118 lines
3.0 KiB
C++
118 lines
3.0 KiB
C++
/**
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* PANDA 3D SOFTWARE
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* Copyright (c) Carnegie Mellon University. All rights reserved.
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*
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* All use of this software is subject to the terms of the revised BSD
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* license. You should have received a copy of this license along
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* with this source code in a file named "LICENSE."
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*
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* @file eggTriangleFan.cxx
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* @author drose
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* @date 2005-03-23
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*/
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#include "eggTriangleFan.h"
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#include "eggGroupNode.h"
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#include "eggPolygon.h"
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#include "indent.h"
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TypeHandle EggTriangleFan::_type_handle;
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/**
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*
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*/
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EggTriangleFan::
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~EggTriangleFan() {
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clear();
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}
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/**
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* Makes a copy of this object.
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*/
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EggTriangleFan *EggTriangleFan::
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make_copy() const {
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return new EggTriangleFan(*this);
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}
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/**
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* Writes the triangle fan to the indicated output stream in Egg format.
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*/
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void EggTriangleFan::
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write(ostream &out, int indent_level) const {
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write_header(out, indent_level, "<TriangleFan>");
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write_body(out, indent_level+2);
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indent(out, indent_level) << "}\n";
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}
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/**
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* Sets the first vertex of the triangle (or each component) to the primitive
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* normal and/or color, if the primitive is flat-shaded. This reflects the
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* DirectX convention of storing flat-shaded properties on the first vertex,
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* although it is not usually a convention in Egg.
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*
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* This may introduce redundant vertices to the vertex pool.
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*/
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void EggTriangleFan::
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apply_first_attribute() {
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// In the case of a triangle fan, the first vertex of the fan is the common
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// vertex, so we consider the second vertex to be the key vertex of the
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// first triangle, and move from there.
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for (int i = 0; i < get_num_components(); i++) {
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EggAttributes *component = get_component(i);
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do_apply_flat_attribute(i + 1, component);
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}
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}
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/**
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* Returns the number of initial vertices that are not used in defining any
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* component; the first component is defined by the (n + 1)th vertex, and then
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* a new component at each vertex thereafter.
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*/
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int EggTriangleFan::
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get_num_lead_vertices() const {
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return 2;
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}
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/**
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* Fills the container up with EggPolygons that represent the component
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* triangles of this triangle fan.
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*
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* It is assumed that the EggTriangleFan is not already a child of any other
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* group when this function is called.
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*
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* Returns true if the triangulation is successful, or false if there was some
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* error (in which case the container may contain some partial triangulation).
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*/
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bool EggTriangleFan::
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do_triangulate(EggGroupNode *container) const {
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if (size() < 3) {
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return false;
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}
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const_iterator vi = begin();
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EggVertex *v0 = (*vi);
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++vi;
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EggVertex *v1 = (*vi);
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++vi;
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for (int i = 0; i < (int)size() - 2; i++) {
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PT(EggPolygon) poly = new EggPolygon;
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poly->copy_attributes(*this);
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const EggAttributes *attrib = get_component(i);
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if (attrib->has_color()) {
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poly->set_color(attrib->get_color());
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}
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if (attrib->has_normal()) {
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poly->set_normal(attrib->get_normal());
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}
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poly->add_vertex(v0);
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poly->add_vertex(v1);
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poly->add_vertex(*vi);
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v1 = *vi;
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container->add_child(poly);
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++vi;
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}
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return true;
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}
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