Android example source code file (M4.java)

This example Android source code file (M4.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Android by Example" ^TM.

Java - Android tags/keywords

glvertex, m4, override, string, stringbuilder

The M4.java Android example source code

/*
 * Copyright (C) 2008 The Android Open Source Project
 *
 * 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.
 */

package com.example.android.apis.graphics.kube;

/** 
 * 
 * A 4x4 float matrix
 *
 */
public class M4 {
	public float[][] m = new float[4][4];
	
	public M4() {
	}
	
	public M4(M4 other) {
		for (int i = 0; i < 4; i++) {
			for (int j = 0; j < 4; j++) {
				m[i][j] = other.m[i][j];
			}
		}		
	}

	public void multiply(GLVertex src, GLVertex dest) {
		dest.x = src.x * m[0][0] + src.y * m[1][0] + src.z * m[2][0] + m[3][0];
		dest.y = src.x * m[0][1] + src.y * m[1][1] + src.z * m[2][1] + m[3][1];
		dest.z = src.x * m[0][2] + src.y * m[1][2] + src.z * m[2][2] + m[3][2];
	}
	
	public M4 multiply(M4 other) {
		M4 result = new M4();
		float[][] m1 = m;
		float[][] m2 = other.m;
		
		for (int i = 0; i < 4; i++) {
			for (int j = 0; j < 4; j++) {
				result.m[i][j] = m1[i][0]*m2[0][j] + m1[i][1]*m2[1][j] + m1[i][2]*m2[2][j] + m1[i][3]*m2[3][j];
			}
		}
		
		return result;
	}
	
	public void setIdentity() {
		for (int i = 0; i < 4; i++) {
			for (int j = 0; j < 4; j++) {
				m[i][j] = (i == j ? 1f : 0f);
			}
		}
	}
	
	@Override
	public String toString() {
		StringBuilder builder = new StringBuilder("[ ");
		for (int i = 0; i < 4; i++) {
			for (int j = 0; j < 4; j++) {
				builder.append(m[i][j]);
				builder.append(" ");
			}
			if (i < 2)
				builder.append("\n  ");
		}
		builder.append(" ]");
		return builder.toString();
	}
}