ddnet/src/base/color.h

#ifndef BASE_COLOR_H
#define BASE_COLOR_H

#include <iostream>
#include "math.h"
#include "vmath.h"

/*
	Title: Color handling
*/

inline float RgbToHue(vec3 rgb)
{
	float h_min = min(rgb.r, rgb.g, rgb.b);
	float h_max = max(rgb.r, rgb.g, rgb.b);

	float hue = 0.0f;
	if(h_max != h_min)
	{
		float c = h_max - h_min;
		if(h_max == rgb.r)
			hue = (rgb.g - rgb.b) / c + (rgb.g < rgb.b ? 6 : 0);
		else if(h_max == rgb.g)
			hue = (rgb.b - rgb.r) / c + 2;
		else
			hue = (rgb.r - rgb.g) / c + 4;
	}

	return hue / 6.0f;
}

/*
	Function: HslToRgb
		Converts HSL to RGB
*/
inline vec3 HslToRgb(vec3 HSL)
{
	vec3 rgb = vec3(0, 0, 0);

	float h1 = HSL.h * 6;
	float c = (1 - absolute(2 * HSL.l - 1)) * HSL.s;
	float x = c * (1 - absolute(fmod(h1, 2) - 1));

	switch(round_truncate(h1)) {
	case 0:
		rgb.r = c, rgb.g = x;
		break;
	case 1:
		rgb.r = x, rgb.g = c;
		break;
	case 2:
		rgb.g = c, rgb.b = x;
		break;
	case 3:
		rgb.g = x, rgb.b = c;
		break;
	case 4:
		rgb.r = x, rgb.b = c;
		break;
	case 5:
		rgb.r = c, rgb.b = x;
		break;
	}

	float m = HSL.l - (c/2);
	return vec3(rgb.r + m, rgb.g + m, rgb.b + m);
}

inline vec3 HsvToRgb(vec3 hsv)
{
	int h = int(hsv.x * 6.0f);
	float f = hsv.x * 6.0f - h;
	float p = hsv.z * (1.0f - hsv.y);
	float q = hsv.z * (1.0f - hsv.y * f);
	float t = hsv.z * (1.0f - hsv.y * (1.0f - f));

	vec3 rgb = vec3(0.0f, 0.0f, 0.0f);

	switch(h % 6)
	{
	case 0:
		rgb.r = hsv.z;
		rgb.g = t;
		rgb.b = p;
		break;

	case 1:
		rgb.r = q;
		rgb.g = hsv.z;
		rgb.b = p;
		break;

	case 2:
		rgb.r = p;
		rgb.g = hsv.z;
		rgb.b = t;
		break;

	case 3:
		rgb.r = p;
		rgb.g = q;
		rgb.b = hsv.z;
		break;

	case 4:
		rgb.r = t;
		rgb.g = p;
		rgb.b = hsv.z;
		break;

	case 5:
		rgb.r = hsv.z;
		rgb.g = p;
		rgb.b = q;
		break;
	}

	return rgb;
}

inline vec3 RgbToHsv(vec3 rgb)
{
	float h_min = min(min(rgb.r, rgb.g), rgb.b);
	float h_max = max(max(rgb.r, rgb.g), rgb.b);

	// hue
	float hue = 0.0f;

	if(h_max == h_min)
		hue = 0.0f;
	else if(h_max == rgb.r)
		hue = (rgb.g-rgb.b) / (h_max-h_min);
	else if(h_max == rgb.g)
		hue = 2.0f + (rgb.b-rgb.r) / (h_max-h_min);
	else
		hue = 4.0f + (rgb.r-rgb.g) / (h_max-h_min);

	hue /= 6.0f;

	if(hue < 0.0f)
		hue += 1.0f;

	// saturation
	float s = 0.0f;
	if(h_max != 0.0f)
		s = (h_max - h_min)/h_max;

	// lightness
	float l = h_max;

	return vec3(hue, s, l);
}

inline vec3 RgbToHsl(vec3 rgb)
{
	float Min = min(rgb.r, rgb.g, rgb.b);
	float Max = max(rgb.r, rgb.g, rgb.b);

	float c = Max - Min;
	float h = RgbToHue(rgb);
	float l = 0.5f * (Max + Min);
	float s = (Max != 0.0f && Min != 1.0f) ? (c/(1 - (absolute(2 * l - 1)))) : 0;

	return vec3(h, s, l);
}

/*
	Function: HexToRgba
		Converts Hex to Rgba

	Remarks: Hex should be RGBA8
*/
inline vec4 HexToRgba(int hex)
{
	vec4 c;
	c.r = ((hex >> 24) & 0xFF) / 255.0f;
	c.g = ((hex >> 16) & 0xFF) / 255.0f;
	c.b = ((hex >> 8) & 0xFF) / 255.0f;
	c.a = (hex & 0xFF) / 255.0f;

	return c;
}

inline vec3 UnpackColor(int v)
{
    return vec3(fmod(((v>>16)&0xff)/255.0f, 1.0f), ((v>>8)&0xff)/255.0f, 0.5f+(v&0xff)/255.0f*0.5f);
}

class color4_base : public vector3_base<float>
{
public:
	float a;

	using vector3_base::vector3_base;
	color4_base() {}

	color4_base(const vec4 &v4)
	{
		x = v4.x;
		y = v4.y;
		z = v4.z;
		a = v4.w;
	}

	color4_base(float nx, float ny, float nz, float na)
	{
		x = nx;
		y = ny;
		z = nz;
		a = na;
	}

	color4_base(int col)
	{
		a = ((col >> 24) & 0xFF) / 255.0f;
		x = ((col >> 16) & 0xFF) / 255.0f;
		y = ((col >> 8) & 0xFF) / 255.0f;
		z = ((col >> 0) & 0xFF) / 255.0f;
	}

	int Pack()
	{
		return ((int)(a * 255.0f) << 24) + ((int)(x * 255.0f) << 16) + ((int)(y * 255.0f) << 8) + (int)(z * 255.0f);
	}
};

class ColorHSLA : public color4_base
{
	using color4_base::color4_base;
	void ClampLighting()
	{
		if(l < 0.5f)
			l = 0.5f + l * 0.5f;
	}
};

class ColorRGBA : public color4_base
{
	using color4_base::color4_base;
};

template <typename T, typename F> T color_cast(const F &f);
template <>
inline ColorHSLA color_cast(const ColorRGBA &rgb)
{
	float Min = min(rgb.r, rgb.g, rgb.b);
	float Max = max(rgb.r, rgb.g, rgb.b);

	float c = Max - Min;
	float h = RgbToHue(rgb);
	float l = 0.5f * (Max + Min);
	float s = (Max != 0.0f && Min != 1.0f) ? (c/(1 - (absolute(2 * l - 1)))) : 0;


	std::cout << "H: " << h << " S: " << s << " L: " << l << " C: " << c << std::endl;

	return ColorHSLA(h, s, l, rgb.a);
}

template <>
inline ColorRGBA color_cast(const ColorHSLA &hsl)
{
	vec3 rgb = vec3(0, 0, 0);

	float h1 = hsl.h * 6;
	float c = (1 - absolute(2 * hsl.l - 1)) * hsl.s;
	float x = c * (1 - absolute(fmod(h1, 2) - 1));

	switch(round_truncate(h1)) {
	case 0:
		rgb.r = c, rgb.g = x;
		break;
	case 1:
		rgb.r = x, rgb.g = c;
		break;
	case 2:
		rgb.g = c, rgb.b = x;
		break;
	case 3:
		rgb.g = x, rgb.b = c;
		break;
	case 4:
		rgb.r = x, rgb.b = c;
		break;
	case 5:
		rgb.r = c, rgb.b = x;
		break;
	}

	float m = hsl.l - (c/2);
	return ColorRGBA(rgb.r + m, rgb.g + m, rgb.b + m, hsl.a);
}

#endif