Panda3D
Public Member Functions | Static Public Member Functions | 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 MemoryBase MemoryBase

Public Member Functions

float getMaxValue ()
 Returns the value for the maximum (farthest) depth value to be stored in the buffer, in the range 0 .. 1. More...
 
float getMinValue ()
 Returns the value for the minimum (closest) depth value to be stored in the buffer, in the range 0 .. 1. 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. In most cases, this is the same as the other attrib; a compose b produces b. Some kinds of attributes, like a TextureTransform, for instance, might produce a new result: a compose b produces c. More...
 
const RenderAttrib getAutoShaderAttrib (const RenderState state)
 Returns the variant of this RenderAttrib that's most relevant for associating with an auto-generated shader. This should be a new RenderAttrib of the same type as this one, with any superfluous data set to neutral. Only the parts of the attrib that contribute to the shader should be reflected in the returned attrib. The idea is to associate the auto-generated shader with the most neutral form of all states, to allow it to be shared across as many RenderState objects as possible. More...
 
size_t 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. This may be the same pointer as this object, or it may be a different pointer; but it will be an equivalent object, and it will be a shared pointer. This may be called from time to time to improve cache benefits. 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. In most cases, this is the same as the other attrib; !a compose b produces b. Some kinds of attributes, like a TextureTransform, for instance, might produce a new result: !a compose b produces c. 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)
 
str encodeToBamStream ()
 Converts the TypedWritable object into a single stream of data using a BamWriter, and returns that data as a string string. Returns empty string on failure. More...
 
bool encodeToBamStream (String data, BamWriter writer)
 Converts the TypedWritable object into a single stream of data using a BamWriter, and stores that data in the indicated string. Returns true on success, false on failure. More...
 
UpdateSeq getBamModified ()
 Returns the current bam_modified counter. This counter is normally incremented automatically whenever the object is modified. More...
 
 markBamModified ()
 Increments the bam_modified counter, so that this object will be invalidated and retransmitted on any open bam streams. This should normally not need to be called by user code; it should be called internally when the object has been changed in a way that legitimately requires its retransmission to any connected clients. More...
 
- Public Member Functions inherited from TypedObject
TypeHandle getType ()
 Derived classes should override this function to return get_class_type(). More...
 
int getTypeIndex ()
 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(). 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. 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. More...
 
bool testRefCountIntegrity ()
 Does some easy checks to make sure that the reference count isn't completely bogus. Returns true if ok, false otherwise. More...
 
bool testRefCountNonzero ()
 Does some easy checks to make sure that the reference count isn't zero, or completely bogus. Returns true if ok, false otherwise. More...
 
bool unref ()
 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.) However, see the helper function unref_delete(). 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 .. 1. This range is 0, 1 by default; setting it to some other range can be used to create additional depth buffer effects. 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. This is called automatically from RenderState::garbage_collect(); see that method for more information. More...
 
static TypeHandle getClassType ()
 
static int getNumAttribs ()
 Returns the total number of unique RenderAttrib objects allocated in the world. This will go up and down during normal operations. More...
 
static listAttribs (Ostream out)
 Lists all of the RenderAttribs in the cache to the output stream, one per line. This can be quite a lot of output if the cache is large, so be prepared. More...
 
static bool validateAttribs ()
 Ensures that the cache is still stored in sorted order. Returns true if so, false if there is a problem (which implies someone has modified one of the supposedly-const RenderAttrib objects). More...
 
- Static Public Member Functions inherited from TypedWritableReferenceCount
static TypedWritableReferenceCount decodeFromBamStream (str data, BamReader reader)
 Reads the string created by a previous call to encode_to_bam_stream(), and extracts and returns the single object on that string. Returns NULL on error. 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 ()
 

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
}
 intentionally defined to match D3DCMPFUNC More...
 
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
}
 This is the enumerated type for TexGenAttrib. It is inherited into TexGenAttrib. It is defined up at this level only to avoid circular dependencies in the header files. More...
 

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.