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/*
* Copyright (C) 2009-2012 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 android.renderscript;
/**
* Class for exposing the native RenderScript rs_matrix2x2 type back to the Android system.
*
**/
public class Matrix2f {
/**
* Creates a new identity 2x2 matrix
*/
public Matrix2f() {
mMat = new float[4];
loadIdentity();
}
/**
* Creates a new matrix and sets its values from the given
* parameter
*
* @param dataArray values to set the matrix to, must be 4
* floats long
*/
public Matrix2f(float[] dataArray) {
mMat = new float[4];
System.arraycopy(dataArray, 0, mMat, 0, mMat.length);
}
/**
* Return a reference to the internal array representing matrix
* values. Modifying this array will also change the matrix
*
* @return internal array representing the matrix
*/
public float[] getArray() {
return mMat;
}
/**
* Returns the value for a given row and column
*
* @param x column of the value to return
* @param y row of the value to return
*
* @return value in the yth row and xth column
*/
public float get(int x, int y) {
return mMat[x*2 + y];
}
/**
* Sets the value for a given row and column
*
* @param x column of the value to set
* @param y row of the value to set
*/
public void set(int x, int y, float v) {
mMat[x*2 + y] = v;
}
/**
* Sets the matrix values to identity
*/
public void loadIdentity() {
mMat[0] = 1;
mMat[1] = 0;
mMat[2] = 0;
mMat[3] = 1;
}
/**
* Sets the values of the matrix to those of the parameter
*
* @param src matrix to load the values from
*/
public void load(Matrix2f src) {
System.arraycopy(src.getArray(), 0, mMat, 0, mMat.length);
}
/**
* Sets current values to be a rotation matrix of given angle
*
* @param rot rotation angle
*/
public void loadRotate(float rot) {
float c, s;
rot *= (float)(java.lang.Math.PI / 180.0f);
c = (float)java.lang.Math.cos(rot);
s = (float)java.lang.Math.sin(rot);
mMat[0] = c;
mMat[1] = -s;
mMat[2] = s;
mMat[3] = c;
}
/**
* Sets current values to be a scale matrix of given dimensions
*
* @param x scale component x
* @param y scale component y
*/
public void loadScale(float x, float y) {
loadIdentity();
mMat[0] = x;
mMat[3] = y;
}
/**
* Sets current values to be the result of multiplying two given
* matrices
*
* @param lhs left hand side matrix
* @param rhs right hand side matrix
*/
public void loadMultiply(Matrix2f lhs, Matrix2f rhs) {
for (int i=0 ; i<2 ; i++) {
float ri0 = 0;
float ri1 = 0;
for (int j=0 ; j<2 ; j++) {
float rhs_ij = rhs.get(i,j);
ri0 += lhs.get(j,0) * rhs_ij;
ri1 += lhs.get(j,1) * rhs_ij;
}
set(i,0, ri0);
set(i,1, ri1);
}
}
/**
* Post-multiplies the current matrix by a given parameter
*
* @param rhs right hand side to multiply by
*/
public void multiply(Matrix2f rhs) {
Matrix2f tmp = new Matrix2f();
tmp.loadMultiply(this, rhs);
load(tmp);
}
/**
* Modifies the current matrix by post-multiplying it with a
* rotation matrix of given angle
*
* @param rot angle of rotation
*/
public void rotate(float rot) {
Matrix2f tmp = new Matrix2f();
tmp.loadRotate(rot);
multiply(tmp);
}
/**
* Modifies the current matrix by post-multiplying it with a
* scale matrix of given dimensions
*
* @param x scale component x
* @param y scale component y
*/
public void scale(float x, float y) {
Matrix2f tmp = new Matrix2f();
tmp.loadScale(x, y);
multiply(tmp);
}
/**
* Sets the current matrix to its transpose
*/
public void transpose() {
float temp = mMat[1];
mMat[1] = mMat[2];
mMat[2] = temp;
}
final float[] mMat;
}
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