Webgl shader builder / expanded functionality

Now takes in a custom object with attributes, uniforms etc. The WebGLPointsLayer uses this to handle image icons.
2019-09-25 14:49:14 +02:00
parent b8564d503a
commit 34572da17b
3 changed files with 258 additions and 148 deletions
--- a/src/ol/layer/WebGLPoints.js
+++ b/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
    });
  }
 }
--- a/src/ol/webgl/ShaderBuilder.js
+++ b/src/ol/webgl/ShaderBuilder.js
@@ -1,5 +1,3 @@
-import {asArray} from '../color.js';
-
 /**
 * Utilities for generating shaders from literal style objects
 * @module ol/webgl/ShaderBuilder
@@ -15,6 +13,15 @@ export function formatNumber(v) {
  return s.indexOf('.') === -1 ? s + '.0' : s;
 }

+/**
+ * Will return the number array as a float with a dot separator, concatenated with ', '.
+ * @param {Array<number>} array Numerical values array.
+ * @returns {string} The array as string, e. g.: `1.0, 2.0, 3.0`.
+ */
+export function formatArray(array) {
+  return array.map(formatNumber).join(', ');
+}
+
 /**
 * Will normalize and converts to string a color array compatible with GLSL.
 * @param {Array<number>} colorArray Color in [r, g, b, a] array form, with RGB components in the
@@ -29,54 +36,78 @@ export function formatColor(colorArray) {
 }

 /**
- * Generates a symbol vertex shader from a literal style,
+ * @typedef {Object} VaryingDescription
+ * @property {string} name Varying name, as will be declared in the header.
+ * @property {string} type Varying type, either `float`, `vec2`, `vec4`...
+ * @property {string} expression Expression which will be assigned to the varying in the vertex shader, and
+ * passed on to the fragment shader.
+ */
+
+/**
+ * @typedef {Object} ShaderParameters
+ * @property {Array<string>} [uniforms] Uniforms; these will be declared in the header (should include the type).
+ * @property {Array<string>} [attributes] Attributes; these will be declared in the header (should include the type).
+ * @property {Array<VaryingDescription>} [varyings] Varyings with a name, a type and an expression.
+ * @property {string} sizeExpression This will be assigned to a `vec2 size` variable.
+ * @property {string} offsetExpression This will be assigned to a `vec2 offset` variable.
+ * @property {string} colorExpression This will be the value assigned to gl_FragColor
+ * @property {string} texCoordExpression This will be the value assigned to the `vec4 v_texCoord` varying.
+ * @property {boolean} [rotateWithView=false] Whether symbols should rotate with view
+ */
+
+/**
+ * Generates a symbol vertex shader from a set of parameters,
 * intended to be used on point geometries.
 *
- * Expected the following attributes to be present in the attribute array:
+ * Three uniforms are hardcoded in all shaders: `u_projectionMatrix`, `u_offsetScaleMatrix` and
+ * `u_offsetRotateMatrix`.
+ *
+ * The following attributes are hardcoded and expected to be present in the vertex buffers:
 * `vec2 a_position`, `float a_index` (being the index of the vertex in the quad, 0 to 3).
 *
- * Transmits the following varyings to the fragment shader:
- * `vec2 v_texCoord`, `float v_opacity`, `vec4 v_color`
- *
- * @param {import('../style/LiteralStyle.js').LiteralSymbolStyle} parameters Parameters for the shader.
+ * @param {ShaderParameters} parameters Parameters for the shader.
 * @returns {string} The full shader as a string.
 */
 export function getSymbolVertexShader(parameters) {
  const offsetMatrix = parameters.rotateWithView ?
-    'mat4 offsetMatrix = u_offsetScaleMatrix * u_offsetRotateMatrix;' :
-    'mat4 offsetMatrix = u_offsetScaleMatrix;';
+    'u_offsetScaleMatrix * u_offsetRotateMatrix' :
+    'u_offsetScaleMatrix';

-  const offset = parameters.offset || [0, 0];
-  const size = Array.isArray(parameters.size) ? parameters.size : [parameters.size, parameters.size];
-  const texCoord = parameters.textureCoord || [0, 0, 1, 1];
-  const opacity = parameters.opacity !== undefined ? parameters.opacity : 1;
-  const color = parameters.color !== undefined ?
-    (typeof parameters.color === 'string' ? asArray(parameters.color) : parameters.color) :
-    [255, 255, 255, 1];
-
-  const f = formatNumber;
+  const uniforms = parameters.uniforms || [];
+  const attributes = parameters.attributes || [];
+  const varyings = parameters.varyings || [];

  const body = `precision mediump float;
 uniform mat4 u_projectionMatrix;
 uniform mat4 u_offsetScaleMatrix;
 uniform mat4 u_offsetRotateMatrix;
+${uniforms.map(function(uniform) {
+    return 'uniform ' + uniform + ';';
+  }).join('\n')}
 attribute vec2 a_position;
 attribute float a_index;
+${attributes.map(function(attribute) {
+    return 'attribute ' + attribute + ';';
+  }).join('\n')}
 varying vec2 v_texCoord;
-varying float v_opacity;
-varying vec4 v_color;
-
+${varyings.map(function(varying) {
+    return 'varying ' + varying.type + ' ' + varying.name + ';';
+  }).join('\n')}
 void main(void) {
-  ${offsetMatrix}
-  float offsetX = a_index == 0.0 || a_index == 3.0 ? ${f(offset[0] - size[0] / 2)} : ${f(offset[0] + size[0] / 2)};
-  float offsetY = a_index == 0.0 || a_index == 1.0 ? ${f(offset[1] - size[1] / 2)} : ${f(offset[1] + size[1] / 2)};
+  mat4 offsetMatrix = ${offsetMatrix};
+  vec2 size = ${parameters.sizeExpression};
+  vec2 offset = ${parameters.offsetExpression};
+  float offsetX = a_index == 0.0 || a_index == 3.0 ? offset.x - size.x / 2.0 : offset.x + size.x / 2.0;
+  float offsetY = a_index == 0.0 || a_index == 1.0 ? offset.y - size.y / 2.0 : offset.y + size.y / 2.0;
  vec4 offsets = offsetMatrix * vec4(offsetX, offsetY, 0.0, 0.0);
  gl_Position = u_projectionMatrix * vec4(a_position, 0.0, 1.0) + offsets;
-  float u = a_index == 0.0 || a_index == 3.0 ? ${f(texCoord[0])} : ${f(texCoord[2])};
-  float v = a_index == 0.0 || a_index == 1.0 ? ${f(texCoord[1])} : ${f(texCoord[3])};
+  vec4 texCoord = ${parameters.texCoordExpression};
+  float u = a_index == 0.0 || a_index == 3.0 ? texCoord.s : texCoord.q;
+  float v = a_index == 2.0 || a_index == 3.0 ? texCoord.t : texCoord.p;
  v_texCoord = vec2(u, v);
-  v_opacity = ${f(opacity)};
-  v_color = vec4(${formatColor(color)});
+${varyings.map(function(varying) {
+    return '  ' + varying.name + ' = ' + varying.expression + ';';
+  }).join('\n')}
 }`;

  return body;
@@ -86,24 +117,25 @@ void main(void) {
 * Generates a symbol fragment shader intended to be used on point geometries.
 *
 * Expected the following varyings to be transmitted by the vertex shader:
- * `vec2 v_texCoord`, `float v_opacity`, `vec4 v_color`
+ * `vec2 v_texCoord`
 *
+ * @param {ShaderParameters} parameters Parameters for the shader.
 * @returns {string} The full shader as a string.
 */
-export function getSymbolFragmentShader() {
-  const body = `precision mediump float;
-uniform sampler2D u_texture;
-varying vec2 v_texCoord;
-varying float v_opacity;
-varying vec4 v_color;
+export function getSymbolFragmentShader(parameters) {
+  const uniforms = parameters.uniforms || [];
+  const varyings = parameters.varyings || [];

+  const body = `precision mediump float;
+${uniforms.map(function(uniform) {
+    return 'uniform ' + uniform + ';';
+  }).join('\n')}
+varying vec2 v_texCoord;
+${varyings.map(function(varying) {
+    return 'varying ' + varying.type + ' ' + varying.name + ';';
+  }).join('\n')}
 void main(void) {
-  if (v_opacity == 0.0) {
-    discard;
-  }
-  vec4 textureColor = texture2D(u_texture, v_texCoord);
-  gl_FragColor = v_color * textureColor;
-  gl_FragColor.a *= v_opacity;
+  gl_FragColor = ${parameters.colorExpression};
  gl_FragColor.rgb *= gl_FragColor.a;
 }`;

--- a/test/spec/ol/webgl/shaderbuilder.test.js
+++ b/test/spec/ol/webgl/shaderbuilder.test.js
@@ -1,4 +1,9 @@
-import {getSymbolVertexShader, formatNumber, getSymbolFragmentShader} from '../../../../src/ol/webgl/ShaderBuilder.js';
+import {
+  getSymbolVertexShader,
+  formatNumber,
+  getSymbolFragmentShader,
+  formatColor, formatArray
+} from '../../../../src/ol/webgl/ShaderBuilder.js';

 describe('ol.webgl.ShaderBuilder', function() {

@@ -12,147 +17,180 @@ describe('ol.webgl.ShaderBuilder', function() {
    });
  });

+  describe('formatArray', function() {
+    it('outputs numbers with dot separators', function() {
+      expect(formatArray([1, 0, 3.45, 0.8888])).to.eql('1.0, 0.0, 3.45, 0.8888');
+    });
+  });
+
+  describe('formatColor', function() {
+    it('normalizes color and outputs numbers with dot separators', function() {
+      expect(formatColor([100, 0, 255, 1])).to.eql('0.39215686274509803, 0.0, 1.0, 1.0');
+    });
+  });
+
  describe('getSymbolVertexShader', function() {
-    it('generates a symbol vertex shader without using additional attributes', function() {
-      expect(getSymbolVertexShader(
-        {
-          rotateWithView: false,
-          color: '#5000ff',
-          opacity: 0.4,
-          offset: [5, -7],
-          size: 6,
-          textureCoord: [0, 0.5, 0.5, 1]
-        })).to.eql(`precision mediump float;
+    it('generates a symbol vertex shader (with varying)', function() {
+      const parameters = {
+        varyings: [{
+          name: 'v_opacity',
+          type: 'float',
+          expression: formatNumber(0.4)
+        }, {
+          name: 'v_test',
+          type: 'vec3',
+          expression: 'vec3(' + formatArray([1, 2, 3]) + ')'
+        }],
+        sizeExpression: 'vec2(' + formatNumber(6) + ')',
+        offsetExpression: 'vec2(' + formatArray([5, -7]) + ')',
+        colorExpression: 'vec4(' + formatColor([80, 0, 255, 1]) + ')',
+        texCoordExpression: 'vec4(' + formatArray([0, 0.5, 0.5, 1]) + ')',
+        rotateWithView: false
+      };
+
+      expect(getSymbolVertexShader(parameters)).to.eql(`precision mediump float;
 uniform mat4 u_projectionMatrix;
 uniform mat4 u_offsetScaleMatrix;
 uniform mat4 u_offsetRotateMatrix;
+
 attribute vec2 a_position;
 attribute float a_index;
+
 varying vec2 v_texCoord;
 varying float v_opacity;
-varying vec4 v_color;
+varying vec3 v_test;
+void main(void) {
+  mat4 offsetMatrix = u_offsetScaleMatrix;
+  vec2 size = vec2(6.0);
+  vec2 offset = vec2(5.0, -7.0);
+  float offsetX = a_index == 0.0 || a_index == 3.0 ? offset.x - size.x / 2.0 : offset.x + size.x / 2.0;
+  float offsetY = a_index == 0.0 || a_index == 1.0 ? offset.y - size.y / 2.0 : offset.y + size.y / 2.0;
+  vec4 offsets = offsetMatrix * vec4(offsetX, offsetY, 0.0, 0.0);
+  gl_Position = u_projectionMatrix * vec4(a_position, 0.0, 1.0) + offsets;
+  vec4 texCoord = vec4(0.0, 0.5, 0.5, 1.0);
+  float u = a_index == 0.0 || a_index == 3.0 ? texCoord.s : texCoord.q;
+  float v = a_index == 2.0 || a_index == 3.0 ? texCoord.t : texCoord.p;
+  v_texCoord = vec2(u, v);
+  v_opacity = 0.4;
+  v_test = vec3(1.0, 2.0, 3.0);
+}`);
+    });
+    it('generates a symbol vertex shader (with uniforms and attributes)', function() {
+      const parameters = {
+        uniforms: ['float u_myUniform'],
+        attributes: ['vec2 a_myAttr'],
+        sizeExpression: 'vec2(' + formatNumber(6) + ')',
+        offsetExpression: 'vec2(' + formatArray([5, -7]) + ')',
+        colorExpression: 'vec4(' + formatColor([80, 0, 255, 1]) + ')',
+        texCoordExpression: 'vec4(' + formatArray([0, 0.5, 0.5, 1]) + ')'
+      };
+
+      expect(getSymbolVertexShader(parameters)).to.eql(`precision mediump float;
+uniform mat4 u_projectionMatrix;
+uniform mat4 u_offsetScaleMatrix;
+uniform mat4 u_offsetRotateMatrix;
+uniform float u_myUniform;
+attribute vec2 a_position;
+attribute float a_index;
+attribute vec2 a_myAttr;
+varying vec2 v_texCoord;

 void main(void) {
  mat4 offsetMatrix = u_offsetScaleMatrix;
-  float offsetX = a_index == 0.0 || a_index == 3.0 ? 2.0 : 8.0;
-  float offsetY = a_index == 0.0 || a_index == 1.0 ? -10.0 : -4.0;
+  vec2 size = vec2(6.0);
+  vec2 offset = vec2(5.0, -7.0);
+  float offsetX = a_index == 0.0 || a_index == 3.0 ? offset.x - size.x / 2.0 : offset.x + size.x / 2.0;
+  float offsetY = a_index == 0.0 || a_index == 1.0 ? offset.y - size.y / 2.0 : offset.y + size.y / 2.0;
  vec4 offsets = offsetMatrix * vec4(offsetX, offsetY, 0.0, 0.0);
  gl_Position = u_projectionMatrix * vec4(a_position, 0.0, 1.0) + offsets;
-  float u = a_index == 0.0 || a_index == 3.0 ? 0.0 : 0.5;
-  float v = a_index == 0.0 || a_index == 1.0 ? 0.5 : 1.0;
+  vec4 texCoord = vec4(0.0, 0.5, 0.5, 1.0);
+  float u = a_index == 0.0 || a_index == 3.0 ? texCoord.s : texCoord.q;
+  float v = a_index == 2.0 || a_index == 3.0 ? texCoord.t : texCoord.p;
  v_texCoord = vec2(u, v);
-  v_opacity = 0.4;
-  v_color = vec4(0.3137254901960784, 0.0, 1.0, 1.0);
-}`);
-    });
-    it('correctly handles size as an array', function() {
-      expect(getSymbolVertexShader(
-        {
-          rotateWithView: false,
-          color: '#5000ff',
-          opacity: 0.4,
-          offset: [5, -7],
-          size: [10, 12],
-          textureCoord: [0, 0.5, 0.5, 1]
-        })).to.eql(`precision mediump float;
-uniform mat4 u_projectionMatrix;
-uniform mat4 u_offsetScaleMatrix;
-uniform mat4 u_offsetRotateMatrix;
-attribute vec2 a_position;
-attribute float a_index;
-varying vec2 v_texCoord;
-varying float v_opacity;
-varying vec4 v_color;

-void main(void) {
-  mat4 offsetMatrix = u_offsetScaleMatrix;
-  float offsetX = a_index == 0.0 || a_index == 3.0 ? 0.0 : 10.0;
-  float offsetY = a_index == 0.0 || a_index == 1.0 ? -13.0 : -1.0;
-  vec4 offsets = offsetMatrix * vec4(offsetX, offsetY, 0.0, 0.0);
-  gl_Position = u_projectionMatrix * vec4(a_position, 0.0, 1.0) + offsets;
-  float u = a_index == 0.0 || a_index == 3.0 ? 0.0 : 0.5;
-  float v = a_index == 0.0 || a_index == 1.0 ? 0.5 : 1.0;
-  v_texCoord = vec2(u, v);
-  v_opacity = 0.4;
-  v_color = vec4(0.3137254901960784, 0.0, 1.0, 1.0);
 }`);
    });
-    it('correctly handles rotate with view', function() {
-      expect(getSymbolVertexShader(
-        {
-          rotateWithView: true,
-          color: '#5000ff',
-          opacity: 0.4,
-          size: 6,
-          textureCoord: [0, 0.5, 0.5, 1]
-        })).to.eql(`precision mediump float;
+    it('generates a symbol vertex shader (with rotateWithView)', function() {
+      const parameters = {
+        sizeExpression: 'vec2(' + formatNumber(6) + ')',
+        offsetExpression: 'vec2(' + formatArray([5, -7]) + ')',
+        colorExpression: 'vec4(' + formatColor([80, 0, 255, 1]) + ')',
+        texCoordExpression: 'vec4(' + formatArray([0, 0.5, 0.5, 1]) + ')',
+        rotateWithView: true
+      };
+
+      expect(getSymbolVertexShader(parameters)).to.eql(`precision mediump float;
 uniform mat4 u_projectionMatrix;
 uniform mat4 u_offsetScaleMatrix;
 uniform mat4 u_offsetRotateMatrix;
+
 attribute vec2 a_position;
 attribute float a_index;
+
 varying vec2 v_texCoord;
-varying float v_opacity;
-varying vec4 v_color;

 void main(void) {
  mat4 offsetMatrix = u_offsetScaleMatrix * u_offsetRotateMatrix;
-  float offsetX = a_index == 0.0 || a_index == 3.0 ? -3.0 : 3.0;
-  float offsetY = a_index == 0.0 || a_index == 1.0 ? -3.0 : 3.0;
+  vec2 size = vec2(6.0);
+  vec2 offset = vec2(5.0, -7.0);
+  float offsetX = a_index == 0.0 || a_index == 3.0 ? offset.x - size.x / 2.0 : offset.x + size.x / 2.0;
+  float offsetY = a_index == 0.0 || a_index == 1.0 ? offset.y - size.y / 2.0 : offset.y + size.y / 2.0;
  vec4 offsets = offsetMatrix * vec4(offsetX, offsetY, 0.0, 0.0);
  gl_Position = u_projectionMatrix * vec4(a_position, 0.0, 1.0) + offsets;
-  float u = a_index == 0.0 || a_index == 3.0 ? 0.0 : 0.5;
-  float v = a_index == 0.0 || a_index == 1.0 ? 0.5 : 1.0;
+  vec4 texCoord = vec4(0.0, 0.5, 0.5, 1.0);
+  float u = a_index == 0.0 || a_index == 3.0 ? texCoord.s : texCoord.q;
+  float v = a_index == 2.0 || a_index == 3.0 ? texCoord.t : texCoord.p;
  v_texCoord = vec2(u, v);
-  v_opacity = 0.4;
-  v_color = vec4(0.3137254901960784, 0.0, 1.0, 1.0);
-}`);
-    });
-    it('correctly handles missing optional parameters', function() {
-      expect(getSymbolVertexShader(
-        {
-          rotateWithView: false,
-          size: 5
-        })).to.eql(`precision mediump float;
-uniform mat4 u_projectionMatrix;
-uniform mat4 u_offsetScaleMatrix;
-uniform mat4 u_offsetRotateMatrix;
-attribute vec2 a_position;
-attribute float a_index;
-varying vec2 v_texCoord;
-varying float v_opacity;
-varying vec4 v_color;

-void main(void) {
-  mat4 offsetMatrix = u_offsetScaleMatrix;
-  float offsetX = a_index == 0.0 || a_index == 3.0 ? -2.5 : 2.5;
-  float offsetY = a_index == 0.0 || a_index == 1.0 ? -2.5 : 2.5;
-  vec4 offsets = offsetMatrix * vec4(offsetX, offsetY, 0.0, 0.0);
-  gl_Position = u_projectionMatrix * vec4(a_position, 0.0, 1.0) + offsets;
-  float u = a_index == 0.0 || a_index == 3.0 ? 0.0 : 1.0;
-  float v = a_index == 0.0 || a_index == 1.0 ? 0.0 : 1.0;
-  v_texCoord = vec2(u, v);
-  v_opacity = 1.0;
-  v_color = vec4(1.0, 1.0, 1.0, 1.0);
 }`);
    });
  });

  describe('getSymbolFragmentShader', function() {
-    it('generates a fixed shader', function() {
-      expect(getSymbolFragmentShader()).to.eql(`precision mediump float;
-uniform sampler2D u_texture;
+    it('generates a symbol fragment shader (with varying)', function() {
+      const parameters = {
+        varyings: [{
+          name: 'v_opacity',
+          type: 'float',
+          expression: formatNumber(0.4)
+        }, {
+          name: 'v_test',
+          type: 'vec3',
+          expression: 'vec3(' + formatArray([1, 2, 3]) + ')'
+        }],
+        sizeExpression: 'vec2(' + formatNumber(6) + ')',
+        offsetExpression: 'vec2(' + formatArray([5, -7]) + ')',
+        colorExpression: 'vec4(' + formatColor([80, 0, 255]) + ', v_opacity)',
+        texCoordExpression: 'vec4(' + formatArray([0, 0.5, 0.5, 1]) + ')',
+        rotateWithView: false
+      };
+
+      expect(getSymbolFragmentShader(parameters)).to.eql(`precision mediump float;
+
 varying vec2 v_texCoord;
 varying float v_opacity;
-varying vec4 v_color;
+varying vec3 v_test;
+void main(void) {
+  gl_FragColor = vec4(0.3137254901960784, 0.0, 1.0, v_opacity);
+  gl_FragColor.rgb *= gl_FragColor.a;
+}`);
+    });
+    it('generates a symbol fragment shader (with uniforms)', function() {
+      const parameters = {
+        uniforms: ['float u_myUniform', 'vec2 u_myUniform2'],
+        sizeExpression: 'vec2(' + formatNumber(6) + ')',
+        offsetExpression: 'vec2(' + formatArray([5, -7]) + ')',
+        colorExpression: 'vec4(' + formatColor([255, 255, 255, 1]) + ')',
+        texCoordExpression: 'vec4(' + formatArray([0, 0.5, 0.5, 1]) + ')'
+      };
+
+      expect(getSymbolFragmentShader(parameters)).to.eql(`precision mediump float;
+uniform float u_myUniform;
+uniform vec2 u_myUniform2;
+varying vec2 v_texCoord;

 void main(void) {
-  if (v_opacity == 0.0) {
-    discard;
-  }
-  vec4 textureColor = texture2D(u_texture, v_texCoord);
-  gl_FragColor = v_color * textureColor;
-  gl_FragColor.a *= v_opacity;
+  gl_FragColor = vec4(1.0, 1.0, 1.0, 1.0);
  gl_FragColor.rgb *= gl_FragColor.a;
 }`);
    });