simvx.core.math.raycast

Rays: the Ray value type and ray-sphere intersection.

Module Contents

Classes

Ray	A half-line in world space: an origin and a unit direction.

Functions

ray_intersect_sphere

Ray-sphere intersection. Returns distance t or None if no hit.

API

class simvx.core.math.raycast.Ray(origin, direction)

A half-line in world space: an origin and a unit direction.

Camera3D.ray_at(screen_pos) is the usual way to get one; build one by hand with Ray(origin, direction), which normalises the direction. Distances along a ray are in world units, the same distance a physics RayHit reports, so ray.at(hit.distance) is the hit point.

Example::

ray = camera.ray_at(Input.mouse_position)
ground = ray.intersect_plane((0, 0, 0), (0, 1, 0))
if ground is not None:
    marker.position = ground

Initialization

origin: simvx.core.math.types.Vec3

None

direction: simvx.core.math.types.Vec3

None

classmethod from_screen(screen_pos, screen_size, view, proj) → simvx.core.math.raycast.Ray

The ray through screen_pos for a camera given as matrices.

For a view drawn by a camera node, Camera3D.ray_at is the spelling to use; this form is for a view whose size or matrices do not come from a node, such as a viewport panel inside a larger window.

Args: screen_pos: Pixel position, (0, 0) at the top left of the view. screen_size: The view’s (width, height) in the same units. view: Row-major 4x4 view matrix. proj: Row-major 4x4 reverse-Z projection matrix, Vulkan Y-flip included or not (the flip is read from the matrix).

at(distance: float) → simvx.core.math.types.Vec3

The point distance world units along the ray.

intersect_plane(point, normal) → simvx.core.math.types.Vec3 | None

Where the ray crosses the plane through point with normal, or None.

None when the ray runs parallel to the plane or the plane is behind the origin. Either side of the plane counts, so a ray from below a floor still meets it.

simvx.core.math.raycast.ray_intersect_sphere(origin, direction, center, radius: float)

Ray-sphere intersection. Returns distance t or None if no hit.