#version 330 core

#define FONT_WIDTH 128
#define FONT_HEIGHT 64
#define FONT_COLS 18
#define FONT_ROWS 7
#define FONT_CH_W (FONT_WIDTH  / FONT_COLS)
#define FONT_CH_H (FONT_HEIGHT / FONT_ROWS)
#define FONT_CH_W_UV (float(FONT_CH_W) / float(FONT_WIDTH))
#define FONT_CH_H_UV (float(FONT_CH_H) / float(FONT_HEIGHT))

uniform sampler2D font;

uniform float time;
uniform vec2 resolution;

in vec2 uv;

in vec2 glyph_uv_pos;
in vec2 glyph_uv_size;
in vec4 glyph_fg_color;
in vec4 glyph_bg_color;

float map01(float x)
{
	return (x + 1) / 2;
}

vec3 hsl2rgb( in vec3 c )
{
	vec3 rgb = clamp( abs(mod(c.x*6.0+vec3(0.0,4.0,2.0),6.0)-3.0)-1.0,
			  0.0, 1.0 );

	return c.z + c.y * (rgb-0.5)*(1.0-abs(2.0*c.z-1.0));
}

void main() {
	// vec2 t = glyph_uv_pos + glyph_uv_size * uv;
	// gl_FragColor = vec4(texture(font, t).x, 0, 0, 1);
	vec2 t = glyph_uv_pos + glyph_uv_size * uv;
	vec4 tc = texture(font, t);
	vec2 frag_uv = gl_FragCoord.xy / resolution;
	vec4 rainbow = vec4(hsl2rgb(vec3((time + frag_uv.x + frag_uv.y), 0.5, 0.5)), 1.0);
	gl_FragColor = glyph_bg_color * (1.0 - tc.x) + tc.x * glyph_fg_color * rainbow;
}