shader_type spatial;
render_mode blend_mix, depth_draw_opaque, cull_back, diffuse_burley, specular_schlick_ggx;

uniform float wave_strength : hint_range(0.0, 0.5) = 0.08;
uniform float wave_speed : hint_range(0.0, 5.0) = 0.8;
uniform float flow_speed : hint_range(0.0, 3.0) = 0.6;
uniform vec3 deep_color : source_color = vec3(0.06, 0.24, 0.38);
uniform vec3 shallow_color : source_color = vec3(0.18, 0.44, 0.58);
uniform vec3 foam_color : source_color = vec3(0.82, 0.88, 0.86);
uniform float rim_power : hint_range(0.5, 5.0) = 2.5;
uniform float sparkle_strength : hint_range(0.0, 1.0) = 0.12;

global uniform vec3 sun_direction = vec3(0.4, 0.8, 0.4);

void vertex() {
	vec3 pos = VERTEX;
	float wave_a = sin(pos.x * 0.35 + pos.z * 0.25 + TIME * wave_speed) * wave_strength;
	float wave_b = cos(pos.x * 0.45 - pos.z * 0.55 + TIME * wave_speed * 0.7) * wave_strength * 0.6;
	float wave_c = sin(pos.z * 0.7 + TIME * wave_speed * 1.3) * wave_strength * 0.35;
	pos.y += wave_a + wave_b + wave_c;
	VERTEX = pos;
}

void fragment() {
	vec3 view_dir = VIEW;
	vec3 normal = NORMAL;
	vec3 view_norm = normalize(view_dir);

	float rim = 1.0 - abs(dot(normal, view_norm));
	rim = pow(rim, rim_power);
	rim = smoothstep(0.15, 0.7, rim);

	vec2 uv = UV;
	uv.x += TIME * flow_speed * 0.4;
	uv.y += TIME * flow_speed * 0.3;
	float flow_a = sin(uv.x * 8.0 + uv.y * 5.0) * 0.5 + 0.5;
	float flow_b = cos(uv.y * 6.0 - uv.x * 4.0 + TIME * 0.25) * 0.5 + 0.5;
	float flow = mix(flow_a, flow_b, 0.5);

	vec3 water_color = mix(deep_color, shallow_color, flow * 0.6 + 0.2);
	water_color = mix(water_color, foam_color, rim * 0.65);

	vec3 half_vec = normalize(view_norm + normalize(sun_direction));
	float specular = pow(max(dot(normal, half_vec), 0.0), 120.0);
	specular *= smoothstep(0.4, 0.85, rim);
	float sparkle = specular * sparkle_strength;

	ALBEDO = water_color;
	METALLIC = 0.08;
	ROUGHNESS = 0.22;
	EMISSION = water_color * 0.04 + foam_color * sparkle;
	ALPHA = 0.76;
	ALPHA_SCISSOR_THRESHOLD = 0.0;
}