Copies a specified source region from bitmap to the position (src_x, src_y) of the given 
            destination texture handle.
<note>The region updated can't be larger than the source bitmap</note>
| this | a Texture pointer | 
| src_x | upper left coordinate to use from the source bitmap. | 
| src_y | upper left coordinate to use from the source bitmap | 
| dst_x | upper left destination horizontal coordinate. | 
| dst_y | upper left destination vertical coordinate. | 
| dst_width | width of destination region to write. (Must be less than or equal to the bitmap width) | 
| dst_height | height of destination region to write. (Must be less than or equal to the bitmap height) | 
| bitmap | The source bitmap to read from | 
| true if the subregion upload was successful, and false otherwise |