MSDF fonts perform pre-multiplied alpha, standard fonts don't

[ZigZaggh]

Hi I was working with the MSDF fonts and ran in to ".blend(colour, alpha)" not working as expected, I tested with a "normal" font, and that works.

It looks like it just blends with Black not matter what color you are setting.

I'm testing on Windows, with the latest stable GMS IDE and Runtime version, Scribble version 7.1.2pre002.

Sincerely

[JujuAdams]

Could you show me what code you're using please?

[ZigZaggh]

Just for testing I'm doing the following:

scribble("[Font12][c_red]88888").blend(c_white, 1).draw(500, 240);
scribble("[Font12][c_red]88888").blend(c_white, 0.75).draw(500, 280);
scribble("[Font12][c_red]88888").blend(c_white, 0.5).draw(500, 320);
scribble("[Font12][c_red]88888").blend(c_white, 0.25).draw(500, 360);

scribble("[MSDF_Roboto_Medium][c_red]88888").blend(c_white, 1).draw(600, 240);
scribble("[MSDF_Roboto_Medium][c_red]88888").blend(c_white, 0.75).draw(600, 280);
scribble("[MSDF_Roboto_Medium][c_red]88888").blend(c_white, 0.5).draw(600, 320);
scribble("[MSDF_Roboto_Medium][c_red]88888").blend(c_white, 0.25).draw(600, 360);

And the attached picture is showing the result, left column "normal" font right is MSDF font.

[JujuAdams]

Huh, for some reason MSDF fonts are doing pre-multiplied alpha. Not sure why I did that! Easy fix though - comment out line 54 in the fragment shader for __shd_scribble_msdf. I'll put out a release with that in at some point

[ZigZaggh]

If I comment out the line 54 I just get no blending at all!?
I'm not much into shaders, so I'm not completely sure what is happening :)

[JujuAdams]

narrows eyes

Yeah ok lol that makes sense. Try gl_FragColor.a *= v_vColour.a; instead.

[ZigZaggh]

Works perfectly, thank you so much for the fast reply Juju 👌 😃

[JujuAdams]

Implemented publicly for v7.1.2