[PATCH v2 1/1] win32u: Fix garbled 24-bit bitmap rendering

[Zowie van Dillen]

From: Zowie van Dillen

---
 dlls/win32u/opengl.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/dlls/win32u/opengl.c b/dlls/win32u/opengl.c
index efd6ea63b1a..63b378affd8 100644
--- a/dlls/win32u/opengl.c
+++ b/dlls/win32u/opengl.c
@@ -1251,9 +1251,10 @@ static BOOL flush_memory_dc( struct wgl_context *context, HDC hdc, BOOL write, v

if (!get_image_from_bitmap( bmp, info, &bits, &src ))
         {
-            int width = info->bmiHeader.biWidth, height = info->bmiHeader.biSizeImage / 4 / width;
-            if (write) funcs->p_glDrawPixels( width, height, GL_BGRA, GL_UNSIGNED_BYTE, bits.ptr );
-            else funcs->p_glReadPixels( 0, 0, width, height, GL_BGRA, GL_UNSIGNED_BYTE, bits.ptr );
+            int width = info->bmiHeader.biWidth, height = abs( info->bmiHeader.biHeight );
+            UINT format = (info->bmiHeader.biBitCount == 24 ? GL_BGR : GL_BGRA);
+            if (write) funcs->p_glDrawPixels( width, height, format, GL_UNSIGNED_BYTE, bits.ptr );
+            else funcs->p_glReadPixels( 0, 0, width, height, format, GL_UNSIGNED_BYTE, bits.ptr );
         }
         GDI_ReleaseObj( dc->hBitmap );
     }