Fix bbox bug

Bounding boxes were being calculated as way too large in the element
processing.

Also wire up counters so winit binary is happy.

piet-gpu/bin/winit.rs

@@ -37,7 +37,7 @@ fn main() -> Result<(), Error> {
             .map(|_| device.create_cmd_buf())
             .collect::<Result<Vec<_>, Error>>()?;
         let query_pools = (0..NUM_FRAMES)
-            .map(|_| device.create_query_pool(6))
+            .map(|_| device.create_query_pool(5))
             .collect::<Result<Vec<_>, Error>>()?;
 
         let mut ctx = PietGpuRenderContext::new();
@@ -70,12 +70,11 @@ fn main() -> Result<(), Error> {
 
                         let timestamps = device.reap_query_pool(query_pool).unwrap();
                         window.set_title(&format!(
-                            "k1: {:.3}ms, k2s: {:.3}ms, k2f: {:.3}ms, k3: {:.3}ms, k4: {:.3}ms",
+                            "e: {:.3}ms, b: {:.3}ms, c: {:.3}ms, f: {:.3}ms",
                             timestamps[0] * 1e3,
                             (timestamps[1] - timestamps[0]) * 1e3,
                             (timestamps[2] - timestamps[1]) * 1e3,
                             (timestamps[3] - timestamps[2]) * 1e3,
-                            (timestamps[4] - timestamps[3]) * 1e3,
                         ));
                     }
 

piet-gpu/shader/elements.comp

@@ -82,6 +82,7 @@ State combine_state(State a, State b) {
     c.translate.y = a.mat.y * b.translate.x + a.mat.w * b.translate.y + a.translate.y;
     c.linewidth = (b.flags & FLAG_SET_LINEWIDTH) == 0 ? a.linewidth : b.linewidth;
     c.flags = (a.flags & (FLAG_SET_LINEWIDTH | FLAG_SET_BBOX)) | b.flags;
+    c.flags |= (a.flags & FLAG_RESET_BBOX) >> 1;
     return c;
 }