feat: add tutorial section

2026-04-10 05:17:30 +08:00
parent 222621139e
commit 5323aea5fb
16 changed files with 828 additions and 5 deletions
@@ -0,0 +1,31 @@
+shader_type canvas_item;
+
+// Spotlight rect in viewport pixel coordinates
+// vec4(x, y, width, height) — set to vec4(0,0,0,0) to dim everything
+uniform vec4 spotlight = vec4(0.0, 0.0, 0.0, 0.0);
+uniform vec2 viewport_size = vec2(1366.0, 720.0);
+uniform float dim_alpha : hint_range(0.0, 1.0) = 0.72;
+uniform float padding : hint_range(0.0, 32.0) = 8.0;
+
+void fragment() {
+	bool has_spotlight = spotlight.z > 1.0 && spotlight.w > 1.0;
+
+	if (has_spotlight) {
+		// Convert spotlight rect to UV space
+		float left   = (spotlight.x - padding) / viewport_size.x;
+		float top    = (spotlight.y - padding) / viewport_size.y;
+		float right  = (spotlight.x + spotlight.z + padding) / viewport_size.x;
+		float bottom = (spotlight.y + spotlight.w + padding) / viewport_size.y;
+
+		bool in_hole = (UV.x >= left) && (UV.x <= right)
+					&& (UV.y >= top)  && (UV.y <= bottom);
+
+		if (in_hole) {
+			COLOR = vec4(0.0, 0.0, 0.0, 0.0); // transparent — element shows through
+		} else {
+			COLOR = vec4(0.0, 0.0, 0.0, dim_alpha);
+		}
+	} else {
+		COLOR = vec4(0.0, 0.0, 0.0, dim_alpha);
+	}
+}