content: /*
   * 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_matrix3x3 type back to the Android system.
   *
   **/
  public class Matrix3f {
  
      /**
      * Creates a new identity 3x3 matrix
      */
      public Matrix3f() {
          mMat = new float[9];
          loadIdentity();
      }
  
      /**
      * Creates a new matrix and sets its values from the given
      * parameter
      *
      * @param dataArray values to set the matrix to, must be 9
      *                  floats long
      */
      public Matrix3f(float[] dataArray) {
          mMat = new float[9];
          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*3 + 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*3 + y] = v;
      }
  
      /**
      * Sets the matrix values to identity
      */
      public void loadIdentity() {
          mMat[0] = 1;
          mMat[1] = 0;
          mMat[2] = 0;
  
          mMat[3] = 0;
          mMat[4] = 1;
          mMat[5] = 0;
  
          mMat[6] = 0;
          mMat[7] = 0;
          mMat[8] = 1;
      }
  
      /**
      * Sets the values of the matrix to those of the parameter
      *
      * @param src matrix to load the values from
      */
      public void load(Matrix3f src) {
          System.arraycopy(src.getArray(), 0, mMat, 0, mMat.length);
      }
  
      /**
      * Sets current values to be a rotation matrix of certain angle
      * about a given axis
      *
      * @param rot angle of rotation
      * @param x rotation axis x
      * @param y rotation axis y
      * @param z rotation axis z
      */
      public void loadRotate(float rot, float x, float y, float z) {
          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);
  
          float len = (float)java.lang.Math.sqrt(x*x + y*y + z*z);
          if (!(len != 1)) {
              float recipLen = 1.f / len;
              x *= recipLen;
              y *= recipLen;
              z *= recipLen;
          }
          float nc = 1.0f - c;
          float xy = x * y;
          float yz = y * z;
          float zx = z * x;
          float xs = x * s;
          float ys = y * s;
          float zs = z * s;
          mMat[0] = x*x*nc +  c;
          mMat[3] =  xy*nc - zs;
          mMat[6] =  zx*nc + ys;
          mMat[1] =  xy*nc + zs;
          mMat[4] = y*y*nc +  c;
          mMat[7] =  yz*nc - xs;
          mMat[2] =  zx*nc - ys;
          mMat[5] =  yz*nc + xs;
          mMat[8] = z*z*nc +  c;
      }
  
      /**
      * Makes the upper 2x2 a rotation matrix of the given angle
      *
      * @param rot rotation angle
      */
      public void loadRotate(float rot) {
          loadIdentity();
          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[3] = s;
          mMat[4] = c;
      }
  
      /**
      * Makes the upper 2x2 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[4] = y;
      }
  
      /**
      * Sets current values to be a scale matrix of given dimensions
      *
      * @param x scale component x
      * @param y scale component y
      * @param z scale component z
      */
      public void loadScale(float x, float y, float z) {
          loadIdentity();
          mMat[0] = x;
          mMat[4] = y;
          mMat[8] = z;
      }
  
      /**
      * Sets current values to be a translation matrix of given
      * dimensions
      *
      * @param x translation component x
      * @param y translation component y
      */
      public void loadTranslate(float x, float y) {
          loadIdentity();
          mMat[6] = x;
          mMat[7] = 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(Matrix3f lhs, Matrix3f rhs) {
          for (int i=0 ; i<3 ; i++) {
              float ri0 = 0;
              float ri1 = 0;
              float ri2 = 0;
              for (int j=0 ; j<3 ; j++) {
                  float rhs_ij = rhs.get(i,j);
                  ri0 += lhs.get(j,0) * rhs_ij;
                  ri1 += lhs.get(j,1) * rhs_ij;
                  ri2 += lhs.get(j,2) * rhs_ij;
              }
              set(i,0, ri0);
              set(i,1, ri1);
              set(i,2, ri2);
          }
      }
  
      /**
      * Post-multiplies the current matrix by a given parameter
      *
      * @param rhs right hand side to multiply by
      */
      public void multiply(Matrix3f rhs) {
          Matrix3f tmp = new Matrix3f();
          tmp.loadMultiply(this, rhs);
          load(tmp);
      }
  
      /**
      * Modifies the current matrix by post-multiplying it with a
      * rotation matrix of certain angle about a given axis
      *
      * @param rot angle of rotation
      * @param x rotation axis x
      * @param y rotation axis y
      * @param z rotation axis z
      */
      public void rotate(float rot, float x, float y, float z) {
          Matrix3f tmp = new Matrix3f();
          tmp.loadRotate(rot, x, y, z);
          multiply(tmp);
      }
  
      /**
      * Modifies the upper 2x2 of the current matrix by
      * post-multiplying it with a rotation matrix of given angle
      *
      * @param rot angle of rotation
      */
      public void rotate(float rot) {
          Matrix3f tmp = new Matrix3f();
          tmp.loadRotate(rot);
          multiply(tmp);
      }
  
      /**
      * Modifies the upper 2x2 of 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) {
          Matrix3f tmp = new Matrix3f();
          tmp.loadScale(x, y);
          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
      * @param z scale component z
      */
      public void scale(float x, float y, float z) {
          Matrix3f tmp = new Matrix3f();
          tmp.loadScale(x, y, z);
          multiply(tmp);
      }
  
      /**
      * Modifies the current matrix by post-multiplying it with a
      * translation matrix of given dimensions
      *
      * @param x translation component x
      * @param y translation component y
      */
      public void translate(float x, float y) {
          Matrix3f tmp = new Matrix3f();
          tmp.loadTranslate(x, y);
          multiply(tmp);
      }
  
      /**
      * Sets the current matrix to its transpose
      */
      public void transpose() {
          for(int i = 0; i < 2; ++i) {
              for(int j = i + 1; j < 3; ++j) {
                  float temp = mMat[i*3 + j];
                  mMat[i*3 + j] = mMat[j*3 + i];
                  mMat[j*3 + i] = temp;
              }
          }
      }
  
      final float[] mMat;
  }
  
  
  