annotate README-SDL.txt @ 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 |
74212992fb08 |
children |
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rev |
line source |
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1
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2 Please distribute this file with the SDL runtime environment:
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3
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4 The Simple DirectMedia Layer (SDL for short) is a cross-platfrom library
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5 designed to make it easy to write multi-media software, such as games and
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6 emulators.
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7
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8 The Simple DirectMedia Layer library source code is available from:
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9 http://www.libsdl.org/
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10
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11 This library is distributed under the terms of the GNU LGPL license:
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12 http://www.gnu.org/copyleft/lesser.html
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13
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