSize.apertureSize / spark.focalDistance);
+        } else {
+            spark.apertureAngle = 0.0;
+        }
+    }
+    updateApertureAngle();
+
+    gui.add(spark, "focalDistance", 0, 15, 0.01).name("Focal plane dist")
+        .onChange(updateApertureAngle);
+    gui.add(apertureSize, "apertureSize", 0, 1, 0.01).name("Aperture size")
+        .onChange(updateApertureAngle);
+
+    const splatURL = await getAssetFileURL("valley.spz");
+    const background = new SplatMesh({ url: splatURL });
+    background.quaternion.set(1, 0, 0, 0);
+    background.scale.setScalar(0.5);
+    scene.add(background);
+
+    const controls = new SparkControls({ canvas: renderer.domElement });
+    renderer.setAnimationLoop(function animate(time) {
+      controls.update(camera);
+      renderer.render(scene, camera);
+    });
+  </script>
+</body>
+
+</html>

index.html

@@ -146,6 +146,7 @@
         <li><a href="/examples/glsl/">GLSL Shaders</a></li>
         <li><a href="/examples/debug-color/">Debug Coloring</a></li>
         <li><a href="/examples/depth-of-field/">Depth of Field</a></li>
+        <li><a href="/examples/splat-texture/">Splat Texture</a></li>
         <li><a href="/examples/editor/">Editor</a></li>
         <li><a href="/examples/viewer/">Viewer</a></li>
       </ul>

src/SparkRenderer.ts

@@ -148,6 +148,17 @@ export class SparkRenderer extends THREE.Mesh {
   apertureAngle: number;
   falloff: number;
   clipXY: number;
+  renderScale = 1.0;
+
+  splatTexture: null | {
+    enable?: boolean;
+    texture?: THREE.Data3DTexture;
+    multiply?: THREE.Matrix2;
+    add?: THREE.Vector2;
+    near?: number;
+    far?: number;
+    mid?: number;
+  } = null;
 
   time?: number;
   deltaTime?: number;
@@ -198,6 +209,8 @@ export class SparkRenderer extends THREE.Mesh {
   } | null = null;
   private static pmrem: THREE.PMREMGenerator | null = null;
 
+  static EMPTY_SPLAT_TEXTURE = new THREE.Data3DTexture();
+
   constructor(options: SparkRendererOptions) {
     const uniforms = SparkRenderer.makeUniforms();
     const shaders = getShaders();
@@ -281,6 +294,9 @@ export class SparkRenderer extends THREE.Mesh {
     const uniforms = {
       // Size of render viewport in pixels
       renderSize: { value: new THREE.Vector2() },
+      // Near and far plane distances
+      near: { value: 0.1 },
+      far: { value: 1000.0 },
       // Total number of Gsplats in packedSplats to render
       numSplats: { value: 0 },
       // SplatAccumulator to view transformation quaternion
@@ -304,6 +320,22 @@ export class SparkRenderer extends THREE.Mesh {
       falloff: { value: 1.0 },
       // Clip Gsplats that are clipXY times beyond the +-1 frustum bounds
       clipXY: { value: 1.4 },
+      // Debug renderSize scale factor
+      renderScale: { value: 1.0 },
+      // Enable splat texture rendering
+      splatTexEnable: { value: false },
+      // Splat texture to render
+      splatTexture: { type: "t", value: SparkRenderer.EMPTY_SPLAT_TEXTURE },
+      // Splat texture UV transform (multiply)
+      splatTexMul: { value: new THREE.Matrix2() },
+      // Splat texture UV transform (add)
+      splatTexAdd: { value: new THREE.Vector2() },
+      // Splat texture near plane distance
+      splatTexNear: { value: 0.1 },
+      // Splat texture far plane distance
+      splatTexFar: { value: 1000.0 },
+      // Splat texture mid plane distance, or 0.0 to disable
+      splatTexMid: { value: 0.0 },
       // Gsplat collection to render
       packedSplats: { type: "t", value: PackedSplats.getEmpty() },
       // Time in seconds for time-based effects
@@ -433,6 +465,11 @@ export class SparkRenderer extends THREE.Mesh {
     }
 
     // Update uniforms from instance properties
+    const typedCamera = camera as
+      | THREE.PerspectiveCamera
+      | THREE.OrthographicCamera;
+    this.uniforms.near.value = typedCamera.near;
+    this.uniforms.far.value = typedCamera.far;
     this.uniforms.encodeLinear.value = viewpoint.encodeLinear;
     this.uniforms.maxStdDev.value = this.maxStdDev;
     this.uniforms.enable2DGS.value = this.enable2DGS;
@@ -442,6 +479,36 @@ export class SparkRenderer extends THREE.Mesh {
     this.uniforms.apertureAngle.value = this.apertureAngle;
     this.uniforms.falloff.value = this.falloff;
     this.uniforms.clipXY.value = this.clipXY;
+    this.uniforms.renderScale.value = this.renderScale;
+
+    if (this.splatTexture) {
+      const { enable, texture, multiply, add, near, far, mid } =
+        this.splatTexture;
+      if (enable && texture) {
+        this.uniforms.splatTexEnable.value = true;
+        this.uniforms.splatTexture.value = texture;
+        if (multiply) {
+          this.uniforms.splatTexMul.value.fromArray(multiply.elements);
+        } else {
+          this.uniforms.splatTexMul.value.set(
+            0.5 / this.maxStdDev,
+            0,
+            0,
+            0.5 / this.maxStdDev,
+          );
+        }
+        this.uniforms.splatTexAdd.value.set(add?.x ?? 0.5, add?.y ?? 0.5);
+        this.uniforms.splatTexNear.value = near ?? this.uniforms.near.value;
+        this.uniforms.splatTexFar.value = far ?? this.uniforms.far.value;
+        this.uniforms.splatTexMid.value = mid ?? 0.0;
+      } else {
+        this.uniforms.splatTexEnable.value = false;
+        this.uniforms.splatTexture.value = SparkRenderer.EMPTY_SPLAT_TEXTURE;
+      }
+    } else {
+      this.uniforms.splatTexEnable.value = false;
+      this.uniforms.splatTexture.value = SparkRenderer.EMPTY_SPLAT_TEXTURE;
+    }
 
     // Calculate the transform from the accumulator to the current camera
     const accumToWorld =

src/shaders/splatFragment.glsl

@@ -4,11 +4,21 @@ precision highp int;
 
 #include <splatDefines>
 
+uniform float near;
+uniform float far;
 uniform bool encodeLinear;
 uniform float maxStdDev;
 uniform bool disableFalloff;
 uniform float falloff;
 
+uniform bool splatTexEnable;
+uniform sampler3D splatTexture;
+uniform mat2 splatTexMul;
+uniform vec2 splatTexAdd;
+uniform float splatTexNear;
+uniform float splatTexFar;
+uniform float splatTexMid;
+
 out vec4 fragColor;
 
 in vec4 vRgba;
@@ -16,20 +26,45 @@ in vec2 vSplatUv;
 in vec3 vNdc;
 
 void main() {
+    vec4 rgba = vRgba;
+
     float z = dot(vSplatUv, vSplatUv);
-    if (z > (maxStdDev * maxStdDev)) {
-        discard;
+    if (!splatTexEnable) {
+        if (z > (maxStdDev * maxStdDev)) {
+            discard;
+        }
+    } else {
+        vec2 uv = splatTexMul * vSplatUv + splatTexAdd;
+        float ndcZ = vNdc.z;
+        float depth = (2.0 * near * far) / (far + near - ndcZ * (far - near));
+        float clampedFar = max(splatTexFar, splatTexNear);
+        float clampedDepth = clamp(depth, splatTexNear, clampedFar);
+        float logDepth = log2(clampedDepth + 1.0);
+        float logNear = log2(splatTexNear + 1.0);
+        float logFar = log2(clampedFar + 1.0);
+
+        float texZ;
+        if (splatTexMid > 0.0) {
+            float clampedMid = clamp(splatTexMid, splatTexNear, clampedFar);
+            float logMid = log2(clampedMid + 1.0);
+            texZ = (clampedDepth <= clampedMid) ?
+                (0.5 * ((logDepth - logNear) / (logMid - logNear))) :
+                (0.5 * ((logDepth - logMid) / (logFar - logMid)) + 0.5);
+        } else {
+            texZ = (logDepth - logNear) / (logFar - logNear);
+        }
+
+        vec4 modulate = texture(splatTexture, vec3(uv, 1.0 - texZ));
+        rgba *= modulate;
     }
 
-    float alpha = vRgba.a;
-    alpha *= mix(1.0, exp(-0.5 * z), falloff);
-    if (alpha < MIN_ALPHA) {
+    rgba.a *= mix(1.0, exp(-0.5 * z), falloff);
+
+    if (rgba.a < MIN_ALPHA) {
         discard;
     }
-
-    vec3 rgb = vRgba.rgb;
     if (encodeLinear) {
-        rgb = srgbToLinear(rgb);
+        rgba.rgb = srgbToLinear(rgba.rgb);
     }
-    fragColor = vec4(rgb, alpha);
+    fragColor = rgba;
 }

src/shaders/splatVertex.glsl

@@ -25,6 +25,7 @@ uniform float preBlurAmount;
 uniform float focalDistance;
 uniform float apertureAngle;
 uniform float clipXY;
+uniform float renderScale;
 
 uniform usampler2DArray packedSplats;
 
@@ -111,7 +112,8 @@ void main() {
     mat3 cov3D = RS * transpose(RS);
 
     // Compute the Jacobian of the splat's projection at its center
-    vec2 focal = 0.5 * renderSize * vec2(projectionMatrix[0][0], projectionMatrix[1][1]);
+    vec2 scaledRenderSize = renderSize * renderScale;
+    vec2 focal = 0.5 * scaledRenderSize * vec2(projectionMatrix[0][0], projectionMatrix[1][1]);
     float invZ = 1.0 / viewCenter.z;
     vec2 J1 = focal * invZ;
     vec2 J2 = -(J1 * viewCenter.xy) * invZ;
@@ -175,7 +177,7 @@ void main() {
 
     // Compute the NDC coordinates for the ellipsoid's diagonal axes.
     vec2 pixelOffset = eigenVec1 * scale1 + eigenVec2 * scale2;
-    vec2 ndcOffset = (2.0 / renderSize) * pixelOffset;
+    vec2 ndcOffset = (2.0 / scaledRenderSize) * pixelOffset;
     vec3 ndc = vec3(ndcCenter.xy + ndcOffset, ndcCenter.z);
 
     vRgba = rgba;