C++ Blitter类代码示例

/** Do palette animation and blit to the window. */
static void PaintWindow(HDC dc)
{
	HDC dc2 = CreateCompatibleDC(dc);
	HBITMAP old_bmp = (HBITMAP)SelectObject(dc2, _wnd.dib_sect);
	HPALETTE old_palette = SelectPalette(dc, _wnd.gdi_palette, FALSE);

	if (_cur_palette.count_dirty != 0) {
		Blitter *blitter = BlitterFactory::GetCurrentBlitter();

		switch (blitter->UsePaletteAnimation()) {
			case Blitter::PALETTE_ANIMATION_VIDEO_BACKEND:
				UpdatePalette(dc2, _local_palette.first_dirty, _local_palette.count_dirty);
				break;

			case Blitter::PALETTE_ANIMATION_BLITTER:
				blitter->PaletteAnimate(_local_palette);
				break;

			case Blitter::PALETTE_ANIMATION_NONE:
				break;

			default:
				NOT_REACHED();
		}
		_cur_palette.count_dirty = 0;
	}

	BitBlt(dc, 0, 0, _wnd.width, _wnd.height, dc2, 0, 0, SRCCOPY);
	SelectPalette(dc, old_palette, TRUE);
	SelectObject(dc2, old_bmp);
	DeleteDC(dc2);
}

/** Draw the chat message-box */
void NetworkDrawChatMessage()
{
	Blitter *blitter = BlitterFactoryBase::GetCurrentBlitter();
	if (!_chatmessage_dirty) return;

	/* First undraw if needed */
	NetworkUndrawChatMessage();

	if (_iconsole_mode == ICONSOLE_FULL) return;

	/* Check if we have anything to draw at all */
	uint count = GetChatMessageCount();
	if (count == 0) return;

	int x      = _chatmsg_box.x;
	int y      = _screen.height - _chatmsg_box.y - _chatmsg_box.height;
	int width  = _chatmsg_box.width;
	int height = _chatmsg_box.height;
	if (y < 0) {
		height = max(height + y, min(_chatmsg_box.height, _screen.height));
		y = 0;
	}
	if (x + width >= _screen.width) {
		width = _screen.width - x;
	}
	if (width <= 0 || height <= 0) return;

	assert(blitter->BufferSize(width, height) <= (int)(_chatmsg_box.width * _chatmsg_box.height * blitter->GetBytesPerPixel()));

	/* Make a copy of the screen as it is before painting (for undraw) */
	blitter->CopyToBuffer(blitter->MoveTo(_screen.dst_ptr, x, y), _chatmessage_backup, width, height);

	_cur_dpi = &_screen; // switch to _screen painting

	/* Paint a half-transparent box behind the chat messages */
	GfxFillRect(
			_chatmsg_box.x,
			_screen.height - _chatmsg_box.y - count * (FONT_HEIGHT_NORMAL + NETWORK_CHAT_LINE_SPACING) - 2,
			_chatmsg_box.x + _chatmsg_box.width - 1,
			_screen.height - _chatmsg_box.y - 2,
			PALETTE_TO_TRANSPARENT, FILLRECT_RECOLOUR // black, but with some alpha for background
		);

	/* Paint the chat messages starting with the lowest at the bottom */
	for (uint y = FONT_HEIGHT_NORMAL + NETWORK_CHAT_LINE_SPACING; count-- != 0; y += (FONT_HEIGHT_NORMAL + NETWORK_CHAT_LINE_SPACING)) {
		DrawString(_chatmsg_box.x + 3, _chatmsg_box.x + _chatmsg_box.width - 1, _screen.height - _chatmsg_box.y - y + 1, _chatmsg_list[count].message, _chatmsg_list[count].colour);
	}

	/* Make sure the data is updated next flush */
	_video_driver->MakeDirty(x, y, width, height);

	_chatmessage_visible = true;
	_chatmessage_dirty = false;
}

void 
Sprite::render(BitmapCanvas& canvas)
{
   // render the current frame at m_x,m_y
   if(m_visible)
   {      
      int frame = m_animations[m_currentAnimation][m_currentFrame];
      if( m_frames[frame]->m_imgMask != NULL )
      {
         // we have a mask that we need to render first
         Blitter bltMask ( *(m_frames[frame]->m_imgMask) );
         bltMask.SetMode (SRCPAINT);
         bltMask.SetDest (m_x, m_y);
         bltMask.BlitTo (canvas);

         Blitter blitFrame( *(m_frames[frame]->m_img) );
         blitFrame.SetMode (SRCAND);
         blitFrame.SetDest (m_x, m_y);
         blitFrame.BlitTo(canvas);
      }
      else
      {
         // no mask, just render the frame
         Blitter bltMask ( *(m_frames[frame]->m_img) );
         bltMask.SetMode (SRCPAINT);
         bltMask.SetDest (m_x, m_y);
         bltMask.BlitTo (canvas);      
      }
      
   }
}

/** Hide the chatbox */
void NetworkUndrawChatMessage()
{
	/* Sometimes we also need to hide the cursor
	 *   This is because both textmessage and the cursor take a shot of the
	 *   screen before drawing.
	 *   Now the textmessage takes his shot and paints his data before the cursor
	 *   does, so in the shot of the cursor is the screen-data of the textmessage
	 *   included when the cursor hangs somewhere over the textmessage. To
	 *   avoid wrong repaints, we undraw the cursor in that case, and everything
	 *   looks nicely ;)
	 * (and now hope this story above makes sense to you ;))
	 */
	if (_cursor.visible &&
			_cursor.draw_pos.x + _cursor.draw_size.x >= _chatmsg_box.x &&
			_cursor.draw_pos.x <= _chatmsg_box.x + _chatmsg_box.width &&
			_cursor.draw_pos.y + _cursor.draw_size.y >= _screen.height - _chatmsg_box.y - _chatmsg_box.height &&
			_cursor.draw_pos.y <= _screen.height - _chatmsg_box.y) {
		UndrawMouseCursor();
	}

	if (_chatmessage_visible) {
		Blitter *blitter = BlitterFactory::GetCurrentBlitter();
		int x      = _chatmsg_box.x;
		int y      = _screen.height - _chatmsg_box.y - _chatmsg_box.height;
		int width  = _chatmsg_box.width;
		int height = _chatmsg_box.height;
		if (y < 0) {
			height = max(height + y, min(_chatmsg_box.height, _screen.height));
			y = 0;
		}
		if (x + width >= _screen.width) {
			width = _screen.width - x;
		}
		if (width <= 0 || height <= 0) return;

		_chatmessage_visible = false;
		/* Put our 'shot' back to the screen */
		blitter->CopyFromBuffer(blitter->MoveTo(_screen.dst_ptr, x, y), _chatmessage_backup, width, height);
		/* And make sure it is updated next time */
		_video_driver->MakeDirty(x, y, width, height);

		_chatmessage_dirty = true;
	}
}

	/**
	 * Find the requested blitter and return his class.
	 * @param name the blitter to select.
	 * @post Sets the blitter so GetCurrentBlitter() returns it too.
	 */
	static Blitter *SelectBlitter(const char *name)
	{
		BlitterFactory *b = GetBlitterFactory(name);
		if (b == nullptr) return nullptr;

		Blitter *newb = b->CreateInstance();
		delete *GetActiveBlitter();
		*GetActiveBlitter() = newb;

		DEBUG(driver, 1, "Successfully %s blitter '%s'", StrEmpty(name) ? "probed" : "loaded", newb->GetName());
		return newb;
	}

static void CheckPaletteAnim()
{
	if (_cur_palette.count_dirty != 0) {
		Blitter *blitter = BlitterFactoryBase::GetCurrentBlitter();

		switch (blitter->UsePaletteAnimation()) {
			case Blitter::PALETTE_ANIMATION_VIDEO_BACKEND:
				UpdatePalette();
				break;

			case Blitter::PALETTE_ANIMATION_BLITTER:
				blitter->PaletteAnimate(_local_palette);
				break;

			case Blitter::PALETTE_ANIMATION_NONE:
				break;

			default:
				NOT_REACHED();
		}
		_cur_palette.count_dirty = 0;
	}
}

	/**
	 * Find the requested blitter and return his class.
	 * @param name the blitter to select.
	 * @post Sets the blitter so GetCurrentBlitter() returns it too.
	 */
	static Blitter *SelectBlitter(const char *name)
	{
		BlitterFactory *b = GetBlitterFactory(name);
		if (b == NULL) return NULL;

		//用工厂生成一个Blitter
		Blitter *newb = b->CreateInstance();
		delete *GetActiveBlitter();
		//得到的是双重地址,可以复制的.
		*GetActiveBlitter() = newb;

		DEBUG(driver, 1, "Successfully %s blitter '%s'", StrEmpty(name) ? "probed" : "loaded", newb->GetName());
		return newb;
	}

bool VideoDriver_SDL::CreateMainSurface(uint w, uint h)
{
	SDL_Surface *newscreen, *icon;
	char caption[50];
	int bpp = BlitterFactoryBase::GetCurrentBlitter()->GetScreenDepth();
	bool want_hwpalette;

	GetAvailableVideoMode(&w, &h);

	DEBUG(driver, 1, "SDL: using mode %ux%ux%d", w, h, bpp);

	if (bpp == 0) usererror("Can't use a blitter that blits 0 bpp for normal visuals");

	char icon_path[MAX_PATH];
	if (FioFindFullPath(icon_path, lengthof(icon_path), BASESET_DIR, "openttd.32.bmp") != NULL) {
		/* Give the application an icon */
		icon = SDL_CALL SDL_LoadBMP(icon_path);
		if (icon != NULL) {
			/* Get the colourkey, which will be magenta */
			uint32 rgbmap = SDL_CALL SDL_MapRGB(icon->format, 255, 0, 255);

			SDL_CALL SDL_SetColorKey(icon, SDL_SRCCOLORKEY, rgbmap);
			SDL_CALL SDL_WM_SetIcon(icon, NULL);
			SDL_CALL SDL_FreeSurface(icon);
		}
	}

	if (_use_hwpalette == 2) {
		/* Default is to autodetect when to use SDL_HWPALETTE.
		 * In this case, SDL_HWPALETTE is only used for 8bpp
		 * blitters in fullscreen.
		 *
		 * When using an 8bpp blitter on a 8bpp system in
		 * windowed mode with SDL_HWPALETTE, OpenTTD will claim
		 * the system palette, making all other applications
		 * get the wrong colours. In this case, we're better of
		 * trying to approximate the colors we need using system
		 * colors, using a shadow surface (see below).
		 *
		 * On a 32bpp system, SDL_HWPALETTE is ignored, so it
		 * doesn't matter what we do.
		 *
		 * When using a 32bpp blitter on a 8bpp system, setting
		 * SDL_HWPALETTE messes up rendering (at least on X11),
		 * so we don't do that. In this case, SDL takes care of
		 * color approximation using its own shadow surface
		 * (which we can't force in 8bpp on 8bpp mode,
		 * unfortunately).
		 */
		want_hwpalette = (bpp == 8 && _fullscreen);
	} else {
		/* User specified a value manually */
		want_hwpalette = _use_hwpalette;
	}

	if (want_hwpalette) DEBUG(driver, 1, "SDL: requesting hardware palete");

	/* Free any previously allocated shadow surface */
	if (_sdl_screen != NULL && _sdl_screen != _sdl_realscreen) SDL_CALL SDL_FreeSurface(_sdl_screen);

	if (_sdl_realscreen != NULL) {
		if (_requested_hwpalette != want_hwpalette) {
			/* SDL (at least the X11 driver), reuses the
			 * same window and palette settings when the bpp
			 * (and a few flags) are the same. Since we need
			 * to hwpalette value to change (in particular
			 * when switching between fullscreen and
			 * windowed), we restart the entire video
			 * subsystem to force creating a new window.
			 */
			DEBUG(driver, 0, "SDL: Restarting SDL video subsystem, to force hwpalette change");
			SDL_CALL SDL_QuitSubSystem(SDL_INIT_VIDEO);
			SDL_CALL SDL_InitSubSystem(SDL_INIT_VIDEO);
			ClaimMousePointer();
			SetupKeyboard();
		}
	}
	/* Remember if we wanted a hwpalette. We can't reliably query
	 * SDL for the SDL_HWPALETTE flag, since it might get set even
	 * though we didn't ask for it (when SDL creates a shadow
	 * surface, for example). */
	_requested_hwpalette = want_hwpalette;

	/* DO NOT CHANGE TO HWSURFACE, IT DOES NOT WORK */
	newscreen = SDL_CALL SDL_SetVideoMode(w, h, bpp, SDL_SWSURFACE | (want_hwpalette ? SDL_HWPALETTE : 0) | (_fullscreen ? SDL_FULLSCREEN : SDL_RESIZABLE));
	if (newscreen == NULL) {
		DEBUG(driver, 0, "SDL: Couldn't allocate a window to draw on");
		return false;
	}
	_sdl_realscreen = newscreen;

	if (bpp == 8 && (_sdl_realscreen->flags & SDL_HWPALETTE) != SDL_HWPALETTE) {
		/* Using an 8bpp blitter, if we didn't get a hardware
		 * palette (most likely because we didn't request one,
		 * see above), we'll have to set up a shadow surface to
		 * render on.
		 *
		 * Our palette will be applied to this shadow surface,
		 * while the real screen surface will use the shared
		 * system palette (which will partly contain our colors,
//.........这里部分代码省略.........

/** Draw the chat message-box */
void NetworkDrawChatMessage()
{
	Blitter *blitter = BlitterFactory::GetCurrentBlitter();
	if (!_chatmessage_dirty) return;

	/* First undraw if needed */
	NetworkUndrawChatMessage();

	if (_iconsole_mode == ICONSOLE_FULL) return;

	/* Check if we have anything to draw at all */
	uint count = GetChatMessageCount();
	if (count == 0) return;

	int x      = _chatmsg_box.x;
	int y      = _screen.height - _chatmsg_box.y - _chatmsg_box.height;
	int width  = _chatmsg_box.width;
	int height = _chatmsg_box.height;
	if (y < 0) {
		height = max(height + y, min(_chatmsg_box.height, _screen.height));
		y = 0;
	}
	if (x + width >= _screen.width) {
		width = _screen.width - x;
	}
	if (width <= 0 || height <= 0) return;

	assert(blitter->BufferSize(width, height) <= (int)(_chatmsg_box.width * _chatmsg_box.height * blitter->GetBytesPerPixel()));

	/* Make a copy of the screen as it is before painting (for undraw) */
	blitter->CopyToBuffer(blitter->MoveTo(_screen.dst_ptr, x, y), _chatmessage_backup, width, height);

	_cur_dpi = &_screen; // switch to _screen painting

	int string_height = 0;
	for (uint i = 0; i < count; i++) {
		SetDParamStr(0, _chatmsg_list[i].message);
		string_height += GetStringLineCount(STR_JUST_RAW_STRING, width - 1) * FONT_HEIGHT_NORMAL + NETWORK_CHAT_LINE_SPACING;
	}

	string_height = min(string_height, MAX_CHAT_MESSAGES * (FONT_HEIGHT_NORMAL + NETWORK_CHAT_LINE_SPACING));

	int top = _screen.height - _chatmsg_box.y - string_height - 2;
	int bottom = _screen.height - _chatmsg_box.y - 2;
	/* Paint a half-transparent box behind the chat messages */
	GfxFillRect(_chatmsg_box.x, top - 2, _chatmsg_box.x + _chatmsg_box.width - 1, bottom,
			PALETTE_TO_TRANSPARENT, FILLRECT_RECOLOUR // black, but with some alpha for background
		);

	/* Paint the chat messages starting with the lowest at the bottom */
	int ypos = bottom - 2;

	for (int i = count - 1; i >= 0; i--) {
		ypos = DrawStringMultiLine(_chatmsg_box.x + 3, _chatmsg_box.x + _chatmsg_box.width - 1, top, ypos, _chatmsg_list[i].message, _chatmsg_list[i].colour, SA_LEFT | SA_BOTTOM | SA_FORCE) - NETWORK_CHAT_LINE_SPACING;
		if (ypos < top) break;
	}

	/* Make sure the data is updated next flush */
	_video_driver->MakeDirty(x, y, width, height);

	_chatmessage_visible = true;
	_chatmessage_dirty = false;
}

/**
 * Callback of the screenshot generator that dumps the current video buffer.
 * @see ScreenshotCallback
 */
static void CurrentScreenCallback(void *userdata, void *buf, uint y, uint pitch, uint n)
{
	Blitter *blitter = BlitterFactoryBase::GetCurrentBlitter();
	void *src = blitter->MoveTo(_screen.dst_ptr, 0, y);
	blitter->CopyImageToBuffer(src, buf, _screen.width, n, pitch);
}