Cleanup: Alembic, moved exporter code into separate directory

This moves most of the exporter-related code
from `source/blender/io/alembic/intern`
to   `source/blender/io/alembic/exporter`

This is to prepare the Alembic code for the switchover to using
`blender::io::AbstractHierarchyIterator`. When that happens, a few more
files will be added, and having things in a separate 'exporter'
directory makes things less cluttered.

Note that exporting consists of multiple steps (determine export
hierarchy, create Alembic archive, and then write data into it), which
is why the directory is called "exporter", but many of the files are
called "writer".

No functional changes.

1 files changed, 239 insertions, 0 deletions

diff --git a/source/blender/io/alembic/exporter/abc_export_capi.cc b/source/blender/io/alembic/exporter/abc_export_capi.cc
new file mode 100644
index 00000000000..3f8e95a6128
--- /dev/null
+++ b/source/blender/io/alembic/exporter/abc_export_capi.cc
@@ -0,0 +1,239 @@
+/*
+ * 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) 2020 Blender Foundation.
+ * All rights reserved.
+ */
+
+#include "ABC_alembic.h"
+#include "abc_writer_camera.h"
+#include "abc_writer_curves.h"
+#include "abc_writer_hair.h"
+#include "abc_writer_mesh.h"
+#include "abc_writer_nurbs.h"
+#include "abc_writer_points.h"
+#include "abc_writer_transform.h"
+
+#include "MEM_guardedalloc.h"
+
+extern "C" {
+#include "DEG_depsgraph.h"
+#include "DEG_depsgraph_build.h"
+
+#include "DNA_modifier_types.h"
+#include "DNA_scene_types.h"
+
+#include "BKE_blender_version.h"
+#include "BKE_context.h"
+#include "BKE_global.h"
+#include "BKE_main.h"
+#include "BKE_scene.h"
+
+#include "BLI_fileops.h"
+#include "BLI_path_util.h"
+#include "BLI_string.h"
+
+#include "WM_api.h"
+#include "WM_types.h"
+}
+
+struct ExportJobData {
+  ViewLayer *view_layer;
+  Main *bmain;
+  wmWindowManager *wm;
+
+  char filename[1024];
+  ExportSettings settings;
+
+  short *stop;
+  short *do_update;
+  float *progress;
+
+  bool was_canceled;
+  bool export_ok;
+};
+
+static void export_startjob(void *customdata, short *stop, short *do_update, float *progress)
+{
+  ExportJobData *data = static_cast<ExportJobData *>(customdata);
+
+  data->stop = stop;
+  data->do_update = do_update;
+  data->progress = progress;
+
+  /* XXX annoying hack: needed to prevent data corruption when changing
+   * scene frame in separate threads
+   */
+  G.is_rendering = true;
+  WM_set_locked_interface(data->wm, true);
+  G.is_break = false;
+
+  DEG_graph_build_from_view_layer(
+      data->settings.depsgraph, data->bmain, data->settings.scene, data->view_layer);
+  BKE_scene_graph_update_tagged(data->settings.depsgraph, data->bmain);
+
+  try {
+    AbcExporter exporter(data->bmain, data->filename, data->settings);
+
+    Scene *scene = data->settings.scene; /* for the CFRA macro */
+    const int orig_frame = CFRA;
+
+    data->was_canceled = false;
+    exporter(do_update, progress, &data->was_canceled);
+
+    if (CFRA != orig_frame) {
+      CFRA = orig_frame;
+
+      BKE_scene_graph_update_for_newframe(data->settings.depsgraph, data->bmain);
+    }
+
+    data->export_ok = !data->was_canceled;
+  }
+  catch (const std::exception &e) {
+    ABC_LOG(data->settings.logger) << "Abc Export error: " << e.what() << '\n';
+  }
+  catch (...) {
+    ABC_LOG(data->settings.logger) << "Abc Export: unknown error...\n";
+  }
+}
+
+static void export_endjob(void *customdata)
+{
+  ExportJobData *data = static_cast<ExportJobData *>(customdata);
+
+  DEG_graph_free(data->settings.depsgraph);
+
+  if (data->was_canceled && BLI_exists(data->filename)) {
+    BLI_delete(data->filename, false, false);
+  }
+
+  std::string log = data->settings.logger.str();
+  if (!log.empty()) {
+    std::cerr << log;
+    WM_report(RPT_ERROR, "Errors occurred during the export, look in the console to know more...");
+  }
+
+  G.is_rendering = false;
+  WM_set_locked_interface(data->wm, false);
+}
+
+bool ABC_export(struct Scene *scene,
+                struct bContext *C,
+                const char *filepath,
+                const struct AlembicExportParams *params,
+                bool as_background_job)
+{
+  ExportJobData *job = static_cast<ExportJobData *>(
+      MEM_mallocN(sizeof(ExportJobData), "ExportJobData"));
+
+  job->view_layer = CTX_data_view_layer(C);
+  job->bmain = CTX_data_main(C);
+  job->wm = CTX_wm_manager(C);
+  job->export_ok = false;
+  BLI_strncpy(job->filename, filepath, 1024);
+
+  /* Alright, alright, alright....
+   *
+   * ExportJobData contains an ExportSettings containing a SimpleLogger.
+   *
+   * Since ExportJobData is a C-style struct dynamically allocated with
+   * MEM_mallocN (see above), its constructor is never called, therefore the
+   * ExportSettings constructor is not called which implies that the
+   * SimpleLogger one is not called either. SimpleLogger in turn does not call
+   * the constructor of its data members which ultimately means that its
+   * std::ostringstream member has a NULL pointer. To be able to properly use
+   * the stream's operator<<, the pointer needs to be set, therefore we have
+   * to properly construct everything. And this is done using the placement
+   * new operator as here below. It seems hackish, but I'm too lazy to
+   * do bigger refactor and maybe there is a better way which does not involve
+   * hardcore refactoring. */
+  new (&job->settings) ExportSettings();
+  job->settings.scene = scene;
+  job->settings.depsgraph = DEG_graph_new(job->bmain, scene, job->view_layer, DAG_EVAL_RENDER);
+
+  /* TODO(Sybren): for now we only export the active scene layer.
+   * Later in the 2.8 development process this may be replaced by using
+   * a specific collection for Alembic I/O, which can then be toggled
+   * between "real" objects and cached Alembic files. */
+  job->settings.view_layer = job->view_layer;
+
+  job->settings.frame_start = params->frame_start;
+  job->settings.frame_end = params->frame_end;
+  job->settings.frame_samples_xform = params->frame_samples_xform;
+  job->settings.frame_samples_shape = params->frame_samples_shape;
+  job->settings.shutter_open = params->shutter_open;
+  job->settings.shutter_close = params->shutter_close;
+
+  /* TODO(Sybren): For now this is ignored, until we can get selection
+   * detection working through Base pointers (instead of ob->flags). */
+  job->settings.selected_only = params->selected_only;
+
+  job->settings.export_face_sets = params->face_sets;
+  job->settings.export_normals = params->normals;
+  job->settings.export_uvs = params->uvs;
+  job->settings.export_vcols = params->vcolors;
+  job->settings.export_hair = params->export_hair;
+  job->settings.export_particles = params->export_particles;
+  job->settings.apply_subdiv = params->apply_subdiv;
+  job->settings.curves_as_mesh = params->curves_as_mesh;
+  job->settings.flatten_hierarchy = params->flatten_hierarchy;
+
+  /* TODO(Sybren): visible_layer & renderable only is ignored for now,
+   * to be replaced with collections later in the 2.8 dev process
+   * (also see note above). */
+  job->settings.visible_objects_only = params->visible_objects_only;
+  job->settings.renderable_only = params->renderable_only;
+
+  job->settings.use_subdiv_schema = params->use_subdiv_schema;
+  job->settings.pack_uv = params->packuv;
+  job->settings.global_scale = params->global_scale;
+  job->settings.triangulate = params->triangulate;
+  job->settings.quad_method = params->quad_method;
+  job->settings.ngon_method = params->ngon_method;
+
+  if (job->settings.frame_start > job->settings.frame_end) {
+    std::swap(job->settings.frame_start, job->settings.frame_end);
+  }
+
+  bool export_ok = false;
+  if (as_background_job) {
+    wmJob *wm_job = WM_jobs_get(CTX_wm_manager(C),
+                                CTX_wm_window(C),
+                                job->settings.scene,
+                                "Alembic Export",
+                                WM_JOB_PROGRESS,
+                                WM_JOB_TYPE_ALEMBIC);
+
+    /* setup job */
+    WM_jobs_customdata_set(wm_job, job, MEM_freeN);
+    WM_jobs_timer(wm_job, 0.1, NC_SCENE | ND_FRAME, NC_SCENE | ND_FRAME);
+    WM_jobs_callbacks(wm_job, export_startjob, NULL, NULL, export_endjob);
+
+    WM_jobs_start(CTX_wm_manager(C), wm_job);
+  }
+  else {
+    /* Fake a job context, so that we don't need NULL pointer checks while exporting. */
+    short stop = 0, do_update = 0;
+    float progress = 0.f;
+
+    export_startjob(job, &stop, &do_update, &progress);
+    export_endjob(job);
+    export_ok = job->export_ok;
+
+    MEM_freeN(job);
+  }
+
+  return export_ok;
+}