Implement screen aligned bitmap drawing support.
diff --git a/rsProgramVertex.h b/rsProgramVertex.h
index e198f23..493668c 100644
--- a/rsProgramVertex.h
+++ b/rsProgramVertex.h
@@ -43,6 +43,9 @@
     void setModelviewMatrix(const rsc_Matrix *) const;
     void setTextureMatrix(const rsc_Matrix *) const;
 
+    void transformToScreen(const Context *, float *v4out, const float *v3in) const;
+
+
 protected:
     uint32_t mLightCount;
     ObjectBaseRef<const Light> mLights[MAX_LIGHTS];