1 files changed, 131 insertions, 0 deletions
diff --git a/source/blender/blenkernel/intern/paint_canvas.cc b/source/blender/blenkernel/intern/paint_canvas.cc
new file mode 100644
index 00000000000..b72418d88c0
--- /dev/null
+++ b/source/blender/blenkernel/intern/paint_canvas.cc
@@ -0,0 +1,131 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#include "BLI_compiler_compat.h"
+
+#include "DNA_material_types.h"
+#include "DNA_mesh_types.h"
+#include "DNA_scene_types.h"
+
+#include "BKE_customdata.h"
+#include "BKE_image.h"
+#include "BKE_material.h"
+#include "BKE_paint.h"
+
+#include "IMB_imbuf_types.h"
+
+namespace blender::bke::paint::canvas {
+static TexPaintSlot *get_active_slot(Object *ob)
+{
+  Material *mat = BKE_object_material_get(ob, ob->actcol);
+  if (mat == nullptr) {
+    return nullptr;
+  }
+  if (mat->texpaintslot == nullptr) {
+    return nullptr;
+  }
+  if (mat->paint_active_slot >= mat->tot_slots) {
+    return nullptr;
+  }
+
+  TexPaintSlot *slot = &mat->texpaintslot[mat->paint_active_slot];
+  return slot;
+}
+
+}  // namespace blender::bke::paint::canvas
+
+extern "C" {
+
+using namespace blender::bke::paint::canvas;
+
+bool BKE_paint_canvas_image_get(PaintModeSettings *settings,
+                                Object *ob,
+                                Image **r_image,
+                                ImageUser **r_image_user)
+{
+  *r_image = nullptr;
+  *r_image_user = nullptr;
+
+  switch (settings->canvas_source) {
+    case PAINT_CANVAS_SOURCE_COLOR_ATTRIBUTE:
+      break;
+
+    case PAINT_CANVAS_SOURCE_IMAGE:
+      *r_image = settings->canvas_image;
+      *r_image_user = &settings->image_user;
+      break;
+
+    case PAINT_CANVAS_SOURCE_MATERIAL: {
+      TexPaintSlot *slot = get_active_slot(ob);
+      if (slot == nullptr) {
+        break;
+      }
+
+      *r_image = slot->ima;
+      *r_image_user = slot->image_user;
+      break;
+    }
+  }
+  return *r_image != nullptr;
+}
+
+int BKE_paint_canvas_uvmap_layer_index_get(const struct PaintModeSettings *settings,
+                                           struct Object *ob)
+{
+  switch (settings->canvas_source) {
+    case PAINT_CANVAS_SOURCE_COLOR_ATTRIBUTE:
+      return -1;
+    case PAINT_CANVAS_SOURCE_IMAGE: {
+      /* Use active uv map of the object. */
+      if (ob->type != OB_MESH) {
+        return -1;
+      }
+
+      const Mesh *mesh = static_cast<Mesh *>(ob->data);
+      return CustomData_get_active_layer_index(&mesh->ldata, CD_MLOOPUV);
+    }
+    case PAINT_CANVAS_SOURCE_MATERIAL: {
+      /* Use uv map of the canvas. */
+      TexPaintSlot *slot = get_active_slot(ob);
+      if (slot == nullptr) {
+        break;
+      }
+
+      if (ob->type != OB_MESH) {
+        return -1;
+      }
+
+      if (slot->uvname == nullptr) {
+        return -1;
+      }
+
+      const Mesh *mesh = static_cast<Mesh *>(ob->data);
+      return CustomData_get_named_layer_index(&mesh->ldata, CD_MLOOPUV, slot->uvname);
+    }
+  }
+  return -1;
+}
+
+char *BKE_paint_canvas_key_get(struct PaintModeSettings *settings, struct Object *ob)
+{
+  std::stringstream ss;
+  int active_uv_map_layer_index = BKE_paint_canvas_uvmap_layer_index_get(settings, ob);
+  ss << "UV_MAP:" << active_uv_map_layer_index;
+
+  Image *image;
+  ImageUser *image_user;
+  if (BKE_paint_canvas_image_get(settings, ob, &image, &image_user)) {
+    ImageUser tile_user = *image_user;
+    LISTBASE_FOREACH (ImageTile *, image_tile, &image->tiles) {
+      tile_user.tile = image_tile->tile_number;
+      ImBuf *image_buffer = BKE_image_acquire_ibuf(image, &tile_user, nullptr);
+      if (!image_buffer) {
+        continue;
+      }
+      ss << ",TILE_" << image_tile->tile_number;
+      ss << "(" << image_buffer->x << "," << image_buffer->y << ")";
+      BKE_image_release_ibuf(image, image_buffer, nullptr);
+    }
+  }
+
+  return BLI_strdup(ss.str().c_str());
+}
+}