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WebGLUtil = (function() {
// ---------------------------------------------------------------------------
// WebGL helpers
// Returns a valid shader, or null on errors.
function createShaderById(gl, id) {
var elem = document.getElementById(id);
if (!elem) {
throw new Error(
"Failed to create shader from non-existent id '" + id + "'."
);
}
var src = elem.innerHTML.trim();
var shader;
if (elem.type == "x-shader/x-fragment") {
shader = gl.createShader(gl.FRAGMENT_SHADER);
} else if (elem.type == "x-shader/x-vertex") {
shader = gl.createShader(gl.VERTEX_SHADER);
} else {
throw new Error(
"Bad MIME type for shader '" + id + "': " + elem.type + "."
);
}
gl.shaderSource(shader, src);
gl.compileShader(shader);
return shader;
}
function createProgramByIds(gl, vsId, fsId) {
var vs = createShaderById(gl, vsId);
var fs = createShaderById(gl, fsId);
if (!vs || !fs) {
return null;
}
var prog = gl.createProgram();
gl.attachShader(prog, vs);
gl.attachShader(prog, fs);
gl.linkProgram(prog);
if (!gl.getProgramParameter(prog, gl.LINK_STATUS)) {
var str = "Shader program linking failed:";
str += "\nShader program info log:\n" + gl.getProgramInfoLog(prog);
str += "\n\nVert shader log:\n" + gl.getShaderInfoLog(vs);
str += "\n\nFrag shader log:\n" + gl.getShaderInfoLog(fs);
console.error(str);
return null;
}
return prog;
}
return {
createShaderById,
createProgramByIds,
};
})();