Cycles/BI: Add a pixel size option for speeding up viewport rendering

This patch adds "Pixel Size" to the performance options, which allows to render
in a smaller resolution, which is especially useful for displays with high DPI.

Reviewers: Severin, dingto, sergey, brecht

Reviewed By: brecht

Subscribers: Severin, venomgfx, eyecandy, brecht

Differential Revision: https://developer.blender.org/D1619

6 files changed, 52 insertions, 6 deletions

diff --git a/source/blender/blenkernel/BKE_scene.h b/source/blender/blenkernel/BKE_scene.h
index f1680b6ccbf..b7ecb85819e 100644
--- a/source/blender/blenkernel/BKE_scene.h
+++ b/source/blender/blenkernel/BKE_scene.h
@@ -152,6 +152,8 @@ bool BKE_scene_check_rigidbody_active(const struct Scene *scene);
 int BKE_scene_num_threads(const struct Scene *scene);
 int BKE_render_num_threads(const struct RenderData *r);
 
+int BKE_render_preview_pixel_size(const struct RenderData *r);
+
 double BKE_scene_unit_scale(const struct UnitSettings *unit, const int unit_type, double value);
 
 /* multiview */
diff --git a/source/blender/blenkernel/intern/scene.c b/source/blender/blenkernel/intern/scene.c
index b7fc6e70e65..b8ad54dc533 100644
--- a/source/blender/blenkernel/intern/scene.c
+++ b/source/blender/blenkernel/intern/scene.c
@@ -2411,6 +2411,14 @@ int BKE_scene_num_threads(const Scene *scene)
 	return BKE_render_num_threads(&scene->r);
 }
 
+int BKE_render_preview_pixel_size(const RenderData *r)
+{
+	if (r->preview_pixel_size == 0) {
+		return (U.pixelsize > 1.5f)? 2 : 1;
+	}
+	return r->preview_pixel_size;
+}
+
 /* Apply the needed correction factor to value, based on unit_type (only length-related are affected currently)
  * and unit->scale_length.
  */
diff --git a/source/blender/editors/render/render_internal.c b/source/blender/editors/render/render_internal.c
index 9d98a3676ac..da14e72f887 100644
--- a/source/blender/editors/render/render_internal.c
+++ b/source/blender/editors/render/render_internal.c
@@ -1171,7 +1171,7 @@ static void render_update_resolution(Render *re, const RenderPreview *rp,
 	}
 
 	if (rp->has_freestyle) {
-		if (rp->resolution_divider == 1) {
+		if (rp->resolution_divider == BKE_render_preview_pixel_size(&rp->scene->r)) {
 			RE_ChangeModeFlag(re, R_EDGE_FRS, false);
 		}
 		else {
@@ -1312,11 +1312,12 @@ static void render_view3d_startjob(void *customdata, short *stop, short *do_upda
 		RE_updateRenderInstances(re, ob_inst_update_flag);
 
 		for (;;) {
+			int pixel_size = BKE_render_preview_pixel_size(&rp->scene->r);
 			if (first_time == false) {
 				if (restore)
 					RE_DataBase_IncrementalView(re, rp->viewmat, 1);
 
-				rp->resolution_divider /= 2;
+				rp->resolution_divider = MAX2(rp->resolution_divider/2, pixel_size);
 				*do_update = 1;
 
 				render_update_resolution(re, rp, use_border, &cliprct);
@@ -1333,7 +1334,7 @@ static void render_view3d_startjob(void *customdata, short *stop, short *do_upda
 
 			first_time = false;
 
-			if (*stop || rp->resolution_divider == 1) {
+			if (*stop || rp->resolution_divider == pixel_size) {
 				break;
 			}
 		}
@@ -1435,7 +1436,7 @@ static void render_view3d_do(RenderEngine *engine, const bContext *C)
 	Scene *scene = CTX_data_scene(C);
 	ARegion *ar = CTX_wm_region(C);
 	int width = ar->winx, height = ar->winy;
-	int divider = 1;
+	int divider = BKE_render_preview_pixel_size(&scene->r);
 	int resolution_threshold = scene->r.preview_start_resolution *
 	                           scene->r.preview_start_resolution;
 
diff --git a/source/blender/makesdna/DNA_scene_types.h b/source/blender/makesdna/DNA_scene_types.h
index 2bca5565553..de516dc0f1f 100644
--- a/source/blender/makesdna/DNA_scene_types.h
+++ b/source/blender/makesdna/DNA_scene_types.h
@@ -790,14 +790,13 @@ typedef struct RenderData {
 	struct BakeData bake;
 
 	int preview_start_resolution;
+	short preview_pixel_size;
 
 	/* Type of the debug pass to use.
 	 * Only used when built with debug passes support.
 	 */
 	short debug_pass_type;
 
-	short pad;
-
 	/* MultiView */
 	ListBase views;  /* SceneRenderView */
 	short actview;
diff --git a/source/blender/makesrna/intern/rna_render.c b/source/blender/makesrna/intern/rna_render.c
index c30765d8857..a66c160ed1a 100644
--- a/source/blender/makesrna/intern/rna_render.c
+++ b/source/blender/makesrna/intern/rna_render.c
@@ -33,6 +33,8 @@
 #include "BLI_utildefines.h"
 #include "BLI_path_util.h"
 
+#include "BKE_scene.h"
+
 #include "RNA_define.h"
 #include "RNA_enum_types.h"
 
@@ -123,6 +125,11 @@ static int engine_support_display_space_shader(RenderEngine *UNUSED(engine), Sce
 	return IMB_colormanagement_support_glsl_draw(&scene->view_settings);
 }
 
+static int engine_get_preview_pixel_size(RenderEngine *UNUSED(engine), Scene *scene)
+{
+	return BKE_render_preview_pixel_size(&scene->r);
+}
+
 static void engine_bind_display_space_shader(RenderEngine *UNUSED(engine), Scene *scene)
 {
 	IMB_colormanagement_setup_glsl_draw(&scene->view_settings,
@@ -647,6 +654,13 @@ static void rna_def_render_engine(BlenderRNA *brna)
 	parm = RNA_def_boolean(func, "supported", 0, "Supported", "");
 	RNA_def_function_return(func, parm);
 
+	func = RNA_def_function(srna, "get_preview_pixel_size", "engine_get_preview_pixel_size");
+	RNA_def_function_ui_description(func, "Get the pixel size that should be used for preview rendering");
+	parm = RNA_def_pointer(func, "scene", "Scene", "", "");
+	RNA_def_parameter_flags(parm, 0, PARM_REQUIRED);
+	parm = RNA_def_int(func, "pixel_size", 0, 1, 8, "Pixel Size", "", 1, 8);
+	RNA_def_function_return(func, parm);
+
 	RNA_define_verify_sdna(0);
 
 	prop = RNA_def_property(srna, "is_animation", PROP_BOOLEAN, PROP_NONE);
diff --git a/source/blender/makesrna/intern/rna_scene.c b/source/blender/makesrna/intern/rna_scene.c
index 2722f8759b8..71350edeb94 100644
--- a/source/blender/makesrna/intern/rna_scene.c
+++ b/source/blender/makesrna/intern/rna_scene.c
@@ -1846,6 +1846,13 @@ static void rna_Scene_simplify_update(Main *bmain, Scene *UNUSED(scene), Pointer
 		rna_Scene_use_simplify_update(bmain, sce, ptr);
 }
 
+static void rna_SceneRenderData_update(Main *UNUSED(bmain), Scene *UNUSED(scene), PointerRNA *ptr)
+{
+	Scene *sce = ptr->id.data;
+
+	DAG_id_tag_update(&sce->id, 0);
+}
+
 static void rna_Scene_use_persistent_data_update(Main *UNUSED(bmain), Scene *UNUSED(scene), PointerRNA *ptr)
 {
 	Scene *sce = ptr->id.data;
@@ -5895,6 +5902,15 @@ static void rna_def_scene_render_data(BlenderRNA *brna)
 		{0, NULL, 0, NULL, NULL}
 	};
 	
+	static EnumPropertyItem pixel_size_items[] = {
+		{0, "AUTO", 0, "Automatic", "Automatic pixel size, depends on the UI scale"},
+		{1, "1", 0, "1x", "Render at full resolution"},
+		{2, "2", 0, "2x", "Render at 50% resolution"},
+		{4, "4", 0, "4x", "Render at 25% resolution"},
+		{8, "8", 0, "8x", "Render at 12.5% resolution"},
+		{0, NULL, 0, NULL, NULL}
+	};
+
 	static EnumPropertyItem octree_resolution_items[] = {
 		{64, "64", 0, "64", ""},
 		{128, "128", 0, "128", ""},
@@ -6018,6 +6034,12 @@ static void rna_def_scene_render_data(BlenderRNA *brna)
 	                                                   "progressively increasing it to the full viewport size");
 	RNA_def_property_update(prop, NC_SCENE | ND_RENDER_OPTIONS, NULL);
 
+	prop = RNA_def_property(srna, "preview_pixel_size", PROP_ENUM, PROP_NONE);
+	RNA_def_property_enum_sdna(prop, NULL, "preview_pixel_size");
+	RNA_def_property_enum_items(prop, pixel_size_items);
+	RNA_def_property_ui_text(prop, "Pixel Size", "Pixel size for viewport rendering");
+	RNA_def_property_update(prop, NC_SCENE | ND_RENDER_OPTIONS, "rna_SceneRenderData_update");
+
 	prop = RNA_def_property(srna, "pixel_aspect_x", PROP_FLOAT, PROP_NONE);
 	RNA_def_property_float_sdna(prop, NULL, "xasp");
 	RNA_def_property_flag(prop, PROP_PROPORTIONAL);