diff --git a/components/servo/Cargo.lock b/components/servo/Cargo.lock
index 40c268d6b24..1f45d97091d 100644
--- a/components/servo/Cargo.lock
+++ b/components/servo/Cargo.lock
@@ -2661,7 +2661,7 @@ dependencies = [
 [[package]]
 name = "webrender"
 version = "0.5.1"
-source = "git+https://github.com/servo/webrender#cf945d15c71c757c6694b40a38fd7cfef1a2f827"
+source = "git+https://github.com/servo/webrender#dfa4246ebe40c78882cdd3e69e776b1e09a2f58e"
 dependencies = [
  "app_units 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "bincode 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2686,7 +2686,7 @@ dependencies = [
 [[package]]
 name = "webrender_traits"
 version = "0.5.1"
-source = "git+https://github.com/servo/webrender#cf945d15c71c757c6694b40a38fd7cfef1a2f827"
+source = "git+https://github.com/servo/webrender#dfa4246ebe40c78882cdd3e69e776b1e09a2f58e"
 dependencies = [
  "app_units 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "byteorder 0.5.3 (registry+https://github.com/rust-lang/crates.io-index)",
diff --git a/components/util/opts.rs b/components/util/opts.rs
index aef7b3a84eb..659ead8b4c5 100644
--- a/components/util/opts.rs
+++ b/components/util/opts.rs
@@ -540,7 +540,7 @@ pub fn default_opts() -> Opts {
         exit_after_load: false,
         no_native_titlebar: false,
         enable_vsync: true,
-        use_webrender: false,
+        use_webrender: true,
         webrender_stats: false,
         use_msaa: false,
         render_api: DEFAULT_RENDER_API,
@@ -556,7 +556,7 @@ pub fn from_cmdline_args(args: &[String]) -> ArgumentParsingResult {
     let (app_name, args) = args.split_first().unwrap();
 
     let mut opts = Options::new();
-    opts.optflag("c", "cpu", "CPU painting (default)");
+    opts.optflag("c", "cpu", "CPU painting");
     opts.optflag("g", "gpu", "GPU painting");
     opts.optopt("o", "output", "Output file", "output.png");
     opts.optopt("s", "size", "Size of tiles", "512");
@@ -790,8 +790,7 @@ pub fn from_cmdline_args(args: &[String]) -> ArgumentParsingResult {
         opt_match.opt_present("b") ||
         !PREFS.get("shell.native-titlebar.enabled").as_boolean().unwrap();
 
-    let use_webrender =
-        PREFS.get("gfx.webrender.enabled").as_boolean().unwrap() || opt_match.opt_present("w");
+    let use_webrender = !opt_match.opt_present("c");
 
     let render_api = match opt_match.opt_str("G") {
         Some(ref ga) if ga == "gl" => RenderApi::GL,
diff --git a/ports/cef/Cargo.lock b/ports/cef/Cargo.lock
index c728aec1e3b..b397478fcba 100644
--- a/ports/cef/Cargo.lock
+++ b/ports/cef/Cargo.lock
@@ -2521,7 +2521,7 @@ dependencies = [
 [[package]]
 name = "webrender"
 version = "0.5.1"
-source = "git+https://github.com/servo/webrender#cf945d15c71c757c6694b40a38fd7cfef1a2f827"
+source = "git+https://github.com/servo/webrender#dfa4246ebe40c78882cdd3e69e776b1e09a2f58e"
 dependencies = [
  "app_units 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "bincode 0.6.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2546,7 +2546,7 @@ dependencies = [
 [[package]]
 name = "webrender_traits"
 version = "0.5.1"
-source = "git+https://github.com/servo/webrender#cf945d15c71c757c6694b40a38fd7cfef1a2f827"
+source = "git+https://github.com/servo/webrender#dfa4246ebe40c78882cdd3e69e776b1e09a2f58e"
 dependencies = [
  "app_units 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "byteorder 0.5.3 (registry+https://github.com/rust-lang/crates.io-index)",
diff --git a/resources/shaders/ps_blend.fs.glsl b/resources/shaders/ps_blend.fs.glsl
index 12ccbf0b6cf..b501d3772a1 100644
--- a/resources/shaders/ps_blend.fs.glsl
+++ b/resources/shaders/ps_blend.fs.glsl
@@ -6,5 +6,5 @@ uniform sampler2D sCache;
 
 void main(void) {
     vec4 color = texture(sCache, vUv);
-    oFragColor = vec4(color.rgb, color.a * vOpacity);
+    oFragColor = vec4(color.rgb * vBrightnessOpacity.x, color.a * vBrightnessOpacity.y);
 }
diff --git a/resources/shaders/ps_blend.glsl b/resources/shaders/ps_blend.glsl
index 773cf91e27e..5e12752629e 100644
--- a/resources/shaders/ps_blend.glsl
+++ b/resources/shaders/ps_blend.glsl
@@ -3,4 +3,4 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 varying vec2 vUv;
-varying float vOpacity;
+varying vec2 vBrightnessOpacity;
diff --git a/resources/shaders/ps_blend.vs.glsl b/resources/shaders/ps_blend.vs.glsl
index 479bd67e432..05d46860d99 100644
--- a/resources/shaders/ps_blend.vs.glsl
+++ b/resources/shaders/ps_blend.vs.glsl
@@ -15,7 +15,7 @@ void main(void) {
     vec2 st0 = vec2(src.target_rect.xy) / 2048.0;
     vec2 st1 = vec2(src.target_rect.xy + src.target_rect.zw) / 2048.0;
     vUv = mix(st0, st1, aPosition.xy);
-    vOpacity = blend.src_id_target_id_opacity.z;
+    vBrightnessOpacity = blend.src_id_target_id_opacity.zw;
 
     gl_Position = uTransform * vec4(local_pos, 0, 1);
 }
diff --git a/resources/shaders/ps_image_clip.fs.glsl b/resources/shaders/ps_image_clip.fs.glsl
index 62da5a846f9..3cc2ba3d632 100644
--- a/resources/shaders/ps_image_clip.fs.glsl
+++ b/resources/shaders/ps_image_clip.fs.glsl
@@ -6,7 +6,7 @@
 
 void main(void) {
 #ifdef WR_FEATURE_TRANSFORM
-    float alpha = 1;
+    float alpha = 1.f;
     vec2 local_pos = init_transform_fs(vLocalPos, vLocalRect, alpha);
 
     // We clamp the texture coordinate calculation here to the local rectangle boundaries,
@@ -14,7 +14,7 @@ void main(void) {
     vec2 pos_for_texture =
          clamp(pos, vLocalRect.xy, vLocalRect.xy + vLocalRect.zw) - vLocalRect.xy;
 #else
-    float alpha = 1;
+    float alpha = 1.f;
     vec2 local_pos = vLocalPos;
     vec2 relative_pos_in_rect = vLocalPos - vLocalRect.xy;
 #endif
diff --git a/resources/shaders/ps_rectangle_clip.fs.glsl b/resources/shaders/ps_rectangle_clip.fs.glsl
index d65ac5fd2ee..61b2b026b7c 100644
--- a/resources/shaders/ps_rectangle_clip.fs.glsl
+++ b/resources/shaders/ps_rectangle_clip.fs.glsl
@@ -4,10 +4,10 @@
 
 void main(void) {
 #ifdef WR_FEATURE_TRANSFORM
-    float alpha = 1;
+    float alpha = 1.f;
     vec2 local_pos = init_transform_fs(vPos, vLocalRect, alpha);
 #else
-    float alpha = 1;
+    float alpha = 1.f;
     vec2 local_pos = vPos;
 #endif