Function WrappedProgram

wrappedgl.js:1156–1197

(wgl, vertexShaderSource, fragmentShaderSource, requestedAttributeLocations)

    //we don't have to specify any or all attribute location bindings
    //any unspecified bindings will be assigned automatically and can be queried with program.getAttribLocation(attributeName)
    function WrappedProgram (wgl, vertexShaderSource, fragmentShaderSource, requestedAttributeLocations) {
        this.uniformLocations = {};
        this.uniforms = {}; //TODO: if we want to cache uniform values in the future

        var gl = wgl.gl;

        //build shaders from source
        var vertexShader = buildShader(gl, gl.VERTEX_SHADER, vertexShaderSource);
        var fragmentShader = buildShader(gl, gl.FRAGMENT_SHADER, fragmentShaderSource);

        //create program and attach shaders
        var program = this.program = gl.createProgram();
        gl.attachShader(program, vertexShader);
        gl.attachShader(program, fragmentShader);
        
        //bind the attribute locations that have been specified in attributeLocations
        if (requestedAttributeLocations !== undefined) {
            for (var attributeName in requestedAttributeLocations) {
                gl.bindAttribLocation(program, requestedAttributeLocations[attributeName], attributeName);
            }
        }
        gl.linkProgram(program);


        //construct this.attributeLocations (maps attribute names to locations)
        this.attributeLocations = {};
        var numberOfAttributes = gl.getProgramParameter(program, gl.ACTIVE_ATTRIBUTES);
        for (var i = 0; i < numberOfAttributes; ++i) {
            var activeAttrib = gl.getActiveAttrib(program, i);
            var attributeName = activeAttrib.name;
            this.attributeLocations[attributeName] = gl.getAttribLocation(program, attributeName);
        }

        //cache uniform locations
        var uniformLocations = this.uniformLocations = {};
        var numberOfUniforms = gl.getProgramParameter(program, gl.ACTIVE_UNIFORMS);
        for (var i = 0; i < numberOfUniforms; i += 1) {
            var activeUniform = gl.getActiveUniform(program, i),
                uniformLocation = gl.getUniformLocation(program, activeUniform.name);
            uniformLocations[activeUniform.name] = uniformLocation;
        }
    };

    //TODO: maybe this should be on WrappedGL?
    WrappedProgram.prototype.getAttribLocation = function (name) {