shader_type spatial;
render_mode unshaded;

// Original Trellis atlas texture
uniform sampler2D albedo_tex : source_color;
// Recolor mask: white = replaceable, black = keep original
uniform sampler2D recolor_mask : hint_default_black;
// Runtime tint color set by game code
uniform vec4 tint_color : source_color = vec4(0.8, 0.8, 0.8, 1.0);
// Subtle darkening on shadow side (0.0 = no shadow, 1.0 = full black)
uniform float shadow_strength : hint_range(0.0, 1.0) = 0.15;
uniform float shadow_threshold : hint_range(0.0, 1.0) = 0.3;

void fragment() {
	vec4 original = texture(albedo_tex, UV);
	float mask = texture(recolor_mask, UV).r;

	// Recolor: blend tint with original, preserving luminance in masked regions
	// This keeps texture detail (shadows, edges, highlights) while changing the hue
	float luma = dot(original.rgb, vec3(0.299, 0.587, 0.114));
	vec3 tinted = tint_color.rgb * (luma * 1.5 + 0.2); // scale luma to avoid too-dark
	vec3 base = mix(original.rgb, tinted, mask);

	// Gentle toon shadow — just a subtle darkening, not a color replacement
	vec3 light_dir = normalize(vec3(0.3, -1.0, 0.5));
	float ndl = dot(NORMAL, -light_dir);
	float toon = smoothstep(shadow_threshold - 0.1, shadow_threshold + 0.1, ndl);
	vec3 color = base * mix(1.0 - shadow_strength, 1.0, toon);

	ALBEDO = color;
}