Webgl shader builder / expanded functionality

Now takes in a custom object with attributes, uniforms etc.
The WebGLPointsLayer uses this to handle image icons.

src/ol/layer/WebGLPoints.js

@@ -4,8 +4,15 @@
 import VectorLayer from './Vector.js';
 import {assign} from '../obj.js';
 import WebGLPointsLayerRenderer from '../renderer/webgl/PointsLayer.js';
-import {getSymbolFragmentShader, getSymbolVertexShader} from '../webgl/ShaderBuilder.js';
+import {
+  formatArray,
+  formatColor,
+  formatNumber,
+  getSymbolFragmentShader,
+  getSymbolVertexShader
+} from '../webgl/ShaderBuilder.js';
 import {assert} from '../asserts.js';
+import {asArray} from '../color.js';
 
 
 /**
@@ -59,9 +66,42 @@ class WebGLPointsLayer extends VectorLayer {
    * @inheritDoc
    */
   createRenderer() {
+    const symbolStyle = this.literalStyle.symbol;
+    const size = Array.isArray(symbolStyle.size) ?
+      formatArray(symbolStyle.size) : formatNumber(symbolStyle.size);
+    const color = symbolStyle.color !== undefined ?
+      (typeof symbolStyle.color === 'string' ? asArray(symbolStyle.color) : symbolStyle.color) :
+      [255, 255, 255, 1];
+    const texCoord = symbolStyle.textureCoord || [0, 0, 1, 1];
+    const offset = symbolStyle.offset || [0, 0];
+    const opacity = symbolStyle.opacity !== undefined ? symbolStyle.opacity : 1;
+
+    /** @type {import('../webgl/ShaderBuilder.js').ShaderParameters} */
+    const params = {
+      uniforms: [],
+      colorExpression: 'vec4(' + formatColor(color) + ') * vec4(1.0, 1.0, 1.0, ' + formatNumber(opacity) + ')',
+      sizeExpression: 'vec2(' + size + ')',
+      offsetExpression: 'vec2(' + formatArray(offset) + ')',
+      texCoordExpression: 'vec4(' + formatArray(texCoord) + ')',
+      rotateWithView: !!symbolStyle.rotateWithView
+    };
+
+    /** @type {Object.<string,import("../webgl/Helper").UniformValue>} */
+    const uniforms = {};
+
+    if (symbolStyle.symbolType === 'image' && symbolStyle.src) {
+      const texture = new Image();
+      texture.src = symbolStyle.src;
+      params.uniforms.push('sampler2D u_texture');
+      params.colorExpression = params.colorExpression +
+        ' * texture2D(u_texture, v_texCoord);';
+      uniforms['u_texture'] = texture;
+    }
+
     return new WebGLPointsLayerRenderer(this, {
-      vertexShader: getSymbolVertexShader(this.literalStyle.symbol),
-      fragmentShader: getSymbolFragmentShader()
+      vertexShader: getSymbolVertexShader(params),
+      fragmentShader: getSymbolFragmentShader(params),
+      uniforms: uniforms
     });
   }
 }