2D Water Effect in WTL

// TortoiseSVN - a Windows shell extension for easy version control

// Copyright (C) 2003-2006 - Stefan Kueng

// 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 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,
// 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
//

// refactored by Tan, Zhi(tomgee) 4/28/2011


#include "stdafx.h"
#include "Renderer.h"

#include <atlimage.h>

#include "cimage_pixel_access_opt.h"

// FOR BPP=32, Each DWORD in the bitmap array represents the relative intensities of blue, green, and red, respectively, for a pixel.
COLORREF ConvertToBPP32(COLORREF clr)
{
	return RGB(GetBValue(clr), GetGValue(clr), GetRValue(clr));
}

CRenderer::~CRenderer()
{
    DeleteObject();
}

void CRenderer::DeleteObject()
{
	// release memory allocated by CreateDIBSection()
    if (m_bmp)    ::DeleteObject(m_bmp);
    m_bmp = NULL;
    m_buffer_source = NULL;
}

void CRenderer::create_buffers(const CDC& dc)
{
	// create source buffer to hold initial background image
    m_bmp_info.bmiHeader.biSize          = sizeof(BITMAPINFOHEADER);
    m_bmp_info.bmiHeader.biWidth         = m_width;		// The width of the bitmap, in pixels.
    m_bmp_info.bmiHeader.biHeight        = m_height;	// The height of the bitmap, in pixels.If positive, the bitmap is a bottom-up DIB, If negative, then top-down DIB
    m_bmp_info.bmiHeader.biPlanes        = 1;			// This value must be set to 1
    m_bmp_info.bmiHeader.biBitCount      = 32;			// maximum of 2^32 colors
    m_bmp_info.bmiHeader.biCompression   = BI_RGB;		// An uncompressed format.
    m_bmp_info.bmiHeader.biSizeImage     = 0;			// set to zero for BI_RGB bitmaps
    m_bmp_info.bmiHeader.biXPelsPerMeter = 0;			// don't care, not to be used by CreateDIBSection()
    m_bmp_info.bmiHeader.biYPelsPerMeter = 0;			// don't care, not to be used by CreateDIBSection() 
    m_bmp_info.bmiHeader.biClrUsed       = 0;			// uses the maximum number of colors corresponding to the value of the biBitCount member for the compression mode specified by biCompression
    m_bmp_info.bmiHeader.biClrImportant  = 0;			// all colors are required.
	
	// Create a 32 bit bitmap
	m_bmp = CreateDIBSection(
			dc, 
			&m_bmp_info, 
			DIB_RGB_COLORS,		// The BITMAPINFO structure contains an array of literal RGB values.
			&m_buffer_source,	// A pointer to a variable that receives a pointer to the location of the DIB bit values
			NULL,				// the system allocates memory for the DIB
			0					// don't care
		);
    GdiFlush();


	// create target buffer to hold processed image and to be rendered from
	m_buffer_target.reset(m_height * m_width);  
}

void CRenderer::fill_buffers(const CImage& img)
{
	// Copy background picture into the 32 bit dib pointed to by m_buffer_source & m_buffer_target.
	//  upside down,  and reverse rgbs.
	DWORD* pAr		=	(DWORD*)m_buffer_source;

	CImagePixelAccessOptimizer p(&img);
	for(int row = 0; row < m_height; row++)
	{	
		for(int col = 0; col < m_width; col++)
		{
			size_t index = row * m_width + col;
			pAr[index] = ConvertToBPP32(/*img*/p.GetPixel(col, row ));			
			m_buffer_target[index] = ConvertToBPP32(/*img*/p.GetPixel(col, row ));			
		}
	}
}

void CRenderer::init (const CImage& img, const CDC& dc)
{
	// init dimensions
	m_width = img.GetWidth();
	m_height= img.GetHeight();

	// init buffers
	create_buffers(dc);
	fill_buffers(img);
}

BOOL CRenderer::Draw(const CPoint& ptDest, CDC& dc) 
{ 
    if (!m_bmp) return FALSE;

    CPoint ScanOrigin(0,0);

	// To reduce the amount of memory required to set bits from a large DIB on a device surface, 
	// an application can band the output by repeatedly calling SetDIBitsToDevice, 
	// placing a different portion of the bitmap into the lpvBits array each time. 
	// The values of the uStartScan and cScanLines parameters identify the portion of 
	// the bitmap contained in the lpvBits array.
    BOOL result = SetDIBitsToDevice(dc, 
                                ptDest.x, ptDest.y,			// upper-left corner of the destination rectangle,
                                m_width, m_height,			// The width & height of the image
                                ScanOrigin.x, ScanOrigin.y,	// lower-left corner of the image
                                ScanOrigin.y,				// The starting scan line in the image
								m_height - ScanOrigin.y,	// The number of DIB scan lines pointed to by the m_buffer_target
                                m_buffer_target, 
								&m_bmp_info, 
                                DIB_RGB_COLORS	// Indicates whether the m_bmp_info.bmiColors contains explicit red, green, blue (RGB) values
								); 

    return result;
}