Webgl buffer / add utility getSize function

Saves checking whether the buffer was initialized with
an array already

src/ol/renderer/webgl/PointsLayer.js

@@ -344,7 +344,7 @@ class WebGLPointsLayerRenderer extends WebGLLayerRenderer {
    * @inheritDoc
    */
   renderFrame(frameState) {
-    const renderCount = this.indicesBuffer_.getArray() ? this.indicesBuffer_.getArray().length : 0;
+    const renderCount = this.indicesBuffer_.getSize();
     this.helper.drawElements(0, renderCount);
     this.helper.finalizeDraw(frameState);
     const canvas = this.helper.getCanvas();
@@ -561,7 +561,7 @@ class WebGLPointsLayerRenderer extends WebGLLayerRenderer {
     this.helper.enableAttributeArray(DefaultAttrib.ROTATE_WITH_VIEW, 1, FLOAT, bytesPerFloat * stride, bytesPerFloat * 7);
     this.helper.enableAttributeArray(DefaultAttrib.COLOR, 4, FLOAT, bytesPerFloat * stride, bytesPerFloat * 8);
 
-    const renderCount = this.indicesBuffer_.getArray() ? this.indicesBuffer_.getArray().length : 0;
+    const renderCount = this.indicesBuffer_.getSize();
     this.helper.drawElements(0, renderCount);
   }
 }

src/ol/webgl/Buffer.js

@@ -95,6 +95,7 @@ class WebGLArrayBuffer {
   }
 
   /**
+   * Will return null if the buffer was not initialized
    * @return {Float32Array|Uint32Array} Array.
    */
   getArray() {
@@ -107,6 +108,14 @@ class WebGLArrayBuffer {
   getUsage() {
     return this.usage;
   }
+
+  /**
+   * Will return 0 if the buffer is not initialized
+   * @return {number} Array size
+   */
+  getSize() {
+    return this.array ? this.array.length : 0;
+  }
 }
 
 /**

test/spec/ol/webgl/buffer.test.js

@@ -75,4 +75,21 @@ describe('ol.webgl.Buffer', function() {
 
   });
 
+  describe('#getSize', function() {
+    let b;
+    beforeEach(function() {
+      b = new WebGLArrayBuffer(ARRAY_BUFFER);
+    });
+
+    it('returns 0 when the buffer array is not initialized', function() {
+      expect(b.getSize()).to.be(0);
+    });
+
+    it('returns the size of the array otherwise', function() {
+      b.ofSize(12);
+      expect(b.getSize()).to.be(12);
+    });
+
+  });
+
 });