[Bf-blender-cvs] [5535b0b8878] master: GPencil Array - Add option for uniform random scaling

[Cody Winchester]

Commit: 5535b0b8878a84325b0f99ad10260e95433facc7
Author: Cody Winchester
Date:   Tue Dec 15 22:14:05 2020 +0100
Branches: master
https://developer.blender.org/rB5535b0b8878a84325b0f99ad10260e95433facc7

GPencil Array - Add option for uniform random scaling

This patch adds the option to make the random scaling from the grease pencil array modifier uniform.
The current settings allow a separate value for each of the 3 scaling axis. The modifier also creates different seed values for each axis so there is no way to keep the random scaling uniform.
This patch creates 1 random seed value and applies it to each of the scaling axis.

Here is a demonstration of the previous behavior and the new optional behavior.
{F9485973}
{F9485981}

{F9485798}

Reviewed By: #grease_pencil, antoniov, pepeland

Differential Revision: https://developer.blender.org/D9764

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

M	source/blender/gpencil_modifiers/intern/MOD_gpencilarray.c
M	source/blender/makesdna/DNA_gpencil_modifier_types.h
M	source/blender/makesrna/intern/rna_gpencil_modifier.c

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

diff --git a/source/blender/gpencil_modifiers/intern/MOD_gpencilarray.c b/source/blender/gpencil_modifiers/intern/MOD_gpencilarray.c
index aa21bf192c4..0b8f150aba4 100644
--- a/source/blender/gpencil_modifiers/intern/MOD_gpencilarray.c
+++ b/source/blender/gpencil_modifiers/intern/MOD_gpencilarray.c
@@ -237,9 +237,17 @@ static void generate_geometry(GpencilModifierData *md,
         /* To ensure a nice distribution, we use halton sequence and offset using the seed. */
         BLI_halton_3d(primes, offset, x, r);
 
-        for (int i = 0; i < 3; i++) {
-          rand[j][i] = fmodf(r[i] * 2.0 - 1.0 + rand_offset, 1.0f);
-          rand[j][i] = fmodf(sin(rand[j][i] * 12.9898 + j * 78.233) * 43758.5453, 1.0f);
+        if ((mmd->flag & GP_ARRAY_UNIFORM_RANDOM_SCALE) && j == 2) {
+          float rand_value;
+          rand_value = fmodf(r[0] * 2.0 - 1.0 + rand_offset, 1.0f);
+          rand_value = fmodf(sin(rand_value * 12.9898 + j * 78.233) * 43758.5453, 1.0f);
+          copy_v3_fl(rand[j] , rand_value);
+        }
+        else {
+          for (int i = 0; i < 3; i++) {
+            rand[j][i] = fmodf(r[i] * 2.0 - 1.0 + rand_offset, 1.0f);
+            rand[j][i] = fmodf(sin(rand[j][i] * 12.9898 + j * 78.233) * 43758.5453, 1.0f);
+          }
         }
       }
       /* Calculate Random matrix. */
@@ -425,6 +433,7 @@ static void random_panel_draw(const bContext *UNUSED(C), Panel *panel)
   uiItemR(layout, ptr, "random_offset", 0, IFACE_("Offset"), ICON_NONE);
   uiItemR(layout, ptr, "random_rotation", 0, IFACE_("Rotation"), ICON_NONE);
   uiItemR(layout, ptr, "random_scale", 0, IFACE_("Scale"), ICON_NONE);
+  uiItemR(layout, ptr, "use_uniform_random_scale", 0, NULL, ICON_NONE);
   uiItemR(layout, ptr, "seed", 0, NULL, ICON_NONE);
 }
 
diff --git a/source/blender/makesdna/DNA_gpencil_modifier_types.h b/source/blender/makesdna/DNA_gpencil_modifier_types.h
index bd5afc457ac..9ac40495887 100644
--- a/source/blender/makesdna/DNA_gpencil_modifier_types.h
+++ b/source/blender/makesdna/DNA_gpencil_modifier_types.h
@@ -351,6 +351,7 @@ typedef enum eArrayGpencil_Flag {
   GP_ARRAY_USE_OFFSET = (1 << 7),
   GP_ARRAY_USE_RELATIVE = (1 << 8),
   GP_ARRAY_USE_OB_OFFSET = (1 << 9),
+  GP_ARRAY_UNIFORM_RANDOM_SCALE = (1 << 10),
 } eArrayGpencil_Flag;
 
 typedef struct BuildGpencilModifierData {
diff --git a/source/blender/makesrna/intern/rna_gpencil_modifier.c b/source/blender/makesrna/intern/rna_gpencil_modifier.c
index 5f131de6a40..f0660392eaf 100644
--- a/source/blender/makesrna/intern/rna_gpencil_modifier.c
+++ b/source/blender/makesrna/intern/rna_gpencil_modifier.c
@@ -1560,6 +1560,11 @@ static void rna_def_modifier_gpencilarray(BlenderRNA *brna)
   RNA_def_property_boolean_sdna(prop, NULL, "flag", GP_ARRAY_USE_RELATIVE);
   RNA_def_property_ui_text(prop, "Shift", "Enable shift");
   RNA_def_property_update(prop, 0, "rna_GpencilModifier_update");
+
+  prop = RNA_def_property(srna, "use_uniform_random_scale", PROP_BOOLEAN, PROP_NONE);
+  RNA_def_property_boolean_sdna(prop, NULL, "flag", GP_ARRAY_UNIFORM_RANDOM_SCALE);
+  RNA_def_property_ui_text(prop, "Uniform Scale", "Use the same random seed for each scale axis for a uniform scale");
+  RNA_def_property_update(prop, 0, "rna_GpencilModifier_update");
 }
 
 static void rna_def_modifier_gpencilbuild(BlenderRNA *brna)