Can't blit_rect_mask

rui_mac

I think they mean to just set the import as image, and load it as

var mask = load("res://images/mask4.png")

That's how I got rid of the error.

rui_mac

I can't swear to that. I did a test, to try to figure the process out for myself. I got the same errors and warnings you did, using something like what you posted above. This is what I ended up with that worked, actually masking the image. Note that both images are imported as "image".

func _ready():
	var final_image = Image.new()
	final_image.create(64,64,true,Image.FORMAT_RGBA8)
	var mask = load("res://icon2.png")
	var source = load("res://icon.png")
	final_image.blit_rect_mask(source,mask,Rect2(0,0,64,64),Vector2(0,0))

	# This is all just to show the images.
	var t1 = ImageTexture.new()
	var t2 = ImageTexture.new()
	var t3 = ImageTexture.new()
	t1.create_from_image(source)
	t2.create_from_image(mask)
	t3.create_from_image(final_image)
	var tr1 = TextureRect.new()
	var tr2 = TextureRect.new()
	var tr3 = TextureRect.new()
	tr1.texture = t1
	tr2.texture = t2
	tr3.texture = t3
	tr2.rect_position = Vector2(80, 0)
	tr3.rect_position = Vector2(160, 0)
	add_child(tr1)
	add_child(tr2)
	add_child(tr3)

This does an alpha-based mask in about 20ms for a set of 64x64 images, so about 0.32 seconds for your example.

func _ready():
#	var final_image = Image.new()
	var final_image = load('res://test_sheet.png')
#	final_image.create(64,64,true,Image.FORMAT_RGBA8)
#	var mask = load("res://icon2.png")
	var source = load("res://icon.png")
#	final_image.blit_rect_mask(source,mask,Rect2(0,0,64,64),Vector2(0,0))

	var bl = Blender.new()
	var mask = bl.gradient()

	var t = OS.get_ticks_msec()
	var comb = bl.blend(source, mask, final_image, Rect2(64,32,64,64), Vector2(64,32))
	print('completed blend in %0.2fms' % [OS.get_ticks_msec() - t])

	var t1 = ImageTexture.new()
	var t2 = ImageTexture.new()
	var t3 = ImageTexture.new()
	t1.create_from_image(source)
	t2.create_from_image(mask)
	t3.create_from_image(comb)
	var tr1 = TextureRect.new()
	var tr2 = TextureRect.new()
	var tr3 = TextureRect.new()
	tr1.texture = t1
	tr2.texture = t2
	tr3.texture = t3
	tr2.rect_position = Vector2(80, 0)
	tr3.rect_position = Vector2(160, 0)
	add_child(tr1)
	add_child(tr2)
	add_child(tr3)

# blender.gd -- a simple, blend with an alpha mask

extends Reference
class_name Blender


func gradient() -> Image:
	# I can't get gimp to spit out a real alpha
	#  gradient, so I'm making one here.

	var grad := Image.new()
	grad.create(64,64,true,Image.FORMAT_RGBA8)
	var dat:PoolByteArray = []
	for i in range(0, 64*64*4, 4):
		var x = int(i / 4.0) % 64
		dat.append(0)
		dat.append(0)
		dat.append(0)
		dat.append(int(255 * x / 64.0))

	grad.create_from_data(grad.get_width(), grad.get_height(),
		false, grad.get_format(), dat)

	return grad


func blend(source:Image, mask:Image, final:Image, rect:Rect2, pos:Vector2) -> Image:
	# This takes the source image according to the
	#  alpha of the mask, and combines it with the
	#  final image, creating and returning a new image.

	# The source and mask must be the same size.
	# *ALL* images must be in RGBA8 format.

	var combine := Image.new()
	var finalc := Image.new()
	var out := Image.new()
	var source_dat:PoolByteArray
	var mask_dat:PoolByteArray
	var final_dat:PoolByteArray
	var combine_dat:PoolByteArray = []
	var height = source.get_height()
	var width = source.get_width()

	finalc.create(width, height, true, Image.FORMAT_RGBA8)
	finalc.blit_rect(final, Rect2(rect.position, Vector2(width, height)), Vector2.ZERO)

	source_dat = source.get_data()
	mask_dat = mask.get_data()
	final_dat = finalc.get_data()

#	print(source.get_format())
	for i in range(0, len(source_dat), 4):
		var alpha:float = mask_dat[i+3] * source_dat[i+3] / 255.0 / 255.0
		var ialpha:float = 1.0 - alpha

		combine_dat.append(int(source_dat[i+0] * alpha + final_dat[i+0] * ialpha))
		combine_dat.append(int(source_dat[i+1] * alpha + final_dat[i+1] * ialpha))
		combine_dat.append(int(source_dat[i+2] * alpha + final_dat[i+2] * ialpha))
		combine_dat.append(int(alpha * 255.0 + final_dat[i+3] * ialpha))

		if false and alpha > 0:
			print('%0.2f, %0.2f' % [alpha, ialpha])
			print('%d, %d, %d, %d' % [mask_dat[i+0], mask_dat[i+1], mask_dat[i+2], mask_dat[i+3]])
			print('%d, %d, %d, %d' % [source_dat[i+0], source_dat[i+1], source_dat[i+2], source_dat[i+3]])
			print('%d, %d, %d, %d' % [final_dat[i+0], final_dat[i+1], final_dat[i+2], final_dat[i+3]])
			print('%d, %d, %d, %d' % [combine_dat[i+0], combine_dat[i+1], combine_dat[i+2], combine_dat[i+3]])

	combine.create_from_data(width, height,
		false, source.get_format(), combine_dat)

	out.copy_from(final)
	out.blit_rect(combine, Rect2(Vector2.ZERO, rect.size), pos)

	return out

Edit: Now it takes the correct piece of the final image, instead of assuming it will be at (0,0).