/*
 * Copyright (C) 2010 by the Widelands Development Team
 *
 * This program 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 2
 * of the License, or (at your option) any later version.
 *
 * This program 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, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 *
 */

#ifndef WL_GRAPHIC_BLEND_MODE_H
#define WL_GRAPHIC_BLEND_MODE_H

// Defines blending during blitting.
enum class BlendMode {
	// Normal blending, equivalent to:
	// glEnable(GL_BLEND);
	// glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
	// glBlendEquation(GL_FUNC_ADD);
	Default,

	// Perform a normal blitting operation that respects the alpha channel if
	// present.
	UseAlpha,

	// Used internally for Surface::brighten_rect() if the rect is actually to
	// be darkened.
	Subtract,

	// Copy all pixel information, including alpha channel information.
	Copy,
};

#endif  // end of include guard: WL_GRAPHIC_BLEND_MODE_H
