Panda3D
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eggTriangleFan.cxx
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1/**
2 * PANDA 3D SOFTWARE
3 * Copyright (c) Carnegie Mellon University. All rights reserved.
4 *
5 * All use of this software is subject to the terms of the revised BSD
6 * license. You should have received a copy of this license along
7 * with this source code in a file named "LICENSE."
8 *
9 * @file eggTriangleFan.cxx
10 * @author drose
11 * @date 2005-03-23
12 */
13
14#include "eggTriangleFan.h"
15#include "eggGroupNode.h"
16#include "eggPolygon.h"
17#include "indent.h"
18
19TypeHandle EggTriangleFan::_type_handle;
20
21/**
22 *
23 */
24EggTriangleFan::
25~EggTriangleFan() {
26 clear();
27}
28
29/**
30 * Makes a copy of this object.
31 */
33make_copy() const {
34 return new EggTriangleFan(*this);
35}
36
37/**
38 * Writes the triangle fan to the indicated output stream in Egg format.
39 */
41write(std::ostream &out, int indent_level) const {
42 write_header(out, indent_level, "<TriangleFan>");
43 write_body(out, indent_level+2);
44 indent(out, indent_level) << "}\n";
45}
46
47/**
48 * Sets the first vertex of the triangle (or each component) to the primitive
49 * normal and/or color, if the primitive is flat-shaded. This reflects the
50 * DirectX convention of storing flat-shaded properties on the first vertex,
51 * although it is not usually a convention in Egg.
52 *
53 * This may introduce redundant vertices to the vertex pool.
54 */
57 // In the case of a triangle fan, the first vertex of the fan is the common
58 // vertex, so we consider the second vertex to be the key vertex of the
59 // first triangle, and move from there.
60 for (size_t i = 0; i < get_num_components(); ++i) {
61 EggAttributes *component = get_component(i);
62 do_apply_flat_attribute(i + 1, component);
63 }
64}
65
66/**
67 * Returns the number of initial vertices that are not used in defining any
68 * component; the first component is defined by the (n + 1)th vertex, and then
69 * a new component at each vertex thereafter.
70 */
71int EggTriangleFan::
72get_num_lead_vertices() const {
73 return 2;
74}
75
76/**
77 * Fills the container up with EggPolygons that represent the component
78 * triangles of this triangle fan.
79 *
80 * It is assumed that the EggTriangleFan is not already a child of any other
81 * group when this function is called.
82 *
83 * Returns true if the triangulation is successful, or false if there was some
84 * error (in which case the container may contain some partial triangulation).
85 */
86bool EggTriangleFan::
87do_triangulate(EggGroupNode *container) const {
88 if (size() < 3) {
89 return false;
90 }
91 const_iterator vi = begin();
92 EggVertex *v0 = (*vi);
93 ++vi;
94 EggVertex *v1 = (*vi);
95 ++vi;
96
97 for (int i = 0; i < (int)size() - 2; i++) {
98 PT(EggPolygon) poly = new EggPolygon;
99 poly->copy_attributes(*this);
100 const EggAttributes *attrib = get_component(i);
101 if (attrib->has_color()) {
102 poly->set_color(attrib->get_color());
103 }
104 if (attrib->has_normal()) {
105 poly->set_normal(attrib->get_normal());
106 }
107
108 poly->add_vertex(v0);
109 poly->add_vertex(v1);
110 poly->add_vertex(*vi);
111 v1 = *vi;
112 container->add_child(poly);
113 ++vi;
114 }
115
116 return true;
117}
The set of attributes that may be applied to vertices as well as polygons, such as surface normal and...
LColor get_color() const
Returns the color set on this particular attribute.
get_num_components
Returns the number of individual component triangles within the composite.
get_component
Returns the attributes for the nth component triangle.
A base class for nodes in the hierarchy that are not leaf nodes.
EggNode * add_child(EggNode *node)
Adds the indicated child to the group and returns it.
void write_header(std::ostream &out, int indent_level, const char *egg_keyword) const
Writes the first line of the egg object, e.g.
A single polygon.
Definition eggPolygon.h:24
void copy_attributes(const EggAttributes &other)
Copies the rendering attributes from the indicated primitive.
void clear()
Removes all of the vertices from the primitive.
A connected fan of triangles.
virtual void write(std::ostream &out, int indent_level) const override
Writes the triangle fan to the indicated output stream in Egg format.
virtual void apply_first_attribute() override
Sets the first vertex of the triangle (or each component) to the primitive normal and/or color,...
virtual EggTriangleFan * make_copy() const override
Makes a copy of this object.
Any one-, two-, three-, or four-component vertex, possibly with attributes such as a normal.
Definition eggVertex.h:39
TypeHandle is the identifier used to differentiate C++ class types.
Definition typeHandle.h:81
PANDA 3D SOFTWARE Copyright (c) Carnegie Mellon University.
PANDA 3D SOFTWARE Copyright (c) Carnegie Mellon University.
PANDA 3D SOFTWARE Copyright (c) Carnegie Mellon University.
std::ostream & indent(std::ostream &out, int indent_level)
A handy function for doing text formatting.
Definition indent.cxx:20
PANDA 3D SOFTWARE Copyright (c) Carnegie Mellon University.