1 #ifndef DEPTHOFFIELD_HXX
  2 #define DEPTHOFFIELD_HXX
  3 
  4 #include "Camera.hxx"
  5 
  6 class DepthOfField : public Camera
  7 {
  8     // input values
  9     Vec3f pos,dir,up;
 10     float angle;
 11     float focallength;
 12     float aperture;
 13 
 14     // preprocessed values
 15     float focus;
 16     Vec3f xAxis,yAxis,zAxis;
 17     float aspect;
 18     
 19 public:
 20     /**
 21      * parameter as normal for PerspectiveCamera, new:
 22      *  (1) focallength:
 23      *      the distance from the camera position to the focal plane
 24      *      thus. the distance where the object is sharp
 25      *  (2) aperture:
 26      *      how blurred should the object look like?
 27      *      (larger value implies more blurring)
 28      */
 29     DepthOfField(Vec3f pos, Vec3f _dir, Vec3f up, float angle, float focallength, float aperture, int resX, int resY )
 30     : Camera(resX,resY), pos(pos), up(up), angle(angle), focallength(focallength), aperture(aperture)
 31     {
 32         /**
 33          * computation as in PerspectiveCamera
 34          */
 35         dir = _dir;
 36         Normalize(_dir);
 37 
 38         zAxis = dir;
 39         xAxis = Cross(dir,up);
 40         yAxis = Cross(xAxis,zAxis);
 41 
 42         Normalize(xAxis);
 43         Normalize(yAxis);
 44         Normalize(zAxis);
 45 
 46         aspect = resX / float(resY);
 47         
 48         float angleInRad = angle * (float)M_PI / 180.f;
 49         focus = 1.f / tan(angleInRad/2.f);      
 50     }
 51 
 52     virtual ~DepthOfField()
 53     {}
 54 
 55     /**
 56      * some set methods
 57      */
 58     void setAperture(float a)
 59     {
 60         aperture = a;
 61     }
 62 
 63     void setFocallength(float f)
 64     {
 65         focallength = f;
 66     }
 67 
 68     virtual bool InitRay(float x, float y, Ray &ray)
 69     {
 70         /**
 71          * compute two random numbers distributed in a unit disk
 72          */
 73         float r = drand48();
 74         float help = 1.0;
 75         while (help == 1.0)
 76             help = drand48();
 77         float theta = 2.0 * M_PI * help;
 78         float xRandom = sqrtf(r) * cosf(theta);
 79         float yRandom = sqrtf(r) * sinf(theta);
 80         
 81         /**
 82          * position computation as in normal PerspectiveCamera
 83          */
 84         ray.org = pos;
 85         ray.dir =       ( 2.0f *  (x/(float)resX - 0.5f) * aspect * xAxis)
 86                     +   ( 2.0f *  (y/(float)resY - 0.5f) * yAxis)
 87                     +   (focus * zAxis);
 88         
 89         /**
 90          * compute then the intersection point of the ray with the plane of focus
 91          * and the corresponding distance
 92          */
 93         float dist = focallength / Dot(ray.dir,zAxis);
 94         Vec3f focuspoint = ray.org + dist * ray.dir;            
 95             
 96         /**
 97          * move origin of the ray in x- and y-direction
 98          * with a maximal movement of 0.5 to the left and to the right
 99          */
100         ray.org += Vec3f( (xRandom-0.5)*aperture, 0, 0) + Vec3f( 0, (yRandom-0.5)*aperture, 0);
101         
102         /**
103          * new direction vector must go through point on plane of focus
104          */
105         ray.dir = focuspoint - ray.org;
106         Normalize(ray.dir);
107         
108         ray.t = Infinity;
109         ray.hit = NULL;
110 
111         return true;
112     };
113 };
114 
115 #endif
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