WebGLUtil.java

package com.google.gwt.webgl.client;

import static com.google.gwt.webgl.client.WebGLRenderingContext.*;

public class WebGLUtil {

	public static float[] createPerspectiveMatrix(int fieldOfViewVertical,
			float aspectRatio, float minimumClearance, float maximumClearance) {
		double fieldOfViewInRad = fieldOfViewVertical * Math.PI / 180.0;
		return new float[] {
				(float) (Math.tan(fieldOfViewInRad) / aspectRatio),
				0,
				0,
				0,
				0,
				(float) (1 / Math.tan(fieldOfViewVertical * Math.PI / 180.0)),
				0,
				0,
				0,
				0,
				(minimumClearance + maximumClearance)
						/ (minimumClearance - maximumClearance),
				-1,
				0,
				0,
				2 * minimumClearance * maximumClearance
						/ (minimumClearance - maximumClearance), 0 };
	}

	public static WebGLProgram createShaderProgram(WebGLRenderingContext gl,
			String vertexSource, String fragmentSource) {
		WebGLShader vertexShader = getShader(gl, VERTEX_SHADER, vertexSource);
		WebGLShader fragmentShader = getShader(gl, FRAGMENT_SHADER,
				fragmentSource);

		WebGLProgram shaderProgram = gl.createProgram();
		gl.attachShader(shaderProgram, fragmentShader);
		gl.attachShader(shaderProgram, vertexShader);
		gl.linkProgram(shaderProgram);

		if (!gl.getProgramParameterb(shaderProgram, LINK_STATUS)) {
			throw new RuntimeException("Could not initialize shaders");
		}

		return shaderProgram;
	}

	private static WebGLShader getShader(WebGLRenderingContext gl,
			int shaderType, String source) {
		WebGLShader shader = gl.createShader(shaderType);
		gl.shaderSource(shader, source);
		gl.compileShader(shader);
		if (!gl.getShaderParameterb(shader, COMPILE_STATUS)) {
			throw new RuntimeException(gl.getShaderInfoLog(shader));
		}
		return shader;
	}
}