[Interest] Qt Quick and animatic 12MP image

[Tomasz Olszak]

Just would like to update if someone is interested.

It was GPU performance issue.
1. I tested it when 2 screens were connected. With one screen it is a lot
more fluent
2. When I tested it with eglfs on small device mother board with Intel HD
Graphics 510 it works super smooth.
3. On Kubuntu 18.04 seems rendering mouse cursor has significant impact on
performance.

Thanks for help!


śr., 5 wrz 2018 o 23:06 Tomasz Olszak <olszak.tomasz at gmail.com> napisał(a):

> Ola, thanks for the snippet.
>
> Unfortunately I don't see any difference.
>
> But what is interesting - at least on my I7 haswell laptop now (also
> Kubuntu 18.04). When my snippet starts it stutters for about 2 seconds then
> is super fluent. There is one condition though - you can't move mouse. As
> soon as you use mouse it stutters a lot.
> Tomorrow I will try with eglfs and QT_QPA_EGLFS_HIDECURSOR=true. Seems
> like it  is related to cursor rendering or input handling.
>
> śr., 5 wrz 2018 o 17:20 Ola Røer Thorsen <ola at silentwings.no> napisał(a):
>
>> 2018-09-05 14:08 GMT+02:00 Tomasz Olszak <olszak.tomasz at gmail.com>:
>>
>>> Hi, I want to animate (change flickable contentX and contentY) image
>>> position in screen. Image is bigger(4000x3000) than screen. Currently, I
>>> implemented it on I7 ivybridge on Kubuntu 18.04.
>>> It simply stutters few times a second. If anyone has integrated Intel
>>> GPU - could I kindly ask to check if it also stutter for him? Is it a GPU
>>> limit to handle such big texture or perhaps I can tweak something to make
>>> it fluent:
>>>
>>>
>> Instead of flickable i'd use GridView (which uses flickable). Only the
>> items actually on screen will be instantiated, so it scales much better.
>>
>> If your real case is an image and your GPU supports texture sizes as big
>> as your image size then maybe something like this could be faster (let a
>> shader to the zooming/cropping):
>>
>>
>> import QtQuick 2.9
>>
>> import QtQuick.Window 2.2
>>
>>
>> Window {
>>
>>     visible: true
>>
>>     width: 640
>>
>>     height: 480
>>
>>
>>     Image {
>>
>>         id: img
>>
>>         source: "http://www.letsgodigital.org/images/producten/1515/testrapport/underwater-photos.jpg"
>>
>>         visible: false
>>
>>     }
>>
>>
>>     Flickable {
>>
>>         anchors.fill: parent
>>
>>         id: flicker
>>
>>         contentWidth: dummyFlickItem.width
>>
>>         contentHeight: dummyFlickItem.height
>>
>>
>>         Item {
>>
>>             id: dummyFlickItem
>>
>>             width: img.sourceSize.width
>>
>>             height: img.sourceSize.height
>>
>>         }
>>
>>     }
>>
>>
>>     ShaderEffect {
>>
>>         anchors.fill: flicker
>>
>>         property variant src: img
>>
>>         property real xPosition: flicker.visibleArea.xPosition
>>
>>         property real yPosition: flicker.visibleArea.yPosition
>>
>>         property real widthRatio: flicker.visibleArea.widthRatio
>>
>>         property real heightRatio: flicker.visibleArea.heightRatio
>>
>>
>>         vertexShader: "
>>
>>                   uniform highp mat4 qt_Matrix;
>>
>>                   attribute highp vec4 qt_Vertex;
>>
>>                   attribute highp vec2 qt_MultiTexCoord0;
>>
>>
>>                   uniform highp float xPosition;
>>
>>                   uniform highp float yPosition;
>>
>>                   uniform highp float widthRatio;
>>
>>                   uniform highp float heightRatio;
>>
>>
>>                   varying highp vec2 coord;
>>
>>                   void main() {
>>
>>                       coord.x = xPosition + widthRatio*qt_MultiTexCoord0.x;
>>
>>                       coord.y = yPosition + heightRatio*qt_MultiTexCoord0.y;
>>
>>                       gl_Position = qt_Matrix * qt_Vertex;
>>
>>                   }"
>>
>>         fragmentShader: "
>>
>>                   varying highp vec2 coord;
>>
>>                   uniform sampler2D src;
>>
>>                   uniform lowp float qt_Opacity;
>>
>>                   void main() {
>>
>>                       gl_FragColor = texture2D(src, coord);
>>
>>                   }"
>>
>>     }
>>
>> }
>>
>>
>>
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>
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