RenderAttrib

from panda3d.core import RenderAttrib

class RenderAttrib

Bases:

Bases: TypedWritableReferenceCount

This is the base class for a number of render attributes (other than transform) that may be set on scene graph nodes to control the appearance of geometry. This includes TextureAttrib, ColorAttrib, etc.

RenderAttrib represents render attributes that always propagate down to the leaves without regard to the particular node they are assigned to. A RenderAttrib will have the same effect on a leaf node whether it is assigned to the graph at the leaf or several nodes above. This is different from RenderEffect, which represents a particular render property that is applied immediately to the node on which it is encountered, like billboarding or decaling.

You should not attempt to create or modify a RenderAttrib directly; instead, use the make() method of the appropriate kind of attrib you want. This will allocate and return a new RenderAttrib of the appropriate type, and it may share pointers if possible. Do not modify the new RenderAttrib if you wish to change its properties; instead, create a new one.

Inheritance diagram

enum PandaCompareFunc

intentionally defined to match D3DCMPFUNC

enumerator M_none = 0

alpha-test disabled (always-draw)

enumerator M_never = 1

Never draw.

enumerator M_less = 2

incoming < reference_alpha

enumerator M_equal = 3

incoming == reference_alpha

enumerator M_less_equal = 4

incoming <= reference_alpha

enumerator M_greater = 5

incoming > reference_alpha

enumerator M_not_equal = 6

incoming != reference_alpha

enumerator M_greater_equal = 7

incoming >= reference_alpha

enumerator M_always = 8

Always draw.

enum TexGenMode

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.

enumerator M_off = 0

enumerator M_eye_sphere_map = 1

Sphere maps are classic static reflection maps. They are supported on just about any hardware, and require a precomputed 360-degree fisheye image. Sphere maps only make sense in eye coordinate space.

enumerator M_world_cube_map = 2

Cube maps are a modern improvement on the sphere map; they don’t suffer from any polar singularities, but they require six texture images. They can also be generated dynamically for real-time reflections (see GraphicsOutput::make_cube_map()). Typically, a statically-generated cube map will be in eye space, while a dynamically-generated map will be in world space. Cube mapping is not supported on all hardware.

enumerator M_eye_cube_map = 3

enumerator M_world_normal = 4

Normal maps are most useful for applying diffuse lighting effects via a pregenerated cube map.

enumerator M_eye_normal = 5

enumerator M_world_position = 6

Position maps convert XYZ coordinates directly to texture coordinates. This is particularly useful for implementing projective texturing (see NodePath::project_texture()).

enumerator M_unused = 7

formerly M_object_position, now deprecated.

enumerator M_eye_position = 8

enumerator M_point_sprite = 9

With M_point_sprite, texture coordinates will be generated for large points in the range (0,0) - (1,1) from upper-left to lower-right across the point’s face. Without this, each point will have just a single uniform texture coordinate value across its face. Unfortunately, the generated texture coordinates are inverted (upside-down) from Panda’s usual convention, but this is what the graphics card manufacturers decided to use. You could use a texture matrix to re-invert the texture, but that will probably force the sprites’ vertices to be computed in the CPU. You’ll have to paint your textures upside-down if you want true hardware sprites.

enumerator M_unused2 = 10

M_light_vector generated special 3-d texture coordinates that represented the vector to a particular Light in the scene graph, expressed in each vertex’s tangent space. This has now been removed. We need to reserve the slot in the enum, though, to make sure the following enum value still has the same value.

enumerator M_constant = 11

M_constant generates the same fixed texture coordinates at each vertex. Not terribly useful, of course, except for certain special effects involving moving a flat color over an object.

compare_to(other: RenderAttrib) → int

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.

compose(other: RenderAttrib) → RenderAttrib

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.

static garbage_collect() → int

Performs a garbage-collection cycle. This is called automatically from RenderState.garbage_collect(); see that method for more information.

static get_class_type() → TypeHandle

get_hash() → int

Returns a suitable hash value for phash_map.

static get_num_attribs() → int

Returns the total number of unique RenderAttrib objects allocated in the world. This will go up and down during normal operations.

get_slot() → int

get_unique() → RenderAttrib

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.

invert_compose(other: RenderAttrib) → RenderAttrib

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.

This is similar to compose() except that the source attrib is inverted first. This is used to compute the relative attribute for one node as viewed from some other node, which is especially useful for transform-type attributes.

static list_attribs(out: ostream)

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.

lower_attrib_can_override() → bool

Intended to be overridden by derived RenderAttrib types to specify how two consecutive RenderAttrib objects of the same type interact.

This should return false if a RenderAttrib on a higher node will compose into a RenderAttrib on a lower node that has a higher override value, or true if the lower RenderAttrib will completely replace the state.

The default behavior is false: normally, a RenderAttrib in the graph cannot completely override a RenderAttrib above it, regardless of its override value–instead, the two attribs are composed. But for some kinds of RenderAttribs, it is useful to allow this kind of override.

This method only handles the one special case of a lower RenderAttrib with a higher override value. If the higher RenderAttrib has a higher override value, it always completely overrides. And if both RenderAttribs have the same override value, they are always composed.

output(out: ostream)

property slot → int

static validate_attribs() → bool

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(out: ostream, indent_level: int)