Adding matrix class methods.

Change-Id: I597b1b3955e29921394909f302800034571e6a50

graphics/java/android/renderscript/Matrix2f.java

@@ -51,6 +51,52 @@ public class Matrix2f {
         System.arraycopy(mMat, 0, src, 0, 4);
     }
 
+    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;
+    }
+
+    public void loadScale(float x, float y) {
+        loadIdentity();
+        mMat[0] = x;
+        mMat[3] = y;
+    }
+    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);
+        }
+    }
+
+    public void multiply(Matrix2f rhs) {
+        Matrix2f tmp = new Matrix2f();
+        tmp.loadMultiply(this, rhs);
+        load(tmp);
+    }
+    public void rotate(float rot) {
+        Matrix2f tmp = new Matrix2f();
+        tmp.loadRotate(rot);
+        multiply(tmp);
+    }
+    public void scale(float x, float y) {
+        Matrix2f tmp = new Matrix2f();
+        tmp.loadScale(x, y);
+        multiply(tmp);
+    }
+
     final float[] mMat;
 }