Hi I don´t know if somelse comment this before, in this case excuseme....
Well I have a doubt, I want to make a simple polyvector, but in some corner I want it is totally transparent... (the sprite, can be have alpha channel or not, can be .JPG or .PNG or .BMP)
I think whit RGB can be done, but the Alpha channel , how I put a transparent value from the RGB command... and technical data... it´s internaly RGB-Alpha or Alpha-RGB, or nothing of both :-[
Thanks in advance...
Not sure if this will help. I'll try anyway.
I don't think you can set the alpha of a polyvector triangle point using RGB. If you could do it, it would be RGB+alpha. For instance something like...
POLYVECTOR sx, sy, px, py, RGB(255,255,255) + ASL(alpha,24)
...will make no difference. The original sprites alpha data and ALPHAMODE are the only ways as far as I know.
What you can do is change the alpha data of a sprite using SPRITE2MEM and MEM2SPRITE to change alpha data. That should work (afaik) even with BMP and JPG. Internally its RGB-Alpha.
I wrote some code to create special font sprite sheets for my Chaos R game. One part checks for black pixels with alpha 3 or less and makes them totally transparent:-
abgr% = pimg%[arpart] // Read the colour as a whole
r = bAND(abgr, 0xff) // Read the individual colour values
g = bAND(ASR(abgr,8), 0xff)
b = bAND(ASR(abgr,16), 0xff)
a = bAND(ASR(abgr,24), 0xff)
IF r = 0 AND g = 0 AND b = 0 AND a < 4 // black with alpha of 3 or less
a = 0 // set alpha TO 0
pimg%[arpart] = bOR(RGB(r,g,b), ASL(a, 24) ) // insert back into array
ENDIF
HI Wampus, thanks a lot :nw: :nw:
I will try your code, and comment...
Thanks in advance...
Just put an ALPHAMODE before each POLYVECTOR to change the corners alpha. Every corner of the same polygon has to be above or under 0. Cant´t change ogl blendmodes in one call, I think. For example if the other corners have an alpha value of -0.999 and 0 in the one corner doesn´t make any differents, try -0.0001 instead.
Thanks Monono very interesting the solution... :nw: :nw:
Thanks to both...
Kinds Regards,