BackBuffer.cpp

//Programmer: Axel Rotter Morgado
//Date: 18.04.2016

#include "..\\2DEngine\BackBuffer.h"

BackBuffer::BackBuffer(HWND hWnd, int width, int height)
{
	//Save a copy of the main window handle
	mhWnd = hWnd;

	//Get a handle to the device context associated with
	// the window
	HDC hWndDC = GetDC(hWnd);

	//Save the backbuffer dimensions
	mWidth = width;
	mHeight = height;

	//Create system memory device context that is compatible
	//with the window one
	mhDC = CreateCompatibleDC(hWndDC);

	//Create the backbuffer surface bitmap that is compatible
	//with the window device context bitmap format. That is
	//the surface we will render onto.
	mhSurface = CreateCompatibleBitmap(hWndDC, width, height);

	//Done with DC
	ReleaseDC(hWnd, hWndDC);

	//At this point, the back buffer surface is uninitialized,
	//so lets clear it to some non-zero value. Note that it 
	//needs to be a non-zero. If it is zero then it will mess 
	//up our sprite blending logic.

	//Select the backbuffer bitmap into the DC
	mhOldObject = (HBITMAP)SelectObject(mhDC, mhSurface);

	//Select a white brush
	HBRUSH white = (HBRUSH)GetStockObject(WHITE_BRUSH);
	HBRUSH oldBrush = (HBRUSH)SelectObject(mhDC, white);

	//Clear the backbuffer rectangle
	Rectangle(mhDC, 0, 0, mWidth, mHeight);

	//Restore the original brush
	SelectObject(mhDC, oldBrush);

}

BackBuffer::~BackBuffer()
{
	SelectObject(mhDC, mhOldObject);
	DeleteObject(mhSurface);
	DeleteDC(mhDC);
}

HDC BackBuffer::getDC()
{
	return mhDC;
}

int BackBuffer::width()
{
	return mWidth;
}

int BackBuffer::height()
{
	return mHeight;
}

void BackBuffer::present()
{
	//Get a handle to the device context associated with 
	//the window
	HDC hWndDC = GetDC(mhWnd);

	//Copy the backbuffer contents over to the
	//window client area
	BitBlt(hWndDC, 0, 0, mWidth, mHeight, mhDC, 0, 0, SRCCOPY);

	//Free window DC when done
	ReleaseDC(mhWnd, hWndDC);
}