// BoTW Toon Shader by NekotoArts
// Migré vers Godot 4.7
shader_type spatial;
render_mode diffuse_toon, specular_toon;

uniform vec4 tint : source_color = vec4(1.0);
uniform sampler2D albedo_texture : source_color;
uniform float metallic : hint_range(0.0, 1.0) = 0.0;
uniform sampler2D normal_map : source_color;
uniform float shadow_size = 0.045;
uniform float shadow_blend = 0.001;
uniform float shadow_extra_intensity = 0.0;
uniform vec4 shadow_color : source_color = vec4(0.0, 0.0, 0.0, 1.0);
uniform vec4 light_tint : source_color = vec4(1.0);
uniform float rimlight_size = 0.921;
uniform float rimlight_blend = 0.01;
uniform vec4 rimlight_color : source_color = vec4(1.0);
uniform bool use_normalmap = true;
uniform bool animated = true;
uniform float time_scale = 0.02;
uniform vec3 normal_bias = vec3(0.0);
uniform vec3 light_bias = vec3(0.0);
uniform bool use_view = true;
uniform vec4 view_bias : source_color = vec4(1.0, 0.0, 1.0, 1.0);
uniform float view_multiplier : hint_range(-1.0, 1.0) = -1.0;

float fresnel(float amount, vec3 normal, vec3 view)
{
	return pow((1.0 - clamp(dot(normalize(normal), normalize(view)), 0.0, 1.0)), amount);
}

void vertex() {
	// VERTEX 和 NORMAL 是 Godot 4 的顶点内置变量
	// TANGENT 在 Godot 4 中仍需从 TANGENT 读取，但已不再推荐存储
	// 如需传递法线，直接用 NORMAL 即可，Godot 会自动处理
}

void fragment() {
	ALBEDO = texture(albedo_texture, UV).rgb * tint.rgb;
	METALLIC = metallic;
}

void light() {
	vec3 normal;
	if (use_normalmap) {
		vec3 normal_from_texture;
		if (animated) {
			normal_from_texture = texture(normal_map, UV + TIME * time_scale).rgb;
		} else {
			normal_from_texture = texture(normal_map, UV).rgb;
		}
		// Godot 4 中法线贴图的解码通常用 texture().rgb * 2.0 - 1.0
		// 但原代码直接做减法，这里保持原逻辑但修正分量使用
		normal = NORMAL - (normal_from_texture * 2.0 - 1.0);
	} else {
		normal = NORMAL;
	}
	
	if (use_view) {
		normal -= VIEW * view_bias.rgb * view_multiplier;
	}
	
	float NdotL = dot(normal + normal_bias, LIGHT + light_bias);
	
	float rounded = smoothstep(shadow_size, shadow_blend + shadow_size, NdotL);
	float one_minus = 1.0 - rounded;
	vec3 mult1 = LIGHT_COLOR * rounded * light_tint.rgb * ATTENUATION;
	vec3 mult2 = (one_minus * 1.4 * shadow_color.rgb) - shadow_extra_intensity;
	vec3 add1 = mult1 + mult2;
	
	float add3 = rimlight_blend + rimlight_size;
	float basic_fresnel = fresnel(1.0, NORMAL, VIEW);
	float smoothed = smoothstep(rimlight_size, add3, basic_fresnel);
	
	vec3 add2 = add1 + smoothed * rimlight_color.rgb;
	DIFFUSE_LIGHT += ALBEDO * add2;
}