Draw semi transparent sprite that replaces pixels of semi transparent sprite below it

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:bust_in_silhouette: Asked By Iftah

I’m trying to draw a map using sprites simple map tiles | OpenGameArt.org

the background is a parchment image, and on top of it different sprites of hills, volcanos, mountains, etc… are drawn. The sprites are semi transparent (ie. pixels have fractional alpha values) in a way that makes it look like a drawing on the parchment.

My problem is that if I want to draw two sprites that overlap, eg. a small hill “in front” of a big volcano, because the hill is semi transparent, you can see the lines of the volcano behind it.

eg screenshot of problem

I tried applying a shader to the sprites, where the shader returns the image as-is except using blend_disabled mode, but it made no difference - why?

is there another solution?

ie. the shader I applied to the sprites (didn’t fix the problem):

shader_type canvas_item;
render_mode blend_disabled;

void fragment() {
	vec4 col = texture(TEXTURE, UV);
	COLOR = col;
}

edit: while waiting for my question to be approved, I solved the problem myself :slight_smile:
I still don’t know why “blend_disabled” isn’t disabling blend.

for those interested - this is my solution:

shader_type canvas_item;

void fragment() {
	vec4 sprite = texture(TEXTURE, UV);
	vec4 background = texture(SCREEN_TEXTURE, SCREEN_UV);
	vec4 mixed = mix(background, sprite, sprite.a);
	mixed.a = 1.0;
	COLOR = mixed;
}