fix T59743: Collada exporter: Add option for exporting flat curves

The Collada exporter suppresses the export of flat animation curves
to optimize the animation (in fact to make the exported file smaller).

But sometimes it is important to also have the flat curves exported
because they may be needed to define an initial transformation to
a fixed location - like translating the weapon from the ground floor
to the back of the model in the report.

I added a new option "all keyed curves" which is disabled by default
but when enabled it also exports flat curves.

feedback is very welcome

2 files changed, 10 insertions, 3 deletions

diff --git a/source/blender/collada/AnimationExporter.cpp b/source/blender/collada/AnimationExporter.cpp
index 69a25ac7a82..f6d9bee4563 100644
--- a/source/blender/collada/AnimationExporter.cpp
+++ b/source/blender/collada/AnimationExporter.cpp
@@ -148,6 +148,7 @@ void AnimationExporter::exportAnimation(Object *ob, BCAnimationSampler &sampler)
 	 * However Armatures also can have Object animation.
 	 */
 	bool export_as_matrix = this->export_settings->export_transformation_type == BC_TRANSFORMATION_TYPE_MATRIX;
+
 	if (export_as_matrix) {
 		export_matrix_animation(ob, sampler); // export all transform_curves as one single matrix animation
 	}
@@ -184,6 +185,7 @@ void AnimationExporter::exportAnimation(Object *ob, BCAnimationSampler &sampler)
 void AnimationExporter::export_curve_animation_set(Object *ob, BCAnimationSampler &sampler, bool export_as_matrix)
 {
 	BCAnimationCurveMap *curves = sampler.get_curves(ob);
+	bool keep_flat_curves = this->export_settings->keep_flat_curves;
 
 	BCAnimationCurveMap::iterator it;
 	for (it = curves->begin(); it != curves->end(); ++it) {
@@ -205,7 +207,7 @@ void AnimationExporter::export_curve_animation_set(Object *ob, BCAnimationSample
 			continue;
 		}
 
-		if (!curve.is_animated()) {
+		if (!keep_flat_curves && !curve.is_animated()) {
 			continue;
 		}
 
@@ -222,12 +224,14 @@ void AnimationExporter::export_curve_animation_set(Object *ob, BCAnimationSample
 
 void AnimationExporter::export_matrix_animation(Object *ob, BCAnimationSampler &sampler)
 {
+	bool keep_flat_curves = this->export_settings->keep_flat_curves;
+
 	std::vector<float> frames;
 	sampler.get_object_frames(frames, ob);
 	if (frames.size() > 0) {
 		BCMatrixSampleMap samples;
 		bool is_animated = sampler.get_object_samples(samples, ob);
-		if (is_animated) {
+		if (keep_flat_curves || is_animated) {
 			bAction *action = bc_getSceneObjectAction(ob);
 			std::string name = encode_xml(id_name(ob));
 			std::string action_name = (action == NULL) ? name + "-action" : id_name(action);
@@ -245,13 +249,15 @@ void AnimationExporter::export_matrix_animation(Object *ob, BCAnimationSampler &
 //write bone animations in transform matrix sources
 void AnimationExporter::export_bone_animations_recursive(Object *ob, Bone *bone, BCAnimationSampler &sampler)
 {
+	bool keep_flat_curves = this->export_settings->keep_flat_curves;
+
 	std::vector<float> frames;
 	sampler.get_bone_frames(frames, ob, bone);
 
 	if (frames.size()) {
 		BCMatrixSampleMap samples;
 		bool is_animated = sampler.get_bone_samples(samples, ob, bone);
-		if (is_animated) {
+		if (keep_flat_curves || is_animated) {
 			export_bone_animation(ob, bone, frames, samples);
 		}
 	}
diff --git a/source/blender/collada/ExportSettings.h b/source/blender/collada/ExportSettings.h
index 3b4397a6093..fa4f0ccb2e1 100644
--- a/source/blender/collada/ExportSettings.h
+++ b/source/blender/collada/ExportSettings.h
@@ -71,6 +71,7 @@ typedef struct ExportSettings {
 	int sampling_rate;
 	bool keep_smooth_curves;
 	bool keep_keyframes;
+	bool keep_flat_curves;
 
 	bool active_uv_only;
 	BC_export_animation_type export_animation_type;