1 #ifndef DALI_INTERNAL_HIT_TEST_ALGORITHM_H
2 #define DALI_INTERNAL_HIT_TEST_ALGORITHM_H
5 * Copyright (c) 2021 Samsung Electronics Co., Ltd.
7 * Licensed under the Apache License, Version 2.0 (the "License");
8 * you may not use this file except in compliance with the License.
9 * You may obtain a copy of the License at
11 * http://www.apache.org/licenses/LICENSE-2.0
13 * Unless required by applicable law or agreed to in writing, software
14 * distributed under the License is distributed on an "AS IS" BASIS,
15 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16 * See the License for the specific language governing permissions and
17 * limitations under the License.
22 #include <dali/devel-api/events/hit-test-algorithm.h>
23 #include <dali/internal/event/render-tasks/render-task-impl.h>
24 #include <dali/public-api/actors/actor.h>
34 * This namespace is provided for application developers to do hit test for the actors.
36 namespace HitTestAlgorithm
40 RenderTaskPtr renderTask; ///< The render-task displaying the actor.
41 Dali::Actor actor; ///< The hit actor.
42 Vector2 actorCoordinates; ///< The actor coordinates.
43 Vector4 rayOrigin; ///< The point of origin of the ray.
44 Vector4 rayDirection; ///< The direction vector of the ray.
48 * Interface used by the hit-test-algorithm to determine whether the actor is hittable or whether
49 * we walk down its hierarchy.
51 struct HitTestInterface
54 * Called by the hit-test algorithm to determine whether the actor is hittable or not.
56 * @param[in] actor Raw pointer to an Actor object.
58 * @return true if actor is hittable, false otherwise.
60 virtual bool IsActorHittable(Actor* actor) = 0;
63 * Called by the hit-test algorithm to determine whether the algorithm should descend the actor's
64 * hierarchy (and hit-test its children as well).
66 * @param[in] actor Raw pointer to an Actor object.
68 * @return true if we should descend the actor's hierarchy, false otherwise.
70 virtual bool DescendActorHierarchy(Actor* actor) = 0;
73 * Called by the hit-test algorithm to determine whether the layer specified consumes the hit
74 * regardless of whether an actor in the layer requires it or not.
76 * @note If true is returned, then no layers behind this layer will be hit-test.
78 * @param[in] layer Raw pointer to a Layer object.
80 * @return true if the layer should consume the hit, false otherwise.
82 virtual bool DoesLayerConsumeHit(Layer* layer) = 0;
86 * Virtual destructor, no deletion through this interface
88 virtual ~HitTestInterface();
92 * Hit test specific to a given scene.
94 * @param[in] sceneSize The size of the scene.
95 * @param[in] renderTaskList The render task list of the scene.
96 * @param[in] layerList The layer list of the scene.
97 * @param[in] screenCoordinates The screen coordinates.
98 * @param[out] results The results of the hit-test.
99 * @param[in] func The function to use in the hit-test algorithm.
100 * @return true if something was hit
102 * @see HitTest(Stage&, const Vector2&, Results&, HitTestInterface&)
104 bool HitTest(const Vector2& sceneSize, RenderTaskList& renderTaskList, LayerList& layerList, const Vector2& screenCoordinates, Dali::HitTestAlgorithm::Results& results, Dali::HitTestAlgorithm::HitTestFunction func);
107 * Given screen coordinates, this method returns the hit actor & the local coordinates relative to the actor etc.
108 * @param[in] sceneSize The size of the scene.
109 * @param[in] renderTaskList The render task list of the scene.
110 * @param[in] layerList The layer list of the scene.
111 * @param[in] screenCoordinates The screen coordinates.
112 * @param[out] results The results of the hit-test.
113 * @param[in] hitTestInterface Used to determine whether the actor is hit or whether we walk down its hierarchy
114 * @return true if something was hit
116 * <h3>Hit Test Algorithm:</h3>
118 * - The regular RenderTaskList is used to hit test the on scene actors.
119 * - The bulk of the hit test algorithm is described in Dali::Actor.
120 * - In each RenderTask's its viewing parameters (the view and projection matrices, and the viewport)
121 * are used to build a picking ray into the scene which is used for our ray tests when hit testing
122 * an actor within each layer.
123 * - If an actor is deemed to be hittable, then a quicker ray sphere test on the actor is performed
124 * first to determine if the ray is in the actor's proximity.
125 * - If this is also successful, then a more accurate ray test is performed to see if we have a hit.
127 * @note Currently, we prefer a child hit over a parent (regardless of the distance from the
128 * camera) unless the parent is a RenderableActor but this is subject to change.
130 bool HitTest(const Vector2& sceneSize, RenderTaskList& renderTaskList, LayerList& layerList, const Vector2& screenCoordinates, Results& results, HitTestInterface& hitTestInterface);
133 * Default HitTest where we check if a touch is required.
135 * @param[in] sceneSize The size of the scene.
136 * @param[in] renderTaskList The render task list of the scene.
137 * @param[in] layerList The layer list of the scene.
138 * @param[in] screenCoordinates The screen coordinates.
139 * @param[out] results The results of the hit-test.
140 * @return true if something was hit
142 * @see HitTest(Stage&, const Vector2&, Results&, HitTestInterface&)
144 bool HitTest(const Vector2& sceneSize, RenderTaskList& renderTaskList, LayerList& layerList, const Vector2& screenCoordinates, Results& results);
146 } // namespace HitTestAlgorithm
148 } // namespace Internal
152 #endif // DALI_INTERNAL_HIT_TEST_ALGORITHM_H