class RootNode(SceneNode):
"""A special node used as root for the scene tree, which `render()` method
renders the entire tree and performs the parent-child transformations
chaining.
"""
def render(self, ctx, transform=None):
self.t = Mat()
def render_all(node, parent_transform):
self.t.identity()
self.t *= parent_transform
self.t *= node.transform
new_t = Mat(self.t)
node.render(ctx, new_t)
for child in node.children:
render_all(child, new_t)
for child in self.children:
render_all(child, self.transform)
def render(self, ctx, transform=None):
self.t = Mat()
def render_all(node, parent_transform):
self.t.identity()
self.t *= parent_transform
self.t *= node.transform
new_t = Mat(self.t)
node.render(ctx, new_t)
for child in node.children:
render_all(child, new_t)
for child in self.children:
render_all(child, self.transform)
class Camera(ABC):
"""Abstract Camera class.
A camera abstracts model-view transformations on the scene in a intuitive
way, that is, a point in the space (eye) looking at a given point (scene
center).
"""
def __init__(self):
self.position = Vec()
self.translate_mat = Mat()
self.modelview_mat = Mat()
self.projection_mat = Mat()
def set_position(self, center):
"""Sets the position of the center of the scene.
:param center: The new center of the scene
:type center: :class:`matlib.Vec`
"""
self.position = center
self.translate_mat.identity()
self.translate_mat.translate(-center)
def look_at(self, eye, center, up=None):
"""Sets up camera look transformation.
:param eye: Eye (camera position) coordinates.
:type eye: :class:`matlib.Vec`
:param eye: Look at (scene center) coordinates.
:type eye: :class:`matlib.Vec`
:param up: Up vector.
:type up: :class:`matlib.Vec`
"""
up = up or Vec(0, 1, 0)
self.modelview_mat.identity()
self.modelview_mat.lookat(eye, center, up)
def unproject(self, vx, vy, vz, vw, vh):
"""Unprojects a point in viewport coordinates into world coordinates.
:param vx: Viewport X coordinate.
:type vx: float
:param vy: Viewport Y coordinate.
:type vy: float
:param vz: Viewport Z coordinate in range [0, 1].
:type vz: float
:param vw: Viewport width.
:type vw: float
:param vh: Viewport height.
:type vh: float
:returns: Unprojected point in world coordinates.
:rtype: :class:`matlib.Vec`
"""
x_ndc = 2.0 * vx / vw - 1.0
y_ndc = 1.0 - (2.0 * vy) / vh
z_ndc = 2 * vz - 1
w_ndc = 1.0
v_clip = Vec(x_ndc, y_ndc, z_ndc, w_ndc)
m = self.projection * self.modelview
m.invert()
out = m * v_clip
out.w = 1.0 / out.w
out.x *= out.w
out.y *= out.w
out.z *= out.w
return out
def trace_ray(self, vx, vy, vw, vh):
"""Traces a ray from viewport point "into the screen" and returns the
ray origin and direction vector.
:param vx: Viewport X coordinate.
:type vx: float
:param vy: Viewport Y coordinate.
:type vy: float
:param vw: Viewport width.
:type vw: float
:param vh: Viewport height.
:type vh: float
:returns: A tuple with the origin being first element and normalized
direction vector the second.
:rtype: (:class:`matlib.Vec`, :class:`matlib.Vec`)
"""
p1 = self.unproject(vx, vy, 0, vw, vh)
p2 = self.unproject(vx, vy, 1, vw, vh)
ray = p2 - p1
ray.norm()
return p1, ray
@property
def modelview(self):
"""Camera modelview 4x4 matrix."""
return self.modelview_mat * self.translate_mat
@property
def projection(self):
"""Camera projection 4x4 matrix."""
return self.projection_mat
def __init__(self):
self.position = Vec()
self.translate_mat = Mat()
self.modelview_mat = Mat()
self.projection_mat = Mat()
