Allow token replacement in shaders

mapbox · Apr 6, 2016 · 75dc9f1 · 75dc9f1
1 parent b7d2847
commit 75dc9f1
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Showing 3 changed files with 24 additions and 11 deletions.
diff --git a/js/render/draw_circle.js b/js/render/draw_circle.js
@@ -9,7 +9,9 @@ function drawCircles(painter, source, layer, coords) {
 
     var gl = painter.gl;
 
-    var program = painter.useProgram('circle');
+    var program = painter.useProgram('circle', {
+        colorType: 'attribute'
+    });
 
     painter.setDepthSublayer(0);
     painter.depthMask(false);

diff --git a/js/render/painter/use_program.js b/js/render/painter/use_program.js
@@ -61,19 +61,19 @@ var definitions = {
     }
 };
 
-module.exports._createProgram = function(name) {
+module.exports._createProgram = function(name, tokens) {
     var gl = this.gl;
     var program = gl.createProgram();
     var definition = definitions[name];
 
     var fragmentShader = gl.createShader(gl.FRAGMENT_SHADER);
-    gl.shaderSource(fragmentShader, definition.fragmentSource);
+    gl.shaderSource(fragmentShader, applyTokens(definition.fragmentSource, tokens));
     gl.compileShader(fragmentShader);
     assert(gl.getShaderParameter(fragmentShader, gl.COMPILE_STATUS), gl.getShaderInfoLog(fragmentShader));
     gl.attachShader(program, fragmentShader);
 
     var vertexShader = gl.createShader(gl.VERTEX_SHADER);
-    gl.shaderSource(vertexShader, definition.vertexSource);
+    gl.shaderSource(vertexShader, applyTokens(definition.vertexSource, tokens));
     gl.compileShader(vertexShader);
     assert(gl.getShaderParameter(vertexShader, gl.COMPILE_STATUS), gl.getShaderInfoLog(vertexShader));
     gl.attachShader(program, vertexShader);
@@ -103,18 +103,19 @@ module.exports._createProgram = function(name) {
     }, attributes, uniforms);
 };
 
-module.exports._createProgramCached = function(name) {
+module.exports._createProgramCached = function(name, tokens) {
     this.cache = this.cache || {};
-    if (!this.cache[name]) {
-        this.cache[name] = this._createProgram(name);
+    var key = JSON.stringify({name: name, tokens: tokens});
+    if (!this.cache[key]) {
+        this.cache[key] = this._createProgram(name, tokens);
     }
-    return this.cache[name];
+    return this.cache[key];
 };
 
-module.exports.useProgram = function (nextProgramName) {
+module.exports.useProgram = function (nextProgramName, tokens) {
     var gl = this.gl;
 
-    var nextProgram = this._createProgramCached(nextProgramName);
+    var nextProgram = this._createProgramCached(nextProgramName, tokens);
     var previousProgram = this.currentProgram;
 
     if (previousProgram !== nextProgram) {
@@ -140,3 +141,12 @@ module.exports.useProgram = function (nextProgramName) {
 
     return nextProgram;
 };
+
+function applyTokens(string, tokens) {
+    tokens = tokens || {};
+    for (var key in tokens) {
+        var value = tokens[key];
+        string = string.replace('{{' + key + '}}', value);
+    }
+    return string;
+}
diff --git a/shaders/circle.vertex.glsl b/shaders/circle.vertex.glsl
@@ -5,7 +5,8 @@ uniform mat4 u_exmatrix;
 uniform mediump float u_size;
 
 attribute vec2 a_pos;
-attribute lowp vec4 a_color;
+
+{{colorType}} lowp vec4 a_color;
 
 varying vec2 v_extrude;
 varying lowp vec4 v_color;