Painting: migrated curve mask generation to CPP.

Curve mask generation is done during 2d texture painting. There are some
performance issues in this part of the code. Before addressing those we
move the code to CPP.

1 files changed, 149 insertions, 0 deletions

diff --git a/source/blender/editors/sculpt_paint/paint_image_2d_curve_mask.cc b/source/blender/editors/sculpt_paint/paint_image_2d_curve_mask.cc
new file mode 100644
index 00000000000..639dfcdae72
--- /dev/null
+++ b/source/blender/editors/sculpt_paint/paint_image_2d_curve_mask.cc
@@ -0,0 +1,149 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * The Original Code is Copyright (C) 2001-2002 by NaN Holding BV.
+ * All rights reserved.
+ */
+
+/** \file
+ * \ingroup ed
+ */
+
+#include "BLI_math.h"
+
+#include "MEM_guardedalloc.h"
+
+#include "DNA_brush_types.h"
+
+#include "BKE_brush.h"
+
+#include "paint_intern.h"
+
+namespace blender::ed::sculpt_paint {
+
+/* create a mask with the falloff strength */
+static void update_curve_mask(CurveMaskCache *curve_mask_cache,
+                              const Brush *brush,
+                              const int diameter,
+                              const float radius,
+                              const float cursor_position[2])
+{
+  BLI_assert(curve_mask_cache->curve_mask != nullptr);
+  int offset = (int)floorf(diameter / 2.0f);
+
+  unsigned short *m = curve_mask_cache->curve_mask;
+
+  int aa_samples = 1.0f / (radius * 0.20f);
+  if (brush->sampling_flag & BRUSH_PAINT_ANTIALIASING) {
+    aa_samples = clamp_i(aa_samples, 3, 16);
+  }
+  else {
+    aa_samples = 1;
+  }
+
+  /* Temporal until we have the brush properties */
+  const float hardness = 1.0f;
+  const float rotation = 0.0f;
+
+  float aa_offset = 1.0f / (2.0f * (float)aa_samples);
+  float aa_step = 1.0f / (float)aa_samples;
+
+  float bpos[2];
+  bpos[0] = cursor_position[0] - floorf(cursor_position[0]) + offset - aa_offset;
+  bpos[1] = cursor_position[1] - floorf(cursor_position[1]) + offset - aa_offset;
+
+  const float co = cosf(DEG2RADF(rotation));
+  const float si = sinf(DEG2RADF(rotation));
+
+  float norm_factor = 65535.0f / (float)(aa_samples * aa_samples);
+
+  for (int y = 0; y < diameter; y++) {
+    for (int x = 0; x < diameter; x++, m++) {
+      float total_samples = 0;
+      for (int i = 0; i < aa_samples; i++) {
+        for (int j = 0; j < aa_samples; j++) {
+          float pixel_xy[2] = {x + (aa_step * i), y + (aa_step * j)};
+          float xy_rot[2];
+          sub_v2_v2(pixel_xy, bpos);
+
+          xy_rot[0] = co * pixel_xy[0] - si * pixel_xy[1];
+          xy_rot[1] = si * pixel_xy[0] + co * pixel_xy[1];
+
+          float len = len_v2(xy_rot);
+          float p = len / radius;
+          if (hardness < 1.0f) {
+            p = (p - hardness) / (1.0f - hardness);
+            p = 1.0f - p;
+            CLAMP(p, 0.0f, 1.0f);
+          }
+          else {
+            p = 1.0;
+          }
+          float hardness_factor = 3.0f * p * p - 2.0f * p * p * p;
+          float curve = BKE_brush_curve_strength_clamped(brush, len, radius);
+          total_samples += curve * hardness_factor;
+        }
+      }
+      *m = (unsigned short)(total_samples * norm_factor);
+    }
+  }
+}
+
+static size_t diameter_to_curve_mask_size(const int diameter)
+{
+  return diameter * diameter * sizeof(ushort);
+}
+
+static bool is_curve_mask_size_valid(const CurveMaskCache *curve_mask_cache, const int diameter)
+{
+  return curve_mask_cache->curve_mask_size == diameter_to_curve_mask_size(diameter);
+}
+
+static void curve_mask_free(CurveMaskCache *curve_mask_cache)
+{
+  curve_mask_cache->curve_mask_size = 0;
+  MEM_SAFE_FREE(curve_mask_cache->curve_mask);
+}
+
+static void curve_mask_allocate(CurveMaskCache *curve_mask_cache, const int diameter)
+{
+  const size_t curve_mask_size = diameter_to_curve_mask_size(diameter);
+  curve_mask_cache->curve_mask = static_cast<unsigned short *>(
+      MEM_mallocN(curve_mask_size, __func__));
+  curve_mask_cache->curve_mask_size = curve_mask_size;
+}
+
+}  // namespace blender::ed::sculpt_paint
+
+using namespace blender::ed::sculpt_paint;
+
+void paint_curve_mask_cache_free_data(CurveMaskCache *curve_mask_cache)
+{
+  curve_mask_free(curve_mask_cache);
+}
+
+void paint_curve_mask_cache_update(CurveMaskCache *curve_mask_cache,
+                                   const Brush *brush,
+                                   const int diameter,
+                                   const float radius,
+                                   const float cursor_position[2])
+{
+  if (!is_curve_mask_size_valid(curve_mask_cache, diameter)) {
+    curve_mask_free(curve_mask_cache);
+    curve_mask_allocate(curve_mask_cache, diameter);
+  }
+  update_curve_mask(curve_mask_cache, brush, diameter, radius, cursor_position);
+}
+