vk: make frames in flight configurable

librashader-runtime-vk/src/filter_chain.rs

@@ -201,8 +201,13 @@ impl FilterChain {
         let (passes, semantics) = FilterChain::load_preset(preset.shaders, &preset.textures)?;
         let device = vulkan.try_into()?;
 
+        let mut frames_in_flight = options.map(|o| o.frames_in_flight).unwrap_or(0);
+        if frames_in_flight == 0 {
+            frames_in_flight = 3;
+        }
+
         // initialize passes
-        let filters = Self::init_passes(&device, passes, &semantics, 3)?;
+        let filters = Self::init_passes(&device, passes, &semantics, frames_in_flight)?;
 
         let luts = FilterChain::load_luts(&device, &preset.textures)?;
         let samplers = SamplerSet::new(&device.device)?;

librashader-runtime-vk/src/options.rs

@@ -14,6 +14,8 @@ pub struct FrameOptions {
 #[repr(C)]
 #[derive(Debug, Clone)]
 pub struct FilterChainOptions {
+    /// The number of frames in flight to keep. If zero, defaults to three.
+    pub frames_in_flight: u32,
     /// Whether or not to explicitly disable mipmap generation regardless of shader preset settings.
     pub force_no_mipmaps: bool,
 }