// Copyright (C) 2021 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GFDL-1.3-no-invariants-only

/*!
    \page studio-3d-custom-shaders.html
    \previouspage studio-3d-effects.html
    \nextpage studio-3d-custom-effects-materials.html

    \title Custom Shaders

    You can use the 3D shader utilities and commands available in
    > \uicontrol Components > \uicontrol {Qt Quick 3D} >
    \uicontrol {Qt Quick 3D Custom Shader Utilities} to create your own effects
    and materials.

    If the custom shader utilities are not displayed in \uicontrol {Components},
    add the \uicontrol QtQuick3D module to your project, as described in
    \l {Adding and Removing Modules}.

    \note If you select \uicontrol {Qt 5} as the \uicontrol {Target Qt Version}
    when \l {Creating Projects}{creating your project}, the available custom
    shader utilities and their properties will be slightly different, and some
    of the components can be found in different locations in
    \uicontrol {Components}.

    \image studio-qtquick-3d-shader-utilities.png "Custom shader utilities in Components"

    You can find additional shader utilities, the \uicontrol Effect and
    \uicontrol {Custom Material} components, in
    \uicontrol Components > \uicontrol {Qt Quick3D} > \uicontrol {Qt Quick 3D}.

    \image studio-qtquick-3d-components.webp "Effect and Custom Material Components in Components"

    \note In Qt 5 the \uicontrol Effect component is located in
    \uicontrol {Qt Quick 3D Effects} >
    \uicontrol {Qt Quick 3D Custom Shader Utilities}. To use the
    \uicontrol Effect component, add the \uicontrol QtQuick3D.Effects module to
    your project.

    \note In Qt 5 the \uicontrol {Custom Material} component can be found in
    \uicontrol {Qt Quick 3D Materials} >
    \uicontrol {Qt Quick 3D Custom Shader Utilities}. To use the
    \uicontrol {Custom Material} component, add the
    \uicontrol QtQuick3D.Materials module to your project.

    For more information about using the shaders, see
    \l {Custom Effects and Materials}.

    See the following tables for available shader utilities and commands.

    \section1 Available Custom Shader Utilities
    \table
    \header
        \li Custom Shader
        \li Qt 5 Only
        \li Description

    \row
        \li \l Buffer
        \li
        \li A buffer to be used for a pass of \uicontrol {Custom Material}
            or \uicontrol Effect instances.

            The \uicontrol Name property identifies the \uicontrol Buffer
            instance. When the value of this property is empty, the buffer will
            refer to the default output texture of the render pass instead of
            allocating a buffer. This can be useful to override certain settings
            of the output, such as the texture format, without introducing a new,
            separate intermediate texture.

            The \uicontrol Format property specifies the format of the buffer.

            The \uicontrol Filter property specifies the filter operation when a
            render pass is reading a buffer that differs in size in comparison
            to the current output buffer.

            The \uicontrol {Coordinate operation} property specifies the texture
            coordinate operation for coordinates outside [0, 1] range.
            Select the \uicontrol ClampToEdge operation to clamp coordinates to
            edges. The \uicontrol Repeat operation wraps the coordinates at the
            edges to tile the texture, while \uicontrol MirroredRepeat also
            mirrors every other repeat of the texture while tiling it.

            The \uicontrol {Allocation flags} property defines allocation flags
            for the \uicontrol Buffer instance. Select \uicontrol SceneLifeTime
            to allocate the buffer for the whole lifetime of the scene.

            \uicontrol {Size multiplier} specifies the size of the
            \uicontrol Buffer instance. Value of 1.0 creates a buffer with the
            same size, while 0.5 creates a buffer with width and height halved.

    \row
        \li \l {CustomMaterial} {Custom Material}
        \li
        \li The base component for creating custom materials used to shade
            model instances.

            The \uicontrol {Shading mode} property specifies whether the material
            is \uicontrol Shaded or \uicontrol Unshaded.

            The \uicontrol {Vertex shader} and \uicontrol {Fragment shader}
            properties define the vertex and fragment shader files for the
            material. Select the shader files from the dropdown menus. You can
            select \inlineimage icons/add-file-16px.png
            to add new shader files to the dropdown menus.

            The \uicontrol {Source blend} and \uicontrol {Destination blend}
            properties specify the source and destination blend factors.

            The \uicontrol {Always dirty} property determines whether the
            material is refreshed every time it is used.

            The \uicontrol {Line Width} property defines the width of the lines
            when the geometry is using lines or line strips.

            Specify the attributes of the \uicontrol {Custom Material} by
            defining the \uicontrol Transparency, \uicontrol Refraction and
            \uicontrol {Always dirty} properties.

            The \uicontrol {Shader Info} specifies the shader info of the
            material. For more information, see \l {Custom Effects and Materials}.

            \note In Qt 5 you can also define render passes for
            \uicontrol {Custom Material} instances by using the
            \uicontrol Passes property, which lists render passes implemented
            by the material.

    \row
        \li \l Effect
        \li
        \li A base component for creating post-processing effects.

            The \uicontrol Passes property contains a list of render passes
            implemented by the effect. You can add more entry fields to the list
            by selecting \inlineimage icons/plus.png
            . For more information, see \l {Custom Effects and Materials}.

    \row
        \li \l Pass
        \li
        \li A render pass of an \uicontrol Effect instance. In Qt 5 you can also
            use render passes for \uicontrol {Custom Materials}.

            The \uicontrol Commands property specifies the list of render
            commands for the \uicontrol Pass instance, while the
            \uicontrol Shaders property lists the shaders for it. Use the
            dropdown menus to select the render commands and shader files of
            your choice.

            The \uicontrol Buffer property specifies an output buffer for the
            \uicontrol Pass instance.
    \row
        \li \l Shader
        \li
        \li A container component for defining shader code used by
            \uicontrol Effect instances.

            The \uicontrol Source property specifies the shader file to be used
            by the \uicontrol Shader instance, and the \uicontrol Stage property
            defines a \uicontrol Vertex or \uicontrol Fragment stage for it.

            \note In Qt 5 you can also set the \uicontrol Stage property to
            \uicontrol Shared, \uicontrol Geometry, or \uicontrol Compute.

    \row
        \li \l {ShaderInfo} {Shader Info}
        \li \inlineimage ok.png
        \li Basic information about custom shader code for Custom Materials.

            The \uicontrol Version property specifies the shader code version,
            while the \uicontrol Type property defines the shader code type.

            The \uicontrol Key property specifies the options used by the shader
            using the combination of shader key values, such as diffuse or
            specular lighting, refraction, transparency, displacement,
            transmissiveness, glossiness, and alpha cutout.

            The \uicontrol Key property specifies the options used by the shader
            using the combination of shader key values. Use the dropdown list
            to select the one of available shader keys:
            \list
                \li The \uicontrol Diffuse shader key applies diffuse lighting
                    and \uicontrol Specular applies specular lighting to the
                    shader instance.
                \li The \uicontrol Cutout shader key applies alpha cutout to
                    the shader instance.
                \li The \uicontrol Refraction shader key applies refraction to
                    the shader instance, while using the \uicontrol Transparent
                    key applies transparency to the shader instance.
                \li The \uicontrol Displace shader key applies displacement
                    mapping to the shader instance.
                \li The \uicontrol Transmissive shader key applies
                    transmissiveness to the shader instance.
                \li The \uicontrol Glossy shader key applies glossiness to the
                    shader instance by default. This shader key is a combination
                    of \uicontrol Diffuse and \uicontrol Specular keys.
            \endlist
    \row
        \li \l {TextureInput} {Texture Input}
        \li
        \li A texture channel for \uicontrol {Custom Material} and Effect
            instances.

            The \uicontrol Texture property specifies the texture to input,
            while \uicontrol Enabled determines whether the texture is
            enabled.
            In \uicontrol Effect instances, setting \uicontrol Enabled
            to \uicontrol false causes the shaders to sample a dummy, opaque
            black texture instead of the one specified by texture.
    \endtable

    \section1 Available Custom Shader Commands
    \table
    \header
        \li Command
        \li Qt 5 Only
        \li Description

    \row
        \li \l Blending
        \li
        \li A pass command that specifies the source blending function.

            The \uicontrol Source property specifies the source blending
            function, while the \uicontrol Destination property specifies the
            destination for it.
    \row
        \li \l {BufferBlit} {Buffer Blit}
        \li \inlineimage ok.png
        \li A copy operation between two buffers in a pass of a Custom Material
            or an Effect.

            The \uicontrol Source and \uicontrol Destination specify the source
            and the destination buffers for the copy-operation.
    \row
        \li \l {BufferInput} {Buffer Input}
        \li
        \li An input buffer to be used for a pass of a Custom Material or an
            Effect.

            The \uicontrol Buffer property specifies the input buffer for an
            instance of the \uicontrol Pass instance. The \uicontrol Parameter
            specifies the name of the input parameter in the shader.

    \row
        \li \l {CullMode} {Cull Mode}
        \li \inlineimage ok.png
        \li A culling mode for a render pass.

            The \uicontrol Mode property specifies the culling mode in a pass
            when the \uicontrol {State} property of the \uicontrol {Render State}
            is set to \uicontrol CullFace. Use the dropdown menu to set the
            culling mode to \uicontrol BackFaceCulling,
            \uicontrol FrontFaceCulling, or \uicontrol NoCulling.

    \row
        \li \l {DepthInput} {Depth Input}
        \li \inlineimage ok.png
        \li An output texture for the depth buffer.

            The \uicontrol Parameter property specifies the name of the texture
            the depth buffer will bind to.

    \row
        \li \l {RenderState} {Render State}
        \li \inlineimage ok.png
        \li The render state to be enabled or disabled in a pass of a
            \uicontrol {Custom Material} or an \uicontrol Effect instance.

            The \uicontrol State property specifies the render state to
            enable or disable in a pass. Use the dropdown menu to set the
            \uicontrol State to \uicontrol Blend, \uicontrol CullFace,
            \uicontrol DepthTest, \uicontrol StencilTest,
            \uicontrol ScissorTest, \uicontrol DepthWrite, or
            \uicontrol Multisample.

            The \uicontrol Enabled property defines the \uicontrol Enable state
            for the \uicontrol {Render State}.

    \row
        \li \l {SetUniformValue} {Set Uniform Value}
        \li
        \li A value to be set during a single pass.

            The \uicontrol Target property specifies the name of the uniform
            that will have its value changed during the pass, while the
            \uicontrol Value specifies the value that will be set on the target
            uniform.
    \endtable

*/
