1 files changed, 64 insertions, 0 deletions
diff --git a/game/shaders/outline.gdshader b/game/shaders/outline.gdshader
new file mode 100644
index 0000000..a925059
--- /dev/null
+++ b/game/shaders/outline.gdshader
@@ -0,0 +1,64 @@
+// Source : https://godotshaders.com/shader/2d-outline-inline/
+
+shader_type canvas_item;
+
+uniform vec4 color : source_color = vec4(1.0);
+uniform float width : hint_range(0, 10) = 1.0;
+uniform int pattern : hint_range(0, 2) = 0; // diamond, circle, square
+uniform bool inside = false;
+uniform bool add_margins = true; // only useful when inside is false
+
+void vertex() {
+	if (add_margins) {
+		VERTEX += (UV * 2.0 - 1.0) * width;
+	}
+}
+
+bool hasContraryNeighbour(vec2 uv, vec2 texture_pixel_size, sampler2D texture) {
+	for (float i = -ceil(width); i <= ceil(width); i++) {
+		float x = abs(i) > width ? width * sign(i) : i;
+		float offset;
+		
+		if (pattern == 0) {
+			offset = width - abs(x);
+		} else if (pattern == 1) {
+			offset = floor(sqrt(pow(width + 0.5, 2) - x * x));
+		} else if (pattern == 2) {
+			offset = width;
+		}
+		
+		for (float j = -ceil(offset); j <= ceil(offset); j++) {
+			float y = abs(j) > offset ? offset * sign(j) : j;
+			vec2 xy = uv + texture_pixel_size * vec2(x, y);
+			
+			if ((xy != clamp(xy, vec2(0.0), vec2(1.0)) || texture(texture, xy).a <= 0.0) == inside) {
+				return true;
+			}
+		}
+	}
+	
+	return false;
+}
+
+void fragment() {
+	vec2 uv = UV;
+	
+	if (add_margins) {
+		vec2 texture_pixel_size = vec2(1.0) / (vec2(1.0) / TEXTURE_PIXEL_SIZE + vec2(width * 2.0));
+		
+		uv = (uv - texture_pixel_size * width) * TEXTURE_PIXEL_SIZE / texture_pixel_size;
+		
+		if (uv != clamp(uv, vec2(0.0), vec2(1.0))) {
+			COLOR.a = 0.0;
+		} else {
+			COLOR = texture(TEXTURE, uv);
+		}
+	} else {
+		COLOR = texture(TEXTURE, uv);
+	}
+	
+	if ((COLOR.a > 0.0) == inside && hasContraryNeighbour(uv, TEXTURE_PIXEL_SIZE, TEXTURE)) {
+		COLOR.rgb = inside ? mix(COLOR.rgb, color.rgb, color.a) : color.rgb;
+		COLOR.a += (1.0 - COLOR.a) * color.a;
+	}
+}
+\ No newline at end of file