source/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         origin(-w/2, -h/2, 0),
  12         side1(w, 0, 0),
  13         side2(0, h, 0),
  14         norm(0, 0, 1),
  15         binorm(0, 1, 0),
  16         u_div(u),
  17         v_div(v)
  18 {
  19         init(false);
  20 }
  21
  22 GridBuilder::GridBuilder(const Vector3 &o, const Vector3 &s, unsigned u, unsigned v):
  23         origin(o),
  24         u_div(u),
  25         v_div(v)
  26 {
  27         if(abs(s.z)<abs(s.x) && abs(s.z)<abs(s.y))
  28         {
  29                 side1 = Vector3(s.x, 0, 0);
  30                 side2 = Vector3(0, s.y, 0);
  31         }
  32         else if(abs(s.y)<abs(s.x))
  33         {
  34                 side1 = Vector3(0, 0, s.z);
  35                 side2 = Vector3(s.x, 0, 0);
  36         }
  37         else
  38         {
  39                 side1 = Vector3(0, s.y, 0);
  40                 side2 = Vector3(0, 0, s.z);
  41         }
  42         init(true);
  43 }
  44
  45 GridBuilder::GridBuilder(const Vector3 &o, const Vector3 &s1, const Vector3 &s2, unsigned u, unsigned v):
  46         origin(o),
  47         side1(s1),
  48         side2(s2),
  49         u_div(u),
  50         v_div(v)
  51 {
  52         init(true);
  53 }
  54
  55 void GridBuilder::init(bool compute_normals)
  56 {
  57         if(u_div<1)
  58                 u_div = 1;
  59         if(v_div<1)
  60                 v_div = 1;
  61
  62         if(compute_normals)
  63         {
  64                 norm.x = side1.y*side2.z-side1.z*side2.y;
  65                 norm.y = side1.z*side2.x-side1.x*side2.z;
  66                 norm.z = side1.x*side2.y-side1.y*side2.x;
  67                 float l = sqrt(norm.x*norm.x+norm.y*norm.y+norm.z*norm.z);
  68                 norm.x /= l;
  69                 norm.y /= l;
  70                 norm.z /= l;
  71
  72                 binorm.x = norm.y*side1.z-norm.z*side1.y;
  73                 binorm.y = norm.z*side1.x-norm.x*side1.z;
  74                 binorm.z = norm.x*side1.y-norm.y*side1.x;
  75                 l = sqrt(binorm.x*binorm.x+binorm.y*binorm.y+binorm.z*binorm.z);
  76                 binorm.x /= l;
  77                 binorm.y /= l;
  78                 binorm.z /= l;
  79         }
  80 }
  81
  82 void GridBuilder::build(PrimitiveBuilder &builder) const
  83 {
  84         float l1_sq = side1.x*side1.x+side1.y*side1.y+side1.z*side1.z;
  85         float l2 = side2.x*binorm.x+side2.y*binorm.y+side2.z*binorm.z;
  86         float u_scale = 1/l1_sq;
  87         float v_scale = 1/l2;
  88         adjust_texture_scale(u_scale, v_scale, sqrt(l1_sq), l2);
  89
  90         builder.normal(norm.x, norm.y, norm.z);
  91         if(tangent_attr>=0)
  92                 builder.attrib(tangent_attr, side1.x, side1.y, side1.z);
  93         if(binormal_attr>=0)
  94                 builder.attrib(tangent_attr, binorm.x, binorm.y, binorm.z);
  95
  96         for(unsigned j=0; j<=v_div; ++j)
  97         {
  98                 float v = j*1.0/v_div;
  99                 Vector3 row(origin.x+side2.x*v, origin.y+side2.y*v, origin.z+side2.z*v);
 100                 v = (row.x*binorm.x+row.y*binorm.y+row.z*binorm.z)*v_scale;
 101                 for(unsigned i=0; i<=u_div; ++i)
 102                 {
 103                         float u = i*1.0/u_div;
 104                         Vector3 p(row.x+side1.x*u, row.y+side1.y*u, row.z+side1.z*u);
 105                         u = (p.x*side1.x+p.y*side1.y+p.z*side1.z)*u_scale;
 106                         builder.texcoord(u, v);
 107                         builder.vertex(p);
 108                 }
 109         }
 110
 111         for(unsigned j=0; j<v_div; ++j)
 112         {
 113                 builder.begin(TRIANGLE_STRIP);
 114                 for(unsigned i=0; i<=u_div; ++i)
 115                 {
 116                         builder.element((j+1)*(u_div+1)+i);
 117                         builder.element(j*(u_div+1)+i);
 118                 }
 119                 builder.end();
 120         }
 121 }
 122
 123 } // namespace GL
 124 } // namespace Msp