Aquaria/BBGE/ScreenTransition.cpp

/*
Copyright (C) 2007, 2010 - Bit-Blot

This file is part of Aquaria.

Aquaria 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., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
*/

#include "ScreenTransition.h"
#include "Core.h"
#include "RenderBase.h"

ScreenTransition::ScreenTransition() : RenderObject()
{
	screen_texture = 0;
	cull = false;
	followCamera = 1;
	alpha = 0;
	createTexture();
}

void ScreenTransition::createTexture()
{
	destroyTexture();

	width = core->getVirtualWidth();
	height = core->getVirtualHeight();

	windowWidth = core->getWindowWidth();
	windowHeight = core->getWindowHeight();

	textureWidth = windowWidth;
	textureHeight = windowHeight;

	sizePowerOf2Texture(textureWidth);
	sizePowerOf2Texture(textureHeight);

	//create our texture
	glGenTextures(1,&screen_texture);
	glBindTexture(GL_TEXTURE_2D, screen_texture);
	glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER, GL_LINEAR);		//GL_NEAREST);		//GL_NEAREST);
	glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER, GL_LINEAR);		//GL_NEAREST);		//GL_NEAREST);
	glTexImage2D(GL_TEXTURE_2D,0,GL_RGB, textureWidth, textureHeight, 0 , GL_RGB, GL_UNSIGNED_BYTE, NULL);
	glBindTexture(GL_TEXTURE_2D,0);
}

void ScreenTransition::destroyTexture()
{
	if (screen_texture)
	{
		glDeleteTextures(1, &screen_texture);
		screen_texture = 0;
	}
}

void ScreenTransition::unloadDevice()
{
	RenderObject::unloadDevice();
	destroyTexture();
}

void ScreenTransition::reloadDevice()
{
	RenderObject::reloadDevice();
	createTexture();
}

void ScreenTransition::capture()
{
	assert(screen_texture);
	core->renderExternal();

	if (screen_texture)
	{
		glBindTexture(GL_TEXTURE_2D,screen_texture);
		glReadBuffer(GL_BACK);
		glCopyTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, 0, 0, windowWidth, windowHeight);
		glBindTexture(GL_TEXTURE_2D, 0);
	}

	core->showBuffer();
}

void ScreenTransition::go(float time)
{
	capture();
	transition(time);
}

void ScreenTransition::transition(float time)
{
	core->resetTimer();
	alpha = 1;
	alpha.interpolateTo(0, time);
}

bool ScreenTransition::isGoing()
{
	return alpha.isInterpolating();
}

void ScreenTransition::onRender(const RenderState& rs) const
{
	if (alpha.x == 0) return;

	float width2 = float(width)/2;
	float height2 = float(height)/2;

	const float pw = float(windowWidth)/float(textureWidth);
	const float ph = float(windowHeight)/float(textureHeight);

	glBindTexture(GL_TEXTURE_2D, screen_texture);

	glBegin(GL_QUADS);
		glTexCoord2f(0, 0);
		glVertex3f(-width2, height2,  0.0);
		glTexCoord2f(pw, 0);
		glVertex3f( width2, height2,  0.0);
		glTexCoord2f(pw, ph);
		glVertex3f( width2,  -height2,  0.0);
		glTexCoord2f(0, ph);
		glVertex3f(-width2,  -height2,  0.0);
	glEnd();

	glBindTexture(GL_TEXTURE_2D, 0);

	RenderObject::lastTextureApplied = 0;
}