Drawing pixels on a window?

hi!
i want to make a software-renderer, like the one i did before in an other programming language. this time, i'll do it in C++. the problem is: how do i draw pixels on the window (FAST) ?
something like a pointer to the screen buffer would be nice
thanks for helping.

Code:

#include <windows.h>

LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wparam, LPARAM lparam);

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR szCmdLine, int iCmdShow)
{
	WNDCLASS wc;
	wc.cbClsExtra = 0;
	wc.cbWndExtra = 0;
	wc.hbrBackground = (HBRUSH)GetStockObject(BLACK_BRUSH);
	wc.hCursor = LoadCursor(NULL, IDC_ARROW);
	wc.hIcon = LoadIcon(NULL, IDI_APPLICATION);
	wc.hInstance = hInstance;
	wc.lpfnWndProc = WndProc;
	wc.lpszClassName = TEXT("MainWindow");
	wc.lpszMenuName = 0;
	wc.style = CS_HREDRAW | CS_VREDRAW;
	RegisterClass(&wc);

	HWND hwnd = CreateWindow(
		TEXT("MainWindow"),
		TEXT("Test"),
		WS_CAPTION | WS_SYSMENU | WS_MINIMIZEBOX,
		100, 100,
		640, 480,
		NULL, NULL,
		hInstance, NULL
	);
	ShowWindow(hwnd, iCmdShow);

	MSG msg;
	while (GetMessage(&msg, NULL, 0, 0 ))
	{
		TranslateMessage(&msg);
		DispatchMessage(&msg);
	}
	return msg.wParam;
}

LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wparam, LPARAM lparam)
{
	switch (message)
	{
		case WM_PAINT:
			HDC hdc;
			PAINTSTRUCT ps;
			hdc = BeginPaint(hwnd, &ps);
			for (int y = 0; y < 480; y++)
			{
				for (int x = 0; x < 640; x++)
				{
					SetPixel(hdc, x, y, 0xffffff);
				}
			}
			EndPaint(hwnd, &ps);
			break;
		case WM_DESTROY:
			PostQuitMessage(0);
			break;
	}
	return DefWindowProc(hwnd, message, wparam, lparam);
}

The simple solution for "pointer to the frame buffer" is to do double-buffered drawing, where you use the BitBlt function to copy your pixels to the actual screen. So, create yourself a piece of memory big enough to hold all your pixels, then draw to your hearts content with a pointer to that memory, and when you are done, use BitBlt() to copy it in the "WM_PAINT" section.

--
Mats

sounds like what i needed. i have an array with a pointer now, and how exactly do i handle the BitBlt() function now?

Let Me Google that for you.

You want the second hit.

--
Mats

lol. i already discovered this function, but there is no argument where i can give my pointer to the screen buffer array??

Ok, so you need to CreatCompatibleBitmap(), and then use SetDIBits(), using the address of your pixels, and then use the handle from CreateCompatibleBitmap() to do the actual BitBlt() operation.

--
Mats

do you have any example for that?
forgive my dumbness

Originally Posted by Devils Child

do you have any example for that?
forgive my dumbness

No, I'm just reading the MSDN web-site and some basic understanding of GDI in general (I did two years of writing Windows graphics device drivers).

This seems like it's in the right general direction: http://www.winprog.org/tutorial/bitmaps.html

--
Mats

and how do i access the memory?
although, i thought you'd use a surface instead of a 'bitmap'?

Is it me or is setting everything pixel per pixel still going to be excruciatingly slow? I think best is to avoid that while you can. And with what you're doing, drawing a square, I bet it's possible without setting it pixel per pixel. Although I've never done windows api coding...

fine. programming a software renderer requires setting everything pixel-per-pixel.
and believe me: it's not slow!

so how do i do it now?

Using SetDIBits, you can set a Bitmap to point to memory that you have allocated.

--
Mats

alright. got it now working
thx a lot!