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         height(0),
  11         aspect(4.0/3.0),
  12         clip_near(0.1),
  13         clip_far(10),
  14         frustum_x(0),
  15         frustum_y(0),
  16         position(0, 0, 0),
  17         look_dir(0, 0, -1),
  18         up_dir(0, 1, 0)
  19 {
  20         update_projection_matrix();
  21         update_object_matrix();
  22 }
  23
  24 void Camera::set_field_of_view(const Geometry::Angle<float> &f)
  25 {
  26         fov = f;
  27         update_projection_matrix();
  28 }
  29
  30 void Camera::set_orthographic(float w, float h)
  31 {
  32         fov = Geometry::Angle<float>::zero();
  33         height = h;
  34         if(w)
  35                 aspect = w/h;
  36         update_projection_matrix();
  37 }
  38
  39 void Camera::set_aspect(float a)
  40 {
  41         aspect = a;
  42         update_projection_matrix();
  43 }
  44
  45 void Camera::set_depth_clip(float n, float f)
  46 {
  47         clip_near = n;
  48         clip_far = f;
  49         update_projection_matrix();
  50 }
  51
  52 void Camera::set_frustum_axis(float x, float y)
  53 {
  54         frustum_x = x;
  55         frustum_y = y;
  56         update_projection_matrix();
  57 }
  58
  59 void Camera::set_position(const Vector3 &p)
  60 {
  61         position = p;
  62         update_object_matrix();
  63 }
  64
  65 void Camera::set_up_direction(const Vector3 &u)
  66 {
  67         up_dir = normalize(u);
  68         update_object_matrix();
  69 }
  70
  71 void Camera::set_look_direction(const Vector3 &l)
  72 {
  73         look_dir = normalize(l);
  74         update_object_matrix();
  75 }
  76
  77 void Camera::look_at(const Vector3 &p)
  78 {
  79         set_look_direction(p-position);
  80 }
  81
  82 Vector3 Camera::project(const Vector4 &p) const
  83 {
  84         Vector4 r = proj_matrix*(view_matrix*p);
  85         return Vector3(r)/r.w;
  86 }
  87
  88 Vector3 Camera::project(const Vector3 &p) const
  89 {
  90         return project(Vector4(p.x, p.y, p.z, 1.0));
  91 }
  92
  93 Vector4 Camera::unproject(const Vector4 &p) const
  94 {
  95         Vector4 r = invert(proj_matrix)*Vector4(p.x, p.y, p.z, 1.0f);
  96         r = object_matrix*Vector4(r.x, r.y, r.z, p.w);
  97         return r;
  98 }
  99
 100 void Camera::apply() const
 101 {
 102         MatrixStack::projection() = proj_matrix;
 103         MatrixStack::modelview() = view_matrix;
 104 }
 105
 106 void Camera::update_projection_matrix()
 107 {
 108         float frustum_h = tan(fov/2.0f)*clip_near;
 109         float frustum_w = frustum_h*aspect;
 110         float left = frustum_w*(frustum_x-1.0f);
 111         float right = frustum_w*(frustum_x+1.0f);
 112         float bottom = frustum_h*(frustum_y-1.0f);
 113         float top = frustum_h*(frustum_y+1.0f);
 114         if(fov>Geometry::Angle<float>::zero())
 115                 proj_matrix = Matrix::frustum(left, right, bottom, top, clip_near, clip_far);
 116         else
 117                 proj_matrix = Matrix::ortho(left, right, bottom, top, clip_near, clip_far);
 118 }
 119
 120 void Camera::update_object_matrix()
 121 {
 122         Vector3 right_dir = normalize(cross(look_dir, up_dir));
 123         Vector4 columns[4];
 124         columns[0] = Vector4(right_dir, 0.0f);
 125         columns[1] = Vector4(cross(right_dir, look_dir), 0.0f);
 126         columns[2] = Vector4(-look_dir, 0.0f);
 127         columns[3] = Vector4(position, 1.0f);
 128         object_matrix = Matrix::from_columns(columns);
 129         view_matrix = invert(object_matrix);
 130 }
 131
 132 } // namespace GL
 133 } // namespace Msp