From 92f6bc99b2e9ed57027ae0033d721408009314d8 Mon Sep 17 00:00:00 2001
From: Simon Stucki <simon_stucki@hotmail.com>
Date: Sun, 18 Aug 2024 11:43:17 +0200
Subject: [PATCH] Extend material validation

---
 strahl-lib/src/path-tracer.ts      |  8 +++-----
 strahl-lib/src/prepare-geometry.ts | 29 ++++++++++++++++++++++++++---
 2 files changed, 29 insertions(+), 8 deletions(-)

diff --git a/strahl-lib/src/path-tracer.ts b/strahl-lib/src/path-tracer.ts
index dfae3fb..8175d4c 100644
--- a/strahl-lib/src/path-tracer.ts
+++ b/strahl-lib/src/path-tracer.ts
@@ -381,11 +381,10 @@ async function runPathTracer(
 
   // Prepare Object Definitions
   const OBJECT_DEFINITION_SIZE_PER_ENTRY = Uint32Array.BYTES_PER_ELEMENT * 3;
-  const groups = modelGroups;
 
   const objectDefinitionsBuffer = device.createBuffer({
     label: "Object definitions buffer",
-    size: OBJECT_DEFINITION_SIZE_PER_ENTRY * groups.length,
+    size: OBJECT_DEFINITION_SIZE_PER_ENTRY * modelGroups.length,
     usage: GPUBufferUsage.STORAGE,
     mappedAtCreation: true,
   });
@@ -394,8 +393,7 @@ async function runPathTracer(
   const objectDefinitionsData = new Uint32Array(objectDefinitionsMapped);
 
   objectDefinitionsData.set(
-    // todo: reconsider type assertion
-    groups.map((g) => [g.start, g.count, g.materialIndex!]).flat(1),
+    modelGroups.map((g) => [g.start, g.count, g.materialIndex]).flat(1),
   );
   objectDefinitionsBuffer.unmap();
 
@@ -659,7 +657,7 @@ async function runPathTracer(
         clearColor: clearColor === false ? [0, 0, 0] : clearColor,
         enableClearColor: clearColor === false ? 0 : 1,
         maxRayDepth,
-        objectDefinitionLength: groups.length,
+        objectDefinitionLength: modelGroups.length,
       });
       // todo: consider buffer writing
       device.queue.writeBuffer(uniformBuffer, 0, uniformData.arrayBuffer);
diff --git a/strahl-lib/src/prepare-geometry.ts b/strahl-lib/src/prepare-geometry.ts
index 41bf1c6..973463d 100644
--- a/strahl-lib/src/prepare-geometry.ts
+++ b/strahl-lib/src/prepare-geometry.ts
@@ -1,9 +1,27 @@
 import { getBVHExtremes, MeshBVH } from "three-mesh-bvh";
 import { logGroup } from "./benchmark/cpu-performance-logger";
 import { consolidateMesh } from "./consolidate-mesh";
-import { Group } from "three";
+import { GeometryGroup, Group } from "three";
 import { assertMeshBVHInternalStructure, bvhToTextures } from "./bvh-util";
-import { InternalError } from "./core/exceptions";
+import { InternalError, InvalidMaterialGroupError } from "./core/exceptions";
+
+export type MaterializedGeometryGroup = {
+  start: number;
+  count: number;
+  materialIndex: number;
+};
+
+function assertMaterializedGeometryGroup(
+  geometryGroup: GeometryGroup,
+): asserts geometryGroup is MaterializedGeometryGroup {
+  if (
+    typeof geometryGroup.start !== "number" ||
+    typeof geometryGroup.count !== "number" ||
+    typeof geometryGroup.materialIndex !== "number"
+  ) {
+    throw new InvalidMaterialGroupError(geometryGroup);
+  }
+}
 
 export function prepareGeometry(model: { scene: Group }) {
   const reducedModel = consolidateMesh([model.scene]);
@@ -34,6 +52,11 @@ export function prepareGeometry(model: { scene: Group }) {
 
   const normals = boundsTree.geometry.attributes.normal.array;
 
+  const modelGroups = reducedModel.geometry.groups.map((geometryGroup) => {
+    assertMaterializedGeometryGroup(geometryGroup);
+    return geometryGroup;
+  });
+
   return {
     indirectBuffer: boundsTree._indirectBuffer,
     boundsArray,
@@ -41,7 +64,7 @@ export function prepareGeometry(model: { scene: Group }) {
     positions,
     normals,
     meshIndices,
-    modelGroups: reducedModel.geometry.groups,
+    modelGroups,
     modelMaterials: reducedModel.materials,
     maxBvhDepth,
     bvhBuildTime,