gistfile1.txt

diff --git a/src/device.rs b/src/device.rs
index eb93dd3..c90247e 100644
--- a/src/device.rs
+++ b/src/device.rs
@@ -670,6 +670,50 @@ impl UniformLocation {
     }
 }
 
+pub struct SamplesPassedQuery {
+    qid: gl::GLuint,
+}
+
+impl SamplesPassedQuery {
+    #[cfg(any(target_os = "linux", target_os = "windows", target_os = "macos"))]
+    pub fn new() -> SamplesPassedQuery {
+        SamplesPassedQuery {
+            qid: gl::gen_queries(1)[0],
+        }
+    }
+
+    #[cfg(target_os = "android")]
+    pub fn new() -> SamplesPassedQuery {
+        SamplesPassedQuery
+    }
+
+    #[cfg(any(target_os = "android", target_os = "gonk"))]
+    pub fn get(&mut self) -> u64 {
+        0
+    }
+
+    #[cfg(any(target_os = "linux", target_os = "windows", target_os = "macos"))]
+    pub fn get(&mut self) -> u64 {
+        gl::get_query_object_uiv(self.qid, gl::QUERY_RESULT) as u64
+    }
+
+    #[cfg(any(target_os = "linux", target_os = "windows", target_os = "macos"))]
+    pub fn begin(&mut self) {
+        gl::begin_query(gl::SAMPLES_PASSED, self.qid);
+    }
+
+    #[cfg(target_os = "android")]
+    pub fn begin(&mut self) {}
+
+    #[cfg(any(target_os = "linux", target_os = "windows", target_os = "macos"))]
+    pub fn end(&mut self) {
+        gl::end_query(gl::SAMPLES_PASSED);
+    }
+
+    #[cfg(target_os = "android")]
+    pub fn end(&mut self) -> u64 { 0 }
+}
+
 // TODO(gw): Fix up notify cargo deps and re-enable this!
 /*
 enum FileWatcherCmd {
diff --git a/src/renderer.rs b/src/renderer.rs
index 5ae8330..095a164 100644
--- a/src/renderer.rs
+++ b/src/renderer.rs
@@ -12,7 +12,7 @@
 use batch::RasterBatch;
 use debug_render::DebugRenderer;
 use device::{Device, ProgramId, TextureId, UniformLocation, VertexFormat, GpuProfile};
-use device::{TextureFilter, VAOId, VertexUsageHint, FileWatcherHandler};
+use device::{SamplesPassedQuery, TextureFilter, VAOId, VertexUsageHint, FileWatcherHandler};
 use euclid::{Matrix4D, Point2D, Rect, Size2D};
 use gleam::gl;
 use internal_types::{RendererFrame, ResultMsg, TextureUpdateOp};
@@ -229,6 +229,7 @@ pub struct Renderer {
 
     gpu_profile_paint: GpuProfile,
     gpu_profile_composite: GpuProfile,
+    samples_passed_query: SamplesPassedQuery,
     quad_vao_id: VAOId,
 }
 
@@ -544,6 +545,7 @@ impl Renderer {
             max_raster_op_size: max_raster_op_size,
             gpu_profile_paint: GpuProfile::new(),
             gpu_profile_composite: GpuProfile::new(),
+            samples_passed_query: SamplesPassedQuery::new(),
             quad_vao_id: quad_vao_id,
         };
 
@@ -620,6 +622,7 @@ impl Renderer {
         // In general this shouldn't block unless heavily GPU limited.
         let paint_ns = self.gpu_profile_paint.get();
         let composite_ns = self.gpu_profile_composite.get();
+        self.samples_passed_query.begin();
 
         profile_timers.cpu_time.profile(|| {
             self.device.begin_frame();
@@ -633,6 +636,9 @@ impl Renderer {
             self.draw_frame(framebuffer_size);
         });
 
+        self.samples_passed_query.end();
+        println!("samples passed: {}", self.samples_passed_query.get());
+
         let current_time = precise_time_ns();
         let ns = current_time - self.last_time;
         self.profile_counters.frame_time.set(ns);
@@ -1249,7 +1255,7 @@ impl Renderer {
                             tile_y1,
                             c);
         if label.len() > 0 {
-            self.debug.add_text((tile_x0.0 as f32 + tile_x1.0 as f32) * 0.5,
+            self.debug.add_text(tile_x0.0 as f32 + (tile_x1.0 as f32 - tile_x0.0 as f32) * 0.25,
                                 (tile_y0.0 as f32 + tile_y1.0 as f32) * 0.5,
                                 label,
                                 c);
diff --git a/src/tiling.rs b/src/tiling.rs
index c67f235..32c6068 100644
--- a/src/tiling.rs
+++ b/src/tiling.rs
@@ -2106,6 +2106,7 @@ impl ScreenTile {
         }
 
         self.prim_count = 0;
+
         for (command_index, command) in mem::replace(&mut self.cmds, vec![]).into_iter()    
                                                                             .enumerate() {
             match command {
@@ -2115,10 +2116,39 @@ impl ScreenTile {
                     }
                     self.prim_count += 1
                 }
+                TileCommand::PopLayer => {
+                    if let Some(&TileCommand::PushLayer(_)) = self.cmds.last() {
+                        self.cmds.pop();
+                        continue
+                    }
+                }
+                _ => {}
+            }
+            self.cmds.push(command);
+        }
+    }
+
+    #[allow(dead_code)]
+    fn dump_primitives(&self, prim_store: &[Primitive]) {
+        let mut string = String::new();
+        for command in &self.cmds {
+            match *command {
+                TileCommand::DrawPrimitive(index) => {
+                    let primitive = &(*prim_store)[index.0];
+                    match primitive.details {
+                        PrimitiveDetails::Rectangle(_) => string.push('C'),
+                        PrimitiveDetails::Text(_) => string.push('T'),
+                        PrimitiveDetails::TextRun(_) => string.push('R'),
+                        PrimitiveDetails::Image(_) => string.push('I'),
+                        PrimitiveDetails::Border(_) => string.push('B'),
+                        PrimitiveDetails::Gradient(_) => string.push('G'),
+                        PrimitiveDetails::BoxShadow(_) => string.push('S'),
+                    }
+                }
                 _ => {}
             }
-            self.cmds.push(command)
         }
+            println!("Tile: {}", string);
     }
 
     fn compile(self, layer_store: &Vec<StackingContext>) -> Option<CompiledScreenTile> {