More minor cleanups

Author: cwfitzgerald

wgpu-ffx/src/jitter.rs

@@ -13,7 +13,7 @@ fn halton(index: i32, base: i32) -> f32 {
     while current_index > 0 {
         f /= base as f32;
         result += f * (current_index % base) as f32;
-        current_index = f32::floor(current_index as f32 / base as f32) as i32;
+        current_index /= base;
     }
 
     result

wgpu-ffx/src/lib.rs

@@ -226,12 +226,18 @@ impl FsrContext {
     /// The returned [`FsrView`] holds all textures and temporal accumulation
     /// state. Multiple views can be created from the same context for
     /// multi-camera or split-screen rendering.
+    ///
+    /// # Panics
+    ///
+    /// Panics if any dimension of `max_render_size` is less than 2, or any
+    /// dimension of `max_upscale_size` is 0.
     pub fn create_view(
         &self,
         queue: &wgpu::Queue,
         max_render_size: [u32; 2],
         max_upscale_size: [u32; 2],
     ) -> FsrView {
+        FsrView::validate_sizes(max_render_size, max_upscale_size);
         FsrView::new(
             self.device.clone(),
             queue,
@@ -657,6 +663,22 @@ impl FsrContext {
 }
 
 impl FsrView {
+    fn validate_sizes(max_render_size: [u32; 2], max_upscale_size: [u32; 2]) {
+        assert!(
+            max_render_size[0] >= 2 && max_render_size[1] >= 2,
+            "max_render_size must be at least [2, 2], got [{}, {}] \
+             (internal half-resolution textures require dimensions >= 1)",
+            max_render_size[0],
+            max_render_size[1],
+        );
+        assert!(
+            max_upscale_size[0] >= 1 && max_upscale_size[1] >= 1,
+            "max_upscale_size must be at least [1, 1], got [{}, {}]",
+            max_upscale_size[0],
+            max_upscale_size[1],
+        );
+    }
+
     fn new(
         device: wgpu::Device,
         queue: &wgpu::Queue,
@@ -698,12 +720,18 @@ impl FsrView {
     ///
     /// Resets all temporal history — the next dispatch will behave as the
     /// first frame.
+    ///
+    /// # Panics
+    ///
+    /// Panics if any dimension of `max_render_size` is less than 2, or any
+    /// dimension of `max_upscale_size` is 0.
     pub fn resize(
         &mut self,
         queue: &wgpu::Queue,
         max_render_size: [u32; 2],
         max_upscale_size: [u32; 2],
     ) {
+        Self::validate_sizes(max_render_size, max_upscale_size);
         self.resources =
             resources::FsrResources::new(&self.device, queue, max_render_size, max_upscale_size);
         self.max_render_size = max_render_size;

wgpu-ffx/src/validation.rs

@@ -61,8 +61,8 @@ pub enum FsrDispatchError {
     )]
     FrameTimeDeltaTooLow(f32),
 
-    #[error("Pre-exposure is 0.0, which is invalid")]
-    PreExposureZero,
+    #[error("Pre-exposure {0} must be greater than 0.0")]
+    PreExposureNotPositive(f32),
 
     #[error(
         "DEPTH_INVERTED flag is set, but camera near ({camera_near}) is less than camera far ({camera_far})"
@@ -193,8 +193,8 @@ pub fn check_dispatch(
     }
 
     // Check pre-exposure
-    if info.pre_exposure == 0.0 {
-        return Err(FsrDispatchError::PreExposureZero);
+    if info.pre_exposure <= 0.0 {
+        return Err(FsrDispatchError::PreExposureNotPositive(info.pre_exposure));
     }
 
     // Check depth configuration