This function can be used to retrieve the current extended blend mode being used for drawing. The function returns a 2 element 1D array with the following elements in it:
-  = Source blend mode (default is bm_src_alpha)
-  = Destination blend mode (default is bm_inv_src_alpha)
The values of the array will be one of the following constants ("s" denotes a value taken from the source while a "d" denotes a value from the destination):
Constant Blend factor (Red, Green, Blue, Alpha) bm_zero (0, 0, 0, 0) bm_one (1, 1, 1, 1) bm_src_colour (Rs, Gs, Bs, As) bm_inv_src_colour (1-Rs, 1-Gs, 1-Bs, 1-As) bm_src_alpha (As, As, As, As) bm_inv_src_alpha (1-As, 1-As, 1-As, 1-As) bm_dest_alpha (Ad, Ad, Ad, Ad) bm_inv_dest_alpha (1-Ad, 1-Ad, 1-Ad, 1-Ad) bm_dest_colour (Rd, Gd, Bd, Ad) bm_inv_dest_colour (1-Rd, 1-Gd, 1-Bd, 1-Ad) bm_src_alpha_sat (f, f, f, 1) where f = min(As, 1-Ad)
Note that you can change these values and pass the full array to the gpu_set_blendmode_ext function as a single argument.
2 element 1D Array (see above for constants)
var bm = gpu_get_blendmode_ext();
bm = bm_src_alpha;
The above code gets the current extended blend mode, modifies the source, and then sets the extended blend mode again.