Fixed pitch alignment problem causing MITSHM error on 16-bit displays

--HG--
extra : convert_revision : svn%3Ac70aab31-4412-0410-b14c-859654838e24/trunk%403378

src/video/x11/SDL_x11modes.c

@@ -136,6 +136,8 @@ X11_InitModes(_THIS)
         SDL_VideoDisplay display;
         SDL_DisplayData *displaydata;
         SDL_DisplayMode mode;
+        XPixmapFormatValues *pixmapFormats;
+        int i, n;
 
         if (get_visualinfo(data->display, screen, &vinfo) < 0) {
             continue;
@@ -155,6 +157,18 @@ X11_InitModes(_THIS)
         displaydata->visual = vinfo.visual;
         displaydata->depth = vinfo.depth;
 
+        displaydata->scanline_pad = SDL_BYTESPERPIXEL(mode.format)*8;
+        pixmapFormats = XListPixmapFormats(data->display, &n);
+        if (pixmapFormats) {
+            for (i = 0; i < n; ++i) {
+                if (pixmapFormats[i].depth == displaydata->depth) {
+                    displaydata->scanline_pad = pixmapFormats[i].scanline_pad;
+                    break;
+                }
+            }
+            XFree(pixmapFormats);
+        }
+
         SDL_zero(display);
         display.desktop_mode = mode;
         display.current_mode = mode;

src/video/x11/SDL_x11modes.h

@@ -29,6 +29,7 @@ typedef struct
     int screen;
     Visual *visual;
     int depth;
+    int scanline_pad;
 
     int use_xinerama;
     int use_xrandr;

src/video/x11/SDL_x11render.c

@@ -83,6 +83,7 @@ typedef struct
     int screen;
     Visual *visual;
     int depth;
+    int scanline_pad;
     Window window;
     Pixmap pixmaps[3];
     int current_pixmap;
@@ -185,6 +186,7 @@ X11_CreateRenderer(SDL_Window * window, Uint32 flags)
     data->screen = displaydata->screen;
     data->visual = displaydata->visual;
     data->depth = displaydata->depth;
+    data->scanline_pad = displaydata->scanline_pad;
     data->window = windowdata->window;
 
     renderer->DisplayModeChanged = X11_DisplayModeChanged;
@@ -316,6 +318,7 @@ X11_CreateTexture(SDL_Renderer * renderer, SDL_Texture * texture)
     SDL_Window *window = SDL_GetWindowFromID(renderer->window);
     SDL_VideoDisplay *display = SDL_GetDisplayFromWindow(window);
     X11_TextureData *data;
+    int pitch_alignmask = ((renderdata->scanline_pad / 8) - 1);
 
     data = (X11_TextureData *) SDL_calloc(1, sizeof(*data));
     if (!data) {
@@ -343,6 +346,7 @@ X11_CreateTexture(SDL_Renderer * renderer, SDL_Texture * texture)
         data->format = texture->format;
     }
     data->pitch = texture->w * SDL_BYTESPERPIXEL(data->format);
+    data->pitch = (data->pitch + pitch_alignmask) & ~pitch_alignmask;
 
     if (data->yuv || texture->access == SDL_TEXTUREACCESS_STREAMING) {
 #ifndef NO_SHARED_MEMORY