From 610435044046335420395c4b748074155d2f273e Mon Sep 17 00:00:00 2001
From: Dzmitry Malyshau <dmalyshau@mozilla.com>
Date: Fri, 5 Jul 2019 21:11:44 +0000
Subject: [PATCH] Bug 1548339 - WR: Remove the color/alpha feature in cs_scale
 shader r=jrmuizel

this makes the shader simpler at no cost

Differential Revision: https://phabricator.services.mozilla.com/D37114

--HG--
extra : moz-landing-system : lando
---
 gfx/wr/webrender/res/cs_scale.glsl | 17 ++---------------
 gfx/wr/webrender/src/renderer.rs   | 23 +++++++++--------------
 gfx/wr/webrender/src/shade.rs      | 21 +++++----------------
 3 files changed, 16 insertions(+), 45 deletions(-)

diff --git a/gfx/wr/webrender/res/cs_scale.glsl b/gfx/wr/webrender/res/cs_scale.glsl
index 03d9f96be3c5..eb398b9c29c4 100644
--- a/gfx/wr/webrender/res/cs_scale.glsl
+++ b/gfx/wr/webrender/res/cs_scale.glsl
@@ -31,12 +31,7 @@ void main(void) {
     RectWithSize src_rect = src_task.task_rect;
     RectWithSize target_rect = scale_task.common_data.task_rect;
 
-#if defined WR_FEATURE_COLOR_TARGET
-    vec2 texture_size = vec2(textureSize(sPrevPassColor, 0).xy);
-#else
-    vec2 texture_size = vec2(textureSize(sPrevPassAlpha, 0).xy);
-#endif
-
+    vec2 texture_size = vec2(textureSize(sColor0, 0).xy);
     vUv.z = src_task.texture_layer_index;
 
     vUvRect = vec4(src_rect.p0 + vec2(0.5),
@@ -52,17 +47,9 @@ void main(void) {
 
 #ifdef WR_FRAGMENT_SHADER
 
-#if defined WR_FEATURE_COLOR_TARGET
-#define SAMPLE_TYPE vec4
-#define SAMPLE_TEXTURE(uv)  texture(sPrevPassColor, uv)
-#else
-#define SAMPLE_TYPE float
-#define SAMPLE_TEXTURE(uv)  texture(sPrevPassAlpha, uv).r
-#endif
-
 void main(void) {
     vec2 st = clamp(vUv.xy, vUvRect.xy, vUvRect.zw);
-    oFragColor = vec4(SAMPLE_TEXTURE(vec3(st, vUv.z)));
+    oFragColor = texture(sColor0, vec3(st, vUv.z));
 }
 
 #endif
diff --git a/gfx/wr/webrender/src/renderer.rs b/gfx/wr/webrender/src/renderer.rs
index 2a35a844cfbd..8345ab114b04 100644
--- a/gfx/wr/webrender/src/renderer.rs
+++ b/gfx/wr/webrender/src/renderer.rs
@@ -3358,24 +3358,19 @@ impl Renderer {
 
         let _timer = self.gpu_profile.start_timer(GPU_TAG_SCALE);
 
-        match source {
-            TextureSource::PrevPassColor => {
-                self.shaders.borrow_mut().cs_scale_rgba8.bind(&mut self.device,
-                                                              &projection,
-                                                              &mut self.renderer_errors);
-            }
-            TextureSource::PrevPassAlpha => {
-                self.shaders.borrow_mut().cs_scale_a8.bind(&mut self.device,
-                                                           &projection,
-                                                           &mut self.renderer_errors);
-            }
-            _ => unreachable!(),
-        }
+        self.shaders
+            .borrow_mut()
+            .cs_scale
+            .bind(
+                &mut self.device,
+                &projection,
+                &mut self.renderer_errors,
+            );
 
         self.draw_instanced_batch(
             &scalings,
             VertexArrayKind::Scale,
-            &BatchTextures::no_texture(),
+            &BatchTextures::color(source),
             stats,
         );
     }
diff --git a/gfx/wr/webrender/src/shade.rs b/gfx/wr/webrender/src/shade.rs
index 35570f5013ed..f52ce374298b 100644
--- a/gfx/wr/webrender/src/shade.rs
+++ b/gfx/wr/webrender/src/shade.rs
@@ -508,8 +508,7 @@ pub struct Shaders {
     pub cs_blur_rgba8: LazilyCompiledShader,
     pub cs_border_segment: LazilyCompiledShader,
     pub cs_border_solid: LazilyCompiledShader,
-    pub cs_scale_a8: LazilyCompiledShader,
-    pub cs_scale_rgba8: LazilyCompiledShader,
+    pub cs_scale: LazilyCompiledShader,
     pub cs_line_decoration: LazilyCompiledShader,
     pub cs_gradient: LazilyCompiledShader,
 
@@ -688,18 +687,10 @@ impl Shaders {
             pls_precache_flags,
         )?;
 
-        let cs_scale_a8 = LazilyCompiledShader::new(
+        let cs_scale = LazilyCompiledShader::new(
             ShaderKind::Cache(VertexArrayKind::Scale),
             "cs_scale",
-            &["ALPHA_TARGET"],
-            device,
-            options.precache_flags,
-        )?;
-
-        let cs_scale_rgba8 = LazilyCompiledShader::new(
-            ShaderKind::Cache(VertexArrayKind::Scale),
-            "cs_scale",
-            &["COLOR_TARGET"],
+            &[],
             device,
             options.precache_flags,
         )?;
@@ -854,8 +845,7 @@ impl Shaders {
             cs_line_decoration,
             cs_gradient,
             cs_border_solid,
-            cs_scale_a8,
-            cs_scale_rgba8,
+            cs_scale,
             brush_solid,
             brush_image,
             brush_fast_image,
@@ -937,8 +927,7 @@ impl Shaders {
     }
 
     pub fn deinit(self, device: &mut Device) {
-        self.cs_scale_a8.deinit(device);
-        self.cs_scale_rgba8.deinit(device);
+        self.cs_scale.deinit(device);
         self.cs_blur_a8.deinit(device);
         self.cs_blur_rgba8.deinit(device);
         self.brush_solid.deinit(device);