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39 | |
40 | /*! |
41 | \class QSGSimpleMaterialShader |
42 | |
43 | \brief The QSGSimpleMaterialShader class provides a convenient way of |
44 | building custom OpenGL-based materials for the scene graph. |
45 | |
46 | \inmodule QtQuick |
47 | \ingroup qtquick-scenegraph-materials |
48 | |
49 | \deprecated |
50 | |
51 | \warning This utility class is only functional when running with the legacy |
52 | OpenGL renderer of the Qt Quick scenegraph. Its usage is not recommended in |
53 | new application code. |
54 | |
55 | Where the QSGMaterial and QSGMaterialShader API requires a bit of |
56 | boilerplate code to create a functioning material, the |
57 | QSGSimpleMaterialShader tries to hide some of this through the use |
58 | of templates. |
59 | |
60 | QSGSimpleMaterialShader::vertexShader() and |
61 | QSGSimpleMaterialShader::fragmentShader() are used to specify the |
62 | actual shader source code. The names of the vertex attributes |
63 | should be listed in the QSGSimpleMaterialShader::attributes() |
64 | |
65 | QSGSimpleMaterialShader::updateState() is used to push the material |
66 | state to the OpenGL shader program. |
67 | |
68 | The actual OpenGL shader program is accessible through the |
69 | QSGSimpleMaterialShader::program() function. |
70 | |
71 | Each QSGSimpleMaterialShader implementation operates on a unique |
72 | state struct. The state struct must be declared using the |
73 | \c {QSG_DECLARE_SIMPLE_SHADER} macro. |
74 | |
75 | Here is a simple example of a custom solid-color: |
76 | |
77 | \code |
78 | struct Color |
79 | { |
80 | float r, g, b, a; |
81 | }; |
82 | |
83 | class MinimalShader : public QSGSimpleMaterialShader<Color> |
84 | { |
85 | QSG_DECLARE_SIMPLE_SHADER(MinimalShader, Color) |
86 | public: |
87 | |
88 | const char *vertexShader() const { |
89 | return |
90 | "attribute highp vec4 vertex; \n" |
91 | "uniform highp mat4 qt_Matrix; \n" |
92 | "void main() { \n" |
93 | " gl_Position = qt_Matrix * vertex; \n" |
94 | "}"; |
95 | } |
96 | |
97 | const char *fragmentShader() const { |
98 | return |
99 | "uniform lowp float qt_Opacity; \n" |
100 | "uniform lowp vec4 color; \n" |
101 | "void main() { \n" |
102 | " gl_FragColor = color * qt_Opacity; \n" |
103 | "}"; |
104 | } |
105 | |
106 | QList<QByteArray> attributes() const { |
107 | return QList<QByteArray>() << "vertex"; |
108 | } |
109 | |
110 | void updateState(const Color *color, const Color *) { |
111 | program()->setUniformValue("color", color->r, color->g, color->b, color->a); |
112 | } |
113 | |
114 | }; |
115 | \endcode |
116 | |
117 | Instances of materials using this shader can be created using the |
118 | createMaterial() function which will be defined by the |
119 | QSG_DECLARE_SIMPLE_SHADER macro. |
120 | |
121 | \code |
122 | QSGSimpleMaterial<Color> *material = MinimalShader::createMaterial(); |
123 | material->state()->r = 1; |
124 | material->state()->g = 0; |
125 | material->state()->b = 0; |
126 | material->state()->a = 1; |
127 | |
128 | node->setMaterial(material); |
129 | \endcode |
130 | |
131 | The scene graph will often try to find materials that have the |
132 | same or at least similar state so that these can be batched |
133 | together inside the renderer, which gives better performance. To |
134 | specify sortable material states, use |
135 | QSG_DECLARE_SIMPLE_COMPARABLE_SHADER instead of |
136 | QSG_DECLARE_SIMPLE_SHADER. The state struct must then also define |
137 | the function: |
138 | |
139 | \code |
140 | int compare(const Type *other) const; |
141 | \endcode |
142 | |
143 | \warning The QSGSimpleMaterialShader relies on template |
144 | instantiation to create a QSGMaterialType which the scene graph |
145 | renderer internally uses to identify this shader. For this reason, |
146 | the unique QSGSimpleMaterialShader implementation must be |
147 | instantiated with a unique C++ type. |
148 | |
149 | \note All classes with QSG prefix should be used solely on the scene graph's |
150 | rendering thread. See \l {Scene Graph and Rendering} for more information. |
151 | |
152 | \sa {Scene Graph - Simple Material} |
153 | */ |
154 | |
155 | /*! |
156 | \macro QSG_DECLARE_SIMPLE_SHADER(Shader, State) |
157 | \relates QSGSimpleMaterialShader |
158 | |
159 | This macro is used to declare a QSGMaterialType and a \c |
160 | createMaterial() function for \a Shader with the given \a State. |
161 | */ |
162 | |
163 | /*! |
164 | \macro QSG_DECLARE_SIMPLE_COMPARABLE_SHADER(Shader, State) |
165 | \relates QSGSimpleMaterialShader |
166 | |
167 | This macro is used to declare a QSGMaterialType and a \c |
168 | createMaterial() function for \a Shader with the given \a State, |
169 | where the \a State class must define a compare function on the |
170 | form: |
171 | |
172 | \code |
173 | int compare(const State *other) const; |
174 | \endcode |
175 | */ |
176 | |
177 | |
178 | /*! |
179 | \fn template <typename State> char const *const *QSGSimpleMaterialShader<State>::attributeNames() const |
180 | \internal |
181 | */ |
182 | |
183 | /*! |
184 | \fn template <typename State> void QSGSimpleMaterialShader<State>::initialize() |
185 | \internal |
186 | */ |
187 | |
188 | /*! |
189 | \fn template <typename State> void QSGSimpleMaterialShader<State>::resolveUniforms() |
190 | |
191 | Reimplement this function to resolve the location of named uniforms |
192 | in the shader program. |
193 | |
194 | This function is called when the material shader is initialized. |
195 | */ |
196 | |
197 | /*! |
198 | \fn template <typename State> const char *QSGSimpleMaterialShader<State>::uniformMatrixName() const |
199 | |
200 | Returns the name for the transform matrix uniform of this item. |
201 | The default value is \c qt_Matrix. |
202 | */ |
203 | |
204 | /*! |
205 | \fn template <typename State> const char *QSGSimpleMaterialShader<State>::uniformOpacityName() const |
206 | |
207 | Returns the name for the opacity uniform of this item. |
208 | The default value is \c qt_Opacity. |
209 | */ |
210 | |
211 | /*! |
212 | \fn template <typename State> void QSGSimpleMaterialShader<State>::updateState(const RenderState &state, QSGMaterial *newMaterial, QSGMaterial *oldMaterial) |
213 | \internal |
214 | */ |
215 | |
216 | |
217 | /*! |
218 | \fn template <typename State> QList<QByteArray> QSGSimpleMaterialShader<State>::attributes() const |
219 | |
220 | Returns a list of names, declaring the vertex attributes in the |
221 | vertex shader. |
222 | */ |
223 | |
224 | /*! |
225 | \fn template <typename State> void QSGSimpleMaterialShader<State>::updateState(const State *newState, const State *oldState) |
226 | |
227 | Called whenever the state of this shader should be updated from |
228 | \a oldState to \a newState, typical for each new set of |
229 | geometries being drawn. |
230 | |
231 | Both the old and the new state are passed in so that the |
232 | implementation can compare and minimize the state changes when |
233 | applicable. |
234 | */ |
235 | |
236 | /*! |
237 | \class QSGSimpleMaterial |
238 | |
239 | \deprecated |
240 | |
241 | \inmodule QtQuick |
242 | \ingroup qtquick-scenegraph-materials |
243 | |
244 | \brief The QSGSimpleMaterial class is a template generated class |
245 | used to store the state used with a QSGSimpleMateralShader. |
246 | |
247 | The state of the material is accessible through the template |
248 | generated state() function. |
249 | |
250 | \inmodule QtQuick |
251 | |
252 | \note All classes with QSG prefix should be used solely on the scene graph's |
253 | rendering thread. See \l {Scene Graph and Rendering} for more information. |
254 | |
255 | \sa QSGSimpleMaterialShader |
256 | */ |
257 | |
258 | |
259 | |