This function can be used to retrieve the current destination extended blend mode alpha factor. The value returned will be one of the following constants ("s" denotes a value taken from the source while a "d" denotes a value from the destination) with only the "A" component being used when drawing:
| 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) |
gpu_get_blendmode_destalpha();
Blend Mode Factor Constant (see above table)
var bm;
bm[0] = gpu_get_blendmode_srcalpha();
bm[1] = gpu_get_blendmode_destalpha();
gpu_set_blendmode_ext_sepalpha(bm_inv_src_alpha, bm_inv_dest_colour, bm[0], bm[1]);
The above code creates a local array and gets the current source and destination blending factors for the alpha component. This array is then used to manipulate the RGB component of the blending factors.