Linear interpolation doesn't work on Intel GPUs

[haesleinhuepf]

Affine transform uses OpenCL interpolation (CLK_FILTER_NEAREST) which is apparently not supported, or not functional.

This bug is reproducible using this macro:

run("T1 Head (16-bits)");
run("Duplicate...", " ");

transform = "-center rotate=45 center";

run("CLIJ2 Macro Extensions", "cl_device=[Intel(R) UHD Graphics 620]");
Ext.CLIJ2_clear();

image = getTitle();
Ext.CLIJ2_push(image);
Ext.CLIJ2_affineTransform2D(image, transformed_image, transform);
Ext.CLIJ2_pull(transformed_image);
Ext.CLIJ2_clear();

run("CLIJ2 Macro Extensions", "cl_device=[Quadro P520]");
Ext.CLIJ2_clear();
Ext.CLIJ2_push(image);
Ext.CLIJ2_affineTransform2D(image, transformed_image, transform);
Ext.CLIJ2_pull(transformed_image);
Ext.CLIJ2_clear();

Thanks to Johannes Girstmair for reporting!

[haesleinhuepf]

The bug does not happen with Float images...

run("T1 Head (16-bits)");
run("32-bit");
run("Duplicate...", " ");

transform = "-center rotate=45 center";

run("CLIJ2 Macro Extensions", "cl_device=[Intel(R) UHD Graphics 620]");
Ext.CLIJ2_clear();

image = getTitle();
Ext.CLIJ2_push(image);
Ext.CLIJ2_affineTransform2D(image, transformed_image, transform);
Ext.CLIJ2_pull(transformed_image);
Ext.CLIJ2_clear();

run("CLIJ2 Macro Extensions", "cl_device=[Quadro P520]");
Ext.CLIJ2_clear();
Ext.CLIJ2_push(image);
Ext.CLIJ2_affineTransform2D(image, transformed_image, transform);
Ext.CLIJ2_pull(transformed_image);
Ext.CLIJ2_clear();