source/capsule.cpp

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