[Interest] EGL & QML

[Jeff Lancaster]

My video app uses the EGL interface of which I created a new qdeclarativevideooutput object to implement it.

But when I run it in the example app, qmlvideo, where the video is displayed in a 250x250 rectangle my video does not play within the designated area (center screen), it is offset in the lower-right corner of the screen with just the upper-left quarter of the video showing. 

I need to understand what I need to do to my declarative interface to have my video feature work properly with any UI view that calls it.

Where can I find information regarding this problem.

I am using the following shader programs:

    virtual const char *vertexShader() const {
        const char *shader =
        "attribute highp vec4 vertexCoordArray;\n"
        "attribute highp vec2 textureCoordArray;\n"
        "uniform highp mat4 positionMatrix;\n"
        "varying highp vec2 textureCoord;\n"
        "void main(void)\n"
        "{\n"
        "   gl_Position = positionMatrix * vertexCoordArray;\n"
        "   textureCoord = textureCoordArray;\n"
        "}\n";
        return shader;
    }

    virtual const char *fragmentShader() const {
        static const char *shader =
        "#extension GL_OES_EGL_image_external : require\n"
        "precision mediump float;\n"
        "uniform samplerExternalOES tex;\n"
        "varying vec2 textureCoord;\n"
        "void main()\n"
        "{\n"
        "    gl_FragColor = texture2D(tex, textureCoord.st);\n"
        "}\n";
        return shader;
    }

And enabling the following features:
    program()->enableAttributeArray("vertexCoordArray");
    program()->enableAttributeArray("textureCoordArray");
    program()->setAttributeArray("vertexCoordArray", vertexCoordArray, 2);
    program()->setAttributeArray("textureCoordArray", textureCoordArray, 2);
    program()->setUniformValue("positionMatrix", positionMatrix);

(I set up the data in vertexCoordArray, textureCoordArray, and positionMatrix before running the above lines of code)

It all runs fine with a simple app:
import QtQuick 2.0
import QtMultimedia 5.0

Rectangle {
    width: 800
    height: 600
    color: "black"

    MediaPlayer {
        id: player
        source: "clip.mp4"
        autoPlay: true
    }

    VideoOutput {
        id: videoOutput
        source: player
        anchors.fill: parent
    }
}



Best regards,

Jeff Lancaster • Sr Software Engineer •
jlancaster at vivint.com  • P: 801.229.6010 • C: 801.xxx.xxxx

simply smarter • vivint.com
2500 West Executive Pkwy. Lehi, UT 84043