TileRender.cpp

/*
 Copyright (c) 2010, The Barbarian Group
 All rights reserved.

 Redistribution and use in source and binary forms, with or without modification, are permitted provided that
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    * Redistributions of source code must retain the above copyright notice, this list of conditions and
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	the following disclaimer in the documentation and/or other materials provided with the distribution.

 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED
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 TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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*/

#include "TileRender.h"
#include "cinder/gl/gl.h"
#include "cinder/app/App.h"

#include <algorithm>
#include <sstream>

namespace cinder { namespace gl {

TileRender::TileRender( int32_t imageWidth, int32_t imageHeight, int32_t tileWidth, int32_t tileHeight )
	: mImageWidth( imageWidth ), mImageHeight( imageHeight )
{
	// if we are using the screen, we can't make tiles bigger than the app's window
	mTileWidth = std::min( tileWidth, (int32_t)app::getWindowWidth() );
	mTileHeight = std::min( tileHeight, (int32_t)app::getWindowHeight() ); 

	mNumTilesX = (int32_t)math<float>::ceil( mImageWidth / (float)mTileWidth );
	mNumTilesY = (int32_t)math<float>::ceil( mImageHeight / (float)mTileHeight );
	
	mCurrentTile = -1;
}

bool TileRender::nextTile()
{
	if( mCurrentTile >= mNumTilesX * mNumTilesY ) {
		// suck the pixels out of the final tile
		mSurface.copyFrom( app::copyWindowSurface( Area( 0, app::getWindowHeight() - mCurrentArea.getHeight(), mCurrentArea.getWidth(), app::getWindowHeight() ) ), 
			Area( 0, 0, mCurrentArea.getWidth(), mCurrentArea.getHeight() ), mCurrentArea.getUL() );
		// all done
        gl::popViewport();
		mCurrentTile = -1;
		return false;
	}
	
	if( mCurrentTile == -1 ) { // first tile of this frame
        gl::pushViewport();
		mCurrentTile = 0;
		mSurface = Surface( mImageWidth, mImageHeight, false );
	}
	else {
		// suck the pixels out of the previous tile
		mSurface.copyFrom( app::copyWindowSurface( Area( 0, app::getWindowHeight() - mCurrentArea.getHeight(), mCurrentArea.getWidth(), app::getWindowHeight() ) ), 
			Area( 0, 0, mCurrentArea.getWidth(), mCurrentArea.getHeight() ), mCurrentArea.getUL() );
	}
	
	int tileX = mCurrentTile % mNumTilesX;
	int tileY = mCurrentTile / mNumTilesX;
	int currentTileWidth = ( ( tileX == mNumTilesX - 1 ) && ( mImageWidth != mTileWidth * mNumTilesX ) ) ? ( mImageWidth % mTileWidth ) : mTileWidth;
	int currentTileHeight = ( ( tileY == mNumTilesY - 1 ) && ( mImageHeight != mTileHeight * mNumTilesY ) ) ? ( mImageHeight % mTileHeight ) : mTileHeight;
	mCurrentArea.x1 = tileX * mTileWidth;
	mCurrentArea.x2 = mCurrentArea.x1 + currentTileWidth;
	mCurrentArea.y1 = tileY * mTileHeight;
	mCurrentArea.y2 = mCurrentArea.y1 + currentTileHeight;

    gl::viewport( vec2(0), mCurrentArea.getSize() );
	updateFrustum();

	mCurrentTile++;
	return true;
}

void TileRender::setMatricesWindowPersp( int screenWidth, int screenHeight, float fovDegrees, float nearPlane, float farPlane )
{
	CameraPersp cam( screenWidth, screenHeight, fovDegrees, nearPlane, farPlane );
	setMatrices( cam );
}

void TileRender::setMatricesWindow( int32_t windowWidth, int32_t windowHeight )
{
    gl::setMatricesWindow ( windowWidth, windowHeight );
	ortho( 0, (float)windowWidth, (float)windowHeight, 0, -1.0f, 1.0f );
}

void TileRender::setMatrices( const cinder::Camera &camera )
{
    gl::setMatrices( camera );
    
	float left, top, right, bottom, nearPlane, farPlane;
	camera.getFrustum( &left, &top, &right, &bottom, &nearPlane, &farPlane );

	if( camera.isPersp() ) {
		frustum( left, right, bottom, top, nearPlane, farPlane );
	}
	else {
		ortho( left, right, bottom, top, nearPlane, farPlane );
	}

}

void TileRender::frustum( float left, float right, float bottom, float top, float nearPlane, float farPlane )
{
	mCurrentFrustumCoords = Rectf( vec2( left, top ), vec2( right, bottom ) );
	mCurrentFrustumNear = nearPlane;
	mCurrentFrustumFar = farPlane;
	mCurrentFrustumPersp = true;
	updateFrustum();
}

void TileRender::ortho( float left, float right, float bottom, float top, float nearPlane, float farPlane )
{
	mCurrentFrustumCoords = Rectf( vec2( left, top ), vec2( right, bottom ) );
	mCurrentFrustumNear = nearPlane;
	mCurrentFrustumFar = farPlane;
	mCurrentFrustumPersp = false;
	updateFrustum();
}

void TileRender::updateFrustum()
{
	float left = mCurrentFrustumCoords.x1 + mCurrentArea.x1 / (float)mImageWidth * mCurrentFrustumCoords.getWidth();
	float right = left + mCurrentArea.getWidth() / (float)mImageWidth * mCurrentFrustumCoords.getWidth();
	float top = mCurrentFrustumCoords.y1 + mCurrentArea.y1 / (float)mImageHeight * mCurrentFrustumCoords.getHeight();
	float bottom = top + mCurrentArea.getHeight() / (float)mImageHeight * mCurrentFrustumCoords.getHeight();

	if( mCurrentFrustumPersp ) {
        gl::setProjectionMatrix( glm::frustum(left, right, bottom, top, mCurrentFrustumNear, mCurrentFrustumFar) );
	}
    else {
        gl::setProjectionMatrix( glm::ortho(left, right, bottom, top, mCurrentFrustumNear, mCurrentFrustumFar) );
    }
}

} } // namespace cinder::gl