Revert "Use a dst size threshold for multitexturing images."

This reverts commit edfa0d2f623dc66e695fac631d5fb03599b264b7.

Reason for revert: ubsan bug

Original change's description:
> Use a dst size threshold for multitexturing images.
> 
> TODO: Set thresholds based on GPU in use.
> 
> Change-Id: I0aeac596d11ab63922f2df0d76c668b4f8be5353
> Reviewed-on: https://skia-review.googlesource.com/77900
> Reviewed-by: Robert Phillips <robertphillips@google.com>
> Commit-Queue: Brian Salomon <bsalomon@google.com>

TBR=bsalomon@google.com,robertphillips@google.com

Change-Id: Iea56ce73cf8f7bca265fe58907a72ecf96497d22
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://skia-review.googlesource.com/78542
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>

4 files changed, 15 insertions, 29 deletions

diff --git a/include/gpu/GrCaps.h b/include/gpu/GrCaps.h
index 86b27b066a..b19281b00d 100644
--- a/include/gpu/GrCaps.h
+++ b/include/gpu/GrCaps.h
@@ -225,6 +225,9 @@ protected:
     // Vulkan doesn't support this (yet) and some drivers have issues, too
     bool fCrossContextTextureSupport                 : 1;
 
+    // Disables using multiple texture units to batch multiple SkImages at once.
+    bool fDisableImageMultitexturingSupport          : 1;
+
     InstancedSupport fInstancedSupport;
 
     BlendEquationSupport fBlendEquationSupport;
diff --git a/include/gpu/GrShaderCaps.h b/include/gpu/GrShaderCaps.h
index 15377ff0b1..4c847ac8b0 100644
--- a/include/gpu/GrShaderCaps.h
+++ b/include/gpu/GrShaderCaps.h
@@ -196,14 +196,7 @@ public:
 
     int maxCombinedSamplers() const { return fMaxCombinedSamplers; }
 
-    /**
-     * In general using multiple texture units for image rendering seems to be a win at smaller
-     * sizes of dst rects and a loss at larger sizes. Dst rects above this pixel area threshold will
-     * not use multitexturing.
-     */
-    size_t disableImageMultitexturingDstRectAreaThreshold() const {
-        return fDisableImageMultitexturingDstRectAreaThreshold;
-    }
+    bool disableImageMultitexturingSupport() const { return fDisableImageMultitexturing; }
 
     /**
      * Given a texture's config, this determines what swizzle must be appended to accesses to the
@@ -252,6 +245,7 @@ private:
     bool fVertexIDSupport : 1;
     bool fFloatIs32Bits : 1;
     bool fHalfIs32Bits : 1;
+    bool fDisableImageMultitexturing : 1;
 
     // Used for specific driver bug work arounds
     bool fCanUseMinAndAbsTogether : 1;
@@ -283,8 +277,6 @@ private:
     int fMaxFragmentSamplers;
     int fMaxCombinedSamplers;
 
-    size_t fDisableImageMultitexturingDstRectAreaThreshold;
-
     AdvBlendEqInteraction fAdvBlendEqInteraction;
 
     GrSwizzle fConfigTextureSwizzle[kGrPixelConfigCnt];
diff --git a/src/gpu/GrShaderCaps.cpp b/src/gpu/GrShaderCaps.cpp
index 65721ee897..2d9cd0a39b 100644
--- a/src/gpu/GrShaderCaps.cpp
+++ b/src/gpu/GrShaderCaps.cpp
@@ -68,9 +68,11 @@ GrShaderCaps::GrShaderCaps(const GrContextOptions& options) {
     fMaxCombinedSamplers = 0;
     fAdvBlendEqInteraction = kNotSupported_AdvBlendEqInteraction;
 
-    // TODO: Default this to 0 and only enable image multitexturing when a "safe" threshold is
-    // known for a GPU class.
-    fDisableImageMultitexturingDstRectAreaThreshold = std::numeric_limits<size_t>::max();
+#if GR_TEST_UTILS
+    fDisableImageMultitexturing = options.fDisableImageMultitexturing;
+#else
+    fDisableImageMultitexturing = false;
+#endif
 }
 
 void GrShaderCaps::dumpJSON(SkJSONWriter* writer) const {
@@ -128,8 +130,7 @@ void GrShaderCaps::dumpJSON(SkJSONWriter* writer) const {
     writer->appendS32("Max Combined Samplers", fMaxFragmentSamplers);
     writer->appendString("Advanced blend equation interaction",
                          kAdvBlendEqInteractionStr[fAdvBlendEqInteraction]);
-    writer->appendU64("Disable image multitexturing dst area threshold",
-                      fDisableImageMultitexturingDstRectAreaThreshold);
+    writer->appendBool("Disable image multitexturing", fDisableImageMultitexturing);
 
     writer->endObject();
 }
@@ -137,8 +138,5 @@ void GrShaderCaps::dumpJSON(SkJSONWriter* writer) const {
 void GrShaderCaps::applyOptionsOverrides(const GrContextOptions& options) {
 #if GR_TEST_UTILS
     fDualSourceBlendingSupport = fDualSourceBlendingSupport && !options.fSuppressDualSourceBlending;
-    if (options.fDisableImageMultitexturing) {
-        fDisableImageMultitexturingDstRectAreaThreshold = 0;
-    }
 #endif
 }
diff --git a/src/gpu/ops/GrTextureOp.cpp b/src/gpu/ops/GrTextureOp.cpp
index 565eb88c52..410257cb7c 100644
--- a/src/gpu/ops/GrTextureOp.cpp
+++ b/src/gpu/ops/GrTextureOp.cpp
@@ -55,7 +55,7 @@ public:
 #endif
 
     static int SupportsMultitexture(const GrShaderCaps& caps) {
-        return caps.integerSupport() && caps.maxFragmentSamplers() > 1;
+        return caps.integerSupport() && !caps.disableImageMultitexturingSupport();
     }
 
     static sk_sp<GrGeometryProcessor> Make(sk_sp<GrTextureProxy> proxies[], int proxyCnt,
@@ -313,8 +313,6 @@ private:
         SkRect bounds;
         bounds.setBounds(draw.fQuad.points(), 4);
         this->setBounds(bounds, HasAABloat::kNo, IsZeroArea::kNo);
-        fMaxApproxDstPixelArea =
-                static_cast<size_t>(SkTMax(bounds.width(), 1.f) * SkTMax(bounds.height(), 1.f));
     }
 
     void onPrepareDraws(Target* target) override {
@@ -433,18 +431,15 @@ private:
 
     bool onCombineIfPossible(GrOp* t, const GrCaps& caps) override {
         const auto* that = t->cast<TextureOp>();
-        const auto& shaderCaps = *caps.shaderCaps();
         if (!GrColorSpaceXform::Equals(fColorSpaceXform.get(), that->fColorSpaceXform.get())) {
             return false;
         }
         // Because of an issue where GrColorSpaceXform adds the same function every time it is used
         // in a texture lookup, we only allow multiple textures when there is no transform.
-        if (TextureGeometryProcessor::SupportsMultitexture(shaderCaps) && !fColorSpaceXform &&
-            fMaxApproxDstPixelArea <= shaderCaps.disableImageMultitexturingDstRectAreaThreshold() &&
-            that->fMaxApproxDstPixelArea <=
-                    shaderCaps.disableImageMultitexturingDstRectAreaThreshold()) {
+        if (TextureGeometryProcessor::SupportsMultitexture(*caps.shaderCaps()) &&
+            !fColorSpaceXform) {
             int map[kMaxTextures];
-            int numNewProxies = this->mergeProxies(that, map, shaderCaps);
+            int numNewProxies = this->mergeProxies(that, map, *caps.shaderCaps());
             if (numNewProxies < 0) {
                 return false;
             }
@@ -484,7 +479,6 @@ private:
             fDraws.push_back_n(that->fDraws.count(), that->fDraws.begin());
         }
         this->joinBounds(*that);
-        fMaxApproxDstPixelArea = SkTMax(that->fMaxApproxDstPixelArea, fMaxApproxDstPixelArea);
         return true;
     }
 
@@ -576,7 +570,6 @@ private:
     // Used to track whether fProxy is ref'ed or has a pending IO after finalize() is called.
     uint8_t fFinalized;
     uint8_t fAllowSRGBInputs;
-    size_t fMaxApproxDstPixelArea;
 
     typedef GrMeshDrawOp INHERITED;
 };