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         update_projection_matrix();
  20         update_object_matrix();
  21 }
  22
  23 void Camera::set_field_of_view(const Geometry::Angle<float> &f)
  24 {
  25         fov = f;
  26         update_projection_matrix();
  27 }
  28
  29 void Camera::set_aspect(float a)
  30 {
  31         aspect = a;
  32         update_projection_matrix();
  33 }
  34
  35 void Camera::set_depth_clip(float n, float f)
  36 {
  37         clip_near = n;
  38         clip_far = f;
  39         update_projection_matrix();
  40 }
  41
  42 void Camera::set_frustum_axis(float x, float y)
  43 {
  44         frustum_x = x;
  45         frustum_y = y;
  46         update_projection_matrix();
  47 }
  48
  49 void Camera::set_position(const Vector3 &p)
  50 {
  51         position = p;
  52         update_object_matrix();
  53 }
  54
  55 void Camera::set_up_direction(const Vector3 &u)
  56 {
  57         up_dir = normalize(u);
  58         update_object_matrix();
  59 }
  60
  61 void Camera::set_look_direction(const Vector3 &l)
  62 {
  63         look_dir = normalize(l);
  64         update_object_matrix();
  65 }
  66
  67 void Camera::look_at(const Vector3 &p)
  68 {
  69         set_look_direction(p-position);
  70 }
  71
  72 Vector3 Camera::project(const Vector4 &p) const
  73 {
  74         Vector4 r = proj_matrix*(view_matrix*p);
  75         return Vector3(r)/r.w;
  76 }
  77
  78 Vector3 Camera::project(const Vector3 &p) const
  79 {
  80         return project(Vector4(p.x, p.y, p.z, 1.0));
  81 }
  82
  83 Vector4 Camera::unproject(const Vector4 &p) const
  84 {
  85         Vector4 r = invert(proj_matrix)*Vector4(p.x, p.y, p.z, 1.0f);
  86         r = object_matrix*Vector4(r.x, r.y, r.z, p.w);
  87         return r;
  88 }
  89
  90 void Camera::apply() const
  91 {
  92         MatrixStack::projection() = proj_matrix;
  93         MatrixStack::modelview() = view_matrix;
  94 }
  95
  96 void Camera::update_projection_matrix()
  97 {
  98         float frustum_h = tan(fov/2.0f)*clip_near;
  99         float frustum_w = frustum_h*aspect;
 100         float left = frustum_w*(frustum_x-1.0f);
 101         float right = frustum_w*(frustum_x+1.0f);
 102         float bottom = frustum_h*(frustum_y-1.0f);
 103         float top = frustum_h*(frustum_y+1.0f);
 104         proj_matrix = Matrix::frustum(left, right, bottom, top, clip_near, clip_far);
 105 }
 106
 107 void Camera::update_object_matrix()
 108 {
 109         Vector3 right_dir = normalize(cross(look_dir, up_dir));
 110         Vector4 columns[4];
 111         columns[0] = Vector4(right_dir, 0.0f);
 112         columns[1] = Vector4(cross(right_dir, look_dir), 0.0f);
 113         columns[2] = Vector4(-look_dir, 0.0f);
 114         columns[3] = Vector4(position, 1.0f);
 115         object_matrix = Matrix::from_columns(columns);
 116         view_matrix = invert(object_matrix);
 117 }
 118
 119 } // namespace GL
 120 } // namespace Msp