I am totally new to vvvv, and when I wanted to create a simple ‘black becomes transparent effect’, I found the alpha_video effect. Only the strange thing is that I see the ‘visible’ part of the video twice, one of them mirrorred.
So I started editing this shader, and even with this very simple function, I see the ‘normal’ image (video or file texture), and I see the ‘mirrorred’ image shine through the first one, and it gets more visible when I decrease the alpha value.
I changed it to D24X8, leaving the backbuffer format to X8R8G8B8.
(I couldn’t find DX24 as an option, only D24X8, D16, D16_lOCKABLE)
At first sight, that seems to do the trick, and it seems logical that it wouldn’t work without it. I also needed to disable clear depth buffer for it to work.
Anyway I don’t have a clue as to where this mirrored image comes from. I mean, the pixelshader doesn’t do that, and that’s the only thing I do with the texture. Do you know why I get that effect?
Is there a ‘standard’ node that simply adds an alpha-channel to a video? Because I want to combine different textures on one screen with a GROUP node, and they only behave the way I expect them to when they all have an alpha channel.
For this example I used the RGBContrast_2 effect (for which you can find the link in an earlier post from catweasel).
The example works, but when I disable the depth and alpha buffer, or when I choose clear alpha buffer (when exactly does that happen?), I see the image twice, once mirrored, as you can see in the added right_and_wrong.png.
I would suppose that disabling the depth buffer wouldn’t add an alpha channel to my video, but that shouldn’t change the image in any way, should it?
Oh, I like to be served ;)
It was just a little thing - you took a box as input mesh. So, your texture will be put on all six sides of a box. The second mirrored image was image of back side.
For plain 2d-images best option is a mesh which is just sort of canvas. I added some toggle-switches for explaination in you patch. Play around with them to see what happens. (fill.node goes between a solid-common view, point-view and grid-view, which is nice for seeing mesh only)