[Bf-blender-cvs] [539b465b321] blender2.8: Implement basic global tablet pressure curve options.

[Alexander Gavrilov]

Commit: 539b465b32102d90a6d356d8f94300e70338856e
Author: Alexander Gavrilov
Date:   Tue Nov 20 15:35:59 2018 +0300
Branches: blender2.8
https://developer.blender.org/rB539b465b32102d90a6d356d8f94300e70338856e

Implement basic global tablet pressure curve options.

Grease Pencil already implements support for full-featured
per-brush pressure curves, but it is useful to have some
basic global settings that affect all brushes and tools.

This adds two simple options:

- Raw pressure required to achieve full brush intensity.
- Softness control, using a gamma curve internally.

The most important one is the max pressure setting, because it is
critical for ergonomics, but the Linux Wacom driver lacks it.

The softness option internally converts to gamma = 4^-softness.

Reviewers: brecht, campbellbarton

Differential Revision: https://developer.blender.org/D3967

===================================================================

M	release/scripts/startup/bl_ui/space_userpref.py
M	source/blender/blenloader/intern/readfile.c
M	source/blender/makesdna/DNA_userdef_types.h
M	source/blender/makesrna/intern/rna_userdef.c
M	source/blender/windowmanager/intern/wm_event_system.c
M	source/blender/windowmanager/intern/wm_window.c
M	source/blender/windowmanager/wm_event_system.h

===================================================================

diff --git a/release/scripts/startup/bl_ui/space_userpref.py b/release/scripts/startup/bl_ui/space_userpref.py
index 7d8be6ceec0..e978a86dcea 100644
--- a/release/scripts/startup/bl_ui/space_userpref.py
+++ b/release/scripts/startup/bl_ui/space_userpref.py
@@ -1121,6 +1121,12 @@ class USERPREF_PT_input(Panel):
         sub.prop(walk, "view_height")
         sub.prop(walk, "jump_height")
 
+        sub.separator()
+        sub = layout.column()
+        sub.label(text="Tablet Pressure:")
+        sub.prop(inputs, "pressure_threshold_max")
+        sub.prop(inputs, "pressure_softness")
+
         if inputs.use_ndof:
             layout.separator()
             layout.label(text="NDOF Device:")
diff --git a/source/blender/blenloader/intern/readfile.c b/source/blender/blenloader/intern/readfile.c
index 50bf2f79fdc..f07f9363167 100644
--- a/source/blender/blenloader/intern/readfile.c
+++ b/source/blender/blenloader/intern/readfile.c
@@ -8793,6 +8793,11 @@ static void do_versions_userdef(FileData *fd, BlendFileData *bfd)
 	if (!DNA_struct_elem_find(fd->filesdna, "UserDef", "short", "gpencil_multisamples")) {
 		user->gpencil_multisamples = 4;
 	}
+
+	/* tablet pressure threshold */
+	if (!DNA_struct_elem_find(fd->filesdna, "UserDef", "float", "pressure_threshold_max")) {
+		user->pressure_threshold_max = 1.0f;
+	}
 }
 
 static void do_versions(FileData *fd, Library *lib, Main *main)
diff --git a/source/blender/makesdna/DNA_userdef_types.h b/source/blender/makesdna/DNA_userdef_types.h
index 6ae6eaed1c6..c9d16351635 100644
--- a/source/blender/makesdna/DNA_userdef_types.h
+++ b/source/blender/makesdna/DNA_userdef_types.h
@@ -618,6 +618,9 @@ typedef struct UserDef {
 	short anisotropic_filter;
 	short use_16bit_textures, use_gpu_mipmap;
 
+	float pressure_threshold_max; /* raw tablet pressure that maps to 100% */
+	float pressure_softness;      /* curve non-linearity parameter */
+
 	float ndof_sensitivity;	/* overall sensitivity of 3D mouse */
 	float ndof_orbit_sensitivity;
 	float ndof_deadzone; /* deadzone of 3D mouse */
diff --git a/source/blender/makesrna/intern/rna_userdef.c b/source/blender/makesrna/intern/rna_userdef.c
index 15618759ffa..03f86eba601 100644
--- a/source/blender/makesrna/intern/rna_userdef.c
+++ b/source/blender/makesrna/intern/rna_userdef.c
@@ -4582,6 +4582,20 @@ static void rna_def_userdef_input(BlenderRNA *brna)
 	RNA_def_property_ui_text(prop, "Tweak Threshold",
 	                         "Number of pixels you have to drag before tweak event is triggered");
 
+	/* tablet pressure curve */
+	prop = RNA_def_property(srna, "pressure_threshold_max", PROP_FLOAT, PROP_FACTOR);
+	RNA_def_property_range(prop, 0.0f, 1.0f);
+	RNA_def_property_float_default(prop, 1.0f);
+	RNA_def_property_ui_range(prop, 0.0f, 1.0f, 0.01f, 3);
+	RNA_def_property_ui_text(prop, "Max Threshold",
+	                         "Raw input pressure value that is interpreted as 100% by Blender");
+
+	prop = RNA_def_property(srna, "pressure_softness", PROP_FLOAT, PROP_FACTOR);
+	RNA_def_property_range(prop, -FLT_MAX, FLT_MAX);
+	RNA_def_property_ui_range(prop, -1.0f, 1.0f, 0.1f, 2);
+	RNA_def_property_ui_text(prop, "Softness",
+	                         "Adjusts softness of the low pressure response onset using a gamma curve");
+
 #ifdef WITH_INPUT_NDOF
 	/* 3D mouse settings */
 	/* global options */
diff --git a/source/blender/windowmanager/intern/wm_event_system.c b/source/blender/windowmanager/intern/wm_event_system.c
index f82df000288..03a80ff240b 100644
--- a/source/blender/windowmanager/intern/wm_event_system.c
+++ b/source/blender/windowmanager/intern/wm_event_system.c
@@ -3662,6 +3662,22 @@ static void wm_eventemulation(wmEvent *event)
 	}
 }
 
+/* applies the global tablet pressure correction curve */
+float wm_pressure_curve(float pressure)
+{
+	if (U.pressure_threshold_max != 0.0f) {
+		pressure /= U.pressure_threshold_max;
+	}
+
+	CLAMP(pressure, 0.0f, 1.0f);
+
+	if (U.pressure_softness != 0.0f) {
+		pressure = powf(pressure, powf(4.0f, -U.pressure_softness));
+	}
+
+	return pressure;
+}
+
 /* adds customdata to event */
 static void update_tablet_data(wmWindow *win, wmEvent *event)
 {
@@ -3672,7 +3688,7 @@ static void update_tablet_data(wmWindow *win, wmEvent *event)
 		struct wmTabletData *wmtab = MEM_mallocN(sizeof(wmTabletData), "customdata tablet");
 
 		wmtab->Active = (int)td->Active;
-		wmtab->Pressure = td->Pressure;
+		wmtab->Pressure = wm_pressure_curve(td->Pressure);
 		wmtab->Xtilt = td->Xtilt;
 		wmtab->Ytilt = td->Ytilt;
 
diff --git a/source/blender/windowmanager/intern/wm_window.c b/source/blender/windowmanager/intern/wm_window.c
index b84b851476a..df20dbd8055 100644
--- a/source/blender/windowmanager/intern/wm_window.c
+++ b/source/blender/windowmanager/intern/wm_window.c
@@ -2014,7 +2014,7 @@ float WM_cursor_pressure(const struct wmWindow *win)
 	const GHOST_TabletData *td = GHOST_GetTabletData(win->ghostwin);
 	/* if there's tablet data from an active tablet device then add it */
 	if ((td != NULL) && td->Active != GHOST_kTabletModeNone) {
-		return td->Pressure;
+		return wm_pressure_curve(td->Pressure);
 	}
 	else {
 		return -1.0f;
diff --git a/source/blender/windowmanager/wm_event_system.h b/source/blender/windowmanager/wm_event_system.h
index a0610ffcff3..fe28cbf9895 100644
--- a/source/blender/windowmanager/wm_event_system.h
+++ b/source/blender/windowmanager/wm_event_system.h
@@ -101,6 +101,8 @@ void        wm_event_do_depsgraph(bContext *C);
 void        wm_event_do_refresh_wm_and_depsgraph(bContext *C);
 void        wm_event_do_notifiers(bContext *C);
 
+float       wm_pressure_curve(float raw_pressure);
+
 /* wm_keymap.c */
 
 /* wm_dropbox.c */