Draws a series of rectangles in the same way that rectangle_with_texture_coords does.
In some situations it can give a significant performance boost to use this function rather than calling rectangle_with_texture_coords separately for each rectangle.
verts should point to an array of floats with n_rects * 8 elements. Each group of 8 values
corresponds to the parameters x1, y1, x2, y2, tx1, ty1, tx2 and ty2 and have the same meaning as in
rectangle_with_texture_coords.
| verts |
an array of vertices |
| n_rects |
number of rectangles to draw |