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, 15 insertions, 11 deletions

diff --git a/source/blender/compositor/operations/COM_OutputFileOperation.cpp b/source/blender/compositor/operations/COM_OutputFileOperation.cpp
index b99b0d5b875..fdf5a0b48cf 100644
--- a/source/blender/compositor/operations/COM_OutputFileOperation.cpp
+++ b/source/blender/compositor/operations/COM_OutputFileOperation.cpp
@@ -40,23 +40,24 @@ extern "C" {
 #  include "IMB_imbuf_types.h"
 }
 
-void add_exr_channels(void *exrhandle, const char *layerName, const DataType datatype, const char *viewName, const size_t width, float *buf)
+void add_exr_channels(void *exrhandle, const char *layerName, const DataType datatype,
+                      const char *viewName, const size_t width, bool use_half_float, float *buf)
 {
 	/* create channels */
 	switch (datatype) {
 		case COM_DT_VALUE:
-			IMB_exr_add_channel(exrhandle, layerName, "V", viewName, 1, width, buf ? buf : NULL);
+			IMB_exr_add_channel(exrhandle, layerName, "V", viewName, 1, width, buf ? buf : NULL, use_half_float);
 			break;
 		case COM_DT_VECTOR:
-			IMB_exr_add_channel(exrhandle, layerName, "X", viewName, 3, 3 * width, buf ? buf : NULL);
-			IMB_exr_add_channel(exrhandle, layerName, "Y", viewName, 3, 3 * width, buf ? buf + 1 : NULL);
-			IMB_exr_add_channel(exrhandle, layerName, "Z", viewName, 3, 3 * width, buf ? buf + 2 : NULL);
+			IMB_exr_add_channel(exrhandle, layerName, "X", viewName, 3, 3 * width, buf ? buf : NULL, use_half_float);
+			IMB_exr_add_channel(exrhandle, layerName, "Y", viewName, 3, 3 * width, buf ? buf + 1 : NULL, use_half_float);
+			IMB_exr_add_channel(exrhandle, layerName, "Z", viewName, 3, 3 * width, buf ? buf + 2 : NULL, use_half_float);
 			break;
 		case COM_DT_COLOR:
-			IMB_exr_add_channel(exrhandle, layerName, "R", viewName, 4, 4 * width, buf ? buf : NULL);
-			IMB_exr_add_channel(exrhandle, layerName, "G", viewName, 4, 4 * width, buf ? buf + 1 : NULL);
-			IMB_exr_add_channel(exrhandle, layerName, "B", viewName, 4, 4 * width, buf ? buf + 2 : NULL);
-			IMB_exr_add_channel(exrhandle, layerName, "A", viewName, 4, 4 * width, buf ? buf + 3 : NULL);
+			IMB_exr_add_channel(exrhandle, layerName, "R", viewName, 4, 4 * width, buf ? buf : NULL, use_half_float);
+			IMB_exr_add_channel(exrhandle, layerName, "G", viewName, 4, 4 * width, buf ? buf + 1 : NULL, use_half_float);
+			IMB_exr_add_channel(exrhandle, layerName, "B", viewName, 4, 4 * width, buf ? buf + 2 : NULL, use_half_float);
+			IMB_exr_add_channel(exrhandle, layerName, "A", viewName, 4, 4 * width, buf ? buf + 3 : NULL, use_half_float);
 			break;
 		default:
 			break;
@@ -227,13 +228,15 @@ OutputOpenExrLayer::OutputOpenExrLayer(const char *name_, DataType datatype_, bo
 }
 
 OutputOpenExrMultiLayerOperation::OutputOpenExrMultiLayerOperation(
-        const RenderData *rd, const bNodeTree *tree, const char *path, char exr_codec, const char *viewName)
+        const RenderData *rd, const bNodeTree *tree, const char *path,
+        char exr_codec, bool exr_half_float, const char *viewName)
 {
 	this->m_rd = rd;
 	this->m_tree = tree;
 	
 	BLI_strncpy(this->m_path, path, sizeof(this->m_path));
 	this->m_exr_codec = exr_codec;
+	this->m_exr_half_float = exr_half_float;
 	this->m_viewName = viewName;
 }
 
@@ -284,7 +287,8 @@ void OutputOpenExrMultiLayerOperation::deinitExecution()
 			if (!layer.imageInput)
 				continue; /* skip unconnected sockets */
 			
-			add_exr_channels(exrhandle, this->m_layers[i].name, this->m_layers[i].datatype, "", width, this->m_layers[i].outputBuffer);
+			add_exr_channels(exrhandle, this->m_layers[i].name, this->m_layers[i].datatype, "", width,
+			                 this->m_exr_half_float, this->m_layers[i].outputBuffer);
 		}
 		
 		/* when the filename has no permissions, this can fail */