274 lines
9.4 KiB
QML
274 lines
9.4 KiB
QML
// Copyright (C) 2022 The Qt Company Ltd.
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// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
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// Qt-Security score:significant reason:default
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import QtQuick
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import Qt5Compat.GraphicalEffects.private
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/*!
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\qmltype ZoomBlur
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\inqmlmodule Qt5Compat.GraphicalEffects
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\since Qt5Compat.GraphicalEffects 1.0
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\inherits QtQuick::Item
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\ingroup qtgraphicaleffects-motion-blur
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\brief Applies directional blur effect towards source items center point.
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Effect creates perceived impression that the source item appears to be
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moving towards the center point in Z-direction or that the camera appears
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to be zooming rapidly. Other available motion blur effects are
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\l{Qt5Compat.GraphicalEffects::DirectionalBlur}{DirectionalBlur}
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and \l{Qt5Compat.GraphicalEffects::RadialBlur}{RadialBlur}.
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\table
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\header
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\li Source
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\li Effect applied
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\row
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\li \image Original_bug.png
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\li \image ZoomBlur_bug.png
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\endtable
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\note This effect is available when running with OpenGL.
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\section1 Example
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The following example shows how to apply the effect.
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\snippet ZoomBlur-example.qml example
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*/
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Item {
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id: rootItem
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/*!
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This property defines the source item that is going to be blurred.
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\note It is not supported to let the effect include itself, for
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instance by setting source to the effect's parent.
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*/
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property variant source
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/*!
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This property defines the maximum perceived amount of movement for each
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pixel. The amount is smaller near the center and reaches the specified
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value at the edges.
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The quality of the blur depends on \l{ZoomBlur::samples}{samples}
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property. If length value is large, more samples are needed to keep the
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visual quality at high level.
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The value ranges from 0.0 to inf. By default the property is set to \c
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0.0 (no blur).
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\table
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\header
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\li Output examples with different length values
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\li
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\li
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\row
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\li \image ZoomBlur_length1.png
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\li \image ZoomBlur_length2.png
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\li \image ZoomBlur_length3.png
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\row
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\li \b { length: 0.0 }
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\li \b { length: 32.0 }
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\li \b { length: 48.0 }
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\row
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\li \l samples: 24
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\li \l samples: 24
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\li \l samples: 24
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\row
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\li \l horizontalOffset: 0
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\li \l horizontalOffset: 0
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\li \l horizontalOffset: 0
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\row
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\li \l verticalOffset: 0
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\li \l verticalOffset: 0
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\li \l verticalOffset: 0
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\endtable
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*/
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property real length: 0.0
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/*!
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This property defines how many samples are taken per pixel when blur
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calculation is done. Larger value produces better quality, but is slower
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to render.
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This property is not intended to be animated. Changing this property may
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cause the underlying OpenGL shaders to be recompiled.
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Allowed values are between 0 and inf (practical maximum depends on GPU).
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By default the property is set to \c 0 (no samples).
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*/
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property int samples: 0
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/*!
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\qmlproperty real QtGraphicalEffects::ZoomBlur::horizontalOffset
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\qmlproperty real QtGraphicalEffects::ZoomBlur::verticalOffset
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These properties define an offset in pixels for the blur direction
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center point.
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The values range from -inf to inf. By default these properties are set
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to \c 0.
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\table
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\header
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\li Output examples with different horizontalOffset values
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\li
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\li
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\row
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\li \image ZoomBlur_horizontalOffset1.png
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\li \image ZoomBlur_horizontalOffset2.png
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\li \image ZoomBlur_horizontalOffset3.png
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\row
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\li \b { horizontalOffset: 100.0 }
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\li \b { horizontalOffset: 0.0 }
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\li \b { horizontalOffset: -100.0 }
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\row
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\li \l samples: 24
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\li \l samples: 24
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\li \l samples: 24
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\row
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\li \l length: 32
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\li \l length: 32
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\li \l length: 32
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\row
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\li \l verticalOffset: 0
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\li \l verticalOffset: 0
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\li \l verticalOffset: 0
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\endtable
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*/
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property real horizontalOffset: 0.0
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property real verticalOffset: 0.0
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/*!
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This property defines the blur behavior near the edges of the item,
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where the pixel blurring is affected by the pixels outside the source
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edges.
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If the property is set to \c true, the pixels outside the source are
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interpreted to be transparent, which is similar to OpenGL
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clamp-to-border extension. The blur is expanded slightly outside the
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effect item area.
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If the property is set to \c false, the pixels outside the source are
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interpreted to contain the same color as the pixels at the edge of the
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item, which is similar to OpenGL clamp-to-edge behavior. The blur does
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not expand outside the effect item area.
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By default, the property is set to \c false.
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*/
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property bool transparentBorder: false
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/*!
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This property allows the effect output pixels to be cached in order to
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improve the rendering performance.
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Every time the source or effect properties are changed, the pixels in
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the cache must be updated. Memory consumption is increased, because an
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extra buffer of memory is required for storing the effect output.
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It is recommended to disable the cache when the source or the effect
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properties are animated.
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By default, the property is set to \c false.
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*/
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property bool cached: false
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SourceProxy {
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id: sourceProxy
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input: rootItem.source
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sourceRect: rootItem.transparentBorder ? Qt.rect(-1, -1, parent.width + 2.0, parent.height + 2.0) : Qt.rect(0, 0, 0, 0)
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}
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ShaderEffectSource {
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id: cacheItem
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anchors.fill: shaderItem
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visible: rootItem.cached
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smooth: true
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sourceItem: shaderItem
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live: true
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hideSource: visible
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}
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ShaderEffect {
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id: shaderItem
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property variant source: sourceProxy.output
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property variant center: Qt.point(0.5 + rootItem.horizontalOffset / width, 0.5 + rootItem.verticalOffset / height)
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property real len: rootItem.length
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property bool transparentBorder: rootItem.transparentBorder
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property real samples: rootItem.samples
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property real weight: 1.0 / Math.max(1.0, rootItem.samples)
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property variant expandPixels: transparentBorder ? Qt.size(rootItem.samples, rootItem.samples) : Qt.size(0,0)
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property variant expand: transparentBorder ? Qt.size(expandPixels.width / width, expandPixels.height / height) : Qt.size(0,0)
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property variant delta: Qt.size(1.0 / rootItem.width, 1.0 / rootItem.height)
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x: transparentBorder ? -expandPixels.width - 1 : 0
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y: transparentBorder ? -expandPixels.height - 1 : 0
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width: transparentBorder ? parent.width + 2.0 * expandPixels.width + 2 : parent.width
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height: transparentBorder ? parent.height + 2.0 * expandPixels.height + 2 : parent.height
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property string fragmentShaderSkeleton: "#version 440
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layout(location = 0) in vec2 qt_TexCoord0;
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layout(location = 0) out vec4 fragColor;
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layout(std140, binding = 0) uniform buf {
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mat4 qt_Matrix;
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float qt_Opacity;
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float len;
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float weight;
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float samples;
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vec2 center;
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vec2 expand;
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vec2 delta;
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};
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layout(binding = 1) uniform sampler2D source;
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void main() {
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vec2 texCoord = qt_TexCoord0;
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vec2 centerCoord = center;
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PLACEHOLDER_EXPAND_STEPS
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vec2 dir = vec2(centerCoord.x - texCoord.s, centerCoord.y - texCoord.t);
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dir /= max(1.0, length(dir) * 2.0);
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vec2 shift = delta * len * dir * 2.0 / max(1.0, samples - 1.0);
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fragColor = vec4(0.0);
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PLACEHOLDER_UNROLLED_LOOP
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fragColor *= weight * qt_Opacity;
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}
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"
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function buildFragmentShader() {
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var shader = fragmentShaderSkeleton
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var expandSteps = ""
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if (transparentBorder) {
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expandSteps += "centerCoord = (centerCoord - expand) / (1.0 - 2.0 * expand);"
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expandSteps += "texCoord = (texCoord - expand) / (1.0 - 2.0 * expand);"
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}
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var unrolledLoop = "fragColor += texture(source, texCoord);\n"
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if (rootItem.samples > 1) {
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unrolledLoop = ""
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for (var i = 0; i < rootItem.samples; i++)
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unrolledLoop += "fragColor += texture(source, texCoord); texCoord += shift;\n"
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}
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shader = shader.replace("PLACEHOLDER_EXPAND_STEPS", expandSteps)
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fragmentShader = ShaderBuilder.buildFragmentShader(shader.replace("PLACEHOLDER_UNROLLED_LOOP", unrolledLoop))
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}
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onFragmentShaderChanged: sourceChanged()
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onSamplesChanged: buildFragmentShader()
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onTransparentBorderChanged: buildFragmentShader()
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Component.onCompleted: buildFragmentShader()
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}
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}
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