From 77bea9a6e35e504071447ca57dedbe74543f871c Mon Sep 17 00:00:00 2001
From: Emmanouil Papadeas <35376950+OverloadedOrama@users.noreply.github.com>
Date: Mon, 1 Apr 2024 17:31:10 +0300
Subject: [PATCH] Re-add old layer blending logic from 0.x, if running on
 headless mode

Only meant to prevent crashes when trying to export from headless mode. This blending logic does not support blend modes, clipping masks, and layer effects.
---
 src/Autoload/DrawingAlgos.gd | 47 ++++++++++++++++++++++++------------
 1 file changed, 31 insertions(+), 16 deletions(-)

diff --git a/src/Autoload/DrawingAlgos.gd b/src/Autoload/DrawingAlgos.gd
index ea89668a3..c30a361bb 100644
--- a/src/Autoload/DrawingAlgos.gd
+++ b/src/Autoload/DrawingAlgos.gd
@@ -25,14 +25,14 @@ func blend_layers(
 	only_selected_cels := false,
 	only_selected_layers := false,
 ) -> void:
+	var frame_index := project.frames.find(frame)
+	var previous_ordered_layers: Array[int] = project.ordered_layers
+	project.order_layers(frame_index)
 	var textures: Array[Image] = []
 	# Nx4 texture, where N is the number of layers and the first row are the blend modes,
 	# the second are the opacities, the third are the origins and the fourth are the
 	# clipping mask booleans.
 	var metadata_image := Image.create(project.layers.size(), 4, false, Image.FORMAT_R8)
-	var frame_index := project.frames.find(frame)
-	var previous_ordered_layers: Array[int] = project.ordered_layers
-	project.order_layers(frame_index)
 	for i in project.layers.size():
 		var ordered_index := project.ordered_layers[i]
 		var layer := project.layers[ordered_index]
@@ -50,19 +50,34 @@ func blend_layers(
 			if not layer_is_selected:
 				include = false
 		var cel := frame.cels[ordered_index]
-		var cel_image := layer.display_effects(cel)
-		textures.append(cel_image)
-		set_layer_metadata_image(layer, cel, metadata_image, ordered_index, include)
-	var texture_array := Texture2DArray.new()
-	texture_array.create_from_images(textures)
-	var params := {
-		"layers": texture_array,
-		"metadata": ImageTexture.create_from_image(metadata_image),
-	}
-	var blended := Image.create(project.size.x, project.size.y, false, image.get_format())
-	var gen := ShaderImageEffect.new()
-	gen.generate_image(blended, blend_layers_shader, params, project.size)
-	image.blend_rect(blended, Rect2i(Vector2i.ZERO, project.size), origin)
+		if DisplayServer.get_name() == "headless":
+			var opacity := cel.get_final_opacity(layer)
+			var cel_image := Image.new()
+			cel_image.copy_from(cel.get_image())
+			if opacity < 1.0:  # If we have cel or layer transparency
+				for xx in cel_image.get_size().x:
+					for yy in cel_image.get_size().y:
+						var pixel_color := cel_image.get_pixel(xx, yy)
+						var alpha := pixel_color.a * opacity
+						cel_image.set_pixel(
+							xx, yy, Color(pixel_color.r, pixel_color.g, pixel_color.b, alpha)
+						)
+			image.blend_rect(cel_image, Rect2i(Vector2i.ZERO, project.size), origin)
+		else:
+			var cel_image := layer.display_effects(cel)
+			textures.append(cel_image)
+			set_layer_metadata_image(layer, cel, metadata_image, ordered_index, include)
+	if DisplayServer.get_name() != "headless":
+		var texture_array := Texture2DArray.new()
+		texture_array.create_from_images(textures)
+		var params := {
+			"layers": texture_array,
+			"metadata": ImageTexture.create_from_image(metadata_image),
+		}
+		var blended := Image.create(project.size.x, project.size.y, false, image.get_format())
+		var gen := ShaderImageEffect.new()
+		gen.generate_image(blended, blend_layers_shader, params, project.size)
+		image.blend_rect(blended, Rect2i(Vector2i.ZERO, project.size), origin)
 	# Re-order the layers again to ensure correct canvas drawing
 	project.ordered_layers = previous_ordered_layers