source/capsule.cpp

   1 /* $Id$
   2
   3 This file is part of libmspgl
   4 Copyright © 2011  Mikko Rasa, Mikkosoft Productions
   5 Distributed under the LGPL
   6 */
   7
   8 #include <cmath>
   9 #include "capsule.h"
  10 #include "primitivebuilder.h"
  11
  12 using namespace std;
  13
  14 namespace Msp {
  15 namespace GL {
  16
  17 CapsuleBuilder::CapsuleBuilder(float r, float l, unsigned s, unsigned n):
  18         radius(r),
  19         length(l),
  20         segments(s),
  21         rings(n)
  22 {
  23         if(segments<3)
  24                 segments = 3;
  25         rings |= 1;
  26         if(rings<3)
  27                 rings = 3;
  28 }
  29
  30 void CapsuleBuilder::build(PrimitiveBuilder &builder) const
  31 {
  32         float u_scale = 1.0/segments;
  33         float v_scale = 1/(length+radius*M_PI);
  34         adjust_texture_scale(u_scale, v_scale, radius*M_PI*2, length+radius*M_PI);
  35
  36         builder.normal(0, 0, -1);
  37         builder.texcoord(0.5, 0);
  38         builder.vertex(0, 0, -length/2-radius);
  39         for(unsigned i=1; i<rings; ++i)
  40         {
  41                 float cz = length*(i>rings/2 ? 0.5 : -0.5);
  42                 float v = ((i>rings/2 ? i-1 : i)*radius*M_PI/(rings-1)+(i>rings/2 ? length : 0))*v_scale;
  43                 float ra = (i>rings/2 ? i-1 : i)*M_PI/(rings-1);
  44                 float rc = cos(ra);
  45                 float rs = sin(ra);
  46                 for(unsigned j=0; j<=segments; ++j)
  47                 {
  48                         float sa = j*M_PI*2/segments;
  49                         float sc = cos(sa);
  50                         float ss = sin(sa);
  51                         builder.normal(rs*sc, rs*ss, -rc);
  52                         if(tangent_attr>=0)
  53                                 builder.attrib(tangent_attr, -ss, sc, 0);
  54                         if(binormal_attr>=0)
  55                                 builder.attrib(binormal_attr, rc*sc, rc*ss, rs);
  56                         builder.texcoord(j*u_scale, v);
  57                         builder.vertex(rs*sc*radius, rs*ss*radius, cz-rc*radius);
  58                 }
  59         }
  60         builder.normal(0, 0, 1);
  61         builder.texcoord(0.5, (length+radius*M_PI)*v_scale);
  62         builder.vertex(0, 0, length/2+radius);
  63
  64         for(unsigned i=0; i<segments; ++i)
  65         {
  66                 builder.begin(GL::TRIANGLE_STRIP);
  67                 builder.element(0);
  68                 for(unsigned j=0; j+1<rings; ++j)
  69                 {
  70                         builder.element(1+j*(segments+1)+i+1);
  71                         builder.element(1+j*(segments+1)+i);
  72                 }
  73                 builder.element((segments+1)*(rings-1)+1);
  74                 builder.end();
  75         }
  76 }
  77
  78 } // namespace GL
  79 } // namespace Msp