1 files changed, 77 insertions, 0 deletions
diff --git a/modules/ray/ray_camera.h b/modules/ray/ray_camera.h
new file mode 100644
index 0000000..387f8c5
--- /dev/null
+++ b/modules/ray/ray_camera.h
@@ -0,0 +1,77 @@
+#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_nlerp(&frame->nw, &frame->sw, frame->y_alpha);
+	frame->cur_e = ray_3f_nlerp(&frame->ne, &frame->se, frame->y_alpha);
+	frame->ray->direction = frame->cur_w;
+
+	return 1;
+}
+
+#endif