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/* Color.h
Copyright (c) 2014 by Michael Zahniser
Endless Sky is free software: you can redistribute it and/or modify it under the
terms of the GNU General Public License as published by the Free Software
Foundation, either version 3 of the License, or (at your option) any later version.
Endless Sky is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with
this program. If not, see <https://www.gnu.org/licenses/>.
*/
#pragma once
#include <string>
// Class representing an RGBA color (for use by OpenGL). The specified colors
// should be in premultiplied alpha mode. For example, a white color which is
// 50% translucent would be {.5, .5, .5} with an alpha of .5. This allows you to
// also specify colors that use additive blending. For example, if the alpha is
// zero the color's components will be added to whatever is underneath them.
class Color {
public:
// Constructor for shades of gray. Opaque unless an alpha is also given.
// IsLoaded is false when using this constructor.
explicit Color(float i = 1.f, float a = 1.f);
// Constructor for colors. Opaque unless an alpha is also given.
Color(float r, float g, float b, float a = 1.f);
bool operator==(const Color &other) const;
bool operator!=(const Color &other) const;
// Set this color to the given RGBA values.
void Load(double r, double g, double b, double a);
// Check if Load() has been called for this color.
bool IsLoaded() const;
void SetTrueName(const std::string &name);
const std::string &TrueName() const;
// Get the color as a float vector, suitable for use by OpenGL.
const float *Get() const;
// Get this color, but entirely opaque. That is, this is the color you would
// get if drawing this color on top of opaque black.
Color Opaque() const;
// Assuming that this color is completely opaque, get the same color with
// the given transparency.
Color Transparent(float alpha) const;
// Assuming that this is an opaque color, get its additive equivalent with
// the given fraction of its full brightness.
Color Additive(float alpha) const;
// Compute a linear combination
static Color Combine(float a1, Color c1, float a2, Color c2);
// Multiply the RGBA values of the given Color by the given scalar and return a new Color.
static Color Multiply(float scalar, const Color &base);
private:
// Store the color as a float vector for easy interfacing with OpenGL.
float color[4];
std::string trueName;
bool isLoaded = false;
};
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