Cleanup: CacheFile, use double precision for time

Both the Alembic and USD libraries use double precision floating
point numbers internally to store time. However the Alembic I/O
code defaulted to floats even though Blender's Scene FPS, which is
generally used for look ups, is stored using a double type. Such
downcasts could lead to imprecise lookups, and would cause
compilation warnings (at least on MSVC).

This modifies the Alembic exporter and importer to make use of
doubles for the current scene time, and only downcasting to float
at the very last steps (e.g. for vertex interpolation). For the
importer, doubles are also used for computing interpolation weights,
as it is based on a time offset.

Although the USD code already used doubles internally, floats were used
at the C API level. Those were replaced as well.

Differential Revision: https://developer.blender.org/D13855

1 files changed, 6 insertions, 6 deletions

diff --git a/source/blender/io/alembic/intern/alembic_capi.cc b/source/blender/io/alembic/intern/alembic_capi.cc
index c9c982aad6c..fe459ce4370 100644
--- a/source/blender/io/alembic/intern/alembic_capi.cc
+++ b/source/blender/io/alembic/intern/alembic_capi.cc
@@ -497,7 +497,7 @@ static void import_startjob(void *user_data, short *stop, short *do_update, floa
   chrono_t min_time = std::numeric_limits<chrono_t>::max();
   chrono_t max_time = std::numeric_limits<chrono_t>::min();
 
-  ISampleSelector sample_sel(0.0f);
+  ISampleSelector sample_sel(0.0);
   std::vector<AbcObjectReader *>::iterator iter;
   for (iter = data->readers.begin(); iter != data->readers.end(); ++iter) {
     AbcObjectReader *reader = *iter;
@@ -555,7 +555,7 @@ static void import_startjob(void *user_data, short *stop, short *do_update, floa
   i = 0;
   for (iter = data->readers.begin(); iter != data->readers.end(); ++iter) {
     AbcObjectReader *reader = *iter;
-    reader->setupObjectTransform(0.0f);
+    reader->setupObjectTransform(0.0);
 
     *data->progress = 0.7f + 0.3f * (++i / size);
     *data->do_update = true;
@@ -724,7 +724,7 @@ bool ABC_import(bContext *C,
 
 /* ************************************************************************** */
 
-void ABC_get_transform(CacheReader *reader, float r_mat_world[4][4], float time, float scale)
+void ABC_get_transform(CacheReader *reader, float r_mat_world[4][4], double time, float scale)
 {
   if (!reader) {
     return;
@@ -775,7 +775,7 @@ static AbcObjectReader *get_abc_reader(CacheReader *reader, Object *ob, const ch
   return abc_reader;
 }
 
-static ISampleSelector sample_selector_for_time(float time)
+static ISampleSelector sample_selector_for_time(chrono_t time)
 {
   /* kFloorIndex is used to be compatible with non-interpolating
    * properties; they use the floor. */
@@ -785,7 +785,7 @@ static ISampleSelector sample_selector_for_time(float time)
 Mesh *ABC_read_mesh(CacheReader *reader,
                     Object *ob,
                     Mesh *existing_mesh,
-                    const float time,
+                    const double time,
                     const char **err_str,
                     const int read_flag,
                     const char *velocity_name,
@@ -804,7 +804,7 @@ Mesh *ABC_read_mesh(CacheReader *reader,
 bool ABC_mesh_topology_changed(CacheReader *reader,
                                Object *ob,
                                const Mesh *existing_mesh,
-                               const float time,
+                               const double time,
                                const char **err_str)
 {
   AbcObjectReader *abc_reader = get_abc_reader(reader, ob, err_str);