source/camera.cpp

   1 #include <cmath>
   2 #include "camera.h"
   3 #include "matrix.h"
   4
   5 namespace Msp {
   6 namespace GL {
   7
   8 Camera::Camera():
   9         fov(Geometry::Angle<float>::from_turns(0.125)),
  10         aspect(4.0/3.0),
  11         clip_near(0.1),
  12         clip_far(10),
  13         frustum_x(0),
  14         frustum_y(0),
  15         position(0, 0, 0),
  16         look_dir(0, 0, -1),
  17         up_dir(0, 1, 0)
  18 { }
  19
  20 void Camera::set_field_of_view(const Geometry::Angle<float> &f)
  21 {
  22         fov = f;
  23 }
  24
  25 void Camera::set_aspect(float a)
  26 {
  27         aspect = a;
  28 }
  29
  30 void Camera::set_depth_clip(float n, float f)
  31 {
  32         clip_near = n;
  33         clip_far = f;
  34 }
  35
  36 void Camera::set_frustum_axis(float x, float y)
  37 {
  38         frustum_x = x;
  39         frustum_y = y;
  40 }
  41
  42 void Camera::set_position(const Vector3 &p)
  43 {
  44         position = p;
  45         update_object_matrix();
  46 }
  47
  48 void Camera::set_up_direction(const Vector3 &u)
  49 {
  50         up_dir = normalize(u);
  51         update_object_matrix();
  52 }
  53
  54 void Camera::set_look_direction(const Vector3 &l)
  55 {
  56         look_dir = normalize(l);
  57         update_object_matrix();
  58 }
  59
  60 void Camera::look_at(const Vector3 &p)
  61 {
  62         set_look_direction(p-position);
  63 }
  64
  65 Vector3 Camera::project(const Vector4 &p) const
  66 {
  67         Vector4 r = proj_matrix*(view_matrix*p);
  68         return Vector3(r)/r.w;
  69 }
  70
  71 Vector3 Camera::project(const Vector3 &p) const
  72 {
  73         return project(Vector4(p.x, p.y, p.z, 1.0));
  74 }
  75
  76 Vector4 Camera::unproject(const Vector4 &p) const
  77 {
  78         Vector4 r = invert(proj_matrix)*LinAl::Vector<double, 4>(p.x, p.y, p.z, 1.0f);
  79         r = object_matrix*Vector4(r.x, r.y, r.z, p.w);
  80         return r;
  81 }
  82
  83 void Camera::apply() const
  84 {
  85         float frustum_h = tan(fov/2.0f)*clip_near;
  86         float frustum_w = frustum_h*aspect;
  87         float left = frustum_w*(frustum_x-1.0f);
  88         float right = frustum_w*(frustum_x+1.0f);
  89         float bottom = frustum_h*(frustum_y-1.0f);
  90         float top = frustum_h*(frustum_y+1.0f);
  91         MatrixStack::projection() = Matrix::frustum(left, right, bottom, top, clip_near, clip_far);
  92         MatrixStack::modelview() = view_matrix;
  93 }
  94
  95 void Camera::update_object_matrix()
  96 {
  97         Vector3 right_dir = normalize(cross(look_dir, up_dir));
  98         LinAl::Vector<double, 4> columns[4];
  99         columns[0] = LinAl::Vector<double, 4>(right_dir, 0.0f);
 100         columns[1] = LinAl::Vector<double, 4>(cross(right_dir, look_dir), 0.0f);
 101         columns[2] = LinAl::Vector<double, 4>(-look_dir, 0.0f);
 102         columns[3] = LinAl::Vector<double, 4>(position, 1.0f);
 103         object_matrix = Matrix::from_columns(columns);
 104         view_matrix = invert(object_matrix);
 105 }
 106
 107 } // namespace GL
 108 } // namespace Msp