Fix regression in viewport background image transparency

Was caused by recent changes to automatically switch between
glaDrawPixelsTex and glaDrawPixelsSafe depending on resolution.

glaDrawPixelsSafe could not be sued for viewport because it'll
miss alpha transparency.

1 files changed, 6 insertions, 1 deletions

diff --git a/source/blender/editors/space_view3d/view3d_draw.c b/source/blender/editors/space_view3d/view3d_draw.c
index e27f00de748..30a6932c60e 100644
--- a/source/blender/editors/space_view3d/view3d_draw.c
+++ b/source/blender/editors/space_view3d/view3d_draw.c
@@ -1819,7 +1819,12 @@ static void view3d_draw_bgpic(Scene *scene, ARegion *ar, View3D *v3d,
 
 			glPixelZoom(zoomx, zoomy);
 			glColor4f(1.0f, 1.0f, 1.0f, 1.0f - bgpic->blend);
-			glaDrawPixelsAuto(x1, y1, ibuf->x, ibuf->y, GL_UNSIGNED_BYTE, GL_LINEAR, ibuf->rect);
+
+			/* could not use glaDrawPixelsAuto because it could fallback to
+			 * glaDrawPixelsSafe in some cases, which will end up in misssing
+			 * alpha transparency for the background image (sergey)
+			 */
+			glaDrawPixelsTex(x1, y1, ibuf->x, ibuf->y, GL_UNSIGNED_BYTE, GL_NEAREST, ibuf->rect);
 
 			glPixelZoom(1.0, 1.0);
 			glPixelTransferf(GL_ALPHA_SCALE, 1.0f);