This function can be used to retrieve the current extended blend mode being used for drawing, separating out the blend modes into two parts - the RGB component and the Alpha component. The function returns a 4 element 1D array with the following elements in it:
-  = Source blend mode minus the alpha component (default is bm_src_alpha (As, As, As))
-  = Destination blend mode minus the alpha component (default is bm_inv_src_alpha (1-As, 1-As, 1-As))
-  = Source alpha component (default is bm_src_alpha (As))
-  = Destination alpha component (default is bm_inv_src_alpha (1-As))
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):
常量 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)
When creating the extended blend modes in this way, the RGB components will be taken from one blend mode and the Alpha component will be taken from another, so that - for example - if you use bm_zero (0, 0, 0, 0) as the RGB blend mode and bm_one as the alpha blend mode, you will get a composite blend of (0,0,0,1).
Note that you can change these values directly within the array and pass the full array to the function as a single argument (as shown in the example below).WARNING! This function is currently only available on the Windows target platform.
4 element 1D Array (see above for constants)
var bm = gpu_get_blendmode_ext_sepalpha();
bm = bm_src_alpha;
bm = bm_inv_src_alpha;
The above code creates a local array and gets the current extended blend mode with separate alpha values. This array is then manipulated and returned to set the blend mode.