GPU: don't use multisample for entire window, only for offscreen 3D viewport.

Now that the new 3D viewport draws to a multisample offscreen buffer, there is
no good reason anymore to create an entire multisample window and pay the
performance/memory cost for other regions that don't need it.

GL_MULTISAMPLE now only gets enabled for offscreen buffers, so we don't need
to check for it throughout the UI code anymore.

Differential Revision: https://developer.blender.org/D3062

1 files changed, 7 insertions, 21 deletions

diff --git a/source/blender/editors/space_view3d/view3d_draw_legacy.c b/source/blender/editors/space_view3d/view3d_draw_legacy.c
index 1c6916d3820..5c3a76aa73b 100644
--- a/source/blender/editors/space_view3d/view3d_draw_legacy.c
+++ b/source/blender/editors/space_view3d/view3d_draw_legacy.c
@@ -213,11 +213,10 @@ static void draw_view_icon(RegionView3D *rv3d, rcti *rect)
 
 static void backdrawview3d(
         const struct EvaluationContext *eval_ctx, Scene *scene, ViewLayer *view_layer,
-        wmWindow *win, ARegion *ar, View3D *v3d)
+        ARegion *ar, View3D *v3d)
 {
 	RegionView3D *rv3d = ar->regiondata;
 	struct Base *base = view_layer->basact;
-	int multisample_enabled;
 
 	BLI_assert(ar->regiontype == RGN_TYPE_WINDOW);
 
@@ -264,14 +263,13 @@ static void backdrawview3d(
 	/* dithering and AA break color coding, so disable */
 	glDisable(GL_DITHER);
 
-	multisample_enabled = glIsEnabled(GL_MULTISAMPLE);
-	if (multisample_enabled)
-		glDisable(GL_MULTISAMPLE);
-
-	if (win->multisamples != USER_MULTISAMPLE_NONE) {
+	if (false) {
 		/* for multisample we use an offscreen FBO. multisample drawing can fail
 		 * with color coded selection drawing, and reading back depths from such
-		 * a buffer can also cause a few seconds freeze on OS X / NVidia. */
+		 * a buffer can also cause a few seconds freeze on OS X / NVidia.
+		 *
+		 * NOTE: code is no longer used now, but offscreen drawing is likely
+		 * what we will always want to do for the new viewport. */
 		int w = BLI_rcti_size_x(&ar->winrct);
 		int h = BLI_rcti_size_y(&ar->winrct);
 		char error[256];
@@ -327,8 +325,6 @@ static void backdrawview3d(
 	v3d->zbuf = false;
 	glDisable(GL_DEPTH_TEST);
 	glEnable(GL_DITHER);
-	if (multisample_enabled)
-		glEnable(GL_MULTISAMPLE);
 
 	if (rv3d->rflag & RV3D_CLIPPING)
 		ED_view3d_clipping_disable();
@@ -358,7 +354,7 @@ static void view3d_opengl_read_Z_pixels(ARegion *ar, int x, int y, int w, int h,
 void ED_view3d_backbuf_validate(const struct EvaluationContext *eval_ctx, ViewContext *vc)
 {
 	if (vc->v3d->flag & V3D_INVALID_BACKBUF) {
-		backdrawview3d(eval_ctx, vc->scene, vc->view_layer, vc->win, vc->ar, vc->v3d);
+		backdrawview3d(eval_ctx, vc->scene, vc->view_layer, vc->ar, vc->v3d);
 	}
 }
 
@@ -2007,11 +2003,6 @@ static void view3d_main_region_draw_objects(
 		do_compositing = GPU_fx_compositor_initialize_passes(rv3d->compositor, &ar->winrct, &ar->drawrct, &fx_settings);
 	}
 	
-	/* enables anti-aliasing for 3D view drawing */
-	if (win->multisamples != USER_MULTISAMPLE_NONE) {
-		glEnable(GL_MULTISAMPLE);
-	}
-
 	/* main drawing call */
 	view3d_draw_objects(C, &eval_ctx, scene, v3d, ar, grid_unit, true, false, do_compositing ? rv3d->compositor : NULL);
 
@@ -2020,11 +2011,6 @@ static void view3d_main_region_draw_objects(
 		GPU_fx_do_composite_pass(rv3d->compositor, rv3d->winmat, rv3d->is_persp, scene, NULL);
 	}
 
-	/* Disable back anti-aliasing */
-	if (win->multisamples != USER_MULTISAMPLE_NONE) {
-		glDisable(GL_MULTISAMPLE);
-	}
-
 	if (v3d->lay_used != lay_used) { /* happens when loading old files or loading with UI load */
 		/* find header and force tag redraw */
 		ScrArea *sa = CTX_wm_area(C);