Merge pull request #15642 from deathride58/multblood

Multiplicative blood

code/datums/dna.dm

@@ -77,6 +77,7 @@
 	new_dna.species = new species.type
 	new_dna.species.say_mod = species.say_mod
 	new_dna.species.exotic_blood_color = species.exotic_blood_color //it can change from the default value
+	new_dna.species.exotic_blood_blend_mode = species.exotic_blood_blend_mode
 	new_dna.species.eye_type = species.eye_type
 	new_dna.species.limbs_id = species.limbs_id || species.id
 	new_dna.real_name = real_name

code/datums/mutable_appearance.dm

@@ -10,7 +10,7 @@
 						// And yes this does have to be in the constructor, BYOND ignores it if you set it as a normal var
 
 // Helper similar to image()
-/proc/mutable_appearance(icon, icon_state = "", layer = FLOAT_LAYER, plane = FLOAT_PLANE, alpha = 255, appearance_flags = NONE, color = "#FFFFFF")
+/proc/mutable_appearance(icon, icon_state = "", layer = FLOAT_LAYER, plane = FLOAT_PLANE, alpha = 255, appearance_flags = NONE, color = "#FFFFFF", blend_mode = BLEND_DEFAULT)
 	var/mutable_appearance/MA = new()
 	MA.icon = icon
 	MA.icon_state = icon_state
@@ -19,5 +19,6 @@
 	MA.alpha = alpha
 	MA.appearance_flags |= appearance_flags
 	MA.color = color
+	MA.blend_mode = blend_mode
 	return MA