*camera, RwInt32 x,
RwInt32 y, RwInt32 width, RwInt32 height);
Sets the rectangular area of the viewport into which the cameras backdrop raster is rendered.
camera Pointer to the camera.
x The X coordinate of rectangle (in viewport space coordinates).
y The Y coordinate of rectangle (in viewport space coordinates).
width The width of the rectangle (in viewport space units).
height The height of the rectangle (in viewport space units).
The argument camera if successful, and NULL otherwise.
The default backdrop viewport rectangle has a width and height of 0. In order to ensure that the backdrop raster is visible it is necessary to set a viewport rectangle which has a non-zero width and height.
If the backdrop viewport rectangle is larger than the backdrop raster, the raster will be tiled to fill the rectangle. If the backdrop raster is larger than the viewport rectangle it will be cropped to fit the rectangle.
If the backdrop viewport rectangle does not fill the entire viewport, areas of the viewport outside the backdrop rectangle will be filled with the cameras background color.
The backdrop viewport rectangle is not automatically changed when the camera viewport is modified. RwSetCameraBackdropViewportRect() should be used to modify the backdrop viewport rectangle appropriately when the cameras viewport is modified.