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 20 /** 21 * Class for exposing the native RenderScript rs_matrix2x2 type back to the Android system. 22 * 23 **/ 24 public class Matrix2f { 25 26 /** 27 * Creates a new identity 2x2 matrix 28 */ 29 public Matrix2f() { 30 mMat = new float[4]; 31 loadIdentity(); 32 } 33 34 /** 35 * Creates a new matrix and sets its values from the given 36 * parameter 37 * 38 * @param dataArray values to set the matrix to, must be 4 39 * floats long 40 */ 41 public Matrix2f(float[] dataArray) { 42 mMat = new float[4]; 43 System.arraycopy(dataArray, 0, mMat, 0, mMat.length); 44 } 45 46 /** 47 * Return a reference to the internal array representing matrix 48 * values. Modifying this array will also change the matrix 49 * 50 * @return internal array representing the matrix 51 */ 52 public float[] getArray() { 53 return mMat; 54 } 55 56 /** 57 * Returns the value for a given row and column 58 * 59 * @param x column of the value to return 60 * @param y row of the value to return 61 * 62 * @return value in the yth row and xth column 63 */ 64 public float get(int x, int y) { 65 return mMat[x*2 + y]; 66 } 67 68 /** 69 * Sets the value for a given row and column 70 * 71 * @param x column of the value to set 72 * @param y row of the value to set 73 */ 74 public void set(int x, int y, float v) { 75 mMat[x*2 + y] = v; 76 } 77 78 /** 79 * Sets the matrix values to identity 80 */ 81 public void loadIdentity() { 82 mMat[0] = 1; 83 mMat[1] = 0; 84 85 mMat[2] = 0; 86 mMat[3] = 1; 87 } 88 89 /** 90 * Sets the values of the matrix to those of the parameter 91 * 92 * @param src matrix to load the values from 93 */ 94 public void load(Matrix2f src) { 95 System.arraycopy(src.getArray(), 0, mMat, 0, mMat.length); 96 } 97 98 /** 99 * Sets current values to be a rotation matrix of given angle 100 * 101 * @param rot rotation angle 102 */ 103 public void loadRotate(float rot) { 104 float c, s; 105 rot *= (float)(java.lang.Math.PI / 180.0f); 106 c = (float)java.lang.Math.cos(rot); 107 s = (float)java.lang.Math.sin(rot); 108 mMat[0] = c; 109 mMat[1] = -s; 110 mMat[2] = s; 111 mMat[3] = c; 112 } 113 114 /** 115 * Sets current values to be a scale matrix of given dimensions 116 * 117 * @param x scale component x 118 * @param y scale component y 119 */ 120 public void loadScale(float x, float y) { 121 loadIdentity(); 122 mMat[0] = x; 123 mMat[3] = y; 124 } 125 126 /** 127 * Sets current values to be the result of multiplying two given 128 * matrices 129 * 130 * @param lhs left hand side matrix 131 * @param rhs right hand side matrix 132 */ 133 public void loadMultiply(Matrix2f lhs, Matrix2f rhs) { 134 for (int i=0 ; i<2 ; i++) { 135 float ri0 = 0; 136 float ri1 = 0; 137 for (int j=0 ; j<2 ; j++) { 138 float rhs_ij = rhs.get(i,j); 139 ri0 += lhs.get(j,0) * rhs_ij; 140 ri1 += lhs.get(j,1) * rhs_ij; 141 } 142 set(i,0, ri0); 143 set(i,1, ri1); 144 } 145 } 146 147 /** 148 * Post-multiplies the current matrix by a given parameter 149 * 150 * @param rhs right hand side to multiply by 151 */ 152 public void multiply(Matrix2f rhs) { 153 Matrix2f tmp = new Matrix2f(); 154 tmp.loadMultiply(this, rhs); 155 load(tmp); 156 } 157 /** 158 * Modifies the current matrix by post-multiplying it with a 159 * rotation matrix of given angle 160 * 161 * @param rot angle of rotation 162 */ 163 public void rotate(float rot) { 164 Matrix2f tmp = new Matrix2f(); 165 tmp.loadRotate(rot); 166 multiply(tmp); 167 } 168 /** 169 * Modifies the current matrix by post-multiplying it with a 170 * scale matrix of given dimensions 171 * 172 * @param x scale component x 173 * @param y scale component y 174 */ 175 public void scale(float x, float y) { 176 Matrix2f tmp = new Matrix2f(); 177 tmp.loadScale(x, y); 178 multiply(tmp); 179 } 180 /** 181 * Sets the current matrix to its transpose 182 */ 183 public void transpose() { 184 float temp = mMat[1]; 185 mMat[1] = mMat[2]; 186 mMat[2] = temp; 187 } 188 189 final float[] mMat; 190 } 191 192 193 194
