This function can be used to retrieve the current blend mode being used for drawing. The returned value wll be one of the following constants (the default value is bm_normal):
Constant Description Extended Blend Mode bm_normal Normal blending (the default blend mode). (bm_src_alpha, bm_inv_src_alpha) bm_add Additive blending. Luminosity values of light areas are added. (bm_src_alpha, bm_one) bm_subtract Subtractive blending. Luminosity values of light areas are subtracted. (bm_zero, bm_inv_src_colour) bm_max Max blending. Similar to additive blending. (bm_src_alpha, bm_inv_src_colour)
Constant (see above for constants)
if gpu_get_blendmode() != bm_normal
The above code gets the current blend mode and if it is not bm_normal it is set to that constant.