/*
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 "FrameBuffer.h"
#include "Core.h"
#include "RenderBase.h"

//WARNING: FrameBuffer objects have to have reloadDevice/unloadDevice called manually!

FrameBuffer::FrameBuffer()
{
	inited = false;
	texw = 0;
	texh = 0;
	g_frameBuffer = 0;
	g_depthRenderBuffer = 0;
	g_dynamicTextureID = 0;
	_w = _h = 0;
}

FrameBuffer::~FrameBuffer()
{
	unloadDevice();
}

float FrameBuffer::getWidthP() const
{
	return (float)core->getWindowWidth()/(float)texw;
}

float FrameBuffer::getHeightP() const
{
	return (float)core->getWindowHeight()/(float)texh;
}

bool FrameBuffer::init(int width, int height, bool fitToScreen)
{
	_w = width;
	_h = height;

	if (width == -1)
		width = core->width;

	if (height == -1)
		height = core->height;

	if (fitToScreen)
	{
		sizePowerOf2Texture(width);
		sizePowerOf2Texture(height);
	}

	_fitToScreen = fitToScreen;
	if (width == 0 || height == 0)
		return false;

	texw = width;
	texh = height;

	std::ostringstream os;
	os << "Loading EXT_framebuffer_object (" << texw << ", " << texh << ")";
	debugLog(os.str());

	if( !glIsRenderbufferEXT || !glBindRenderbufferEXT || !glDeleteRenderbuffersEXT ||
		!glGenRenderbuffersEXT || !glRenderbufferStorageEXT || !glGetRenderbufferParameterivEXT ||
		!glIsFramebufferEXT || !glBindFramebufferEXT || !glDeleteFramebuffersEXT ||
		!glGenFramebuffersEXT || !glCheckFramebufferStatusEXT || !glFramebufferTexture1DEXT ||
		!glFramebufferTexture2DEXT || !glFramebufferTexture3DEXT || !glFramebufferRenderbufferEXT||
		!glGetFramebufferAttachmentParameterivEXT)
	{
		debugLog("One or more EXT_framebuffer_object functions were not found");
		return false;
	}

	unloadDevice();

	//
	// Create a frame-buffer object and a render-buffer object...
	//

	glGenFramebuffersEXT( 1, &g_frameBuffer );
	glGenRenderbuffersEXT( 1, &g_depthRenderBuffer );

	// Initialize the render-buffer for usage as a depth buffer.
	// We don't really need this to render things into the frame-buffer object,
	// but without it the geometry will not be sorted properly.
	glBindRenderbufferEXT( GL_RENDERBUFFER_EXT, g_depthRenderBuffer );
	glRenderbufferStorageEXT( GL_RENDERBUFFER_EXT, GL_DEPTH_COMPONENT24, width, height );


	glGenTextures( 1, &g_dynamicTextureID );

	glBindTexture( GL_TEXTURE_2D, g_dynamicTextureID );
	// GL_LINEAR
	glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR );
	glTexParameteri( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR );

	// FIXME: check for GL_ARB_texture_float; otherwise stick with old format
	glTexImage2D( GL_TEXTURE_2D, 0, GL_RGBA16F_ARB,
				width, height,
				0, GL_RGBA, GL_FLOAT, 0 );


	// Put together

	glBindFramebufferEXT( GL_FRAMEBUFFER_EXT, g_frameBuffer );
	glFramebufferTexture2DEXT( GL_FRAMEBUFFER_EXT, GL_COLOR_ATTACHMENT0_EXT, GL_TEXTURE_2D, g_dynamicTextureID, 0 );
	glFramebufferRenderbufferEXT( GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT, GL_RENDERBUFFER_EXT, g_depthRenderBuffer );

	//
	// Check for errors...
	//

	GLenum status = glCheckFramebufferStatusEXT( GL_FRAMEBUFFER_EXT );

	glBindTexture(GL_TEXTURE_2D, 0);
	glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
	glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, 0);

	switch( status )
	{
	case GL_FRAMEBUFFER_COMPLETE_EXT:
		break;

	case GL_FRAMEBUFFER_UNSUPPORTED_EXT:
		debugLog("GL_FRAMEBUFFER_UNSUPPORTED_EXT!");
	default:
		unloadDevice();
		return false;
	}

	debugLog("Done");
	inited = true;
	return true;
}

void FrameBuffer::unloadDevice()
{
	debugLog("frameBuffer::unloadDevice");
	inited = false;

	if (glDeleteFramebuffersEXT == NULL)
	{
		debugLog("Already shut down the GL, don't delete framebuffers");
		return;
	}

	if (g_frameBuffer)
	{
		glBindRenderbufferEXT( GL_RENDERBUFFER_EXT, 0 );

		debugLog("frameBuffer handle present, deleting");
		glDeleteFramebuffersEXT(1, &g_frameBuffer);
		g_frameBuffer = 0;
	}

	if (g_dynamicTextureID)
	{
		glBindRenderbufferEXT( GL_RENDERBUFFER_EXT, 0 );

		debugLog("dynamic texture ID handle present, deleting");
		glDeleteTextures(1, &g_dynamicTextureID);
		g_dynamicTextureID = 0;
	}

	if (g_depthRenderBuffer)
	{
		glBindRenderbufferEXT( GL_RENDERBUFFER_EXT, 0 );

		debugLog("depth render buffer handle present, deleting");
		glDeleteRenderbuffersEXT(1, &g_depthRenderBuffer);
		g_depthRenderBuffer = 0;
	}

	debugLog("done");
}

void FrameBuffer::reloadDevice()
{
	debugLog("frameBuffer::reloadDevice");
	init(_w, _h, _fitToScreen);
}

void FrameBuffer::startCapture() const
{
	assert(inited);
	glBindFramebufferEXT( GL_FRAMEBUFFER_EXT, g_frameBuffer );
	glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
}

void FrameBuffer::endCapture() const
{
	assert(inited);
	glBindFramebufferEXT( GL_FRAMEBUFFER_EXT, 0 );
}

void FrameBuffer::bindTexture() const
{
	assert(inited);
	glBindTexture( GL_TEXTURE_2D, g_dynamicTextureID );
}