/*
* Copyright 2003-2006, 2009, 2017, United States Government, as represented by the Administrator of the
* National Aeronautics and Space Administration. All rights reserved.
*
* The NASAWorldWind/WebWorldWind platform is licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/**
* @exports GpuShader
*/
define([
'../error/ArgumentError',
'../util/Logger'
],
function (ArgumentError,
Logger) {
"use strict";
/**
* Constructs a GPU shader of a specified type with specified GLSL source code.
*
* @alias GpuShader
* @constructor
* @classdesc
* Represents an OpenGL shading language (GLSL) shader and provides methods for compiling and disposing
* of them.
*
* @param {WebGLRenderingContext} gl The current WebGL context.
* @param {Number} shaderType The type of shader, either WebGLRenderingContext.VERTEX_SHADER
* or WebGLRenderingContext.FRAGMENT_SHADER.
* @param {String} shaderSource The shader's source code.
* @throws {ArgumentError} If the shader type is unrecognized, the shader source is null or undefined or shader
* compilation fails. If the compilation fails the error thrown contains any compilation messages.
*/
var GpuShader = function (gl, shaderType, shaderSource) {
if (!(shaderType === gl.VERTEX_SHADER
|| shaderType === gl.FRAGMENT_SHADER)) {
throw new ArgumentError(Logger.logMessage(Logger.LEVEL_SEVERE, "GpuShader", "constructor",
"The specified shader type is unrecognized."));
}
if (!shaderSource) {
throw new ArgumentError(Logger.logMessage(Logger.LEVEL_SEVERE, "GpuShader", "constructor",
"The specified shader source is null or undefined."));
}
var shader = gl.createShader(shaderType);
if (!shader) {
throw new ArgumentError(Logger.logMessage(Logger.LEVEL_SEVERE, "GpuShader", "constructor",
"Unable to create shader of type " +
(shaderType == gl.VERTEX_SHADER ? "VERTEX_SHADER." : "FRAGMENT_SHADER.")));
}
if (!this.compile(gl, shader, shaderType, shaderSource)) {
var infoLog = gl.getShaderInfoLog(shader);
gl.deleteShader(shader);
throw new ArgumentError(Logger.logMessage(Logger.LEVEL_SEVERE, "GpuShader", "constructor",
"Unable to compile shader: " + infoLog));
}
this.shaderId = shader;
};
/**
* Compiles the source code for this shader. This method is not meant to be invoked by applications. It is
* invoked internally as needed.
* @param {WebGLRenderingContext} gl The current WebGL rendering context.
* @param {WebGLShader} shaderId The shader ID.
* @param {Number} shaderType The type of shader, either WebGLRenderingContext.VERTEX_SHADER
* or WebGLRenderingContext.FRAGMENT_SHADER.
* @param {String} shaderSource The shader's source code.
* @returns {boolean} <code>true</code> if the shader compiled successfully, otherwise <code>false</code>.
*/
GpuShader.prototype.compile = function (gl, shaderId, shaderType, shaderSource) {
gl.shaderSource(shaderId, shaderSource);
gl.compileShader(shaderId);
return gl.getShaderParameter(shaderId, gl.COMPILE_STATUS);
};
/**
* Releases this shader's WebGL shader.
* @param {WebGLRenderingContext} gl The current WebGL rendering context.
*/
GpuShader.prototype.dispose = function (gl) {
if (this.shaderId) {
gl.deleteShader(this.shaderId);
delete this.shaderId;
}
};
return GpuShader;
});