/*
Utilities for the OpenGL ES 2.0 HTML Canvas context
*/
/*
Copyright (c) 2019 The Khronos Group Inc.
Use of this source code is governed by an MIT-style license that can be
found in the LICENSE.txt file.
*/
function loadTexture(gl, elem, mipmaps) {
var tex = gl.createTexture();
gl.bindTexture(gl.TEXTURE_2D, tex);
gl.texImage2D(gl.TEXTURE_2D, 0, gl.RGBA, gl.RGBA, gl.UNSIGNED_BYTE, elem);
if (mipmaps != false)
gl.generateMipmap(gl.TEXTURE_2D);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE);
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.LINEAR);
if (mipmaps)
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR_MIPMAP_LINEAR);
else
gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.LINEAR);
return tex;
}
function getShader(gl, id) {
var shaderScript = document.getElementById(id);
if (!shaderScript) {
throw(new Error("No shader element with id: "+id));
}
var str = "";
var k = shaderScript.firstChild;
while (k) {
if (k.nodeType == 3)
str += k.textContent;
k = k.nextSibling;
}
var shader;
if (shaderScript.type == "x-shader/x-fragment") {
shader = gl.createShader(gl.FRAGMENT_SHADER);
} else if (shaderScript.type == "x-shader/x-vertex") {
shader = gl.createShader(gl.VERTEX_SHADER);
} else {
throw(new Error("Unknown shader type "+shaderScript.type));
}
gl.shaderSource(shader, str);
gl.compileShader(shader);
if (gl.getShaderParameter(shader, gl.COMPILE_STATUS) != 1) {
var ilog = gl.getShaderInfoLog(shader);
gl.deleteShader(shader);
throw(new Error("Failed to compile shader "+shaderScript.id + ", Shader info log: " + ilog));
}
return shader;
}
function loadShaderArray(gl, shaders) {
var id = gl.createProgram();
var shaderObjs = [];
for (var i=0; i