1 /* 2 * Copyright (C) 2009-2012 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package android.renderscript; 18 19 import java.lang.Math; 20 import android.util.Log; 21 22 23 /** 24 * Class for exposing the native RenderScript rs_matrix2x2 type back to the Android system. 25 * 26 **/ 27 public class Matrix2f { 28 29 /** 30 * Creates a new identity 2x2 matrix 31 */ 32 public Matrix2f() { 33 mMat = new float[4]; 34 loadIdentity(); 35 } 36 37 /** 38 * Creates a new matrix and sets its values from the given 39 * parameter 40 * 41 * @param dataArray values to set the matrix to, must be 4 42 * floats long 43 */ 44 public Matrix2f(float[] dataArray) { 45 mMat = new float[4]; 46 System.arraycopy(dataArray, 0, mMat, 0, mMat.length); 47 } 48 49 /** 50 * Return a reference to the internal array representing matrix 51 * values. Modifying this array will also change the matrix 52 * 53 * @return internal array representing the matrix 54 */ 55 public float[] getArray() { 56 return mMat; 57 } 58 59 /** 60 * Returns the value for a given row and column 61 * 62 * @param x column of the value to return 63 * @param y row of the value to return 64 * 65 * @return value in the yth row and xth column 66 */ 67 public float get(int x, int y) { 68 return mMat[x*2 + y]; 69 } 70 71 /** 72 * Sets the value for a given row and column 73 * 74 * @param x column of the value to set 75 * @param y row of the value to set 76 */ 77 public void set(int x, int y, float v) { 78 mMat[x*2 + y] = v; 79 } 80 81 /** 82 * Sets the matrix values to identity 83 */ 84 public void loadIdentity() { 85 mMat[0] = 1; 86 mMat[1] = 0; 87 88 mMat[2] = 0; 89 mMat[3] = 1; 90 } 91 92 /** 93 * Sets the values of the matrix to those of the parameter 94 * 95 * @param src matrix to load the values from 96 */ 97 public void load(Matrix2f src) { 98 System.arraycopy(src.getArray(), 0, mMat, 0, mMat.length); 99 } 100 101 /** 102 * Sets current values to be a rotation matrix of given angle 103 * 104 * @param rot rotation angle 105 */ 106 public void loadRotate(float rot) { 107 float c, s; 108 rot *= (float)(java.lang.Math.PI / 180.0f); 109 c = (float)java.lang.Math.cos(rot); 110 s = (float)java.lang.Math.sin(rot); 111 mMat[0] = c; 112 mMat[1] = -s; 113 mMat[2] = s; 114 mMat[3] = c; 115 } 116 117 /** 118 * Sets current values to be a scale matrix of given dimensions 119 * 120 * @param x scale component x 121 * @param y scale component y 122 */ 123 public void loadScale(float x, float y) { 124 loadIdentity(); 125 mMat[0] = x; 126 mMat[3] = y; 127 } 128 129 /** 130 * Sets current values to be the result of multiplying two given 131 * matrices 132 * 133 * @param lhs left hand side matrix 134 * @param rhs right hand side matrix 135 */ 136 public void loadMultiply(Matrix2f lhs, Matrix2f rhs) { 137 for (int i=0 ; i<2 ; i++) { 138 float ri0 = 0; 139 float ri1 = 0; 140 for (int j=0 ; j<2 ; j++) { 141 float rhs_ij = rhs.get(i,j); 142 ri0 += lhs.get(j,0) * rhs_ij; 143 ri1 += lhs.get(j,1) * rhs_ij; 144 } 145 set(i,0, ri0); 146 set(i,1, ri1); 147 } 148 } 149 150 /** 151 * Post-multiplies the current matrix by a given parameter 152 * 153 * @param rhs right hand side to multiply by 154 */ 155 public void multiply(Matrix2f rhs) { 156 Matrix2f tmp = new Matrix2f(); 157 tmp.loadMultiply(this, rhs); 158 load(tmp); 159 } 160 /** 161 * Modifies the current matrix by post-multiplying it with a 162 * rotation matrix of given angle 163 * 164 * @param rot angle of rotation 165 */ 166 public void rotate(float rot) { 167 Matrix2f tmp = new Matrix2f(); 168 tmp.loadRotate(rot); 169 multiply(tmp); 170 } 171 /** 172 * Modifies the current matrix by post-multiplying it with a 173 * scale matrix of given dimensions 174 * 175 * @param x scale component x 176 * @param y scale component y 177 */ 178 public void scale(float x, float y) { 179 Matrix2f tmp = new Matrix2f(); 180 tmp.loadScale(x, y); 181 multiply(tmp); 182 } 183 /** 184 * Sets the current matrix to its transpose 185 */ 186 public void transpose() { 187 float temp = mMat[1]; 188 mMat[1] = mMat[2]; 189 mMat[2] = temp; 190 } 191 192 final float[] mMat; 193 } 194 195 196 197
