view src/video/dummy/SDL_nullvideo.c @ 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 99210400e8b9
children 83518f8fcd61
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/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2009 Sam Lantinga

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.

    This library 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
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

    Sam Lantinga
    slouken@libsdl.org
*/
#include "SDL_config.h"

/* Dummy SDL video driver implementation; this is just enough to make an
 *  SDL-based application THINK it's got a working video driver, for
 *  applications that call SDL_Init(SDL_INIT_VIDEO) when they don't need it,
 *  and also for use as a collection of stubs when porting SDL to a new
 *  platform for which you haven't yet written a valid video driver.
 *
 * This is also a great way to determine bottlenecks: if you think that SDL
 *  is a performance problem for a given platform, enable this driver, and
 *  then see if your application runs faster without video overhead.
 *
 * Initial work by Ryan C. Gordon (icculus@icculus.org). A good portion
 *  of this was cut-and-pasted from Stephane Peter's work in the AAlib
 *  SDL video driver.  Renamed to "DUMMY" by Sam Lantinga.
 */

#include "SDL_video.h"
#include "SDL_mouse.h"
#include "../SDL_sysvideo.h"
#include "../SDL_pixels_c.h"
#include "../../events/SDL_events_c.h"

#include "SDL_nullvideo.h"
#include "SDL_nullevents_c.h"
#include "SDL_nullrender_c.h"

#define DUMMYVID_DRIVER_NAME "dummy"

/* Initialization/Query functions */
static int DUMMY_VideoInit(_THIS);
static int DUMMY_SetDisplayMode(_THIS, SDL_DisplayMode * mode);
static void DUMMY_VideoQuit(_THIS);

/* DUMMY driver bootstrap functions */

static int
DUMMY_Available(void)
{
    const char *envr = SDL_getenv("SDL_VIDEODRIVER");
    if ((envr) && (SDL_strcmp(envr, DUMMYVID_DRIVER_NAME) == 0)) {
        return (1);
    }

    return (0);
}

static void
DUMMY_DeleteDevice(SDL_VideoDevice * device)
{
    SDL_free(device);
}

static SDL_VideoDevice *
DUMMY_CreateDevice(int devindex)
{
    SDL_VideoDevice *device;

    /* Initialize all variables that we clean on shutdown */
    device = (SDL_VideoDevice *) SDL_calloc(1, sizeof(SDL_VideoDevice));
    if (!device) {
        SDL_OutOfMemory();
        if (device) {
            SDL_free(device);
        }
        return (0);
    }

    /* Set the function pointers */
    device->VideoInit = DUMMY_VideoInit;
    device->VideoQuit = DUMMY_VideoQuit;
    device->SetDisplayMode = DUMMY_SetDisplayMode;
    device->PumpEvents = DUMMY_PumpEvents;

    device->free = DUMMY_DeleteDevice;

    return device;
}

VideoBootStrap DUMMY_bootstrap = {
    DUMMYVID_DRIVER_NAME, "SDL dummy video driver",
    DUMMY_Available, DUMMY_CreateDevice
};


int
DUMMY_VideoInit(_THIS)
{
    SDL_DisplayMode mode;

    /* Use a fake 32-bpp desktop mode */
    mode.format = SDL_PIXELFORMAT_RGB888;
    mode.w = 1024;
    mode.h = 768;
    mode.refresh_rate = 0;
    mode.driverdata = NULL;
    SDL_AddBasicVideoDisplay(&mode);
    SDL_AddRenderDriver(0, &SDL_DUMMY_RenderDriver);

    SDL_zero(mode);
    SDL_AddDisplayMode(0, &mode);

    /* We're done! */
    return 0;
}

static int
DUMMY_SetDisplayMode(_THIS, SDL_DisplayMode * mode)
{
    return 0;
}

void
DUMMY_VideoQuit(_THIS)
{
}

/* vi: set ts=4 sw=4 expandtab: */