Support half float file format storage for Multilayer EXR

Quite straightforward implementation -- all the conversion magic is
happening in IMB_exr_write_channels() and remained changes are only
needed to pass information whether channels is to be converted to
half float or not.

Regular file output will use full-float for Z pass, which matches
behavior of the single layer EXR files. But when saving happens
with File Output node then all the passes are respecting half float
settings because it's not possible to distinguish whether we're
saving Z pass or not.

Reviewers: juicyfruit, campbellbarton

Reviewed By: campbellbarton

Subscribers: maxon, effstops, fsiddi

Differential Revision: https://developer.blender.org/D1353

1 files changed, 5 insertions, 1 deletions

diff --git a/source/blender/imbuf/intern/openexr/openexr_multi.h b/source/blender/imbuf/intern/openexr/openexr_multi.h
index 77fa420322e..97e8042caa6 100644
--- a/source/blender/imbuf/intern/openexr/openexr_multi.h
+++ b/source/blender/imbuf/intern/openexr/openexr_multi.h
@@ -52,7 +52,11 @@ struct StampData;
 
 void *IMB_exr_get_handle(void);
 void *IMB_exr_get_handle_name(const char *name);
-void    IMB_exr_add_channel(void *handle, const char *layname, const char *passname, const char *view, int xstride, int ystride, float *rect);
+void  IMB_exr_add_channel(void *handle,
+                          const char *layname, const char *passname, const char *view,
+                          int xstride, int ystride,
+                          float *rect,
+                          bool use_half_float);
 
 int     IMB_exr_begin_read(void *handle, const char *filename, int *width, int *height);
 int     IMB_exr_begin_write(void *handle, const char *filename, int width, int height, int compress, const struct StampData *stamp);