I wonder if there is a way to prevent the background color from bleeding into edge pixels when rendering objects on a fully transparent background (alpha=0). This happens when you calculate more than one sample per pixel for anti-aliasing. The following images show the effect, once for a black but transparent background (background=(0,0,0,0)) and once for a white transparent one (background=(1,1,1,0)).
To demonstrate the issue, I read the rendered RGBA image from the ANARI framebuffer to compose it on top of a checkerboard pattern using "source over" blending.
The following reference picture was created using my own OpenGL-based renderer, employing a simple supersampling technique to achieve anti-aliasing. It shows how the result should ideally look.
I would like to allow users of my application to render transparent graphics that are saved as a PNG file, e.g. to insert them later into a PowerPoint presentation. At the time of rendering, the user may not yet know whether the graphic will later be placed against a dark or a light background.
A possible workaround could be to render only 1 sample per pixel in VisRTX, but with a higher image resolution (true supersampling). The application can then downscale the final image, similar to what I did with the OpenGL image. However, it would be nicer if VisRTX directly supported a rendering mode that produces a clean image with smooth edges.
I wonder if there is a way to prevent the background color from bleeding into edge pixels when rendering objects on a fully transparent background (alpha=0). This happens when you calculate more than one sample per pixel for anti-aliasing. The following images show the effect, once for a black but transparent background (
background=(0,0,0,0)) and once for a white transparent one (background=(1,1,1,0)).To demonstrate the issue, I read the rendered RGBA image from the ANARI framebuffer to compose it on top of a checkerboard pattern using "source over" blending.
The following reference picture was created using my own OpenGL-based renderer, employing a simple supersampling technique to achieve anti-aliasing. It shows how the result should ideally look.
I would like to allow users of my application to render transparent graphics that are saved as a PNG file, e.g. to insert them later into a PowerPoint presentation. At the time of rendering, the user may not yet know whether the graphic will later be placed against a dark or a light background.
A possible workaround could be to render only 1 sample per pixel in VisRTX, but with a higher image resolution (true supersampling). The application can then downscale the final image, similar to what I did with the OpenGL image. However, it would be nicer if VisRTX directly supported a rendering mode that produces a clean image with smooth edges.