fold more in SkRasterPipelineBlitter

No change in behavior.  This just moves the responsibility for this optimization to the blitter (which knows what it's doing) rather than to compile_pipeline(), which sort of has to guess.

CQ_INCLUDE_TRYBOTS=skia.primary:Test-Ubuntu-GCC-GCE-CPU-AVX2-x86_64-Release-SKNX_NO_SIMD

Change-Id: I93ad0ac896075deab995b865b188b42de637f0f7
Reviewed-on: https://skia-review.googlesource.com/5398
Commit-Queue: Mike Klein <mtklein@chromium.org>
Reviewed-by: Herb Derby <herb@google.com>

1 files changed, 33 insertions, 15 deletions

diff --git a/src/core/SkRasterPipelineBlitter.cpp b/src/core/SkRasterPipelineBlitter.cpp
index d7d66cfc72..8adb328315 100644
--- a/src/core/SkRasterPipelineBlitter.cpp
+++ b/src/core/SkRasterPipelineBlitter.cpp
@@ -26,6 +26,7 @@ public:
         : fDst(dst)
         , fBlend(blend)
         , fPaintColor(paintColor)
+        , fShaderIsConstant(true)
         , fScratchAlloc(fScratch, sizeof(fScratch))
         , fScratchFallback(&fScratchAlloc)
     {}
@@ -39,15 +40,18 @@ public:
     // blits using something like a SkRasterPipeline::runFew() method.
 
 private:
-    void append_load_d(SkRasterPipeline*) const;
-    void append_store (SkRasterPipeline*) const;
-    void append_blend (SkRasterPipeline*) const;
-    void maybe_clamp  (SkRasterPipeline*) const;
+    void append_load_d  (SkRasterPipeline*) const;
+    void append_blend   (SkRasterPipeline*) const;
+    void maybe_clamp    (SkRasterPipeline*) const;
+    void append_swizzles(SkRasterPipeline*) const;
+    void append_store   (SkRasterPipeline*) const;
 
     SkPixmap         fDst;
     SkBlendMode      fBlend;
     SkPM4f           fPaintColor;
     SkRasterPipeline fShader;
+    bool             fShaderIsConstant;
+    SkPM4f           fTrivialBlendColor;
 
     // These functions are compiled lazily when first used.
     std::function<void(size_t, size_t, size_t)> fBlitH         = nullptr,
@@ -99,9 +103,10 @@ SkBlitter* SkRasterPipelineBlitter::Create(const SkPixmap& dst,
         return nullptr;
     };
 
-    SkBlendMode*      blend      = &blitter->fBlend;
-    SkPM4f*           paintColor = &blitter->fPaintColor;
-    SkRasterPipeline* pipeline   = &blitter->fShader;
+    SkBlendMode*      blend       = &blitter->fBlend;
+    SkPM4f*           paintColor  = &blitter->fPaintColor;
+    SkRasterPipeline* pipeline    = &blitter->fShader;
+    bool*             is_constant = &blitter->fShaderIsConstant;
 
     SkShader*      shader      = paint.getShader();
     SkColorFilter* colorFilter = paint.getColorFilter();
@@ -111,9 +116,7 @@ SkBlitter* SkRasterPipelineBlitter::Create(const SkPixmap& dst,
         return earlyOut();
     }
 
-    bool is_opaque   = paintColor->a() == 1.0f,
-         is_constant = true;
-
+    bool is_opaque = paintColor->a() == 1.0f;
     if (shader) {
         if (!shader->appendStages(pipeline, dst.colorSpace(), &blitter->fScratchFallback,
                                   ctm, paint)) {
@@ -125,7 +128,7 @@ SkBlitter* SkRasterPipelineBlitter::Create(const SkPixmap& dst,
         }
 
         is_opaque   = is_opaque && shader->isOpaque();
-        is_constant = shader->isConstant();
+       *is_constant = shader->isConstant();
     } else {
         pipeline->append(SkRasterPipeline::constant_color, paintColor);
     }
@@ -138,7 +141,7 @@ SkBlitter* SkRasterPipelineBlitter::Create(const SkPixmap& dst,
         is_opaque = is_opaque && (colorFilter->getFlags() & SkColorFilter::kAlphaUnchanged_Flag);
     }
 
-    if (is_constant) {
+    if (*is_constant) {
         pipeline->append(SkRasterPipeline::store_f32, &paintColor);
         pipeline->run(0,0, 1);
 
@@ -173,15 +176,18 @@ void SkRasterPipelineBlitter::append_load_d(SkRasterPipeline* p) const {
     }
 }
 
-void SkRasterPipelineBlitter::append_store(SkRasterPipeline* p) const {
-    SkASSERT(supported(fDst.info()));
-
+void SkRasterPipelineBlitter::append_swizzles(SkRasterPipeline* p) const {
     if (fDst.info().gammaCloseToSRGB()) {
         p->append(SkRasterPipeline::to_srgb);
     }
     if (fDst.info().colorType() == kBGRA_8888_SkColorType) {
         p->append(SkRasterPipeline::swap_rb);
     }
+}
+
+void SkRasterPipelineBlitter::append_store(SkRasterPipeline* p) const {
+    SkASSERT(supported(fDst.info()));
+
     switch (fDst.info().colorType()) {
         case kRGB_565_SkColorType:   p->append(SkRasterPipeline::store_565,  &fDstPtr); break;
         case kBGRA_8888_SkColorType:
@@ -210,6 +216,15 @@ void SkRasterPipelineBlitter::blitH(int x, int y, int w) {
             this->append_blend(&p);
             this->maybe_clamp(&p);
         }
+        this->append_swizzles(&p);
+        if (fBlend == SkBlendMode::kSrc && fShaderIsConstant) {
+            auto trivial = &fTrivialBlendColor;
+            p.append(SkRasterPipeline::store_f32, &trivial);
+            p.run(0,0, 1);
+
+            p = SkRasterPipeline();
+            p.append(SkRasterPipeline::constant_color, trivial);
+        }
         this->append_store(&p);
         fBlitH = p.compile();
     }
@@ -232,6 +247,7 @@ void SkRasterPipelineBlitter::blitAntiH(int x, int y, const SkAlpha aa[], const
             p.append(SkRasterPipeline::lerp_1_float, &fCurrentCoverage);
         }
         this->maybe_clamp(&p);
+        this->append_swizzles(&p);
         this->append_store(&p);
         fBlitAntiH = p.compile();
     }
@@ -270,6 +286,7 @@ void SkRasterPipelineBlitter::blitMask(const SkMask& mask, const SkIRect& clip)
             p.append(SkRasterPipeline::lerp_u8, &fMaskPtr);
         }
         this->maybe_clamp(&p);
+        this->append_swizzles(&p);
         this->append_store(&p);
         fBlitMaskA8 = p.compile();
     }
@@ -281,6 +298,7 @@ void SkRasterPipelineBlitter::blitMask(const SkMask& mask, const SkIRect& clip)
         this->append_blend(&p);
         p.append(SkRasterPipeline::lerp_565, &fMaskPtr);
         this->maybe_clamp(&p);
+        this->append_swizzles(&p);
         this->append_store(&p);
         fBlitMaskLCD16 = p.compile();
     }