QML ShaderEffect and property type

[apap_]

Hi all,

I would like to pass a matrix3x3 to my openGL script but I can't find the right type to use in QML.
It works with a matrix4x4 in the following example :

@
ShaderEffect {
...

property matrix4x4 uMatrix: Qt.matrix4x4(1,0,0,0, 0,1,0,0, 0,0,1,0, 0,0,0,1)

...

}
@

Unfortunately the QML type "matrix3x3" does not exist. I tried many other types without success.
Does anyone have a solution please ?

[amund_l]

Could you just use the matrix4x4, and then just fill the 4th column with '1'?
The shaders are always using 4x4 and 4x1, and I guess that you are using the matrix in your shader. Post your full code, maybe I can help some more.

[apap_]

amund_l Thanks for reply.
In my shader I use a matrix3x3 so I would like to set it directly from QML.
Another solution would be to convert a matrix4x4 to matrix3x3 at the beginning of my shader. Is it possible ?
Something like :
@
mat3 matrix3x3 = matrix4x4 * ???;"
@

[chrisadams]

The property types which are provided by QtQuick are listed at http://doc-snapshot.qt-project.org/qt5-stable/qtquick/qtquick-qmltypereference.html#basic-types however not all of them have conversions to uniforms/varyings in ShaderEffect. Matrix3x3 doesn't exist at all. vector2d, vector3d, vector4d, quaternion and matrix4x4 should all have conversions.

Cheers,
Chris.