| // Copyright 2017 The Fuchsia Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #include "garnet/bin/ui/scene_manager/resources/shapes/planar_shape.h" |
| |
| namespace scene_manager { |
| |
| PlanarShape::PlanarShape(Session* session, |
| scenic::ResourceId id, |
| const ResourceTypeInfo& type_info) |
| : Shape(session, id, type_info) {} |
| |
| bool PlanarShape::GetIntersection(const escher::ray4& ray, |
| float* out_distance) const { |
| // Reject if the ray origin is behind the Z=0 plane. |
| if (ray.origin.z < 0.f) |
| return false; |
| |
| // Reject if the ray is not pointing down towards the Z=0 plane. |
| float delta_z = -ray.direction.z; |
| if (delta_z < std::numeric_limits<float>::epsilon()) |
| return false; |
| |
| // Compute the distance to the plane in multiples of the ray's direction |
| // vector and the point of intersection. |
| float distance = ray.origin.z / delta_z; |
| escher::vec2 point = |
| (escher::vec2(ray.origin) + distance * escher::vec2(ray.direction)) / |
| ray.origin.w; |
| |
| // Reject if the shape does not contain the point of intersection. |
| if (!ContainsPoint(point)) |
| return false; |
| |
| *out_distance = distance; |
| return true; |
| } |
| |
| } // namespace scene_manager |
