# TexProjectorEffect

from pandac.PandaModules import TexProjectorEffect

Class : TexProjectorEffect
Description : This effect automatically applies a computed texture matrix to the specified texture stage, according to the relative position of two specified nodes.
The relative transform from the "from" node to the "to" node is applied directly to the texture matrix each frame. If the "to" node happens to be a LensNode, its lens projection matrix is applied as well.
This can be used to apply a number of special effects. Fundamentally, it may simply be used to provide a separate PandaNode that may be adjusted (e.g. via a LerpInterval) in order to easily apply a linear transformation to an object's texture coordinates (rather than having to explicitly call NodePath.set_tex_transform() each frame).
In a more sophisticated case, the TexProjectorEffect is particularly useful in conjunction with a TexGenAttrib that specifies a mode of M_world_position (which copies the world position of each vertex to the texture coordinates). Then the TexProjector can be used to convert these world coordinates to the relative coordinates of a particular node, causing (for instance) a texture to appear to follow a node around as it moves through the world. With a LensNode, you can project a texture onto the walls, for instance to apply a flashlight effect or an image-based shadow.

## Inheritance:

TexProjectorEffect: RenderEffect
RenderEffect: TypedWritableReferenceCount
TypedWritableReferenceCount: TypedWritable ReferenceCount
TypedWritable: TypedObject
TypedObject: MemoryBase
MemoryBase:
ReferenceCount: MemoryBase

## Methods of TexProjectorEffect:

addStage
getClassType
getFrom
getTo
hasStage
isEmpty
make
removeStage

## Methods of RenderEffect:

compareTo
getClassType
getNumEffects
listEffects
output
validateEffects
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

addStage ConstPointerTo< RenderEffect > TexProjectorEffect::add_stage(TextureStage *stage, NodePath const &from, NodePath const &to) const; Description: Returns a new TexProjectorEffect just like this one, with the indicated projection for the given stage. If this stage already exists, its projection definition is replaced. The relative transform between the "from" and the "to" nodes is automatically applied to the texture transform each frame. Furthermore, if the "to" node is a LensNode, its projection matrix is also applied to the texture transform.

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

getFrom NodePath TexProjectorEffect::get_from(TextureStage *stage) const; Description: Returns the "from" node associated with the TexProjectorEffect on the indicated stage. The relative transform between the "from" and the "to" nodes is automatically applied to the texture transform each frame.

getTo NodePath TexProjectorEffect::get_to(TextureStage *stage) const; Description: Returns the "to" node associated with the TexProjectorEffect on the indicated stage. The relative transform between the "from" and the "to" nodes is automatically applied to the texture transform each frame. Furthermore, if the "to" node is a LensNode, its projection matrix is also applied to the texture transform.

hasStage bool TexProjectorEffect::has_stage(TextureStage *stage) const; Description: Returns true if there is a transform associated with the indicated stage, or false otherwise (in which case get_transform(stage) will return the identity transform).

isEmpty bool TexProjectorEffect::is_empty(void) const; Description: Returns true if no stages are defined in the TexProjectorEffect, false if at least one is.

make static ConstPointerTo< RenderEffect > TexProjectorEffect::make(void); Description: Constructs a TexProjectorEffect that modifies no stages at all.

removeStage ConstPointerTo< RenderEffect > TexProjectorEffect::remove_stage(TextureStage *stage) const; Description: Returns a new TexProjectorEffect just like this one, with the indicated stage removed.

compareTo int RenderEffect::compare_to(RenderEffect const &other) const; Description: Provides an arbitrary ordering among all unique RenderEffects, 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 RenderEffect class because all equivalent RenderEffect objects are guaranteed to share the same pointer; thus, a pointer comparison is always sufficient.

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

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

listEffects static void RenderEffect::list_effects(ostream &out); Description: Lists all of the RenderEffects 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 RenderEffect::output(ostream &out) const; Description:

validateEffects static bool RenderEffect::validate_effects(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 RenderEffect objects).

write virtual void RenderEffect::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.