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