ray: libize raytracer core, introduces src/libs

This is the first step of breaking out all the core rendering stuffs
into reusable libraries and making modules purely compositional,
consumers of various included rendering/effects libraries.

Expect multiple modules leveraging libray for a variety of scenes and
such.  Also expect compositions mixing the various libraries for more
interesting visuals.

1 files changed, 61 insertions, 0 deletions

diff --git a/src/libs/ray/ray_render_object_plane.h b/src/libs/ray/ray_render_object_plane.h
new file mode 100644
index 0000000..6e00089
--- /dev/null
+++ b/src/libs/ray/ray_render_object_plane.h
@@ -0,0 +1,61 @@
+#ifndef _RAY_RENDER_OBJECT_PLANE_H
+#define _RAY_RENDER_OBJECT_PLANE_H
+
+#include "ray_3f.h"
+#include "ray_camera.h"
+#include "ray_object_plane.h"
+#include "ray_object_type.h"
+#include "ray_ray.h"
+#include "ray_surface.h"
+
+
+typedef struct ray_render_object_plane_t {
+	ray_object_plane_t	object;
+	float			primary_dot_plus;
+} ray_render_object_plane_t;
+
+
+static ray_render_object_plane_t ray_render_object_plane_prepare(const ray_object_plane_t *plane, const ray_camera_t *camera)
+{
+	ray_render_object_plane_t	prepared = { .object = *plane };
+
+	prepared.primary_dot_plus = ray_3f_dot(&plane->normal, &camera->position) + plane->distance;
+
+	return prepared;
+}
+
+
+static inline int ray_render_object_plane_intersects_ray(ray_render_object_plane_t *plane, unsigned depth, ray_ray_t *ray, float *res_distance)
+{
+	float	d = ray_3f_dot(&plane->object.normal, &ray->direction);
+
+	if (d < 0.0f) {
+		float	distance = plane->primary_dot_plus;
+
+		if (depth)
+			distance = (ray_3f_dot(&plane->object.normal, &ray->origin) + plane->object.distance);
+
+		distance /= -d;
+		if (distance > 0.0f) {
+			*res_distance = distance;
+
+			return 1;
+		}
+	}
+
+	return 0;
+}
+
+
+static inline ray_3f_t ray_render_object_plane_normal(ray_render_object_plane_t *plane, ray_3f_t *point)
+{
+	return plane->object.normal;
+}
+
+
+static inline ray_surface_t ray_render_object_plane_surface(ray_render_object_plane_t *plane, ray_3f_t *point)
+{
+	return plane->object.surface;
+}
+
+#endif