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#ifndef _RAY_CAMERA_H
#define _RAY_CAMERA_H
#include <math.h>
#include "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 */
float focal_length; /* controls the field of view */
unsigned width; /* width of camera viewport in pixels */
unsigned height; /* height of camera viewport in pixels */
} ray_camera_t;
typedef struct ray_camera_frame_t {
ray_camera_t *camera; /* the camera supplied to frame_begin() */
fb_fragment_t *fragment; /* the fragment supplied to frame_begin() */
ray_ray_t *ray; /* the ray supplied to frame_begin(), which gets updated as we step through the frame. */
ray_3f_t nw, ne, sw, se; /* directions pointing through the corners of the frame fragment */
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 */
float x_delta, y_delta; /* interpolation step delta along the x and y axis */
unsigned x, y; /* integral position within frame fragment */
} ray_camera_frame_t;
void ray_camera_frame_begin(ray_camera_t *camera, fb_fragment_t *fragment, ray_ray_t *ray, ray_camera_frame_t *frame);
/* Step the ray through the frame on the x axis, returns 1 when rays remain on this axis, 0 at the end. */
/* When 1 is returned, frame->ray is left pointing through the new coordinate. */
static inline int ray_camera_frame_x_step(ray_camera_frame_t *frame)
{
frame->x++;
if (frame->x >= frame->fragment->width) {
frame->x = 0;
frame->x_alpha = frame->x_delta * (float)frame->fragment->x;
return 0;
}
frame->x_alpha += frame->x_delta;
frame->ray->direction = ray_3f_nlerp(&frame->cur_w, &frame->cur_e, frame->x_alpha);
return 1;
}
/* Step the ray through the frame on the y axis, returns 1 when rays remain on this axis, 0 at the end. */
/* When 1 is returned, frame->ray is left pointing through the new coordinate. */
static inline int ray_camera_frame_y_step(ray_camera_frame_t *frame)
{
frame->y++;
if (frame->y >= frame->fragment->height) {
frame->y = 0;
frame->y_alpha = frame->y_delta * (float)frame->fragment->y;
return 0;
}
frame->y_alpha += frame->y_delta;
frame->cur_w = ray_3f_lerp(&frame->nw, &frame->sw, frame->y_alpha);
frame->cur_e = ray_3f_lerp(&frame->ne, &frame->se, frame->y_alpha);
frame->ray->direction = ray_3f_nlerp(&frame->cur_w, &frame->cur_e, frame->x_alpha);
return 1;
}
#endif
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