view README @ 3485:e77a69aae239

Mason Wheeler to sdl I updated SDL, and suddenly my SDL frames stopped working. They'd "initialize" full of gibberish, and I couldn't render anything to them. After a bit of digging, I found a problem: the renderer initialization routine in my SDL frame code wasn't getting called anymore. procedure TSdlFrame.Paint; begin if SDL_SelectRenderer(FWindowID) = -1 then CreateRenderer; SDL_RenderPresent; end; function TSdlFrame.CreateRenderer: boolean; const pf: tagPIXELFORMATDESCRIPTOR = (nSize: sizeof(pf); nVersion: 1; dwFlags: PFD_DRAW_TO_WINDOW or PFD_SUPPORT_OPENGL or PFD_DOUBLEBUFFER; iPixelType: PFD_TYPE_RGBA; cColorBits: 24; cAlphaBits: 8; iLayerType: PFD_MAIN_PLANE); RENDERERS: array[TRendererType] of AnsiString = ('software', 'gdi', 'opengl', 'd3d'); var pFormat: integer; begin if (SDL_SelectRenderer(FWindowID) = 0) then begin result := true; Exit; end; if FRendererType = rtOpenGL then begin pFormat := ChoosePixelFormat(canvas.Handle, @pf); if not SetPixelFormat(canvas.Handle, pFormat, @pf) then outputDebugString(PChar(SysErrorMessage(GetLastError))); if wglCreateContext(canvas.Handle) = 0 then outputDebugString(PChar(SysErrorMessage(GetLastError))); end; if (SDL_CreateRenderer(FWindowID, SDL_RendererIndex(RENDERERS[FRendererType]), [sdlrPresentFlip3, sdlrAccelerated]) = 0) then begin SDL_ShowWindow(FWindowID); assert(SDL_SetRenderDrawColor(0, 0, 0, 255) = 0); FFlags := SDL_GetWindowFlags(FWindowID); if assigned(FOnAvailable) then FOnAvailable(self); end else outputDebugString(pChar(format('SDL_CreateRenderer failed: %s', [sdl_GetError]))); result := SDL_SelectRenderer(FWindowID) = 0; end; This is a critical issue. The Paint method gets called when the control receives a WM_PAINT message from Windows. I can't create the renderer before then, or it will fail and cause trouble. And when I do create it, it needs to be created with certain parameters. So imagine my surprise when I started debugging into the DLL and found that SDL_SelectRenderer was trying to be "helpful" by creating the renderer for me if it didn't already exist! Now not only does my initialization code not get called, I end up with the wrong renderer and so things don't render as expected when I try to use the window.
author Sam Lantinga <slouken@libsdl.org>
date Tue, 24 Nov 2009 04:48:12 +0000
parents 1ed5d432e468
children 797b37c0c046
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                         Simple DirectMedia Layer

                                  (SDL)

                                Version 1.2

---
http://www.libsdl.org/

This is the Simple DirectMedia Layer, a general API that provides low
level access to audio, keyboard, mouse, joystick, 3D hardware via OpenGL,
and 2D framebuffer across multiple platforms.

The current version supports Linux, Windows, Windows CE, BeOS, MacOS,
Mac OS X, FreeBSD, NetBSD, OpenBSD, BSD/OS, Solaris, IRIX, and QNX.
The code contains support for AIX, OSF/Tru64, RISC OS, and SymbianOS,
but these are not officially supported.

SDL is written in C, but works with C++ natively, and has bindings to
several other languages, including Ada, C#, Eiffel, Erlang, Euphoria,
Guile, Haskell, Java, Lisp, Lua, ML, Objective C, Pascal, Perl, PHP,
Pike, Pliant, Python, Ruby, and Smalltalk.

This library is distributed under GNU LGPL version 2, which can be
found in the file  "COPYING".  This license allows you to use SDL
freely in commercial programs as long as you link with the dynamic
library.

The best way to learn how to use SDL is to check out the header files in
the "include" subdirectory and the programs in the "test" subdirectory.
The header files and test programs are well commented and always up to date.
More documentation is available in HTML format in "docs/index.html", and
a documentation wiki is available online at:
	http://www.libsdl.org/cgi/docwiki.cgi

The test programs in the "test" subdirectory are in the public domain.

Frequently asked questions are answered online:
	http://www.libsdl.org/faq.php

If you need help with the library, or just want to discuss SDL related
issues, you can join the developers mailing list:
	http://www.libsdl.org/mailing-list.php

Enjoy!
	Sam Lantinga				(slouken@libsdl.org)