fix bandcount per texture for 8, 12, 16, etc bands

src/ol/webgl/TileTexture.js

@@ -278,7 +278,7 @@ class TileTexture extends EventTarget {
       this.textures.push(texture);
 
       const bandCount =
-        textureIndex < textureCount - 1 ? 4 : this.bandCount % 4;
+        textureIndex < textureCount - 1 ? 4 : ((this.bandCount - 1) % 4) + 1;
       textureDataArrays[textureIndex] = new DataType(pixelCount * bandCount);
     }
 

test/rendering/cases/webgl-data-tile-8-band/main.js

@@ -0,0 +1,59 @@
+import DataTile from '../../../../src/ol/source/DataTile.js';
+import Map from '../../../../src/ol/Map.js';
+import TileLayer from '../../../../src/ol/layer/WebGLTile.js';
+import View from '../../../../src/ol/View.js';
+
+const size = [81, 99];
+
+const canvas = document.createElement('canvas');
+canvas.width = size[0];
+canvas.height = size[1];
+
+const context = canvas.getContext('2d');
+context.strokeStyle = 'white';
+context.textAlign = 'center';
+const lineHeight = 16;
+context.font = `${lineHeight}px sans-serif`;
+
+new Map({
+  target: 'map',
+  layers: [
+    new TileLayer({
+      source: new DataTile({
+        tileSize: size,
+        bandCount: 8,
+        loader: function (z, x, y) {
+          const halfWidth = size[0] / 2;
+          const halfHeight = size[1] / 2;
+          context.fillStyle = '#00AAFF';
+          context.fillRect(0, 0, size[0], size[1]);
+          context.fillStyle = 'white';
+          context.fillText(`z: ${z}`, halfWidth, halfHeight - lineHeight);
+          context.fillText(`x: ${x}`, halfWidth, halfHeight);
+          context.fillText(`y: ${y}`, halfWidth, halfHeight + lineHeight);
+          context.strokeRect(0, 0, size[0], size[1]);
+          const input = context.getImageData(0, 0, size[0], size[1]).data;
+          const length = input.length;
+          const output = new Uint8Array(length * 2);
+          for (let i = 0, j = 4; i < length; i += 4) {
+            output[j] = input[i];
+            output[j + 1] = input[i + 1];
+            output[j + 2] = input[i + 2];
+            output[j + 3] = input[i + 3];
+            j += 8;
+          }
+          return output;
+        },
+      }),
+      style: {
+        color: ['array', ['band', 5], ['band', 6], ['band', 7], ['band', 8]],
+      },
+    }),
+  ],
+  view: new View({
+    center: [0, 0],
+    zoom: 4,
+  }),
+});
+
+render({tolerance: 0.03});