game: water shader experiments

assets/shaders/water.gdshader

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+shader_type canvas_item;
+
+// Parameters
+uniform sampler2D water_texture;      // Your 3x3 water texture
+uniform vec4 water_color : source_color = vec4(0.0, 0.0, 1.0, 1.0);
+uniform float speed : hint_range(0.0, 10.0) = 1.0;
+uniform float strength : hint_range(0.0, 0.2) = 0.05;
+uniform float tile_repeat : hint_range(1.0, 10.0) = 3.0;
+uniform vec2 pan_speed = vec2(0.2, 0.1); // how fast the water texture moves
+
+void fragment() {
+    vec2 uv = UV;
+
+    // Sample the base tile texture
+    vec4 base_tex = texture(TEXTURE, uv);
+
+    // Compute mask for water pixels only
+    float is_water = step(0.8, 1.0 - distance(base_tex.rgb, water_color.rgb));
+
+    // Tile the water texture
+    vec2 water_uv = uv * tile_repeat;
+	water_uv = fract(water_uv);
+
+    // Apply panning / movement
+    water_uv += pan_speed * TIME;
+
+    // Add wave distortion on top of the moving texture
+    water_uv.y += sin(water_uv.x * 2.0 + TIME * speed) * strength * is_water;
+    water_uv.x += cos(water_uv.y * 2.0 + TIME * speed * 0.5) * strength * is_water;
+
+    // Sample the animated water texture
+    vec4 water_sample = texture(water_texture, water_uv);
+
+    // Combine: water animates, other pixels stay the same
+    COLOR = mix(base_tex, water_sample, is_water);
+}