curve.js

/* Copyright (c) 2009-2010 King Abdullah University of Science and Technology
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

// This class encapsulates curves
function curve(string, color, options) {
	
	this.gl = null;
	this.f  = string;
	
	this.vertexVBO	= null;
	this.indexVBO		= null;
	this.count			= 1000;
	this.parameters = null;
	this.options    = options || (CARTESIAN | X_LIN | Y_LIN);
	
	this.color = color || [0, 0, 0, 1];

	this.initialize = function(gl, scr, parameters) {
		this.gl = gl;
		this.parameters = parameters;
		this.refresh(scr);
		this.gen_program();
	}
	
	this.refresh = function(scr) {
		this.gen_vbo(scr);
	}

	this.gen_vbo = function(scr) {
		var vertices = [];
		var indices	 = [];
		
		var a = scr.minx;
		var dx = (scr.maxx - scr.minx) / this.count;
		
		for (var i = 0; i < this.count; ++i) {
			vertices.push(a);
			indices.push(i);
			a += dx;
		}

		/* Delete vertex buffers if they exist already */
		if (this.vertexVBO) {
			this.gl.deleteBuffer(this.vertexVBO);
		}
		
		if (this.indexVBO) {
			this.gl.deleteBuffer(this.indexVBO);
		}
		
		this.vertexVBO = this.gl.createBuffer();
		this.gl.bindBuffer(this.gl.ARRAY_BUFFER, this.vertexVBO);
		this.gl.bufferData(this.gl.ARRAY_BUFFER, new WebGLFloatArray(vertices), this.gl.STATIC_DRAW);
		
		this.indexVBO = this.gl.createBuffer();
		this.gl.bindBuffer(this.gl.ELEMENT_ARRAY_BUFFER, this.indexVBO);
		this.gl.bufferData(this.gl.ELEMENT_ARRAY_BUFFER, new WebGLUnsignedShortArray(indices), this.gl.STATIC_DRAW);
	}
	
	this.draw = function(scr) {
		this.setUniforms(scr);
		
		this.gl.enableVertexAttribArray(0);
		
		this.gl.bindBuffer(this.gl.ARRAY_BUFFER, this.vertexVBO);
		this.gl.vertexAttribPointer(0, 1, this.gl.FLOAT, this.gl.FALSE, 0, 0);
		
		this.gl.bindBuffer(this.gl.ELEMENT_ARRAY_BUFFER, this.indexVBO);
		
		this.gl.drawElements(this.gl.LINE_STRIP, this.count, this.gl.UNSIGNED_SHORT, 0);
		
		this.gl.disableVertexAttribArray(0);
	}
	
	this.gen_program = function() {
		var vertex_source = this.read("shaders/curve.vert").replace("USER_FUNCTION", this.f);
		var frag_source		= this.read("shaders/curve.frag");
		
		this.program = this.compile_program(vertex_source, frag_source, this.parameters);
	}
}

curve.prototype = new primitive();