Implementation of baseVertex support

src/extras/mini-stats/render2d.js

@@ -144,6 +144,7 @@ class Render2d {
             type: PRIMITIVE_TRIANGLES,
             indexed: true,
             base: 0,
+            baseVertex: 0,
             count: 0
         };
         this.quads = 0;

src/platform/graphics/transform-feedback.js

@@ -159,6 +159,7 @@ class TransformFeedback {
         device.draw({
             type: PRIMITIVE_POINTS,
             base: 0,
+            baseVertex: 0,
             count: this._inputBuffer.numVertices,
             indexed: false
         });

src/platform/graphics/webgpu/webgpu-clear-renderer.js

@@ -16,6 +16,7 @@ import { DepthState } from '../depth-state.js';
 const primitive = {
     type: PRIMITIVE_TRISTRIP,
     base: 0,
+    baseVertex: 0,
     count: 4,
     indexed: false
 };

src/platform/graphics/webgpu/webgpu-graphics-device.js

@@ -595,7 +595,7 @@ class WebgpuGraphicsDevice extends GraphicsDevice {
             // draw
             if (indexBuffer) {
                 passEncoder.setIndexBuffer(indexBuffer.impl.buffer, indexBuffer.impl.format);
-                passEncoder.drawIndexed(primitive.count, numInstances, primitive.base, 0, 0);
+                passEncoder.drawIndexed(primitive.count, numInstances, primitive.base, primitive.baseVertex ?? 0, 0);
             } else {
                 passEncoder.draw(primitive.count, numInstances, primitive.base, 0);
             }

src/scene/batching/batch-manager.js

@@ -658,7 +658,7 @@ class BatchManager {
             batch = new Batch(meshInstances, dynamic, batchGroupId);
             this._batchList.push(batch);
 
-            let indexBase, numIndices, indexData;
+            let indexBase, indexBaseVertex, numIndices, indexData;
             let verticesOffset = 0;
             let indexOffset = 0;
             let transform;
@@ -760,6 +760,7 @@ class BatchManager {
                 // index buffer
                 if (mesh.primitive[0].indexed) {
                     indexBase = mesh.primitive[0].base;
+                    indexBaseVertex = mesh.primitive[0].baseVertex || 0;
                     numIndices = mesh.primitive[0].count;
 
                     // source index buffer data mapped to its format
@@ -768,6 +769,8 @@ class BatchManager {
 
                 } else { // non-indexed
 
+                    indexBaseVertex = 0;
+
                     const primitiveType = mesh.primitive[0].type;
                     if (primitiveType === PRIMITIVE_TRIFAN || primitiveType === PRIMITIVE_TRISTRIP) {
                         if (mesh.primitive[0].count === 4) {
@@ -782,7 +785,7 @@ class BatchManager {
                 }
 
                 for (let j = 0; j < numIndices; j++) {
-                    indices[j + indexOffset] = indexData[indexBase + j] + verticesOffset;
+                    indices[j + indexOffset] = indexData[indexBase + j] + indexBaseVertex + verticesOffset;
                 }
 
                 indexOffset += numIndices;

src/scene/graphics/quad-render.js

@@ -14,6 +14,7 @@ import { ShaderUtils } from '../shader-lib/shader-utils.js';
 const _quadPrimitive = {
     type: PRIMITIVE_TRISTRIP,
     base: 0,
+    baseVertex: 0,
     count: 4,
     indexed: false
 };

src/scene/mesh.js

@@ -201,15 +201,17 @@ class Mesh extends RefCountedObject {
      *   - {@link PRIMITIVE_TRIFAN}
      *
      * - `base` is the offset of the first index or vertex to dispatch in the draw call.
+     * - `baseVertex` is the number added to each index value before indexing into the vertex buffers. (supported only in WebGPU, ignored in WebGL2)
      * - `count` is the number of indices or vertices to dispatch in the draw call.
      * - `indexed` specifies whether to interpret the primitive as indexed, thereby using the
      * currently set index buffer.
      *
-     * @type {{type: number, base: number, count: number, indexed?: boolean}[]}
+     * @type {{type: number, base: number, baseVertex: number, count: number, indexed?: boolean}[]}
      */
     primitive = [{
         type: 0,
         base: 0,
+        baseVertex: 0,
         count: 0
     }];
 
@@ -1044,6 +1046,7 @@ class Mesh extends RefCountedObject {
             this.primitive[RENDERSTYLE_POINTS] = {
                 type: PRIMITIVE_POINTS,
                 base: 0,
+                baseVertex: 0,
                 count: this.vertexBuffer ? this.vertexBuffer.numVertices : 0,
                 indexed: false
             };
@@ -1108,6 +1111,7 @@ class Mesh extends RefCountedObject {
         this.primitive[RENDERSTYLE_WIREFRAME] = {
             type: PRIMITIVE_LINES,
             base: 0,
+            baseVertex: 0,
             count: lines.length,
             indexed: true
         };