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77 lines
3.5 KiB
77 lines
3.5 KiB
/* |
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This file is part of Magnum. |
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Copyright © 2010, 2011, 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019, |
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2020, 2021, 2022, 2023, 2024, 2025, 2026 |
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Vladimír Vondruš <mosra@centrum.cz> |
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Permission is hereby granted, free of charge, to any person obtaining a |
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copy of this software and associated documentation files (the "Software"), |
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to deal in the Software without restriction, including without limitation |
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the rights to use, copy, modify, merge, publish, distribute, sublicense, |
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and/or sell copies of the Software, and to permit persons to whom the |
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Software is furnished to do so, subject to the following conditions: |
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The above copyright notice and this permission notice shall be included |
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in all copies or substantial portions of the Software. |
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
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IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL |
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THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
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LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING |
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FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER |
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DEALINGS IN THE SOFTWARE. |
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*/ |
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namespace Magnum { |
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/** @page method-chaining Method chaining |
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@brief Little feature helping to reduce typing and encourage best practices. |
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@m_footernavigation |
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Method chaining ([Wikipedia](https://en.wikipedia.org/wiki/Method_chaining)) is |
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a feature which allows you to chain method calls one after another without |
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repeatedly specifying variable the method is called on. Its primary goal is to |
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reduce unnecessary repeated names, improving code readability. |
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Magnum uses this feature mainly for configuring OpenGL objects (such as |
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various mesh and framebuffer options, shader uniforms etc.). Because OpenGL was |
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designed with "bind-to-modify" approach, most configuration calls internally |
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need to bind the object first and only after that change the parameters (unless |
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@gl_extension{ARB,direct_state_access} extension is available to avoid this). To |
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reduce unneeded bind calls, Magnum binds the object only if it is not already |
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bound somewhere. Method chaining encourages you to configure whole object in |
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one run, effectively reducing the number of needed bindings. Consider the |
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following example: |
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@snippet GL.cpp method-chaining-texture |
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This code is written that similar configuration steps are grouped together, |
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which might be good when somebody needs to change something for all three |
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textures at once, but on the other hand the code is cluttered with repeated |
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names and after each configuration step the texture must be rebound to another. |
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With method chaining used the code looks much lighter and each object is |
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configured in one run, reducing count of bind calls from 9 to 3. |
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@snippet GL.cpp method-chaining-texture-chained |
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Method chaining is not used on non-configuring functions, such as |
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@ref GL::Framebuffer::clear() or @ref GL::AbstractShaderProgram::draw(), as |
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their desired use is commonly as a last step in the chain, after everything |
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else. |
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Method chaining is also used in @ref SceneGraph and other libraries and in some |
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cases it allows you to just "configure and forget" without even saving the |
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created object to some variable, for example when adding static object to an |
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scene: |
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@code{.cpp} |
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Scene3D scene; |
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(*(new MyObject(&scene))) |
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.rotateX(90.0_degf) |
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.translate({-1.5f, 0.5f, 7.0f}); |
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@endcode |
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*/ |
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}
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