Implement screen aligned bitmap drawing support.
diff --git a/libs/rs/rsMatrix.cpp b/libs/rs/rsMatrix.cpp
index 5f68197..2f21405 100644
--- a/libs/rs/rsMatrix.cpp
+++ b/libs/rs/rsMatrix.cpp
@@ -85,7 +85,7 @@
     const float zx = z * x;
     const float xs = x * s;
     const float ys = y * s;
-    const float zs = z * s;		
+    const float zs = z * s;
     m[ 0] = x*x*nc +  c;
     m[ 4] =  xy*nc - zs;
     m[ 8] =  zx*nc + ys;
@@ -156,4 +156,9 @@
     m[15]= 0;
 }
 
-
+void Matrix::vectorMultiply(float *out, const float *in) const {
+    out[0] = (m[0] * in[0]) + (m[4] * in[1]) + (m[8] * in[2]) + m[12];
+    out[1] = (m[1] * in[0]) + (m[5] * in[1]) + (m[9] * in[2]) + m[13];
+    out[2] = (m[2] * in[0]) + (m[6] * in[1]) + (m[10] * in[2]) + m[14];
+    out[3] = (m[3] * in[0]) + (m[7] * in[1]) + (m[11] * in[2]) + m[15];
+}