# LightRampAttrib

from pandac.PandaModules import LightRampAttrib

Class : LightRampAttrib
Description : A Light Ramp is any unary operator that takes a rendered pixel as input, and adjusts the brightness of that pixel. For example, gamma correction is a kind of light ramp. So is HDR tone mapping. So is cartoon shading. See the constructors for an explanation of each kind of ramp.

## Inheritance:

LightRampAttrib: RenderAttrib
RenderAttrib: TypedWritableReferenceCount
TypedWritableReferenceCount: TypedWritable ReferenceCount
TypedWritable: TypedObject
TypedObject: MemoryBase
MemoryBase:
ReferenceCount: MemoryBase

## Methods of LightRampAttrib:

getClassType
getLevel
getMode
getThreshold
makeDefault
makeDoubleThreshold
makeHdr0
makeHdr1
makeHdr2
makeIdentity
makeSingleThreshold

## Methods of RenderAttrib:

compareTo
getClassType
getNumAttribs
listAttribs
output
unref
validateAttribs
write

## Methods of TypedWritableReferenceCount:

getClassType

## Methods of TypedWritable:

getClassType

## Methods of TypedObject:

getClassType
getType
getTypeIndex
isExactType
isOfType

## Methods of ReferenceCount:

getClassType
getRefCount
ref
testRefCountIntegrity
testRefCountNonzero
unref

## Constants in LightRampAttrib:

LRTDefault | (LightRampMode)
LRTIdentity | (LightRampMode)
LRTSingleThreshold | (LightRampMode)
LRTDoubleThreshold | (LightRampMode)
LRTHdr0 | (LightRampMode)
LRTHdr1 | (LightRampMode)
LRTHdr2 | (LightRampMode)

## Constants in RenderAttrib:

MNone | (PandaCompareFunc)
MNever | (PandaCompareFunc)
MLess | (PandaCompareFunc)
MEqual | (PandaCompareFunc)
MLessEqual | (PandaCompareFunc)
MGreater | (PandaCompareFunc)
MNotEqual | (PandaCompareFunc)
MGreaterEqual | (PandaCompareFunc)
MAlways | (PandaCompareFunc)
MOff | (TexGenMode)
MEyeSphereMap | (TexGenMode)
MWorldCubeMap | (TexGenMode)
MEyeCubeMap | (TexGenMode)
MWorldNormal | (TexGenMode)
MEyeNormal | (TexGenMode)
MWorldPosition | (TexGenMode)
MUnused | (TexGenMode)
MEyePosition | (TexGenMode)
MPointSprite | (TexGenMode)
MLightVector | (TexGenMode)
MConstant | (TexGenMode)

getClassType static TypeHandle LightRampAttrib::get_class_type(void); Undocumented function.

getLevel float LightRampAttrib::get_level(int n) const; Description: Returns the nth lighting level.

getMode LightRampAttrib::LightRampMode LightRampAttrib::get_mode(void) const; Description: Returns the LightRampAttrib mode.

getThreshold float LightRampAttrib::get_threshold(int n) const; Description: Returns the nth threshold level.

makeDefault static ConstPointerTo< RenderAttrib > LightRampAttrib::make_default(void); Description: Constructs a new LightRampAttrib object. This is the standard OpenGL lighting ramp, which clamps the final light total to the 0-1 range.

makeDoubleThreshold static ConstPointerTo< RenderAttrib > LightRampAttrib::make_double_threshold(float thresh0, float lev0, float thresh1, float lev1); Description: Constructs a new LightRampAttrib object. This causes the luminance of the diffuse lighting contribution to be quantized using two thresholds: if (original_luminance > threshold1) { luminance = level1; } else if (original_luminance > threshold0) { luminance = level0; } else { luminance = 0.0; }

makeHdr0 static ConstPointerTo< RenderAttrib > LightRampAttrib::make_hdr0(void); Description: Constructs a new LightRampAttrib object. This causes an HDR tone mapping operation to be applied. Normally, brightness values greater than 1 cannot be distinguished from each other, causing very brightly lit objects to wash out white and all detail to be erased. HDR tone mapping remaps brightness values in the range 0-infinity into the range (0,1), making it possible to distinguish detail in scenes whose brightness exceeds 1. However, the monitor has finite contrast. Normally, all of that contrast is used to represent brightnesses in the range 0-1. The HDR0 tone mapping operator 'steals' one quarter of that contrast to represent brightnesses in the range 1-infinity. FINAL_RGB = (RGB^3 + RGB^2 + RGB) / (RGB^3 + RGB^2 + RGB + 1)

makeHdr1 static ConstPointerTo< RenderAttrib > LightRampAttrib::make_hdr1(void); Description: Constructs a new LightRampAttrib object. This causes an HDR tone mapping operation to be applied. Normally, brightness values greater than 1 cannot be distinguished from each other, causing very brightly lit objects to wash out white and all detail to be erased. HDR tone mapping remaps brightness values in the range 0-infinity into the range (0,1), making it possible to distinguish detail in scenes whose brightness exceeds 1. However, the monitor has finite contrast. Normally, all of that contrast is used to represent brightnesses in the range 0-1. The HDR1 tone mapping operator 'steals' one third of that contrast to represent brightnesses in the range 1-infinity. FINAL_RGB = (RGB^2 + RGB) / (RGB^2 + RGB + 1)

makeHdr2 static ConstPointerTo< RenderAttrib > LightRampAttrib::make_hdr2(void); Description: Constructs a new LightRampAttrib object. This causes an HDR tone mapping operation to be applied. Normally, brightness values greater than 1 cannot be distinguished from each other, causing very brightly lit objects to wash out white and all detail to be erased. HDR tone mapping remaps brightness values in the range 0-infinity into the range (0,1), making it possible to distinguish detail in scenes whose brightness exceeds 1. However, the monitor has finite contrast. Normally, all of that contrast is used to represent brightnesses in the range 0-1. The HDR2 tone mapping operator 'steals' one half of that contrast to represent brightnesses in the range 1-infinity. FINAL_RGB = (RGB) / (RGB + 1)

makeIdentity static ConstPointerTo< RenderAttrib > LightRampAttrib::make_identity(void); Description: Constructs a new LightRampAttrib object. This differs from the usual OpenGL lighting model in that it does not clamp the final lighting total to (0,1).

makeSingleThreshold static ConstPointerTo< RenderAttrib > LightRampAttrib::make_single_threshold(float thresh0, float lev0); Description: Constructs a new LightRampAttrib object. This causes the luminance of the diffuse lighting contribution to be quantized using a single threshold: if (original_luminance > threshold0) { luminance = level0; } else { luminance = 0.0; }

compareTo int RenderAttrib::compare_to(RenderAttrib const &other) const; Description: 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.

getClassType static TypeHandle RenderAttrib::get_class_type(void); Undocumented function.

getNumAttribs static int RenderAttrib::get_num_attribs(void); Description: Returns the total number of unique RenderAttrib objects allocated in the world. This will go up and down during normal operations.

listAttribs static void RenderAttrib::list_attribs(ostream &out); Description: 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.

output virtual void RenderAttrib::output(ostream &out) const; Description:

unref bool RenderAttrib::unref(void) const; Description: This method overrides ReferenceCount::unref() to clear the pointer from the global object pool when its reference count goes to zero.

validateAttribs static bool RenderAttrib::validate_attribs(void); Description: 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).

write virtual void RenderAttrib::write(ostream &out, int indent_level) const; Description:

getClassType static TypeHandle TypedWritableReferenceCount::get_class_type(void); Undocumented function.

getClassType static TypeHandle TypedWritable::get_class_type(void); Undocumented function.

getClassType static TypeHandle TypedObject::get_class_type(void); Undocumented function.

getType virtual TypeHandle TypedObject::get_type(void) const = 0; Derived classes should override this function to return get_class_type().

getTypeIndex int TypedObject::get_type_index(void) const; Description: 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().

isExactType bool TypedObject::is_exact_type(TypeHandle handle) const; Description: Returns true if the current object is the indicated type exactly.

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

getClassType static TypeHandle ReferenceCount::get_class_type(void); Undocumented function.

getRefCount int ReferenceCount::get_ref_count(void) const; Description: Returns the current reference count.

ref void ReferenceCount::ref(void) const; Description: 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.

testRefCountIntegrity bool ReferenceCount::test_ref_count_integrity(void) const; Description: Does some easy checks to make sure that the reference count isn't completely bogus. Returns true if ok, false otherwise.

testRefCountNonzero bool ReferenceCount::test_ref_count_nonzero(void) const; Description: Does some easy checks to make sure that the reference count isn't zero, or completely bogus. Returns true if ok, false otherwise.

unref bool ReferenceCount::unref(void) const; Description: 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 true if the new reference count is nonzero, false if it is zero.