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DepthOffsetAttrib Class Reference

This is a special kind of attribute that instructs the graphics driver to apply an offset or bias to the generated depth values for rendered polygons, before they are written to the depth buffer. More...

#include <depthOffsetAttrib.h>

Inheritance diagram for DepthOffsetAttrib:

RenderAttrib TypedWritableReferenceCount TypedWritable ReferenceCount TypedObject List of all members.

Public Types

enum  PandaCompareFunc {
  M_none = 0, M_never, M_less, M_equal,
  M_less_equal, M_greater, M_not_equal, M_greater_equal,
  M_always
}

Public Member Functions

int get_offset () const
 Returns the depth offset represented by this attrib.

virtual void issue (GraphicsStateGuardianBase *gsg) const
 Calls the appropriate method on the indicated GSG to issue the graphics commands appropriate to the given attribute.

virtual void output (ostream &out) const
virtual void write_datagram (BamWriter *manager, Datagram &dg)
 Writes the contents of this object to the datagram for shipping out to a Bam file.

virtual TypeHandle get_type () const
virtual TypeHandle force_init_type ()
ConstPointerTo< RenderAttribcompose (const RenderAttrib *other) const
ConstPointerTo< RenderAttribinvert_compose (const RenderAttrib *other) const
ConstPointerTo< RenderAttribmake_default () const
int compare_to (const RenderAttrib &other) const
 Provides an arbitrary ordering among all unique RenderAttribs, so we can store the essentially different ones in a big set and throw away the rest.

virtual void write (ostream &out, int indent_level) const
virtual void finalize ()
 Method to ensure that any necessary clean up tasks that have to be performed by this object are performed.

virtual int complete_pointers (TypedWritable **p_list, BamReader *manager)
 Receives an array of pointers, one for each time manager->read_pointer() was called in fillin().

int get_type_index () const
 Returns the internal index number associated with this object's TypeHandle, a unique number for each different type.

bool is_of_type (TypeHandle handle) const
 Returns true if the current object is or derives from the indicated type.

bool is_exact_type (TypeHandle handle) const
 Returns true if the current object is the indicated type exactly.

int get_ref_count () const
 Returns the current reference count.

int ref () const
 Explicitly increments the reference count.

int unref () const
 Explicitly decrements the reference count.

void test_ref_count_integrity () const
 Does some easy checks to make sure that the reference count isn't completely bogus.


Static Public Member Functions

ConstPointerTo< RenderAttribmake (int offset=1)
 Constructs a new DepthOffsetAttrib object that indicates the relative amount of bias to write to the depth buffer for subsequent geometry.

void register_with_read_factory ()
 Tells the BamReader how to create objects of type DepthOffsetAttrib.

TypeHandle get_class_type ()
void init_type ()
TypedWritablechange_this (TypedWritable *old_ptr, BamReader *manager)
 Called immediately after complete_pointers(), this gives the object a chance to adjust its own pointer if desired.


Static Public Attributes

TypedWritable *const Null = (TypedWritable*)0L

Protected Member Functions

virtual int compare_to_impl (const RenderAttrib *other) const
 Intended to be overridden by derived DepthOffsetAttrib types to return a unique number indicating whether this DepthOffsetAttrib is equivalent to the other one.

virtual ConstPointerTo< RenderAttribcompose_impl (const RenderAttrib *other) const
 Intended to be overridden by derived RenderAttrib types to specify how two consecutive RenderAttrib objects of the same type interact.

virtual ConstPointerTo< RenderAttribinvert_compose_impl (const RenderAttrib *other) const
 Intended to be overridden by derived RenderAttrib types to specify how two consecutive RenderAttrib objects of the same type interact.

virtual RenderAttribmake_default_impl () const
 Intended to be overridden by derived DepthOffsetAttrib types to specify what the default property for a DepthOffsetAttrib of this type should be.

void fillin (DatagramIterator &scan, BamReader *manager)
 This internal function is called by make_from_bam to read in all of the relevant data from the BamFile for the new DepthOffsetAttrib.

void output_comparefunc (ostream &out, PandaCompareFunc fn) const

Static Protected Member Functions

TypedWritablemake_from_bam (const FactoryParams &params)
 This function is called by the BamReader's factory when a new object of type DepthOffsetAttrib is encountered in the Bam file.

ConstPointerTo< RenderAttribreturn_new (RenderAttrib *attrib)
 This function is used by derived RenderAttrib types to share a common RenderAttrib pointer for all equivalent RenderAttrib objects.

TypedWritablenew_from_bam (RenderAttrib *attrib, BamReader *manager)

Private Member Functions

 DepthOffsetAttrib (int offset)
 Use DepthOffsetAttrib::make() to construct a new DepthOffsetAttrib object.


Private Attributes

int _offset

Static Private Attributes

TypeHandle _type_handle

Detailed Description

This is a special kind of attribute that instructs the graphics driver to apply an offset or bias to the generated depth values for rendered polygons, before they are written to the depth buffer.

This can be used to shift polygons forward slightly, to resolve depth conflicts. The cull traverser may optionally use this, for instance, to implement decals. However, driver support for this feature seems to be spotty, so use with caution.

The bias is always an integer number, and each integer increment represents the smallest possible increment in Z that is sufficient to completely resolve two coplanar polygons. Positive numbers are closer towards the camera.

Nested DepthOffsetAttrib values accumulate; that is, a DepthOffsetAttrib with a value of 1 beneath another DepthOffsetAttrib with a value of 2 presents a net offset of 3. (A DepthOffsetAttrib will not, however, combine with any other DepthOffsetAttribs with a lower override parameter.) The net value should probably not exceed 16 or drop below 0 for maximum portability.

Definition at line 85 of file depthOffsetAttrib.h.


Member Enumeration Documentation

enum RenderAttrib::PandaCompareFunc [inherited]
 

Enumeration values:
M_none 
M_never 
M_less 
M_equal 
M_less_equal 
M_greater 
M_not_equal 
M_greater_equal 
M_always 

Definition at line 107 of file renderAttrib.h.

Referenced by AlphaTestAttrib::AlphaTestAttrib(), DepthTestAttrib::DepthTestAttrib(), DXGraphicsStateGuardian8::enable_texturing(), GLGraphicsStateGuardian::issue_tex_matrix(), and GLGraphicsStateGuardian::issue_transform().


Constructor & Destructor Documentation

DepthOffsetAttrib::DepthOffsetAttrib int  offset  )  [inline, private]
 

Use DepthOffsetAttrib::make() to construct a new DepthOffsetAttrib object.

Definition at line 34 of file depthOffsetAttrib.I.

References _offset, and INLINE.

Referenced by invert_compose_impl().


Member Function Documentation

TypedWritable * RenderAttrib::change_this TypedWritable old_ptr,
BamReader manager
[static, inherited]
 

Called immediately after complete_pointers(), this gives the object a chance to adjust its own pointer if desired.

Most objects don't change pointers after completion, but some need to.

Once this function has been called, the old pointer will no longer be accessed.

Definition at line 362 of file renderAttrib.cxx.

int RenderAttrib::compare_to const RenderAttrib other  )  const [inline, inherited]
 

Provides an arbitrary ordering among all unique RenderAttribs, so we can store the essentially different ones in a big set and throw away the rest.

This method is not needed outside of the RenderAttrib class because all equivalent RenderAttrib objects are guaranteed to share the same pointer; thus, a pointer comparison is always sufficient.

Definition at line 125 of file renderAttrib.I.

int DepthOffsetAttrib::compare_to_impl const RenderAttrib other  )  const [protected, virtual]
 

Intended to be overridden by derived DepthOffsetAttrib types to return a unique number indicating whether this DepthOffsetAttrib is equivalent to the other one.

This should return 0 if the two DepthOffsetAttrib objects are equivalent, a number less than zero if this one should be sorted before the other one, and a number greater than zero otherwise.

This will only be called with two DepthOffsetAttrib objects whose get_type() functions return the same.

Reimplemented from RenderAttrib.

Definition at line 113 of file depthOffsetAttrib.cxx.

int TypedWritable::complete_pointers TypedWritable **  p_list,
BamReader manager
[virtual, inherited]
 

Receives an array of pointers, one for each time manager->read_pointer() was called in fillin().

Returns the number of pointers processed.

This is the callback function that is made by the BamReader at some later point, after all of the required pointers have been filled in. It is necessary because there might be forward references in a bam file; when we call read_pointer() in fillin(), the object may not have been read from the file yet, so we do not have a pointer available at that time. Thus, instead of returning a pointer, read_pointer() simply reserves a later callback. This function provides that callback. The calling object is responsible for keeping track of the number of times it called read_pointer() and extracting the same number of pointers out of the supplied vector, and storing them appropriately within the object.

Reimplemented in AnimBundleNode, AnimGroup, PartBundleNode, PartGroup, Character, CharacterJoint, CollisionNode, GeomSprite, PiecewiseCurve, ClipPlaneAttrib, FogAttrib, LensNode, LightAttrib, MaterialAttrib, RenderEffects, RenderState, TextureAttrib, Person, and Child.

Definition at line 94 of file typedWritable.cxx.

Referenced by RenderState::do_invert_compose().

ConstPointerTo< RenderAttrib > RenderAttrib::compose const RenderAttrib other  )  const [inline, inherited]
 

Referenced by LightAttrib::get_light(), LightAttrib::get_num_lights(), ClipPlaneAttrib::get_num_planes(), and ClipPlaneAttrib::get_plane().

ConstPointerTo< RenderAttrib > DepthOffsetAttrib::compose_impl const RenderAttrib other  )  const [protected, virtual]
 

Intended to be overridden by derived RenderAttrib types to specify how two consecutive RenderAttrib objects of the same type interact.

This should return the result of applying the other RenderAttrib to a node in the scene graph below this RenderAttrib, which was already applied. In most cases, the result is the same as the other RenderAttrib (that is, a subsequent RenderAttrib completely replaces the preceding one). On the other hand, some kinds of RenderAttrib (for instance, ColorTransformAttrib) might combine in meaningful ways.

Reimplemented from RenderAttrib.

Definition at line 152 of file depthOffsetAttrib.cxx.

References get_class_type(), BamReader::get_factory(), make_from_bam(), and Factory< TypedWritable >::register_factory().

void DepthOffsetAttrib::fillin DatagramIterator scan,
BamReader manager
[protected]
 

This internal function is called by make_from_bam to read in all of the relevant data from the BamFile for the new DepthOffsetAttrib.

Reimplemented from RenderAttrib.

Definition at line 283 of file depthOffsetAttrib.cxx.

Referenced by invert_compose_impl().

void RenderAttrib::finalize void   )  [virtual, inherited]
 

Method to ensure that any necessary clean up tasks that have to be performed by this object are performed.

Reimplemented from TypedWritable.

Definition at line 393 of file renderAttrib.cxx.

virtual TypeHandle DepthOffsetAttrib::force_init_type void   )  [inline, virtual]
 

Reimplemented from RenderAttrib.

Definition at line 127 of file depthOffsetAttrib.h.

TypeHandle DepthOffsetAttrib::get_class_type void   )  [inline, static]
 

Reimplemented from RenderAttrib.

Definition at line 116 of file depthOffsetAttrib.h.

Referenced by compose_impl().

int DepthOffsetAttrib::get_offset  )  const [inline]
 

Returns the depth offset represented by this attrib.

Definition at line 48 of file depthOffsetAttrib.I.

Referenced by DXGraphicsStateGuardian8::issue_material(), and GLGraphicsStateGuardian::issue_texture_apply().

int ReferenceCount::get_ref_count  )  const [inline, inherited]
 

Returns the current reference count.

Definition at line 183 of file referenceCount.I.

Referenced by RenderState::determine_bin_index(), RenderEffects::determine_show_bounds(), FontPool::ns_garbage_collect(), TexturePool::ns_garbage_collect(), MaterialPool::ns_get_material(), and TexturePool::ns_release_texture().

virtual TypeHandle DepthOffsetAttrib::get_type void   )  const [inline, virtual]
 

Reimplemented from RenderAttrib.

Definition at line 124 of file depthOffsetAttrib.h.

int TypedObject::get_type_index  )  const [inline, inherited]
 

Returns the internal index number associated with this object's TypeHandle, a unique number for each different type.

This is equivalent to get_type().get_index().

Definition at line 71 of file typedObject.I.

References TypeHandle::get_name(), TypedObject::get_type(), and INLINE.

void DepthOffsetAttrib::init_type void   )  [inline, static]
 

Reimplemented from RenderAttrib.

Definition at line 119 of file depthOffsetAttrib.h.

ConstPointerTo< RenderAttrib > RenderAttrib::invert_compose const RenderAttrib other  )  const [inline, inherited]
 

ConstPointerTo< RenderAttrib > DepthOffsetAttrib::invert_compose_impl const RenderAttrib other  )  const [protected, virtual]
 

Intended to be overridden by derived RenderAttrib types to specify how two consecutive RenderAttrib objects of the same type interact.

See invert_compose() and compose_impl().

Reimplemented from RenderAttrib.

Definition at line 178 of file depthOffsetAttrib.cxx.

References DepthOffsetAttrib(), fillin(), and parse_params().

bool TypedObject::is_exact_type TypeHandle  handle  )  const [inline, inherited]
 

Returns true if the current object is the indicated type exactly.

Definition at line 101 of file typedObject.I.

Referenced by PT(), and CollisionNode::xform().

bool TypedObject::is_of_type TypeHandle  handle  )  const [inline, inherited]
 

Returns true if the current object is or derives from the indicated type.

Definition at line 86 of file typedObject.I.

Referenced by EggMaterialCollection::collapse_equivalent_materials(), EggTextureCollection::collapse_equivalent_textures(), DeferredNodeProperty::compose(), AnimBundleMaker::create_s_channel(), CharacterMaker::create_slider(), ProjectionScreen::cull_callback(), DataNode::define_output(), EggNode::determine_draw_order(), CharacterMaker::egg_to_index(), EggGroupUniquifier::EggGroupUniquifier(), EggPoolUniquifier::EggPoolUniquifier(), EggGroupNode::find_textures(), StaticTextFont::get_glyph(), EggMaterialCollection::insert_materials(), EggTextureCollection::insert_textures(), CharacterJoint::make_copy(), PT(), EggGroupNode::r_flatten_transforms(), EggGroupNode::r_transform_vertices(), EggGroupNode::recompute_polygon_normals(), CollisionLevelState::reserve(), PandaFramework::reset_frame_rate(), PandaFramework::set_texture(), EggGroupNode::steal_children(), and DataGraphTraverser::traverse().

void DepthOffsetAttrib::issue GraphicsStateGuardianBase gsg  )  const [virtual]
 

Calls the appropriate method on the indicated GSG to issue the graphics commands appropriate to the given attribute.

This is normally called (indirectly) only from GraphicsStateGuardian::set_state() or modify_state().

Reimplemented from RenderAttrib.

Definition at line 67 of file depthOffsetAttrib.cxx.

ConstPointerTo< RenderAttrib > DepthOffsetAttrib::make int  offset = 1  )  [static]
 

Constructs a new DepthOffsetAttrib object that indicates the relative amount of bias to write to the depth buffer for subsequent geometry.

Definition at line 45 of file depthOffsetAttrib.cxx.

References GraphicsStateGuardianBase::issue_depth_offset().

Referenced by CullTraverser::get_bounds_outer_viz_state().

ConstPointerTo< RenderAttrib > RenderAttrib::make_default  )  const [inline, inherited]
 

RenderAttrib * DepthOffsetAttrib::make_default_impl  )  const [protected, virtual]
 

Intended to be overridden by derived DepthOffsetAttrib types to specify what the default property for a DepthOffsetAttrib of this type should be.

This should return a newly-allocated DepthOffsetAttrib of the same type that corresponds to whatever the standard default for this kind of DepthOffsetAttrib is.

Implements RenderAttrib.

Definition at line 208 of file depthOffsetAttrib.cxx.

TypedWritable * DepthOffsetAttrib::make_from_bam const FactoryParams params  )  [static, protected]
 

This function is called by the BamReader's factory when a new object of type DepthOffsetAttrib is encountered in the Bam file.

It should create the DepthOffsetAttrib and extract its information from the file.

Definition at line 259 of file depthOffsetAttrib.cxx.

Referenced by compose_impl().

TypedWritable* RenderAttrib::new_from_bam RenderAttrib attrib,
BamReader manager
[static, protected, inherited]
 

void DepthOffsetAttrib::output ostream &  out  )  const [virtual]
 

Reimplemented from RenderAttrib.

Definition at line 80 of file depthOffsetAttrib.cxx.

References _offset, and DCAST_INTO_R.

void RenderAttrib::output_comparefunc ostream &  out,
PandaCompareFunc  fn
const [protected, inherited]
 

Definition at line 141 of file renderAttrib.cxx.

References RenderAttrib::_attribs, RenderAttrib::_saved_entry, nassertr, and NULL.

int ReferenceCount::ref  )  const [inline, inherited]
 

Explicitly increments the reference count.

User code should avoid using ref() and unref() directly, which can result in missed reference counts. Instead, let a PointerTo object manage the reference counting automatically.

This function is const, even though it changes the object, because generally fiddling with an object's reference count isn't considered part of fiddling with the object. An object might be const in other ways, but we still need to accurately count the number of references to it.

The return value is the new reference count.

Definition at line 225 of file referenceCount.I.

Referenced by ClientDevice::ClientDevice(), EggGroupNode::find_textures(), EggGroupNode::r_apply_texmats(), EggGroupNode::r_flatten_transforms(), and EggGroupNode::reverse_vertex_ordering().

void DepthOffsetAttrib::register_with_read_factory void   )  [static]
 

Tells the BamReader how to create objects of type DepthOffsetAttrib.

Definition at line 223 of file depthOffsetAttrib.cxx.

ConstPointerTo< RenderAttrib > RenderAttrib::return_new RenderAttrib attrib  )  [static, protected, inherited]
 

This function is used by derived RenderAttrib types to share a common RenderAttrib pointer for all equivalent RenderAttrib objects.

The make() function of the derived type should create a new RenderAttrib and pass it through return_new(), which will either save the pointer and return it unchanged (if this is the first similar such object) or delete it and return an equivalent pointer (if there was already a similar object saved).

Definition at line 186 of file renderAttrib.cxx.

Referenced by CullFaceAttrib::compare_to_impl(), TextureAttrib::make(), MaterialAttrib::make(), LightAttrib::make(), FogAttrib::make(), CullFaceAttrib::make(), ClipPlaneAttrib::make(), LightAttrib::make_all_off(), ClipPlaneAttrib::make_all_off(), ColorAttrib::make_flat(), and ColorAttrib::make_vertex().

void ReferenceCount::test_ref_count_integrity  )  const [inline, inherited]
 

Does some easy checks to make sure that the reference count isn't completely bogus.

Definition at line 328 of file referenceCount.I.

References INLINE.

Referenced by EggNode::determine_bin(), and ReferenceCount::~ReferenceCount().

int ReferenceCount::unref  )  const [inline, inherited]
 

Explicitly decrements the reference count.

Note that the object will not be implicitly deleted by unref() simply because the reference count drops to zero. (Having a member function delete itself is problematic; plus, we don't have a virtual destructor anyway.) However, see the helper function unref_delete().

User code should avoid using ref() and unref() directly, which can result in missed reference counts. Instead, let a PointerTo object manage the reference counting automatically.

This function is const, even though it changes the object, because generally fiddling with an object's reference count isn't considered part of fiddling with the object. An object might be const in other ways, but we still need to accurately count the number of references to it.

The return value is the new reference count.

Definition at line 293 of file referenceCount.I.

References INLINE.

Referenced by RenderState::determine_bin_index(), and RenderEffects::determine_show_bounds().

void RenderAttrib::write ostream &  out,
int  indent_level
const [virtual, inherited]
 

Definition at line 155 of file renderAttrib.cxx.

References RenderAttrib::_attribs.

void DepthOffsetAttrib::write_datagram BamWriter manager,
Datagram dg
[virtual]
 

Writes the contents of this object to the datagram for shipping out to a Bam file.

Reimplemented from RenderAttrib.

Definition at line 238 of file depthOffsetAttrib.cxx.


Member Data Documentation

int DepthOffsetAttrib::_offset [private]
 

Definition at line 105 of file depthOffsetAttrib.h.

Referenced by DepthOffsetAttrib(), and output().

TypeHandle DepthOffsetAttrib::_type_handle [static, private]
 

Reimplemented from RenderAttrib.

Definition at line 30 of file depthOffsetAttrib.cxx.

TypedWritable *const TypedWritable::Null = (TypedWritable*)0L [static, inherited]
 

Definition at line 25 of file typedWritable.cxx.

Referenced by Child::complete_pointers(), Parent::complete_pointers(), Person::complete_pointers(), LoaderFileTypeBam::get_extension(), PartGroup::pick_channel_index(), BamReader::read_pointer(), and AnimGroup::write_datagram().


The documentation for this class was generated from the following files:
Generated on Fri May 2 00:49:16 2003 for Panda by doxygen1.3