Panda3D
Public Member Functions | Static Public Member Functions | Public Attributes | List of all members
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...

Inheritance diagram for DepthOffsetAttrib:
RenderAttrib TypedWritableReferenceCount TypedWritable ReferenceCount TypedObject

Public Member Functions

float getMaxValue ()
 Returns the value for the maximum (farthest) depth value to be stored in the buffer, in the range 0 . More...
 
float getMinValue ()
 Returns the value for the minimum (closest) depth value to be stored in the buffer, in the range 0 . More...
 
int getOffset ()
 Returns the depth offset represented by this attrib. More...
 
- Public Member Functions inherited from RenderAttrib
int compareTo (const RenderAttrib other)
 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...
 
const RenderAttrib compose (const RenderAttrib other)
 Returns a new RenderAttrib object that represents the composition of this attrib with the other attrib. More...
 
int getHash ()
 Returns a suitable hash value for phash_map. More...
 
int getSlot ()
 
const RenderAttrib getUnique ()
 Returns the pointer to the unique RenderAttrib in the cache that is equivalent to this one. More...
 
const RenderAttrib invertCompose (const RenderAttrib other)
 Returns a new RenderAttrib object that represents the composition of the inverse of this attrib with the other attrib. More...
 
bool lowerAttribCanOverride ()
 Intended to be overridden by derived RenderAttrib types to specify how two consecutive RenderAttrib objects of the same type interact. More...
 
 output (Ostream out)
 
 write (Ostream out, int indent_level)
 
- Public Member Functions inherited from TypedWritable
object __reduce__ ()
 
object __reduce_persist__ (object pickler)
 
VectorUchar encodeToBamStream ()
 Converts the TypedWritable object into a single stream of data using a BamWriter, and returns that data as a bytes object. More...
 
bool encodeToBamStream (VectorUchar data, BamWriter writer)
 Converts the TypedWritable object into a single stream of data using a BamWriter, and stores that data in the indicated string. More...
 
 fillin (DatagramIterator scan, BamReader manager)
 This internal function is intended to be called by each class's make_from_bam() method to read in all of the relevant data from the BamFile for the new object. More...
 
UpdateSeq getBamModified ()
 Returns the current bam_modified counter. More...
 
 markBamModified ()
 Increments the bam_modified counter, so that this object will be invalidated and retransmitted on any open bam streams. More...
 
- Public Member Functions inherited from TypedObject
TypeHandle getType ()
 
int getTypeIndex ()
 Returns the internal index number associated with this object's TypeHandle, a unique number for each different type. More...
 
bool isExactType (TypeHandle handle)
 Returns true if the current object is the indicated type exactly. More...
 
bool isOfType (TypeHandle handle)
 Returns true if the current object is or derives from the indicated type. More...
 
- Public Member Functions inherited from ReferenceCount
int getRefCount ()
 Returns the current reference count. More...
 
 ref ()
 Explicitly increments the reference count. More...
 
bool testRefCountIntegrity ()
 Does some easy checks to make sure that the reference count isn't completely bogus. More...
 
bool testRefCountNonzero ()
 Does some easy checks to make sure that the reference count isn't zero, or completely bogus. More...
 
bool unref ()
 Explicitly decrements the reference count. More...
 

Static Public Member Functions

static int getClassSlot ()
 
static TypeHandle getClassType ()
 
static const RenderAttrib make (int offset)
 Constructs a new DepthOffsetAttrib object that indicates the relative amount of bias to write to the depth buffer for subsequent geometry. More...
 
static const RenderAttrib make (int offset, float min_value, float max_value)
 Constructs a new DepthOffsetAttrib object that indicates the bias, and also specifies a minimum and maximum (or, more precisely, nearest and farthest) values to write to the depth buffer, in the range 0 . More...
 
static const RenderAttrib makeDefault ()
 Returns a RenderAttrib that corresponds to whatever the standard default properties for render attributes of this type ought to be. More...
 
- Static Public Member Functions inherited from RenderAttrib
static int garbageCollect ()
 Performs a garbage-collection cycle. More...
 
static TypeHandle getClassType ()
 
static int getNumAttribs ()
 Returns the total number of unique RenderAttrib objects allocated in the world. More...
 
static listAttribs (Ostream out)
 Lists all of the RenderAttribs in the cache to the output stream, one per line. More...
 
static bool validateAttribs ()
 Ensures that the cache is still stored in sorted order. More...
 
- Static Public Member Functions inherited from TypedWritableReferenceCount
static TypedWritableReferenceCount decodeFromBamStream (VectorUchar data, BamReader reader)
 Reads the bytes created by a previous call to encode_to_bam_stream(), and extracts and returns the single object on those bytes. More...
 
static TypeHandle getClassType ()
 
- Static Public Member Functions inherited from TypedWritable
static TypeHandle getClassType ()
 
- Static Public Member Functions inherited from TypedObject
static TypeHandle getClassType ()
 
- Static Public Member Functions inherited from ReferenceCount
static TypeHandle getClassType ()
 

Public Attributes

int class_slot
 
float max_value
 Returns the value for the maximum (farthest) depth value to be stored in the buffer, in the range 0 . More...
 
float min_value
 Returns the value for the minimum (closest) depth value to be stored in the buffer, in the range 0 . More...
 
int offset
 Returns the depth offset represented by this attrib. More...
 
- Public Attributes inherited from RenderAttrib
int slot
 
- Public Attributes inherited from TypedObject
TypeHandle type
 Returns the TypeHandle representing this object's type. More...
 
- Public Attributes inherited from ReferenceCount
int ref_count
 The current reference count. More...
 

Additional Inherited Members

- Public Types inherited from RenderAttrib
enum  PandaCompareFunc {
  M_none = 0, M_never = 1, M_less = 2, M_equal = 3,
  M_less_equal = 4, M_greater = 5, M_not_equal = 6, M_greater_equal = 7,
  M_always = 8
}
 
enum  TexGenMode {
  M_off = 0, M_eye_sphere_map = 1, M_world_cube_map = 2, M_eye_cube_map = 3,
  M_world_normal = 4, M_eye_normal = 5, M_world_position = 6, M_unused = 7,
  M_eye_position = 8, M_point_sprite = 9, M_unused2 = 10, M_constant = 11
}
 

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.

Member Function Documentation

◆ getClassSlot()

static int getClassSlot ( )
static

◆ getClassType()

static TypeHandle getClassType ( )
static

◆ getMaxValue()

float getMaxValue ( )

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

. 1.

◆ getMinValue()

float getMinValue ( )

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

. 1.

◆ getOffset()

int getOffset ( )

Returns the depth offset represented by this attrib.

◆ make() [1/2]

static const RenderAttrib make ( int  offset)
static

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

◆ make() [2/2]

static const RenderAttrib make ( int  offset,
float  min_value,
float  max_value 
)
static

Constructs a new DepthOffsetAttrib object that indicates the bias, and also specifies a minimum and maximum (or, more precisely, nearest and farthest) values to write to the depth buffer, in the range 0 .

. 1. This range is 0, 1 by default; setting it to some other range can be used to create additional depth buffer effects.

◆ makeDefault()

static const RenderAttrib makeDefault ( )
static

Returns a RenderAttrib that corresponds to whatever the standard default properties for render attributes of this type ought to be.

Member Data Documentation

◆ class_slot

int class_slot

◆ max_value

float max_value

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

. 1.

◆ min_value

float min_value

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

. 1.

◆ offset

int offset

Returns the depth offset represented by this attrib.