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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 MemoryBase MemoryBase

Public Member Functions

virtual TypeHandle force_init_type ()
 
PN_stdfloat get_max_value () const
 Returns the value for the maximum (farthest) depth value to be stored in the buffer, in the range 0 More...
 
PN_stdfloat get_min_value () const
 Returns the value for the minimum (closest) depth value to be stored in the buffer, in the range 0 More...
 
int get_offset () const
 Returns the depth offset represented by this attrib. More...
 
virtual int get_slot () const
 
virtual TypeHandle get_type () const
 
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. More...
 
- Public Member Functions inherited from RenderAttrib
virtual ~RenderAttrib ()
 The destructor is responsible for removing the RenderAttrib from the global set if it is there. More...
 
bool always_reissue () 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. More...
 
 CPT (RenderAttrib) compose(const RenderAttrib *other) const
 
 CPT (RenderAttrib) invert_compose(const RenderAttrib *other) const
 
 CPT (RenderAttrib) get_unique() const
 
 CPT (RenderAttrib) get_auto_shader_attrib(const RenderState *state) const
 
virtual bool cull_callback (CullTraverser *trav, const CullTraverserData &data) const
 If has_cull_callback() returns true, this function will be called during the cull traversal to perform any additional operations that should be performed at cull time. More...
 
virtual void finalize (BamReader *manager)
 Called by the BamReader to perform any final actions needed for setting up the object after all objects have been read and all pointers have been completed. More...
 
size_t get_hash () const
 Returns a suitable hash value for phash_map. More...
 
virtual bool has_cull_callback () const
 Should be overridden by derived classes to return true if cull_callback() has been defined. More...
 
virtual bool lower_attrib_can_override () const
 Intended to be overridden by derived RenderAttrib types to specify how two consecutive RenderAttrib objects of the same type interact. More...
 
virtual bool unref () const FINAL
 Explicitly decrements the reference count. More...
 
virtual void write (ostream &out, int indent_level) const
 
- Public Member Functions inherited from TypedWritableReferenceCount
 TypedWritableReferenceCount (const TypedWritableReferenceCount &copy)
 
virtual ReferenceCountas_reference_count ()
 Returns the pointer cast to a ReferenceCount pointer, if it is in fact of that type. More...
 
void operator= (const TypedWritableReferenceCount &copy)
 
- Public Member Functions inherited from TypedWritable
 TypedWritable (const TypedWritable &copy)
 
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(). More...
 
string encode_to_bam_stream () const
 Converts the TypedWritable object into a single stream of data using a BamWriter, and returns that data as a string string. More...
 
bool encode_to_bam_stream (string &data, BamWriter *writer=NULL) const
 Converts the TypedWritable object into a single stream of data using a BamWriter, and stores that data in the indicated string. More...
 
UpdateSeq get_bam_modified () const
 Returns the current bam_modified counter. More...
 
void mark_bam_modified ()
 Increments the bam_modified counter, so that this object will be invalidated and retransmitted on any open bam streams. More...
 
void operator= (const TypedWritable &copy)
 
virtual bool require_fully_complete () const
 Some objects require all of their nested pointers to have been completed before the objects themselves can be completed. More...
 
virtual void update_bam_nested (BamWriter *manager)
 Called by the BamWriter when this object has not itself been modified recently, but it should check its nested objects for updates. More...
 
- Public Member Functions inherited from TypedObject
 TypedObject (const TypedObject &copy)
 
TypedObjectas_typed_object ()
 Returns the object, upcast (if necessary) to a TypedObject pointer. More...
 
const TypedObjectas_typed_object () const
 Returns the object, upcast (if necessary) to a TypedObject pointer. More...
 
int get_best_parent_from_Set (const std::set< int > &) const
 
int get_type_index () const
 Returns the internal index number associated with this object's TypeHandle, a unique number for each different type. More...
 
bool is_exact_type (TypeHandle handle) const
 Returns true if the current object is the indicated type exactly. More...
 
bool is_of_type (TypeHandle handle) const
 Returns true if the current object is or derives from the indicated type. More...
 
void operator= (const TypedObject &copy)
 
- Public Member Functions inherited from ReferenceCount
int get_ref_count () const
 Returns the current reference count. More...
 
WeakReferenceListget_weak_list () const
 Returns the WeakReferenceList associated with this ReferenceCount object. More...
 
bool has_weak_list () const
 Returns true if this particular ReferenceCount object has a WeakReferenceList created, false otherwise. More...
 
void local_object ()
 This function should be called, once, immediately after creating a new instance of some ReferenceCount-derived object on the stack. More...
 
void ref () const
 Explicitly increments the reference count. More...
 
bool test_ref_count_integrity () const
 Does some easy checks to make sure that the reference count isn't completely bogus. More...
 
bool test_ref_count_nonzero () const
 Does some easy checks to make sure that the reference count isn't zero, or completely bogus. More...
 
void weak_ref (WeakPointerToVoid *ptv)
 Adds the indicated PointerToVoid as a weak reference to this object. More...
 
void weak_unref (WeakPointerToVoid *ptv)
 Removes the indicated PointerToVoid as a weak reference to this object. More...
 

Static Public Member Functions

static CPT (RenderAttrib) make(int offset
 
static CPT (RenderAttrib) make(int offset
 
static CPT (RenderAttrib) make_default()
 
static int get_class_slot ()
 
static TypeHandle get_class_type ()
 
static void init_type ()
 
static void register_with_read_factory ()
 Tells the BamReader how to create objects of type DepthOffsetAttrib. More...
 
- Static Public Member Functions inherited from RenderAttrib
static 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. More...
 
static int garbage_collect ()
 Performs a garbage-collection cycle. More...
 
static TypeHandle get_class_type ()
 
static int get_num_attribs ()
 Returns the total number of unique RenderAttrib objects allocated in the world. More...
 
static void init_attribs ()
 Make sure the global _attribs map is allocated. More...
 
static void init_type ()
 
static void list_attribs (ostream &out)
 Lists all of the RenderAttribs in the cache to the output stream, one per line. More...
 
static int register_slot (TypeHandle type_handle, int sort, RenderAttribRegistry::MakeDefaultFunc *make_default_func)
 Adds the indicated TypeHandle to the registry, if it is not there already, and returns a unique slot number. More...
 
static bool validate_attribs ()
 Ensures that the cache is still stored in sorted order. More...
 
- Static Public Member Functions inherited from TypedWritableReferenceCount
static TypeHandle get_class_type ()
 
static void init_type ()
 
static PT (TypedWritableReferenceCount) decode_from_bam_stream(const string &data
 
- Static Public Member Functions inherited from TypedWritable
static bool decode_raw_from_bam_stream (TypedWritable *&ptr, ReferenceCount *&ref_ptr, const string &data, BamReader *reader=NULL)
 Reads the string created by a previous call to encode_to_bam_stream(), and extracts the single object on that string. More...
 
static TypeHandle get_class_type ()
 
static void init_type ()
 
- Static Public Member Functions inherited from TypedObject
static TypeHandle get_class_type ()
 
static void init_type ()
 This function is declared non-inline to work around a compiler bug in g++ 2.96. More...
 
- Static Public Member Functions inherited from ReferenceCount
static TypeHandle get_class_type ()
 
static void init_type ()
 

Public Attributes

static PN_stdfloat PN_stdfloat max_value
 
static PN_stdfloat min_value
 
- Public Attributes inherited from TypedWritableReferenceCount
static BamReaderreader = NULL)
 

Additional Inherited Members

- Public Types inherited from RenderAttrib
enum  PandaCompareFunc {
  M_none =0, M_never, M_less, M_equal,
  M_less_equal, M_greater, M_not_equal, M_greater_equal,
  M_always
}
 
enum  TexGenMode {
  M_off, M_eye_sphere_map, M_world_cube_map, M_eye_cube_map,
  M_world_normal, M_eye_normal, M_world_position, M_unused,
  M_eye_position, M_point_sprite, M_unused2, M_constant
}
 
- Static Public Attributes inherited from TypedWritable
static TypedWritable *const Null = (TypedWritable*)0L
 

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.

Also, and only tangentially related, the DepthOffsetAttrib can be used to constrain the Z output value to a subset of the usual [0, 1] range (or reversing its direction) by specifying a new min_value and max_value.

Definition at line 59 of file depthOffsetAttrib.h.

Member Function Documentation

PN_stdfloat DepthOffsetAttrib::get_max_value ( ) const
inline

Returns the value for the maximum (farthest) depth value to be stored in the buffer, in the range 0

. 1.

Definition at line 60 of file depthOffsetAttrib.I.

PN_stdfloat DepthOffsetAttrib::get_min_value ( ) const
inline

Returns the value for the minimum (closest) depth value to be stored in the buffer, in the range 0

. 1.

Definition at line 48 of file depthOffsetAttrib.I.

int DepthOffsetAttrib::get_offset ( ) const
inline

Returns the depth offset represented by this attrib.

Definition at line 36 of file depthOffsetAttrib.I.

Referenced by NodePath::get_depth_offset().

void DepthOffsetAttrib::register_with_read_factory ( )
static

Tells the BamReader how to create objects of type DepthOffsetAttrib.

Definition at line 184 of file depthOffsetAttrib.cxx.

References BamReader::get_factory(), and Factory< Type >::register_factory().

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 195 of file depthOffsetAttrib.cxx.

References Datagram::add_int32(), Datagram::add_stdfloat(), and RenderAttrib::write_datagram().


The documentation for this class was generated from the following files: