source/builders/grid.cpp

   1 #include <cmath>
   2 #include "grid.h"
   3 #include "primitivebuilder.h"
   4
   5 using namespace std;
   6
   7 namespace Msp {
   8 namespace GL {
   9
  10 GridBuilder::GridBuilder(float w, float h, unsigned u, unsigned v):
  11         GridBuilder(Vector3(-w/2, -h/2, 0), Vector3(w, 0, 0), Vector3(0, h, 0), u, v)
  12 { }
  13
  14 GridBuilder::GridBuilder(const Vector3 &o, const Vector3 &s, unsigned u, unsigned v):
  15         GridBuilder(o, get_side(s, 0), get_side(s, 1), u, v)
  16 { }
  17
  18 GridBuilder::GridBuilder(const Vector3 &o, const Vector3 &s1, const Vector3 &s2, unsigned u, unsigned v):
  19         origin(o),
  20         side1(s1),
  21         side2(s2),
  22         u_div(max(u, 1U)),
  23         v_div(max(v, 1U))
  24 {
  25         norm = normalize(cross(side1, side2));
  26         binorm = normalize(cross(norm, side1));
  27 }
  28
  29 Vector3 GridBuilder::get_side(const Vector3 &size, unsigned index)
  30 {
  31         if(!size.x)
  32                 return Vector3(0, (index==0 ? size.y : 0), (index==1 ? size.z : 0));
  33         else if(!size.y)
  34                 return Vector3((index==0 ? size.x : 0), 0, (index==1 ? size.z : 0));
  35         else
  36                 return Vector3((index==0 ? size.x : 0), (index==1 ? size.z : 0), 0);
  37 }
  38
  39 void GridBuilder::build(PrimitiveBuilder &builder) const
  40 {
  41         float l1_sq = dot(side1, side1);
  42         float l2 = dot(side2, binorm);
  43         float u_scale = 1/l1_sq;
  44         float v_scale = 1/l2;
  45         adjust_texture_scale(u_scale, v_scale, sqrt(l1_sq), l2);
  46
  47         builder.normal(norm.x, norm.y, norm.z);
  48         if(generate_tan)
  49                 builder.tangent(side1);
  50
  51         for(unsigned j=0; j<=v_div; ++j)
  52         {
  53                 Vector3 row = side2*(j*1.0f/v_div);
  54                 float v = dot(row, binorm)*v_scale;
  55                 for(unsigned i=0; i<=u_div; ++i)
  56                 {
  57                         Vector3 p = row+side1*(i*1.0f/u_div);
  58                         float u = dot(p, side1)*u_scale;
  59                         builder.texcoord(u, v);
  60                         builder.vertex(origin+p);
  61                 }
  62         }
  63
  64         for(unsigned j=0; j<v_div; ++j)
  65         {
  66                 builder.begin(TRIANGLE_STRIP);
  67                 for(unsigned i=0; i<=u_div; ++i)
  68                 {
  69                         builder.element((j+1)*(u_div+1)+i);
  70                         builder.element(j*(u_div+1)+i);
  71                 }
  72                 builder.end();
  73         }
  74 }
  75
  76 } // namespace GL
  77 } // namespace Msp