source/capsule.cpp

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