Fix T40939: Border render and SSS doesn't work correct in rendered viewport

There were some missing updates in the viewport render job which lead to
wrong SSS mapping on the final resolution.

There was also wrong scaling applying when border render is used.

And last but not least(?) strands render was using first level of the
resolution leading to really thick strands in the final viewport.

2 files changed, 75 insertions, 31 deletions

diff --git a/source/blender/editors/render/render_internal.c b/source/blender/editors/render/render_internal.c
index 19290ef0f48..bf7b4cf785b 100644
--- a/source/blender/editors/render/render_internal.c
+++ b/source/blender/editors/render/render_internal.c
@@ -1128,6 +1128,30 @@ static void render_view3d_renderinfo_cb(void *rjp, RenderStats *rs)
 	}
 }
 
+BLI_INLINE void rcti_scale_coords(rcti *scaled_rect, const rcti *rect,
+                                  const float scale)
+{
+	scaled_rect->xmin = rect->xmin * scale;
+	scaled_rect->ymin = rect->ymin * scale;
+	scaled_rect->xmax = rect->xmax * scale;
+	scaled_rect->ymax = rect->ymax * scale;
+}
+
+static void render_update_resolution(Render *re, const RenderPreview *rp,
+                                     bool use_border, const rcti *clip_rect)
+{
+	int winx = rp->ar->winx / rp->resolution_divider,
+	    winy = rp->ar->winy / rp->resolution_divider;
+	if (use_border) {
+		rcti scaled_cliprct;
+		rcti_scale_coords(&scaled_cliprct, clip_rect,
+		                  1.0f / rp->resolution_divider);
+		RE_ChangeResolution(re, winx, winy, &scaled_cliprct);
+	}
+	else {
+		RE_ChangeResolution(re, winx, winy, NULL);
+	}
+}
 
 static void render_view3d_startjob(void *customdata, short *stop, short *do_update, float *UNUSED(progress))
 {
@@ -1140,6 +1164,7 @@ static void render_view3d_startjob(void *customdata, short *stop, short *do_upda
 	bool orth, restore = 0;
 	char name[32];
 	int update_flag;
+	bool use_border = false;
 
 	update_flag = rp->engine->job_update_flag;
 	rp->engine->job_update_flag = 0;
@@ -1171,10 +1196,11 @@ static void render_view3d_startjob(void *customdata, short *stop, short *do_upda
 		rp->resolution_divider = START_RESOLUTION_DIVIDER;
 	}
 
+	use_border = render_view3d_disprect(rp->scene, rp->ar, rp->v3d,
+	                                    rp->rv3d, &cliprct);
+
 	if ((update_flag & (PR_UPDATE_RENDERSIZE | PR_UPDATE_DATABASE)) || rstats->convertdone == 0) {
 		RenderData rdata;
-		int winx = rp->ar->winx / rp->resolution_divider,
-		    winy = rp->ar->winy / rp->resolution_divider;
 
 		/* no osa, blur, seq, layers, etc for preview render */
 		rdata = rp->scene->r;
@@ -1186,17 +1212,12 @@ static void render_view3d_startjob(void *customdata, short *stop, short *do_upda
 		rdata.scemode |= R_SINGLE_LAYER;
 
 		/* initalize always */
-		if (render_view3d_disprect(rp->scene, rp->ar, rp->v3d, rp->rv3d, &cliprct)) {
+		if (use_border) {
 			rdata.mode |= R_BORDER;
-			RE_InitState(re, NULL, &rdata, NULL, winx, winy, &cliprct);
+			RE_InitState(re, NULL, &rdata, NULL, rp->ar->winx, rp->ar->winy, &cliprct);
 		}
 		else
-			RE_InitState(re, NULL, &rdata, NULL, winx, winy, NULL);
-	}
-	else if (update_flag & PR_UPDATE_VIEW) {
-		int winx = rp->ar->winx / rp->resolution_divider,
-		    winy = rp->ar->winy / rp->resolution_divider;
-		RE_ChangeResolution(re, winx, winy, NULL);
+			RE_InitState(re, NULL, &rdata, NULL, rp->ar->winx, rp->ar->winy, NULL);
 	}
 
 	if (orth)
@@ -1244,26 +1265,30 @@ static void render_view3d_startjob(void *customdata, short *stop, short *do_upda
 
 	/* OK, can we enter render code? */
 	if (rstats->convertdone) {
+		bool first_time = true;
 		for (;;) {
-			RE_TileProcessor(re);
+			if (first_time == false) {
+				if (restore)
+					RE_DataBase_IncrementalView(re, rp->viewmat, 1);
 
-			if (!*stop && rp->resolution_divider > 1) {
-				int winx, winy;
 				rp->resolution_divider /= 2;
-				winx = rp->ar->winx / rp->resolution_divider;
-				winy = rp->ar->winy / rp->resolution_divider;
 				*do_update = 1;
-				RE_ChangeResolution(re, winx, winy, NULL);
 
-				/* Otherwise shadows are incorrect. */
-				if (orth) {
-					RE_SetOrtho(re, &viewplane, clipsta, clipend);
-				}
-				else {
-					RE_SetWindow(re, &viewplane, clipsta, clipend);
-				}
+				render_update_resolution(re, rp, use_border, &cliprct);
+
+				RE_DataBase_IncrementalView(re, rp->viewmat, 0);
+				RE_DataBase_ApplyWindow(re);
+				restore = 1;
 			}
 			else {
+				render_update_resolution(re, rp, use_border, &cliprct);
+			}
+
+			RE_TileProcessor(re);
+
+			first_time = false;
+
+			if (*stop || rp->resolution_divider == 1) {
 				break;
 			}
 		}
@@ -1427,13 +1452,29 @@ void render_view3d_draw(RenderEngine *engine, const bContext *C)
 	RE_AcquireResultImage(re, &rres);
 	
 	if (rres.rectf) {
+		RegionView3D *rv3d = CTX_wm_region_view3d(C);
+		View3D *v3d = CTX_wm_view3d(C);
 		Scene *scene = CTX_data_scene(C);
 		ARegion *ar = CTX_wm_region(C);
 		bool force_fallback = false;
 		bool need_fallback = true;
 		float dither = scene->r.dither_intensity;
-		float scale_x = (float) ar->winx / rres.rectx;
-		float scale_y = (float) ar->winy / rres.recty;
+		float scale_x, scale_y;
+		rcti clip_rect;
+		int xof, yof;
+
+		if (render_view3d_disprect(scene, ar, v3d, rv3d, &clip_rect)) {
+			scale_x = (float) BLI_rcti_size_x(&clip_rect) / rres.rectx;
+			scale_y = (float) BLI_rcti_size_y(&clip_rect) / rres.recty;
+			xof = clip_rect.xmin;
+			yof = clip_rect.ymin;
+		}
+		else {
+			scale_x = (float) ar->winx / rres.rectx;
+			scale_y = (float) ar->winy / rres.recty;
+			xof = rres.xof;
+			yof = rres.yof;
+		}
 
 		/* If user decided not to use GLSL, fallback to glaDrawPixelsAuto */
 		force_fallback |= (U.image_draw_method != IMAGE_DRAW_METHOD_GLSL);
@@ -1444,8 +1485,8 @@ void render_view3d_draw(RenderEngine *engine, const bContext *C)
 				glEnable(GL_BLEND);
 				glColor4f(1.0f, 1.0f, 1.0f, 1.0f);
 				glPixelZoom(scale_x, scale_y);
-				glaDrawPixelsTex(rres.xof, rres.yof, rres.rectx, rres.recty, GL_RGBA, GL_FLOAT,
-				                 GL_NEAREST, rres.rectf);
+				glaDrawPixelsTex(xof, yof, rres.rectx, rres.recty,
+				                 GL_RGBA, GL_FLOAT, GL_NEAREST, rres.rectf);
 				glPixelZoom(1.0f, 1.0f);
 				glDisable(GL_BLEND);
 
@@ -1465,7 +1506,8 @@ void render_view3d_draw(RenderEngine *engine, const bContext *C)
 			glEnable(GL_BLEND);
 			glColor4f(1.0f, 1.0f, 1.0f, 1.0f);
 			glPixelZoom(scale_x, scale_y);
-			glaDrawPixelsAuto(rres.xof, rres.yof, rres.rectx, rres.recty, GL_RGBA, GL_UNSIGNED_BYTE,
+			glaDrawPixelsAuto(xof, yof, rres.rectx, rres.recty,
+			                  GL_RGBA, GL_UNSIGNED_BYTE,
 			                  GL_NEAREST, display_buffer);
 			glPixelZoom(1.0f, 1.0f);
 			glDisable(GL_BLEND);
diff --git a/source/blender/render/intern/source/pipeline.c b/source/blender/render/intern/source/pipeline.c
index e6a9303a982..2131b820bd4 100644
--- a/source/blender/render/intern/source/pipeline.c
+++ b/source/blender/render/intern/source/pipeline.c
@@ -729,9 +729,11 @@ void RE_ChangeResolution(Render *re, int winx, int winy, rcti *disprect)
 {
 	re_init_resolution(re, NULL, winx, winy, disprect);
 
-	BLI_rw_mutex_lock(&re->resultmutex, THREAD_LOCK_WRITE);
-	render_result_rescale(re);
-	BLI_rw_mutex_unlock(&re->resultmutex);
+	if (re->result) {
+		BLI_rw_mutex_lock(&re->resultmutex, THREAD_LOCK_WRITE);
+		render_result_rescale(re);
+		BLI_rw_mutex_unlock(&re->resultmutex);
+	}
 }
 
 /* update some variables that can be animated, and otherwise wouldn't be due to