1 | /* |
2 | * SPDX-FileCopyrightText: 2025 Arjen Hiemstra <ahiemstra@heimr.nl> |
3 | * |
4 | * SPDX-License-Identifier: LGPL-2.0-or-later |
5 | */ |
6 | |
7 | #pragma once |
8 | |
9 | #include <QSGGeometryNode> |
10 | #include <QSGMaterial> |
11 | #include <QSGMaterialShader> |
12 | #include <QSGTextureProvider> |
13 | #include <QVariant> |
14 | |
15 | #include "uniformdatastream.h" |
16 | |
17 | class ShaderMaterial; |
18 | |
19 | /*! |
20 | * A base class for scene graph nodes that want to use a shader to render something. |
21 | */ |
22 | class ShaderNode : public QSGGeometryNode |
23 | { |
24 | public: |
25 | using TextureChannel = unsigned char; |
26 | |
27 | struct TextureInfo { |
28 | TextureChannel channel = 0; |
29 | QQuickWindow::CreateTextureOptions options; |
30 | std::shared_ptr<QSGTexture> texture = nullptr; |
31 | QPointer<QSGTextureProvider> provider = nullptr; |
32 | QMetaObject::Connection providerConnection; |
33 | }; |
34 | |
35 | ShaderNode(); |
36 | ~ShaderNode() override; |
37 | |
38 | void preprocess() override; |
39 | |
40 | /*! |
41 | * The rectangle describing the geometry of this node. |
42 | */ |
43 | QRectF rect() const; |
44 | void setRect(const QRectF &newRect); |
45 | |
46 | /*! |
47 | * The UV coordinates of the geometry of this node. |
48 | */ |
49 | QRectF uvs(TextureChannel channel) const; |
50 | void setUVs(TextureChannel channel, const QRectF &newUvs); |
51 | |
52 | /*! |
53 | * The variant of the material used for rendering. |
54 | * |
55 | * This will be passed to createMaterialVariant() to perform the actual |
56 | * creation of the material. |
57 | */ |
58 | QSGMaterialType *materialVariant() const; |
59 | void setMaterialVariant(QSGMaterialType *variant); |
60 | |
61 | /*! |
62 | * Set the name of the shader to use for rendering. |
63 | * |
64 | * By default this will create and use an instance of ShaderMaterial that |
65 | * corresponds to the given shader. |
66 | */ |
67 | void setShader(const QString &shader); |
68 | |
69 | /*! |
70 | * Set the size of buffer used by the material for storing uniform values. |
71 | * |
72 | * The given size is in bytes. Note that you should account for all uniforms |
73 | * in your shader's uniform buffer. |
74 | */ |
75 | void setUniformBufferSize(qsizetype size); |
76 | |
77 | /*! |
78 | * A writeable view of the material's uniform data buffer. |
79 | * |
80 | * This can be used in combination with UniformDataStream to write the |
81 | * values of your uniforms. |
82 | */ |
83 | std::span<char> uniformData(); |
84 | |
85 | /*! |
86 | * Set the number of texture channels. |
87 | * |
88 | * Each texture channel gets its own set of UV coordinates and texture. By |
89 | * default, the UVs will be set to (0, 0, 1, 1) unless the texture is an |
90 | * atlas texture, in which case coordinates matching the atlas will be used. |
91 | * Use setTexture() to set the texture to use for a channel. |
92 | */ |
93 | void setTextureChannels(unsigned char count); |
94 | |
95 | /*! |
96 | * Set the texture for a channel to an image. |
97 | * |
98 | * This will create a texture from \a image using \a window and the options |
99 | * specified by \a options, then assign it to texture channel \a channel. |
100 | * Textures created from images are cached, if an image has the same cache |
101 | * ID as a previous call to setTexture(), no new texture will be created. |
102 | */ |
103 | void setTexture(TextureChannel channel, const QImage &image, QQuickWindow *window, QQuickWindow::CreateTextureOptions options = {}); |
104 | |
105 | /*! |
106 | * Set the texture for a channel to a texture provider. |
107 | * |
108 | * This will use \a provider to provide the texture for channel \a channel. |
109 | * \a options will be used whenever a new texture is created from |
110 | * \a provider. |
111 | */ |
112 | void setTexture(TextureChannel channel, QSGTextureProvider *provider, QQuickWindow::CreateTextureOptions options = {}); |
113 | |
114 | /*! |
115 | * Update internal state based on newly-set parameters. |
116 | * |
117 | * This is done as an explicit step to ensure we don't modify expensive GPU |
118 | * resources like geometry multiple times during a single update. |
119 | */ |
120 | virtual void update(); |
121 | |
122 | /*! |
123 | * Helper function that returns a pre-multiplied version of a color. |
124 | */ |
125 | static inline QColor toPremultiplied(const QColor &value) |
126 | { |
127 | return QColor::fromRgbF(r: value.redF() * value.alphaF(), // |
128 | g: value.greenF() * value.alphaF(), |
129 | b: value.blueF() * value.alphaF(), |
130 | a: value.alphaF()); |
131 | } |
132 | |
133 | protected: |
134 | /*! |
135 | * Create a new instance of a certain material variant. |
136 | * |
137 | * This should return a new instance of the material that matches \a variant, |
138 | * or nullptr if the specified variant cannot be handled by the current node. |
139 | */ |
140 | virtual QSGMaterial *createMaterialVariant(QSGMaterialType *variant); |
141 | |
142 | private: |
143 | void preprocessTexture(const TextureInfo &texture); |
144 | |
145 | QRectF m_rect; |
146 | QVarLengthArray<QRectF, 16> m_uvs; |
147 | bool m_geometryUpdateNeeded = true; |
148 | unsigned char m_textureChannels = 1; |
149 | |
150 | QSGMaterialType *m_materialVariant = nullptr; |
151 | ShaderMaterial *m_shaderMaterial = nullptr; |
152 | |
153 | QList<TextureInfo> m_textures; |
154 | |
155 | QSGGeometry::AttributeSet *m_attributeSet = nullptr; |
156 | }; |
157 | |