/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * 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 3 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, see <http://www.gnu.org/licenses/>.
 *
 */

#include "engines/stark/gfx/opengltexture.h"

#include "engines/stark/gfx/driver.h"

#include "graphics/surface.h"

#if defined(USE_OPENGL_GAME) || defined(USE_OPENGL_SHADERS)

#include "graphics/opengl/context.h"

namespace Stark {
namespace Gfx {

OpenGlTexture::OpenGlTexture() :
	Texture(),
	_id(0),
	_levelCount(0) {
	glGenTextures(1, &_id);

	bind();

	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);

	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
}

OpenGlTexture::~OpenGlTexture() {
	glDeleteTextures(1, &_id);
}

void OpenGlTexture::bind() const {
	glBindTexture(GL_TEXTURE_2D, _id);
}

void OpenGlTexture::updateLevel(uint32 level, const Graphics::Surface *surface, const byte *palette) {
	const Graphics::Surface *rgbaSurface = surface;
	if (surface->format != Driver::getRGBAPixelFormat()) {
		// Convert the surface to texture format
		rgbaSurface = surface->convertTo(Driver::getRGBAPixelFormat(), palette);
	}

	// Stark textures (not bitmaps!) are always POT
	glTexImage2D(GL_TEXTURE_2D, level, GL_RGBA, rgbaSurface->w, rgbaSurface->h, 0, GL_RGBA, GL_UNSIGNED_BYTE, rgbaSurface->getPixels());

	if (rgbaSurface != surface) {
		const_cast<Graphics::Surface *>(rgbaSurface)->free();
		delete rgbaSurface;
	}
}

void OpenGlTexture::setLevelCount(uint32 count) {
	_levelCount = count;

	if (count >= 1) {
		// GLES1 and GLES2 do not allow setting the max provided mipmap level.
		// It expects all the levels to be provided, which is not the case in TLJ.
		// FIXME: Enable mipmapping on GLES without this extension
		if (OpenGLContext.textureMaxLevelSupported) {
			glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_LEVEL, count - 1);

			glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_NEAREST);
			glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
		}

		// TODO: Provide a fallback if this isn't available.
		if (OpenGLContext.textureMirrorRepeatSupported) {
			glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_MIRRORED_REPEAT);
			glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_MIRRORED_REPEAT);
		}
	}
}

void OpenGlTexture::addLevel(uint32 level, const Graphics::Surface *surface, const byte *palette) {
	assert(level < _levelCount);

	if (level == 0 || OpenGLContext.textureMaxLevelSupported) {
		updateLevel(level, surface, palette);
	}
}

} // End of namespace Gfx
} // End of namespace Stark

#endif // defined(USE_OPENGL_GAME) || defined(USE_OPENGL_SHADERS)