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:
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):
| Blend Mode Factor Constant | |
|---|---|
| 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) |
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).
gpu_get_blendmode_ext_sepalpha();
Array (4 elements only; see above for constants)
var bm = gpu_get_blendmode_ext_sepalpha();
bm[0] = bm_src_alpha;
bm[1] = bm_inv_src_alpha;
gpu_set_blendmode_ext_sepalpha(bm);
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.