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modified bug report

bug report.txt (text/plain), 6.10 KB, created by elite_jwp on 2020-04-21 12:23:39 UTC

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Description:

Filename:

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Creator: elite_jwp

Created: 2020-04-21 12:23:39 UTC

Size: 6.10 KB

patch

obsolete

>In my project, a window was created by 'SDL_CreateWindowFrom' in main-thread
>and rendered in another sub-thread.
>I used d3d as the render's driver and met a issue which can cause 
>the video area wrong when adjusting the window's size. A snapshot
>of that scene was shown in attachment file.
>
>So I study the codes and try to fix it:
>
>When adjusting the window's size, the render will be notified by 
>'SDL_RendererEventWatch' and it will further call 'D3D_WindowEvent'
>in which a member named 'updateSize' of D3D_RenderData is set to SDL_TRUE.
>
>In SDL_render.c:
>static int SDLCALL SDL_RendererEventWatch(void *userdata, SDL_Event *event)
>{
>    SDL_Renderer *renderer = (SDL_Renderer *)userdata;
>    if (event->type == SDL_WINDOWEVENT) {
>        SDL_Window *window = SDL_GetWindowFromID(event->window.windowID);
>        if (window == renderer->window) {
>            if (renderer->WindowEvent) {
>                // here call 'D3D_WindowEvent'
>                renderer->WindowEvent(renderer, &event->window);
>            }
>            ...
>        }
>    }
>    ...
>    return 0;
>}
>
>In SDL_render_d3d.c:
>static void D3D_WindowEvent(SDL_Renderer * renderer, const SDL_WindowEvent *event)
>{
>    D3D_RenderData *data = (D3D_RenderData *) renderer->driverdata;
>    if (event->event == SDL_WINDOWEVENT_SIZE_CHANGED) {
>        data->updateSize = SDL_TRUE;
>    }
>}
>
>The member 'updateSize' is used in 'SDL_render_d3d.c:D3D_ActivateRenderer()' to reset
>d3d device context after the window was adjusted.
>
>In SDL_render_d3d.c:
>static int D3D_ActivateRenderer(SDL_Renderer * renderer)
>{
>    D3D_RenderData *data = (D3D_RenderData *) renderer->driverdata;
>    HRESULT result;
>    if (data->updateSize) {
>        SDL_Window *window = renderer->window;
>        int w, h;
>        Uint32 window_flags = SDL_GetWindowFlags(window);
>        SDL_GetWindowSize(window, &w, &h);
>        data->pparams.BackBufferWidth = w;
>        data->pparams.BackBufferHeight = h;
>        ...
>        if (D3D_Reset(renderer) < 0) {
>            return -1;
>        }
>        data->updateSize = SDL_FALSE;
>    }
>    ...
>    return 0;
>}
>
>So, here exists a problem when adjusting the window's size twice in a small interval time.
>The pseudo code and the excuting schedule were shown as:
>
>main-thread                                                             sub-thread
>(WIN_WindowProc-->SDL_PushEvent-->SDL_RendererEventWatch)               (rendering operations)
>
>first adjusting to size_1:
>SDL_RendererEventWatch() {
>    D3D_WindowEvent() {
>        renderer->driverdata->updateSize = SDL_TRUE;
>        }
>}
>
>                                                                        D3D_ActivateRenderer()
>                                                                        {
>                                                                            if (data->updateSize) {
>                                                                                ...
>second adjusting to size_2:                                                        D3D_Reset(renderer);
>SDL_RendererEventWatch() {                                                        ...
>    D3D_WindowEvent() {                                                            ...
>        renderer->driverdata->updateSize = SDL_TRUE;                            ...
>        }                                                                        ...
>}                                                                                ...
>                                                                                ...
>                                                                                ...
>                                                                                data->updateSize = SDL_FALSE;
>                                                                            }
>                                                                            ...
>                                                                            return 0;
>                                                                        }
>
>In above excuting schedule, the second adjusting to size_2 was wrongly ignored as
>the member 'updateSize' was reset to 'SDL_FALSE' in 'D3D_ActivateRenderer' which was 
>excuted in sub-thread.
>
>In according to that, I give a suggestion:
>1) don't use the member 'updateSize';
>2) modify 'D3D_ActivateRenderer()' as below:
>
>static int
>D3D_ActivateRenderer(SDL_Renderer * renderer)
>{
>    D3D_RenderData *data = (D3D_RenderData *) renderer->driverdata;
>    HRESULT result;
>    SDL_Window *window = renderer->window;
>    int w, h;
>
>    SDL_GetWindowSize(window, &w, &h);
>
>    // here compare the new window's size and the device's back buffer's size.
>    if (w != data->pparams.BackBufferWidth ||
>        h != data->pparams.BackBufferHeight) {
>        Uint32 window_flags = SDL_GetWindowFlags(window);
>
>        data->pparams.BackBufferWidth = w;
>        data->pparams.BackBufferHeight = h;
>        if (window_flags & SDL_WINDOW_FULLSCREEN && (window_flags & SDL_WINDOW_FULLSCREEN_DESKTOP) != SDL_WINDOW_FULLSCREEN_DESKTOP) {
>            SDL_DisplayMode fullscreen_mode;
>            SDL_GetWindowDisplayMode(window, &fullscreen_mode);
>            data->pparams.Windowed = FALSE;
>            data->pparams.BackBufferFormat = PixelFormatToD3DFMT(fullscreen_mode.format);
>            data->pparams.FullScreen_RefreshRateInHz = fullscreen_mode.refresh_rate;
>        } else {
>            data->pparams.Windowed = TRUE;
>            data->pparams.BackBufferFormat = D3DFMT_UNKNOWN;
>            data->pparams.FullScreen_RefreshRateInHz = 0;
>        }
>        if (D3D_Reset(renderer) < 0) {
>            return -1;
>        }
>    }
>    if (data->beginScene) {
>        result = IDirect3DDevice9_BeginScene(data->device);
>        if (result == D3DERR_DEVICELOST) {
>            if (D3D_Reset(renderer) < 0) {
>                return -1;
>            }
>            result = IDirect3DDevice9_BeginScene(data->device);
>        }
>        if (FAILED(result)) {
>            return D3D_SetError("BeginScene()", result);
>        }
>        data->beginScene = SDL_FALSE;
>    }
>    return 0;
>}

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Attachments on bug 5102: 4314 | 4315 | 4316

We are currently migrating Bugzilla to GitHub issues.Any changes made to the bug tracker now will be lost, so please do not post new bugs or make changes to them.When we're done, all bug URLs will redirect to their equivalent location on the new bug tracker.

We are currently migrating Bugzilla to GitHub issues.
Any changes made to the bug tracker now will be lost, so please do not post new bugs or make changes to them.
When we're done, all bug URLs will redirect to their equivalent location on the new bug tracker.