ray: split object render from object description

This moves the per-object _prepared state into ray_render_object_$type
structs with all the rendering-related object methods switched to
operate on the new render structs.

Since the current rendering code just makes all these assumptions
about light objects being point lights, I've just dropped all the
stuff associated with rendering light objects for now.  I think it
will be refactored a bit later on when the rendering code stops
hard-coding the point light stuff.

These changes open up the possibility of constifying the scene and
constituent objects, now that rendering doesn't shove the prepared
state into the embedded _prepared object substructs.

1 files changed, 121 insertions, 0 deletions

diff --git a/src/modules/ray/ray_render_object.h b/src/modules/ray/ray_render_object.h
new file mode 100644
index 0000000..5b4ce25
--- /dev/null
+++ b/src/modules/ray/ray_render_object.h
@@ -0,0 +1,121 @@
+#ifndef _RAY_RENDER_OBJECT_H
+#define _RAY_RENDER_OBJECT_H
+
+#include <assert.h>
+
+#include "ray_camera.h"
+#include "ray_object.h"
+#include "ray_object_type.h"
+#include "ray_render_object_plane.h"
+#include "ray_render_object_point.h"
+#include "ray_render_object_sphere.h"
+#include "ray_ray.h"
+#include "ray_surface.h"
+
+typedef union ray_render_object_t {
+	ray_object_type_t		type;
+	ray_render_object_sphere_t	sphere;
+	ray_render_object_point_t	point;
+	ray_render_object_plane_t	plane;
+} ray_render_object_t;
+
+
+
+/* Prepare an object for rendering.
+ * If the object has any pre-calculating to do, this is where it happens.
+ * The pre-calculated stuff is object-resident under a _prepared struct member.
+ */
+static inline ray_render_object_t ray_render_object_prepare(ray_object_t *object, ray_camera_t *camera)
+{
+	ray_render_object_t	prepared = { .type = object->type };
+
+	switch (object->type) {
+	case RAY_OBJECT_TYPE_SPHERE:
+		prepared.sphere = ray_render_object_sphere_prepare(&object->sphere, camera);
+		break;
+
+	case RAY_OBJECT_TYPE_POINT:
+		prepared.point = ray_render_object_point_prepare(&object->point, camera);
+		break;
+
+	case RAY_OBJECT_TYPE_PLANE:
+		prepared.plane = ray_render_object_plane_prepare(&object->plane, camera);
+		break;
+
+	case RAY_OBJECT_TYPE_LIGHT:
+		/* TODO */
+		break;
+
+	default:
+		assert(0);
+	}
+
+	return prepared;
+}
+
+
+/* Determine if a ray intersects object.
+ * If the object is intersected, store where along the ray the intersection occurs in res_distance.
+ */
+static inline int ray_render_object_intersects_ray(ray_render_object_t *object, unsigned depth, ray_ray_t *ray, float *res_distance)
+{
+	switch (object->type) {
+	case RAY_OBJECT_TYPE_SPHERE:
+		return ray_render_object_sphere_intersects_ray(&object->sphere, depth, ray, res_distance);
+
+	case RAY_OBJECT_TYPE_POINT:
+		return ray_render_object_point_intersects_ray(&object->point, depth, ray, res_distance);
+
+	case RAY_OBJECT_TYPE_PLANE:
+		return ray_render_object_plane_intersects_ray(&object->plane, depth, ray, res_distance);
+
+	case RAY_OBJECT_TYPE_LIGHT:
+		/* TODO */
+	default:
+		assert(0);
+	}
+}
+
+
+/* Return the surface normal of object @ point */
+static inline ray_3f_t ray_render_object_normal(ray_render_object_t *object, ray_3f_t *point)
+{
+	switch (object->type) {
+	case RAY_OBJECT_TYPE_SPHERE:
+		return ray_render_object_sphere_normal(&object->sphere, point);
+
+	case RAY_OBJECT_TYPE_POINT:
+		return ray_render_object_point_normal(&object->point, point);
+
+	case RAY_OBJECT_TYPE_PLANE:
+		return ray_render_object_plane_normal(&object->plane, point);
+
+	case RAY_OBJECT_TYPE_LIGHT:
+		/* TODO */
+	default:
+		assert(0);
+	}
+}
+
+
+/* Return the surface of object @ point */
+static inline ray_surface_t ray_render_object_surface(ray_render_object_t *object, ray_3f_t *point)
+{
+	switch (object->type) {
+	case RAY_OBJECT_TYPE_SPHERE:
+		return ray_render_object_sphere_surface(&object->sphere, point);
+
+	case RAY_OBJECT_TYPE_POINT:
+		return ray_render_object_point_surface(&object->point, point);
+
+	case RAY_OBJECT_TYPE_PLANE:
+		return ray_render_object_plane_surface(&object->plane, point);
+
+	case RAY_OBJECT_TYPE_LIGHT:
+		/* TODO */
+	default:
+		assert(0);
+	}
+}
+
+#endif