white sprite on black - remove black?

[anomalous]

I have a white sprite with gradient to black (like a particle glow in white on black background).
Is there a way to change the black to transparency, such that it becomes a white sprite gradient to transparent?
I would like ultimately to draw to a surface than save the surface as a sprite.

I tried a few types...clear to black and use bm_normal and bm_add, no luck so far.

If I use this as a particle with bm_add set, it actually doesn't draw the black..which is what gave me the idea. (but I still need it as a white gradient to transparency).

 

[elementbound]

If you'd like to do this in runtime ( aka. via GM's tools ), you can do that with a shader. Just create a new one, and modify the fragment shader's main:

gl_FragColor = vec4(1.0, 1.0, 1.0, texture2D(gm_BaseTexture, v_vTexcoord).r);

Bind this shader, and draw whatever you want. The shader will actually use the red channel, but since we are using a grayscale shader, all the channels look the same. The shader will output a purely white image, with transparency based on brightness ( red channel )

 

[anomalous]

Great thank you!
I also figured out how to do it in photoshop, but I like the game maker version..can do a lot at once.

 

[iMilchshake]

You could also go into the Sprite-editor. Then Go to "Image" -> "Erase a Colour"

 

[anomalous]

Unfortunately erase a color won't give white to transparent, it will just cut out the black pixels entirely (and more than black with tolerance, its a nice feature for other stuff)

 

[iMilchshake]

Unfortunately erase a color won't give white to transparent, it will just cut out the black pixels entirely (and more than black with tolerance, its a nice feature for other stuff)

Ohh.. Yeah i forgot..
Good you found a solution^^.