#version 460

#extension GL_GOOGLE_include_directive : require
#extension GL_EXT_debug_printf : require

#include "gui.layout"

layout (location = 0) flat in uint in_has_texture;

layout (location = 1) in struct FragDataIn {
	vec4  color;
	vec2  uv;
	vec2  dst_pos;
	vec2  dst_center;
	vec2  dst_half_size;
	vec2  sdf_sample_pos;
	float corner_radius;
	float softness;
	float raised;
	float border_thickness;
} FD;


layout (location = 0) out vec4 FragColor;

float RectSDF(vec2 pos, vec2 half_size, float radius)
{
	return length(max(abs(pos) - half_size + radius, 0.0)) - radius;
}

float ToSRGB(float col)
{
	return pow(col, 1.0/2.2);
}

vec4 ToSRGB(vec4 col)
{
	return vec4(ToSRGB(col.r), ToSRGB(col.g), ToSRGB(col.b), col.a);
}

vec4 ToLinear(vec4 col)
{
	return pow(col, vec4(vec3(2.2), 1.0));
}

void main()
{
	float softness = FD.softness;
	vec2 softness_padding = vec2(max(0, softness*2-1), max(0, softness*2-1));

	float border_factor = 1.0;
	if(FD.border_thickness > 0.0)
	{
		float border_sdf = RectSDF(FD.sdf_sample_pos, 
															 FD.dst_half_size - vec2(FD.softness*2.0f) - FD.border_thickness,
															 max(FD.corner_radius - FD.border_thickness, 0.0f));
		border_factor = smoothstep(0.0f, 2.0f * FD.softness, border_sdf);
	}

	if(border_factor < 0.001f)
	{
		discard;
	}

	float corner_factor = 1.0;
	if(FD.corner_radius > 0.0 || FD.softness > 0.0)
	{
		float corner_sdf = RectSDF(FD.sdf_sample_pos,
														   FD.dst_half_size - vec2(FD.softness * 2.0f),
														 	 FD.corner_radius);
		corner_factor = 1.0f - smoothstep(0.0, 2.0f * FD.softness, corner_sdf);
	}

	vec4 inv_gamma = vec4(1.4);
	vec4 gamma = vec4(1.0/1.4);

	vec4 tex_color = vec4(1.0);
	if(in_has_texture != 0)
	{
		tex_color = texture(sampler2D(SpriteAtlas, SamplerNearest), FD.uv);
	}

	vec4 color = FD.color; // ToLinear(FD.color);
	vec4 out_color = color * tex_color;

	out_color.a *= corner_factor;
	out_color.a *= border_factor;

	FragColor = out_color;
}