Cycles: Expose user-defined shutter curve to the interface

Shutter curve now can be controlled using curve mapping widget in the motion
blur panel in Render buttons. Only mapping from 0..1 by x axis are allowed,
Y values will be normalized to fill in 0..1 space as well automatically.

Y values of 0 means fully closed shutter, Y values of 1 means fully opened
shutter.

Default mapping is set to old behavior when shutter opens and closes instantly.

This shutter mapping curve could easily be used by any other render engine by
accessing scene.render.motion_blur_shutter_curve.

Reviewers: #cycles, brecht, juicyfruit, campbellbarton

Differential Revision: https://developer.blender.org/D1585

15 files changed, 112 insertions, 2 deletions

diff --git a/intern/cycles/blender/addon/ui.py b/intern/cycles/blender/addon/ui.py
index 3700da3263e..3678391ccd5 100644
--- a/intern/cycles/blender/addon/ui.py
+++ b/intern/cycles/blender/addon/ui.py
@@ -268,6 +268,19 @@ class CyclesRender_PT_motion_blur(CyclesButtonsPanel, Panel):
         col.prop(cscene, "motion_blur_position", text="Position")
         col.prop(rd, "motion_blur_shutter")
 
+        col = layout.column()
+        col.label("Shutter curve:")
+        col.template_curve_mapping(rd, "motion_blur_shutter_curve")
+
+        col = layout.column(align=True)
+        row = col.row(align=True)
+        row.operator("render.shutter_curve_preset", icon='SMOOTHCURVE', text="").shape = 'SMOOTH'
+        row.operator("render.shutter_curve_preset", icon='SPHERECURVE', text="").shape = 'ROUND'
+        row.operator("render.shutter_curve_preset", icon='ROOTCURVE', text="").shape = 'ROOT'
+        row.operator("render.shutter_curve_preset", icon='SHARPCURVE', text="").shape = 'SHARP'
+        row.operator("render.shutter_curve_preset", icon='LINCURVE', text="").shape = 'LINE'
+        row.operator("render.shutter_curve_preset", icon='NOCURVE', text="").shape = 'MAX'
+
 
 class CyclesRender_PT_film(CyclesButtonsPanel, Panel):
     bl_label = "Film"
diff --git a/intern/cycles/blender/blender_camera.cpp b/intern/cycles/blender/blender_camera.cpp
index 7cb5e38d4e5..cde3840b796 100644
--- a/intern/cycles/blender/blender_camera.cpp
+++ b/intern/cycles/blender/blender_camera.cpp
@@ -37,6 +37,7 @@ struct BlenderCamera {
 	float lens;
 	float shuttertime;
 	Camera::MotionPosition motion_position;
+	float shutter_curve[RAMP_TABLE_SIZE];
 
 	float aperturesize;
 	uint apertureblades;
@@ -417,6 +418,8 @@ static void blender_camera_sync(Camera *cam, BlenderCamera *bcam, int width, int
 	cam->fov_post = cam->fov;
 	cam->motion_position = bcam->motion_position;
 
+	memcpy(cam->shutter_curve, bcam->shutter_curve, sizeof(cam->shutter_curve));
+
 	/* border */
 	cam->border = bcam->border;
 	cam->viewport_camera_border = bcam->viewport_camera_border;
@@ -437,6 +440,9 @@ void BlenderSync::sync_camera(BL::RenderSettings b_render, BL::Object b_override
 	bcam.pixelaspect.x = b_render.pixel_aspect_x();
 	bcam.pixelaspect.y = b_render.pixel_aspect_y();
 	bcam.shuttertime = b_render.motion_blur_shutter();
+	curvemapping_to_array(b_render.motion_blur_shutter_curve(),
+	                      bcam.shutter_curve,
+	                      RAMP_TABLE_SIZE);
 
 	PointerRNA cscene = RNA_pointer_get(&b_scene.ptr, "cycles");
 	switch(RNA_enum_get(&cscene, "motion_blur_position")) {
@@ -545,6 +551,9 @@ static void blender_camera_from_view(BlenderCamera *bcam, BL::RenderEngine b_eng
 	bcam->farclip = b_v3d.clip_end();
 	bcam->lens = b_v3d.lens();
 	bcam->shuttertime = b_scene.render().motion_blur_shutter();
+	curvemapping_to_array(b_scene.render().motion_blur_shutter_curve(),
+	                      bcam->shutter_curve,
+	                      RAMP_TABLE_SIZE);
 
 	if(b_rv3d.view_perspective() == BL::RegionView3D::view_perspective_CAMERA) {
 		/* camera view */
diff --git a/intern/cycles/blender/blender_util.h b/intern/cycles/blender/blender_util.h
index bd1c37a7560..2e9e9266404 100644
--- a/intern/cycles/blender/blender_util.h
+++ b/intern/cycles/blender/blender_util.h
@@ -62,6 +62,16 @@ static inline void colorramp_to_array(BL::ColorRamp ramp, float4 *data, int size
 	}
 }
 
+static inline void curvemapping_to_array(BL::CurveMapping cumap, float *data, int size)
+{
+	cumap.update();
+	BL::CurveMap curve = cumap.curves[0];
+	for(int i = 0; i < size; i++) {
+		float t = (float)i/(float)(size-1);
+		data[i] = curve.evaluate(t);
+	}
+}
+
 static inline void curvemapping_color_to_array(BL::CurveMapping cumap, float4 *data, int size, bool rgb_curve)
 {
 	cumap.update();
diff --git a/source/blender/blenkernel/BKE_colortools.h b/source/blender/blenkernel/BKE_colortools.h
index b88972b74e1..e5d348031e9 100644
--- a/source/blender/blenkernel/BKE_colortools.h
+++ b/source/blender/blenkernel/BKE_colortools.h
@@ -54,7 +54,7 @@ void                curvemapping_set_black_white(struct CurveMapping *cumap, con
 enum {
 	CURVEMAP_SLOPE_NEGATIVE   = 0,
 	CURVEMAP_SLOPE_POSITIVE   = 1,
-	CURVEMAP_SLOPE_RAISE_FALL = 2,
+	CURVEMAP_SLOPE_POS_NEG    = 2,
 };
 
 void                    curvemap_reset(struct CurveMap *cuma, const struct rctf *clipr, int preset, int slope);
diff --git a/source/blender/blenkernel/intern/colortools.c b/source/blender/blenkernel/intern/colortools.c
index c6e3d1919e1..3fb9ff1c9e8 100644
--- a/source/blender/blenkernel/intern/colortools.c
+++ b/source/blender/blenkernel/intern/colortools.c
@@ -368,7 +368,7 @@ void curvemap_reset(CurveMap *cuma, const rctf *clipr, int preset, int slope)
 		MEM_freeN(cuma->curve);
 		cuma->curve = newpoints;
 	}
-	else if (slope == CURVEMAP_SLOPE_RAISE_FALL) {
+	else if (slope == CURVEMAP_SLOPE_POS_NEG) {
 		const int num_points = cuma->totpoint * 2 - 1;
 		CurveMapPoint *new_points = MEM_mallocN(num_points * sizeof(CurveMapPoint),
 		                                       "curve symmetric points");
diff --git a/source/blender/blenkernel/intern/scene.c b/source/blender/blenkernel/intern/scene.c
index d73797ccbd1..bb61ecd63cb 100644
--- a/source/blender/blenkernel/intern/scene.c
+++ b/source/blender/blenkernel/intern/scene.c
@@ -351,6 +351,8 @@ Scene *BKE_scene_copy(Scene *sce, int type)
 		scen->preview = BKE_previewimg_copy(sce->preview);
 	}
 
+	curvemapping_copy_data(&scen->r.mblur_shutter_curve, &sce->r.mblur_shutter_curve);
+
 	return scen;
 }
 
@@ -462,6 +464,7 @@ void BKE_scene_free(Scene *sce)
 	BKE_color_managed_view_settings_free(&sce->view_settings);
 
 	BKE_previewimg_free(&sce->preview);
+	curvemapping_free_data(&sce->r.mblur_shutter_curve);
 }
 
 void BKE_scene_init(Scene *sce)
diff --git a/source/blender/blenloader/intern/readfile.c b/source/blender/blenloader/intern/readfile.c
index b112f3d43d6..d6ba79f5a98 100644
--- a/source/blender/blenloader/intern/readfile.c
+++ b/source/blender/blenloader/intern/readfile.c
@@ -6007,6 +6007,8 @@ static void direct_link_scene(FileData *fd, Scene *sce)
 	}
 
 	sce->preview = direct_link_preview_image(fd, sce->preview);
+
+	direct_link_curvemapping(fd, &sce->r.mblur_shutter_curve);
 }
 
 /* ************ READ WM ***************** */
diff --git a/source/blender/blenloader/intern/versioning_270.c b/source/blender/blenloader/intern/versioning_270.c
index 16635851032..72f9897730a 100644
--- a/source/blender/blenloader/intern/versioning_270.c
+++ b/source/blender/blenloader/intern/versioning_270.c
@@ -53,6 +53,7 @@
 
 #include "DNA_genfile.h"
 
+#include "BKE_colortools.h"
 #include "BKE_main.h"
 #include "BKE_modifier.h"
 #include "BKE_node.h"
@@ -909,4 +910,19 @@ void blo_do_versions_270(FileData *fd, Library *UNUSED(lib), Main *main)
 		}
 
 	}
+
+	{
+		if (!DNA_struct_elem_find(fd->filesdna, "RenderData", "CurveMapping", "mblur_shutter_curve")) {
+			Scene *scene;
+			for (scene = main->scene.first; scene != NULL; scene = scene->id.next) {
+				CurveMapping *curve_mapping = &scene->r.mblur_shutter_curve;
+				curvemapping_set_defaults(curve_mapping, 1, 0.0f, 0.0f, 1.0f, 1.0f);
+				curvemapping_initialize(curve_mapping);
+				curvemap_reset(curve_mapping->cm,
+				               &curve_mapping->clipr,
+				               CURVE_PRESET_MAX,
+				               CURVEMAP_SLOPE_POS_NEG);
+			}
+		}
+	}
 }
diff --git a/source/blender/blenloader/intern/writefile.c b/source/blender/blenloader/intern/writefile.c
index 4449db14c50..bc94ef9cc19 100644
--- a/source/blender/blenloader/intern/writefile.c
+++ b/source/blender/blenloader/intern/writefile.c
@@ -2576,6 +2576,7 @@ static void write_scenes(WriteData *wd, ListBase *scebase)
 		}
 		
 		write_previews(wd, sce->preview);
+		write_curvemapping_curves(wd, &sce->r.mblur_shutter_curve);
 
 		sce= sce->id.next;
 	}
diff --git a/source/blender/editors/render/render_intern.h b/source/blender/editors/render/render_intern.h
index 26f313cb3fe..fb07b03c286 100644
--- a/source/blender/editors/render/render_intern.h
+++ b/source/blender/editors/render/render_intern.h
@@ -89,6 +89,7 @@ void TEXTURE_OT_envmap_clear_all(struct wmOperatorType *ot);
 
 /* render_internal.c */
 void RENDER_OT_render(struct wmOperatorType *ot);
+void RENDER_OT_shutter_curve_preset(struct wmOperatorType *ot);
 void render_view3d_update(struct RenderEngine *engine, const struct bContext *C);
 void render_view3d_draw(struct RenderEngine *engine, const struct bContext *C);
 
diff --git a/source/blender/editors/render/render_internal.c b/source/blender/editors/render/render_internal.c
index 57aafb549ac..f44374b1d7b 100644
--- a/source/blender/editors/render/render_internal.c
+++ b/source/blender/editors/render/render_internal.c
@@ -1640,3 +1640,45 @@ Scene *ED_render_job_get_current_scene(const bContext *C)
 	}
 	return NULL;
 }
+
+/* Motion blur curve preset */
+
+static int render_shutter_curve_preset_exec(bContext *C, wmOperator *op)
+{
+	Scene *scene = CTX_data_scene(C);
+	CurveMapping *mblur_shutter_curve = &scene->r.mblur_shutter_curve;
+	CurveMap *cm = mblur_shutter_curve->cm;
+	int preset = RNA_enum_get(op->ptr, "shape");
+
+	cm->flag &= ~CUMA_EXTEND_EXTRAPOLATE;
+	mblur_shutter_curve->preset = preset;
+	curvemap_reset(cm,
+	               &mblur_shutter_curve->clipr,
+	               mblur_shutter_curve->preset,
+	               CURVEMAP_SLOPE_POS_NEG);
+	curvemapping_changed(mblur_shutter_curve, false);
+
+	return OPERATOR_FINISHED;
+}
+
+void RENDER_OT_shutter_curve_preset(wmOperatorType *ot)
+{
+	PropertyRNA *prop;
+	static EnumPropertyItem prop_shape_items[] = {
+		{CURVE_PRESET_SHARP, "SHARP", 0, "Sharp", ""},
+		{CURVE_PRESET_SMOOTH, "SMOOTH", 0, "Smooth", ""},
+		{CURVE_PRESET_MAX, "MAX", 0, "Max", ""},
+		{CURVE_PRESET_LINE, "LINE", 0, "Line", ""},
+		{CURVE_PRESET_ROUND, "ROUND", 0, "Round", ""},
+		{CURVE_PRESET_ROOT, "ROOT", 0, "Root", ""},
+		{0, NULL, 0, NULL, NULL}};
+
+	ot->name = "Shutter Curve Preset";
+	ot->description = "Set shutter curve";
+	ot->idname = "RENDER_OT_shutter_curve_preset";
+
+	ot->exec = render_shutter_curve_preset_exec;
+
+	prop = RNA_def_enum(ot->srna, "shape", prop_shape_items, CURVE_PRESET_SMOOTH, "Mode", "");
+	RNA_def_property_translation_context(prop, BLT_I18NCONTEXT_ID_CURVE); /* Abusing id_curve :/ */
+}
diff --git a/source/blender/editors/render/render_ops.c b/source/blender/editors/render/render_ops.c
index f98083f7e74..c09e8576dc2 100644
--- a/source/blender/editors/render/render_ops.c
+++ b/source/blender/editors/render/render_ops.c
@@ -93,6 +93,7 @@ void ED_operatortypes_render(void)
 	WM_operatortype_append(RENDER_OT_view_show);
 	WM_operatortype_append(RENDER_OT_render);
 	WM_operatortype_append(RENDER_OT_view_cancel);
+	WM_operatortype_append(RENDER_OT_shutter_curve_preset);
 
 	/* render_opengl.c */
 	WM_operatortype_append(RENDER_OT_opengl);
diff --git a/source/blender/makesdna/DNA_scene_types.h b/source/blender/makesdna/DNA_scene_types.h
index 89f5e6499bf..26b1d7bd645 100644
--- a/source/blender/makesdna/DNA_scene_types.h
+++ b/source/blender/makesdna/DNA_scene_types.h
@@ -702,6 +702,9 @@ typedef struct RenderData {
 	short actview;
 	short views_format;
 	short pad8[2];
+
+	/* Motion blur shutter */
+	struct CurveMapping mblur_shutter_curve;
 } RenderData;
 
 /* *************************************************************** */
diff --git a/source/blender/makesrna/intern/rna_scene.c b/source/blender/makesrna/intern/rna_scene.c
index 403b59f1371..1149214e533 100644
--- a/source/blender/makesrna/intern/rna_scene.c
+++ b/source/blender/makesrna/intern/rna_scene.c
@@ -5366,6 +5366,11 @@ static void rna_def_scene_render_data(BlenderRNA *brna)
 	RNA_def_property_ui_text(prop, "Shutter", "Time taken in frames between shutter open and close");
 	RNA_def_property_clear_flag(prop, PROP_ANIMATABLE);
 	RNA_def_property_update(prop, NC_SCENE | ND_RENDER_OPTIONS, "rna_Scene_glsl_update");
+
+	prop = RNA_def_property(srna, "motion_blur_shutter_curve", PROP_POINTER, PROP_NONE);
+	RNA_def_property_pointer_sdna(prop, NULL, "mblur_shutter_curve");
+	RNA_def_property_struct_type(prop, "CurveMapping");
+	RNA_def_property_ui_text(prop, "Shutter Curve", "Curve defining the shutter's openness over time");
 	
 	/* border */
 	prop = RNA_def_property(srna, "use_border", PROP_BOOLEAN, PROP_NONE);
diff --git a/source/blender/render/intern/source/pipeline.c b/source/blender/render/intern/source/pipeline.c
index eb0b331f866..17e5751c38b 100644
--- a/source/blender/render/intern/source/pipeline.c
+++ b/source/blender/render/intern/source/pipeline.c
@@ -59,6 +59,7 @@
 
 #include "BKE_animsys.h"  /* <------ should this be here?, needed for sequencer update */
 #include "BKE_camera.h"
+#include "BKE_colortools.h"
 #include "BKE_depsgraph.h"
 #include "BKE_global.h"
 #include "BKE_image.h"
@@ -505,6 +506,8 @@ void RE_FreeRender(Render *re)
 	BLI_freelistN(&re->r.layers);
 	BLI_freelistN(&re->r.views);
 
+	curvemapping_free_data(&re->r.mblur_shutter_curve);
+
 	/* main dbase can already be invalid now, some database-free code checks it */
 	re->main = NULL;
 	re->scene = NULL;
@@ -666,6 +669,7 @@ void RE_InitState(Render *re, Render *source, RenderData *rd,
 	re->r = *rd;
 	BLI_duplicatelist(&re->r.layers, &rd->layers);
 	BLI_duplicatelist(&re->r.views, &rd->views);
+	curvemapping_copy_data(&re->r.mblur_shutter_curve, &rd->mblur_shutter_curve);
 
 	if (source) {
 		/* reuse border flags from source renderer */