Im using Vulkan to render simple textured meshes. To achieve a smooth result, I tried to use the built-in multisampling, but the maximum available number of samples for the render target (image) is only x4. This is not enough for my purposes, I need x8/x16.
How to efficiently implement antialiasing manually?
Multisample antialiasing is a technique that requires cooperation from the rasterizer, render targets, and other portions of the per-fragment processing hardware. It's a technique that rasterizes at a higher resolution, but only executes the fragment shader at a lower resolution, broadcasting the results across multiple samples within the same pixel area.
That's not something you can do manually.
You can always resort to super-sampling (render at a high resolution and then downsample). Or you can use faux antialiasing techniques like FXAA and the like. But you can't emulate MSAA manually.