another texture thing, transparency

how i can make my texture transparenT?
glBlendFunc(GL_DST_COLOR, GL_ZERO);
DrawCube(0,0,0,2);
the mask, it works, the white thing is transparent, the rest of the cube is black than :

like here, u can see another smaler cube inside the cube with the texture, the big cube uses the mask texture i added at first

but how i can make transparency with this texture?

is there maybe a posibility to draw it into a buffer and delete the white pixel so that they dont get displayed`?

i got it i do now a 32bit Alpha-Channel bitmap for transparency
and use this function

glBlendFunc(GL_SRC_ALPHA,GL_ONE_MINUS_SRC_ALPHA);
glAlphaFunc(GL_GREATER,0.1f);
and glEnable(GL_ALPHA_TEST);

for transparency, but if anyone knows to delte custom pixel out of the buffer to get custom transparenzy by pixel plz tell me

here is the result:

another question would be a png or tga file better for transparency

“if anyone knows to delte custom pixel out of the buffer to get custom transparenzy by pixel plz tell me”
What do you mean ?

in older double buffers it was possible to delete a pixel out. or at old dos assembler example:
memory adress $A0000 delete pixel at offset 0xA0005
to get a transperancy, just to delete a pixel out of the buffer so that it does not get displayed anymore