Unify the two gradient shaders into one

src/Shaders/Effects/Gradients/LinearDithering.gdshader → src/Shaders/Effects/Gradient.gdshader

@@ -2,14 +2,21 @@ shader_type canvas_item;
 render_mode unshaded;
 
 uniform sampler2D selection : filter_nearest;
+// The gradient texture itself, with interpolation.
 uniform sampler2D gradient_texture : filter_nearest;
+// A Nx1 image, where N is the amount of the different colors of gradient_texture,
+// without interpolating between them. Used in dithering.
+uniform sampler2D gradient_texture_no_interpolation : filter_nearest;
+// A Nx1 grayscale image, where N is the amount of the different colors of gradient_texture,
+// where each pixel contains the offset, ranging from 0-1 of each color. Used in dithering.
+uniform sampler2D gradient_offset_texture : filter_nearest;
 uniform sampler2D dither_texture : filter_nearest, repeat_enable;
-uniform sampler2D offset_texture : filter_nearest;
 uniform float position : hint_range(-0.5, 0.5) = 0.0;
 uniform float size : hint_range(0.01, 2.0) = 1.0;
 uniform float angle : hint_range(0.0, 360.0) = 0.0;
 uniform vec2 center = vec2(0.5);
 uniform vec2 radius = vec2(1.0);
+uniform bool use_dithering = false;
 uniform int shape = 0; // 0 = linear, 1 = radial
 uniform int repeat = 0; // 0 = none, 1 = repeat, 2 = mirrored, 3 = truncate
 
@@ -62,36 +69,42 @@ float dither(vec2 uv, float modified_uv, ivec2 image_size) {
 void fragment() {
 	vec4 original_color = texture(TEXTURE, UV);
 	vec4 selection_color = texture(selection, UV);
+	//vec2 tex_size = 1.0 / TEXTURE_PIXEL_SIZE;
+	//vec2 uv = floor(UV * tex_size) / (tex_size - 1.0);
 	float modified_uv = modify_uv(UV);
 	if (repeat == 1)
 		modified_uv = fract(modified_uv);
 	else if (repeat == 2)
 		modified_uv = mirror_fract(modified_uv);
 
-	int n_of_colors = textureSize(offset_texture, 0).x;
-	float colors_minus = float(n_of_colors - 1);
 	vec4 output;
-	for (int i = 1; i <= n_of_colors; i++) {
-		float off = texture(offset_texture, vec2(float(i) / colors_minus)).r;
-		float off_prev = texture(offset_texture, vec2(float(i - 1) / colors_minus)).r;
-		vec4 first = texture(gradient_texture, vec2(float((i - 1)) / colors_minus));
-		vec4 second = texture(gradient_texture, vec2(float(i) / colors_minus));
-		if (modified_uv < off_prev) {
-			if (i == 1) {
-				output = first;
+	if (use_dithering) {
+		int n_of_colors = textureSize(gradient_offset_texture, 0).x;
+		float colors_minus = float(n_of_colors - 1);
+		for (int i = 1; i <= n_of_colors; i++) {
+			float off = texture(gradient_offset_texture, vec2(float(i) / colors_minus)).r;
+			float off_prev = texture(gradient_offset_texture, vec2(float(i - 1) / colors_minus)).r;
+			vec4 first = texture(gradient_texture_no_interpolation, vec2(float((i - 1)) / colors_minus));
+			vec4 second = texture(gradient_texture_no_interpolation, vec2(float(i) / colors_minus));
+			if (modified_uv < off_prev) {
+				if (i == 1) {
+					output = first;
+				}
+				continue;
 			}
-			continue;
-		}
-		if (modified_uv > off) {
-			if (i == n_of_colors) {
-				output = second;
+			if (modified_uv > off) {
+				if (i == n_of_colors) {
+					output = second;
+				}
+				continue;
 			}
-			continue;
+			float uvt = (modified_uv - off_prev) / (off - off_prev);
+			float col_sample = dither(UV, uvt, textureSize(TEXTURE, 0));
+			output = mix(first, second, col_sample);
 		}
-		float uvt = (modified_uv - off_prev) / (off - off_prev);
-		float col_sample = dither(UV, uvt, textureSize(TEXTURE, 0));
-		output = mix(first, second, col_sample);
 	}
+	else
+		output = texture(gradient_texture, vec2(modified_uv));
 	if (repeat == 3)
 		output.a = min(step(modified_uv, 1.0) * step(0.0, modified_uv), output.a);
 	output = mix(original_color, output, output.a);

src/UI/Dialogs/ImageEffects/GradientDialog.gd

@@ -3,10 +3,7 @@ extends ImageEffect
 enum { LINEAR, RADIAL, LINEAR_DITHERING, RADIAL_DITHERING }
 enum Animate { POSITION, SIZE, ANGLE, CENTER_X, CENTER_Y, RADIUS_X, RADIUS_Y }
 
-var shader_linear := preload("res://src/Shaders/Effects/Gradients/Linear.gdshader")
-var shader_linear_dither := preload("res://src/Shaders/Effects/Gradients/LinearDithering.gdshader")
-
-var shader := shader_linear
+var shader := preload("res://src/Shaders/Effects/Gradient.gdshader")
 var selected_dither_matrix := ShaderLoader.dither_matrices[0]
 
 @onready var options_cont: Container = $VBoxContainer/GradientOptions
@@ -51,11 +48,11 @@ func commit_action(cel: Image, project := Global.current_project) -> void:
 	var offsets := gradient.offsets
 	offsets.sort()
 	var n_of_colors := offsets.size()
-	# Pass the gradient offsets as an array to the shader
-	# ...but we can't provide arrays with variable sizes as uniforms, instead we construct
-	# a nx1 grayscale texture with each offset stored in each pixel, and pass it to the shader
+	# Pass the gradient offsets as an array to the shader,
+	# but we can't provide arrays with variable sizes as uniforms, instead we construct
+	# a Nx1 grayscale texture with each offset stored in each pixel, and pass it to the shader.
 	var offsets_image := Image.create(n_of_colors, 1, false, Image.FORMAT_L8)
-	# Construct an image that contains the selected colors of the gradient without interpolation
+	# Construct an image that contains the selected colors of the gradient without interpolation.
 	var gradient_image := Image.create(n_of_colors, 1, false, Image.FORMAT_RGBA8)
 	for i in n_of_colors:
 		var c := offsets[i]
@@ -64,12 +61,6 @@ func commit_action(cel: Image, project := Global.current_project) -> void:
 		if actual_index == -1:
 			actual_index = i
 		gradient_image.set_pixel(i, 0, gradient.colors[actual_index])
-	var offsets_tex := ImageTexture.create_from_image(offsets_image)
-	var gradient_tex: Texture2D
-	if shader == shader_linear:
-		gradient_tex = gradient_edit.texture
-	else:
-		gradient_tex = ImageTexture.create_from_image(gradient_image)
 	var center := Vector2(
 		animate_panel.get_animated_value(commit_idx, Animate.CENTER_X),
 		animate_panel.get_animated_value(commit_idx, Animate.CENTER_Y)
@@ -79,8 +70,10 @@ func commit_action(cel: Image, project := Global.current_project) -> void:
 		animate_panel.get_animated_value(commit_idx, Animate.RADIUS_Y)
 	)
 	var params := {
-		"gradient_texture": gradient_tex,
-		"offset_texture": offsets_tex,
+		"gradient_texture": gradient_edit.texture,
+		"gradient_texture_no_interpolation": ImageTexture.create_from_image(gradient_image),
+		"gradient_offset_texture": ImageTexture.create_from_image(offsets_image),
+		"use_dithering": dithering_option_button.selected > 0,
 		"selection": selection_tex,
 		"repeat": repeat_option_button.selected,
 		"position": (animate_panel.get_animated_value(commit_idx, Animate.POSITION) / 100.0) - 0.5,
@@ -124,10 +117,7 @@ func _value_v2_changed(_value: Vector2) -> void:
 
 func _on_DitheringOptionButton_item_selected(index: int) -> void:
 	if index > 0:
-		shader = shader_linear_dither
 		selected_dither_matrix = ShaderLoader.dither_matrices[index - 1]
-	else:
-		shader = shader_linear
 	update_preview()