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#ifndef _RAY_CAMERA_H
#define _RAY_CAMERA_H
#include <math.h>
#include "til_fb.h"
#include "ray_3f.h"
#include "ray_euler.h"
#include "ray_ray.h"
typedef struct ray_camera_t {
ray_3f_t position; /* position of camera, the origin of all its rays */
ray_euler_t orientation; /* orientation of the camera */
/* Units for focal_length, width, and height, are undefined in absolute terms or any
* kind of SI unit - they're the same units of the virtual scene shared
* with the objects.
*/
float focal_length; /* controls the field of view */
/* XXX: Note these are not the same as the rendered frame width and height in pixels,
* these influence the frustum size and shape in the 3D world by controlling the 2D
* plane size and shape that frustum intersects.
*/
float film_width; /* width of camera's virtual "film" */
float film_height; /* height of camera's virtual "film" */
} ray_camera_t;
typedef struct ray_camera_frame_t {
const ray_camera_t *camera; /* the camera supplied to frame_begin() */
ray_3f_t nw, ne, sw, se; /* directions pointing through the corners of the frame fragment */
float x_delta, y_delta; /* interpolation step delta along the x and y axis */
} ray_camera_frame_t;
typedef struct ray_camera_fragment_t {
ray_camera_frame_t *frame; /* the frame supplied to fragment_begin() */
til_fb_fragment_t *fb_fragment; /* the fragment supplied to fragment_begin() */
ray_ray_t *ray; /* the ray supplied to frame_begin(), which gets updated as we step through the frame. */
ray_3f_t cur_w, cur_e; /* current row's west and east ends */
float x_alpha, y_alpha; /* interpolation position along the x and y axis */
unsigned x, y; /* integral position within frame fragment */
} ray_camera_fragment_t;
void ray_camera_frame_prepare(const ray_camera_t *camera, unsigned frame_width, unsigned frame_height, ray_camera_frame_t *res_frame);
void ray_camera_fragment_begin(ray_camera_frame_t *frame, til_fb_fragment_t *fb_fragment, ray_ray_t *res_ray, ray_camera_fragment_t *res_fragment);
/* Step the ray through the fragment on the x axis, returns 1 when rays remain on this axis, 0 at the end. */
/* When 1 is returned, fragment->ray is left pointing through the new coordinate. */
static inline int ray_camera_fragment_x_step(ray_camera_fragment_t *fragment)
{
fragment->x++;
if (fragment->x >= fragment->fb_fragment->width) {
fragment->x = 0;
fragment->x_alpha = fragment->frame->x_delta * (float)fragment->fb_fragment->x;
return 0;
}
fragment->x_alpha += fragment->frame->x_delta;
fragment->ray->direction = ray_3f_nlerp(&fragment->cur_w, &fragment->cur_e, fragment->x_alpha);
return 1;
}
/* Step the ray through the fragment on the y axis, returns 1 when rays remain on this axis, 0 at the end. */
/* When 1 is returned, fragment->ray is left pointing through the new coordinate. */
static inline int ray_camera_fragment_y_step(ray_camera_fragment_t *fragment)
{
fragment->y++;
if (fragment->y >= fragment->fb_fragment->height) {
fragment->y = 0;
fragment->y_alpha = fragment->frame->y_delta * (float)fragment->fb_fragment->y;
return 0;
}
fragment->y_alpha += fragment->frame->y_delta;
fragment->cur_w = ray_3f_lerp(&fragment->frame->nw, &fragment->frame->sw, fragment->y_alpha);
fragment->cur_e = ray_3f_lerp(&fragment->frame->ne, &fragment->frame->se, fragment->y_alpha);
fragment->ray->direction = ray_3f_nlerp(&fragment->cur_w, &fragment->cur_e, fragment->x_alpha);
return 1;
}
#endif
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