[SOLVED] Weird transparency with framebuffer

[vmatikainen]

Hi,

I am using a custom a custom QQuickFramebufferObject and Renderer to draw 2d mesh inside an item. Its basically a texture, uvs and vertices drawn as triangles to the framebuffer. !https://dl.dropboxusercontent.com/u/22270982/weird_render.png(weird render)!

The example contains 5 vertices and four triangles. As you can see two of the triangles are drawn partly transparent. although if the mid vertex coordinate is not moved to top to twist the image, they are drawn fully opaque as they should, because neither the vertices or image has that kind of transparency.

It gets even weirder as this is somehow connected to Renderer::createFramebufferObject and specifically the size of the new fbo. In my understanding you could return any (allowed) sized fbo to render to and the engine should handle it fine (although it would get pixelated if smaller than the item dimensions. What happens is that smaller the framebuffer I create the more those triangles get transparent and eventually disappear.

Any idea why the framebuffer size "works" in this way.