From 27246428ba04093cf3c0f4abd55366e49a741bb9 Mon Sep 17 00:00:00 2001
From: Dzmitry Malyshau <kvark@mozilla.com>
Date: Mon, 1 May 2017 14:12:49 -0400
Subject: [PATCH] Render option that disables batching

---
 webrender/src/renderer.rs | 19 ++++++++++++++++---
 wrench/src/args.yaml      |  3 +++
 wrench/src/main.rs        |  3 ++-
 wrench/src/wrench.rs      |  4 +++-
 4 files changed, 24 insertions(+), 5 deletions(-)

diff --git a/webrender/src/renderer.rs b/webrender/src/renderer.rs
index 2cda9f470d..ad75db19c1 100644
--- a/webrender/src/renderer.rs
+++ b/webrender/src/renderer.rs
@@ -532,6 +532,7 @@ pub struct Renderer {
     clear_color: ColorF,
     debug: DebugRenderer,
     render_target_debug: bool,
+    enable_batcher: bool,
     backend_profile_counters: BackendProfileCounters,
     profile_counters: RendererProfileCounters,
     profiler: Profiler,
@@ -1061,6 +1062,7 @@ impl Renderer {
             notifier: notifier,
             debug: debug_renderer,
             render_target_debug: render_target_debug,
+            enable_batcher: options.enable_batcher,
             backend_profile_counters: BackendProfileCounters::new(),
             profile_counters: RendererProfileCounters::new(),
             profiler: Profiler::new(),
@@ -1437,10 +1439,19 @@ impl Renderer {
             self.device.bind_texture(TextureSampler::Dither, id);
         }
 
-        self.device.update_vao_instances(vao, data, VertexUsageHint::Stream);
-        self.device.draw_indexed_triangles_instanced_u16(6, data.len() as i32);
+        if self.enable_batcher {
+            self.device.update_vao_instances(vao, data, VertexUsageHint::Stream);
+            self.device.draw_indexed_triangles_instanced_u16(6, data.len() as i32);
+            self.profile_counters.draw_calls.inc();
+        } else {
+            for i in 0 .. data.len() {
+                self.device.update_vao_instances(vao, &data[i..i+1], VertexUsageHint::Stream);
+                self.device.draw_triangles_u16(0, 6);
+                self.profile_counters.draw_calls.inc();
+            }
+        }
+
         self.profile_counters.vertices.add(6 * data.len());
-        self.profile_counters.draw_calls.inc();
     }
 
     fn submit_batch(&mut self,
@@ -2120,6 +2131,7 @@ pub struct RendererOptions {
     pub enable_subpixel_aa: bool,
     pub clear_framebuffer: bool,
     pub clear_color: ColorF,
+    pub enable_batcher: bool,
     pub render_target_debug: bool,
     pub max_texture_size: Option<u32>,
     pub workers: Option<Arc<Mutex<ThreadPool>>>,
@@ -2143,6 +2155,7 @@ impl Default for RendererOptions {
             enable_subpixel_aa: false,
             clear_framebuffer: true,
             clear_color: ColorF::new(1.0, 1.0, 1.0, 1.0),
+            enable_batcher: true,
             render_target_debug: false,
             max_texture_size: None,
             workers: None,
diff --git a/wrench/src/args.yaml b/wrench/src/args.yaml
index 45643d68b1..b24a1aedea 100644
--- a/wrench/src/args.yaml
+++ b/wrench/src/args.yaml
@@ -50,6 +50,9 @@ args:
   - vsync:
       long: vsync
       help: Enable vsync for OpenGL window
+  - no_batch:
+      long: no-batch
+      help: Disable batching of instanced draw calls
 
 subcommands:
     - png:
diff --git a/wrench/src/main.rs b/wrench/src/main.rs
index 60ab46236e..021edad733 100644
--- a/wrench/src/main.rs
+++ b/wrench/src/main.rs
@@ -324,7 +324,8 @@ fn main() {
                                  args.is_present("rebuild"),
                                  args.is_present("subpixel_aa"),
                                  args.is_present("debug"),
-                                 args.is_present("verbose"));
+                                 args.is_present("verbose"),
+                                 args.is_present("no_batch"));
 
     let mut thing =
         if let Some(subargs) = args.subcommand_matches("show") {
diff --git a/wrench/src/wrench.rs b/wrench/src/wrench.rs
index 55e3a0a56b..d064e59075 100644
--- a/wrench/src/wrench.rs
+++ b/wrench/src/wrench.rs
@@ -146,7 +146,8 @@ impl Wrench {
                do_rebuild: bool,
                subpixel_aa: bool,
                debug: bool,
-               verbose: bool)
+               verbose: bool,
+               no_batch: bool)
            -> Wrench
     {
         println!("Shader override path: {:?}", shader_override_path);
@@ -171,6 +172,7 @@ impl Wrench {
             recorder: recorder,
             enable_subpixel_aa: subpixel_aa,
             debug: debug,
+            enable_batcher: !no_batch,
             max_recorded_profiles: 16,
             .. Default::default()
         };