My questions is as simple as the answer might be :
“is it possible to have no background (transparent) in GDI render, in case i’d like to use it as a GDI texture. Just want to show the drawn elements on top of a video?” easy to tell i just droped into vvvv. i’m searching for a while now.
ok thanks …
martin
short answer: no, the GDI texture doesnt generate an alpha channel.
there are at least four different workarounds:
*use the Blend (EX9.Renderstate) node to draw your objects in Add mode on top of the video
*use multiple objects to draw the video. connect the your object transformation also to the texture transformation - so you can move your objects “behind” the texture
*use a pixel shader to do some kind of chroma keying and replace e.g. all 100% blue with transparency
*use two GDI renderers, one for color, one for alpha and use a shader to combine these two.
see benefits shader tutorial for details.
What can i say … thanks so far … it is not like, i couldnt come up with some ideas ... i simply thought im to stupid to find the right “click” …
thanks once again for your more than helpful advices …
m…
actually there is a very limited support for direct alpha-channels from gdi-renderers. you can achieve 1bit alpha (means without antialiased text) by doing the following:
view the gdi-texture with an inspektor and select A1R5G5B5 on the “Texture Format” pin. may be sufficient for some rare cases.