Skip to content

Cycles : Simplify transform handling #7136

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
murraystevenson merged 2 commits into from
Sep 4, 2026
+55 −175
Merged

Cycles : Simplify transform handling #7136

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
8b09266
Cycles : Simplify transform handling for cameras
johnhaddon Sep 2, 2026
8b988a2
Cycles : Simplify object transform handling
johnhaddon Sep 2, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
10 changes: 8 additions & 2 deletions src/GafferCycles/IECoreCyclesPreview/CameraAlgo.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -77,7 +77,12 @@ void IECoreCycles::CameraAlgo::convert( const IECoreScene::Camera *source, ccl::
destination->set_full_height( resolution[1] );
destination->set_viewplane_left( frustum.min.x );
destination->set_viewplane_right( frustum.max.x );
// Invert the viewplane in Y so Gaffer's aperture offsets and overscan are applied in the correct direction
// Invert the viewplane in Y so Gaffer's aperture offsets and overscan are
// applied in the correct direction.
/// \todo This forces us to flip in Y in `CyclesCamera::transform()` to
/// compensate. I suspect the real issue is that our display driver API is top-down
/// and Cycles is bottom-up. If we fixed in the display driver then I think
/// CameraAlgo and CyclesCamera could just do the obvious thing.
destination->set_viewplane_bottom( -frustum.max.y );
destination->set_viewplane_top( -frustum.min.y );
destination->set_aperture_ratio( pixelAspectRatio ); // This is more for the bokeh, maybe it should be a separate parameter?
Expand All @@ -98,7 +103,8 @@ void IECoreCycles::CameraAlgo::convert( const IECoreScene::Camera *source, ccl::
}

/// \todo Set `motion_position`. We'd need to do this by comparing the camera's shutter
/// to the Renderer's `frame` option.
/// to the Renderer's `frame` option. I don't know how important this is - it only seems
/// to be used by Cycles for volume motion blur.

// Additional parameters

Expand Down
214 changes: 44 additions & 170 deletions src/GafferCycles/IECoreCyclesPreview/Renderer.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1622,10 +1622,10 @@ class CyclesObject : public IECoreScenePreview::Renderer::ObjectInterface

public :

CyclesObject( ccl::Scene *scene, const SharedGeometryPtr &geometry, const std::string &name, const float frame, LightLinker *lightLinker, NodeDeleter *nodeDeleter )
CyclesObject( ccl::Scene *scene, const SharedGeometryPtr &geometry, const std::string &name, LightLinker *lightLinker, NodeDeleter *nodeDeleter )
: m_scene( scene ),
m_object( SceneAlgo::createNodeWithLock<ccl::Object>( scene ), NodeDeleter::ObjectDeleter( nodeDeleter ) ),
m_geometry( geometry ), m_frame( frame ), m_attributes( nullptr ), m_lightLinker( lightLinker )
m_geometry( geometry ), m_attributes( nullptr ), m_lightLinker( lightLinker )
{
assert( m_geometry );
m_object->name = ccl::ustring( name.c_str() );
Expand Down Expand Up @@ -1699,119 +1699,38 @@ class CyclesObject : public IECoreScenePreview::Renderer::ObjectInterface

void transform( const IECoreScenePreview::Renderer::TransformSamples &samples, const IECoreScenePreview::Renderer::SampleTimes &times ) override
{
ccl::array<ccl::Transform> motion;
ccl::Geometry *geo = m_object->get_geometry();
if( geo->get_use_motion_blur() && geo->get_motion_steps() != samples.size() )
{
IECore::msg(
IECore::Msg::Error, "IECoreCycles::Renderer",
fmt::format( "Transform step size on \"{}\" must match deformation step size.", m_object->name.c_str() )
);
m_object->set_tfm( SocketAlgo::setTransform( samples.front() ) );
motion.resize( geo->get_motion_steps(), ccl::transform_empty() );
for( size_t i = 0; i < motion.size(); ++i )
{
motion[i] = m_object->get_tfm();
m_object->set_motion( motion );
}
SceneAlgo::tagUpdateWithLock( m_object.get(), m_scene );
return;
}

const size_t numSamples = samples.size();
const size_t primarySampleIndex = (samples.size() - 1) / 2;
m_object->set_tfm( SocketAlgo::setTransform( samples[primarySampleIndex] ) );

if( numSamples == 1 )
{
m_object->set_tfm( SocketAlgo::setTransform( samples.front() ) );
SceneAlgo::tagUpdateWithLock( m_object.get(), m_scene );
return;
}

int frameIdx = -1;
for( size_t i = 0; i < numSamples; ++i )
{
if( times[i] == m_frame )
{
frameIdx = i;
}
}

if( numSamples % 2 ) // Odd numSamples
{
motion.resize( numSamples, ccl::transform_empty() );

for( int i = 0; i < (int)numSamples; ++i )
{
if( i == frameIdx )
{
m_object->set_tfm( SocketAlgo::setTransform( samples[i] ) );
}

motion[i] = SocketAlgo::setTransform( samples[i] );
}
}
else if( numSamples == 2 )
{
Imath::M44f matrix;
motion.resize( numSamples+1, ccl::transform_empty() );
IECore::LinearInterpolator<Imath::M44f>()( samples[0], samples[1], 0.5f, matrix );

if( frameIdx == -1 ) // Center frame
{
m_object->set_tfm( SocketAlgo::setTransform( matrix ) );
}
else if( frameIdx == 0 ) // Start frame
{
m_object->set_tfm( SocketAlgo::setTransform( samples[0] ) );
}
else // End frame
{
m_object->set_tfm( SocketAlgo::setTransform( samples[1] ) );
}
motion[0] = SocketAlgo::setTransform( samples[0] );
motion[1] = SocketAlgo::setTransform( matrix );
motion[2] = SocketAlgo::setTransform( samples[1] );
}
else // Even numSamples
ccl::array<ccl::Transform> motion;
if( samples.size() > 1 )
{
motion.resize( numSamples, ccl::transform_empty() );

if( frameIdx == -1 ) // Center frame
{
const int mid = numSamples / 2 - 1;
Imath::M44f matrix;
IECore::LinearInterpolator<Imath::M44f>()( samples[mid], samples[mid+1], 0.5f, matrix );
m_object->set_tfm( SocketAlgo::setTransform( matrix ) );
}
else if( frameIdx == 0 ) // Start frame
{
m_object->set_tfm( SocketAlgo::setTransform( samples[0] ) );
}
else // End frame
{
m_object->set_tfm( SocketAlgo::setTransform( samples[numSamples-1] ) );
}

for( size_t i = 0; i < numSamples; ++i )
motion.resize( samples.size() );
for( size_t i = 0; i < samples.size(); ++i )
{
motion[i] = SocketAlgo::setTransform( samples[i] );
}
}

m_object->set_motion( motion );
if( !geo->get_use_motion_blur() )
{
/// \todo This is not thread-safe, nor is it compatible
/// with instancing.
geo->set_motion_steps( motion.size() );
}

if( geo->is_mesh() )
if( m_geometry->is_mesh() )
{
auto mesh = static_cast<ccl::Mesh *>( geo );
if( mesh->get_num_subd_faces() )
auto mesh = static_cast<ccl::Mesh *>( m_geometry.get() );
if( mesh->get_subdivision_type() != ccl::Mesh::SUBDIVISION_NONE )
{
mesh->set_subd_objecttoworld( m_object->get_tfm() );
if( mesh->get_subd_adaptive_space() == ccl::Mesh::SUBDIVISION_ADAPTIVE_SPACE_PIXEL )
{
// View-dependent subdivs aren't auto-instanced, so we
// should be the only one managing `subd_objecttoworld`.
assert( m_geometry.use_count() == 1 );
mesh->set_subd_objecttoworld( m_object->get_tfm() );
SceneAlgo::tagUpdateWithLock( m_geometry.get(), m_scene, /* rebuild = */ true );
}
else
{
// Non-view-dependent subdivs don't use `subd_objecttoworld`,
// so we don't need to set it.
}
}
}

Expand Down Expand Up @@ -1847,7 +1766,6 @@ class CyclesObject : public IECoreScenePreview::Renderer::ObjectInterface
using UniqueObjectPtr = std::unique_ptr<ccl::Object, NodeDeleter::ObjectDeleter>;
UniqueObjectPtr m_object;
SharedGeometryPtr m_geometry;
const float m_frame;
ConstCyclesAttributesPtr m_attributes;
LightLinker *m_lightLinker;
IECoreScenePreview::Renderer::ConstObjectSetPtr m_linkedLights;
Expand Down Expand Up @@ -2103,9 +2021,9 @@ class CyclesCamera : public IECoreScenePreview::Renderer::ObjectInterface
IE_CORE_DECLAREMEMBERPTR( CyclesCamera );

CyclesCamera( const IECoreScene::ConstCameraPtr &camera )
: m_camera( camera ),
m_transformSamples( { M44f() } )
: m_camera( camera )
{
transform( { M44f() }, { 0.0f } );
}

~CyclesCamera() override
Expand All @@ -2118,7 +2036,16 @@ class CyclesCamera : public IECoreScenePreview::Renderer::ObjectInterface

void transform( const IECoreScenePreview::Renderer::TransformSamples &samples, const IECoreScenePreview::Renderer::SampleTimes &times ) override
{
m_transformSamples = samples;
m_transformSamples.resize( samples.size() );
for( size_t i = 0; i < samples.size(); ++i )
{
/// \todo Should we really be scaling in Y? It seems we're doing
/// it to counteract the flipping of the top/bottom view planes
/// in CameraAlgo, so perhaps we can stop doing that?
M44f m = samples[i];
m.scale( Imath::V3f( 1, -1, -1 ) );
m_transformSamples[i] = SocketAlgo::setTransform( m );
}
}

bool attributes( const IECoreScenePreview::Renderer::AttributesInterface *attributes ) override
Expand All @@ -2139,69 +2066,16 @@ class CyclesCamera : public IECoreScenePreview::Renderer::ObjectInterface
{
CameraAlgo::convert( m_camera.get(), destination );

const size_t numSamples = m_transformSamples.size();
const size_t primarySampleIndex = (m_transformSamples.size() - 1) / 2;
destination->set_matrix( m_transformSamples[primarySampleIndex] );

ccl::array<ccl::Transform> motion;

const Imath::V3f scale = Imath::V3f( 1.0f, -1.0f, -1.0f );
Imath::M44f matrix;

if( destination->get_motion_position() == ccl::MOTION_POSITION_START )
{
matrix = m_transformSamples.front();
matrix.scale( scale );
destination->set_matrix( SocketAlgo::setTransform( matrix ) );
if( numSamples != 1 )
{
motion = ccl::array<ccl::Transform>( 3 );
motion[0] = destination->get_matrix();
IECore::LinearInterpolator<Imath::M44f>()( m_transformSamples.front(), m_transformSamples.back(), 0.5f, matrix );
matrix.scale( scale );
motion[1] = SocketAlgo::setTransform( matrix );
matrix = m_transformSamples.back();
matrix.scale( scale );
motion[2] = SocketAlgo::setTransform( matrix );
}
}
else if( destination->get_motion_position() == ccl::MOTION_POSITION_END )
if( m_transformSamples.size() > 1 )
{
matrix = m_transformSamples.back();
matrix.scale( scale );
destination->set_matrix( SocketAlgo::setTransform( matrix ) );
if( numSamples != 1 )
motion.resize( m_transformSamples.size() );
for( size_t i = 0; i < m_transformSamples.size(); ++i )
{
motion = ccl::array<ccl::Transform>( 3 );
motion[0] = destination->get_matrix();
IECore::LinearInterpolator<Imath::M44f>()( m_transformSamples.back(), m_transformSamples.front(), 0.5f, matrix );
matrix.scale( scale );
motion[1] = SocketAlgo::setTransform( matrix );
matrix = m_transformSamples.front();
matrix.scale( scale );
motion[2] = SocketAlgo::setTransform( matrix );
}
}
else // ccl::Camera::MOTION_POSITION_CENTER
{
if( numSamples == 1 ) // One sample
{
matrix = m_transformSamples.front();
matrix.scale( scale );
destination->set_matrix( SocketAlgo::setTransform( matrix ) );
}
else
{
IECore::LinearInterpolator<Imath::M44f>()( m_transformSamples.front(), m_transformSamples.back(), 0.5f, matrix );
matrix.scale( scale );
destination->set_matrix( SocketAlgo::setTransform( matrix ) );

motion = ccl::array<ccl::Transform>( 3 );
matrix = m_transformSamples.front();
matrix.scale( scale );
motion[0] = SocketAlgo::setTransform( matrix );
motion[1] = destination->get_matrix();
matrix = m_transformSamples.back();
matrix.scale( scale );
motion[2] = SocketAlgo::setTransform( matrix );
motion[i] = m_transformSamples[i];
}
}
destination->set_motion( motion );
Expand All @@ -2210,7 +2084,7 @@ class CyclesCamera : public IECoreScenePreview::Renderer::ObjectInterface
private :

IECoreScene::ConstCameraPtr m_camera;
IECoreScenePreview::Renderer::TransformSamples m_transformSamples;
ccl::array<ccl::Transform> m_transformSamples;

};

Expand Down Expand Up @@ -2587,7 +2461,7 @@ class CyclesRenderer final : public IECoreScenePreview::Renderer
return nullptr;
}

ObjectInterfacePtr result = new CyclesObject( m_scene, geometry, name, frame(), &m_lightLinker, m_nodeDeleter.get() );
ObjectInterfacePtr result = new CyclesObject( m_scene, geometry, name, &m_lightLinker, m_nodeDeleter.get() );
result->attributes( attributes );
return result;
}
Expand Down
6 changes: 3 additions & 3 deletions src/GafferCycles/IECoreCyclesPreview/SceneAlgo.h
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -50,11 +50,11 @@ template<typename T, typename... Args> T *createNodeWithLock( ccl::Scene *scene,
return scene->create_node<T>( std::forward<Args>( args )... );
}

template<typename T>
void tagUpdateWithLock( T *node, ccl::Scene *scene )
template<typename T, typename... Args>
void tagUpdateWithLock( T *node, ccl::Scene *scene, Args &&...args )
{
std::scoped_lock lock( scene->mutex );
node->tag_update( scene );
node->tag_update( scene, std::forward<Args>( args )... );
}

} // IECoreCycles::SceneAlgo
Loading