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Transform.ixx File

Represents a 3D transformation consisting of translation, rotation and scale. More...

Included Headers​

#include <helios.math.transform> #include <helios.math.types>

Namespaces Index​

namespacehelios
namespacecore

Core utilities shared across the helios engine. More...

namespacespatial

Spatial transformation utilities. More...

Classes Index​

classTransform

Represents a 3D transformation consisting of translation, rotation and scale. More...

Description​

Represents a 3D transformation consisting of translation, rotation and scale.

File Listing​

The file content with the documentation metadata removed is:

1/**
2 * @file Transform.ixx
3 * @brief Represents a 3D transformation consisting of translation, rotation
4 * and scale.
5 */
6module;
7
8
9export module helios.core.spatial.Transform;
10
11import helios.math.types;
12import helios.math.transform;
13
14
15export namespace helios::core::spatial {
16
17 /**
18 * @brief Represents a 3D transformation consisting of translation, rotation
19 * and scale.
20 *
21 * This class encapsulates the components of a local transform for SceneNodes.
22 * It uses lazy evaluation to compute the final transform.
23 * The current scale, translation and rotation is queryable.
24 * Changing the transformation is always considered against an
25 * "origin" of an object, that is, a 4x4 identity matrix
26 *
27 * @todo use quaternions for rotation
28 */
29 class Transform {
30
31 private:
32 /**
33 * @brief Flag indicating whether this Transform needs to recompute
34 * its transformation matrix.
35 */
36 mutable bool needsUpdate_ = true;
37
38 /**
39 * @brief The rotation component of the transformation, stored as a 4x4 matrix.
40 */
41 helios::math::mat4f rotation_ = helios::math::mat4f::identity();
42
43 /**
44 * @brief The scaling component of the transformation, stored as a 3D vector.
45 */
46 helios::math::vec3f scale_ = helios::math::vec3f(1);
47
48 /**
49 * @brief The translation component of the transformation, stored as a 3D vector.
50 */
51 helios::math::vec3f translation_ = helios::math::vec3f(0);
52
53 /**
54 * @brief The cached 4x4 matrix, computed from scale, rotation and translation
55 * (in this order: T * (R * S)).
56 */
57 mutable helios::math::mat4f cached_ = helios::math::mat4f::identity();
58
59 /**
60 * @brief Internal helper function to compute the full 4x4 affine transformation
61 * matrix.
62 *
63 * @return The newly computed transformation matrix.
64 */
65 helios::math::mat4f updateCache() const {
66 needsUpdate_ = false;
67 return math::translate(
68 helios::math::mat4f::identity(),
69 translation_) *
70 (rotation_ * helios::math::mat4f(scale_)
71 );
72 }
73
74 public:
75 ~Transform() = default;
76
77 /**
78 * @brief Constructs a new Transform object with the default identity transformation,
79 * i.e. scale (1, 1, 1), rotation 4x4_id, translate (0, 0, 0).
80 */
81 Transform() = default;
82
83 /**
84 * @brief Constructs a new Transformation matrix from the specified rotation, scale and translation.
85 *
86 * @param rotation The initial rotation matrix.
87 * @param scale The initial scaling vector.
88 * @param translation The initial translation vector.
89 */
90 Transform(const helios::math::mat4f& rotation,
91 helios::math::vec3f scale,
92 helios::math::vec3f translation
93 ) noexcept :
94 rotation_(rotation),
95 scale_(scale),
96 translation_(translation),
97 needsUpdate_(true)
98 {}
99
100 /**
101 * @brief Sets the rotation component of this Transform.
102 * Marks this Transform object as dirty.
103 *
104 * @param rotation A const ref to the new rotation matrix.
105 */
106 void setRotation(const math::mat4f& rotation) noexcept {
107 rotation_ = rotation;
108 needsUpdate_ = true;
109 }
110
111 /**
112 * @brief Sets the translation component of this Transform.
113 * Marks this Transform object as dirty.
114 *
115 * @param translation A const ref to the new translation vector.
116 */
117 void setTranslation(const math::vec3f& translation) noexcept {
118 translation_ = translation;
119 needsUpdate_ = true;
120 }
121
122 /**
123 * @brief Sets the scale component of this Transform.
124 * Marks this Transform object as dirty.
125 *
126 * @param scale A const ref to the new scale vector.
127 */
128 void setScale(const math::vec3f& scale) noexcept {
129 scale_ = scale;
130 needsUpdate_ = true;
131 }
132
133 /**
134 * @brief Returns the current rotation component of this Transform object.
135 *
136 * @return The current 4x4 rotation matrix.
137 */
138 [[nodiscard]] helios::math::mat4f rotation() const noexcept {
139 return rotation_;
140 }
141
142 /**
143 * @brief Returns the current translation component of this Transform object.
144 *
145 * @return The current 3D translation vector.
146 */
147 [[nodiscard]] helios::math::vec3f translation() const noexcept {
148 return translation_;
149 }
150
151 /**
152 * @brief Returns the current scale component of this Transform object.
153 *
154 * @return The current 3D scale vector.
155 */
156 [[nodiscard]] helios::math::vec3f scaling() const noexcept {
157 return scale_;
158 }
159
160 /**
161 * @brief Returns the 4x4 transformation matrix combined from scale, rotation, and translation.
162 *
163 * @return The current 4x4 affine transformation matrix.
164 */
165 [[nodiscard]] helios::math::mat4f transform() const noexcept {
166 if (needsUpdate_) {
167 cached_ = updateCache();
168 }
169 return cached_;
170 }
171
172 /**
173 * @brief Checks whether this Transform needs to be updated, e.g. because the
174 * various components changed.
175 *
176 * @return true if this Transform is considered to be dirty, otherwise
177 * false.
178 */
179 [[nodiscard]] bool needsUpdate() const noexcept {
180 return needsUpdate_;
181 }
182
183 };
184
185};

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