Add onGetBlendInfo to GrXferProcessor

Add onGetBlendInfo to GrXferProcessor

Adds an onGetBlendInfo method for GrXferProcessor subclasses to
override instead of overriding getBlendInfo directly. This gives the
base class a chance to initialize the struct with default values
before passing it on. As the BlendInfo struct grows, this will keep
things simple and less error prone.


BUG=skia:
NOTREECHECKS=true
NOTRY=true

Committed: https://skia.googlesource.com/skia/+/f4f2b442228ca188cfb6b44ee3faa86773bb9db3

[Mark Kilgard, 2015-04-02 22:45:24]

markkilgard@gmail.com changed reviewers:
+ markkilgard@gmail.com

[Mark Kilgard, 2015-04-02 22:45:24]

lgtm

[bsalomon, 2015-04-22 13:42:55]

bsalomon@google.com changed reviewers:
+ bsalomon@google.com

[bsalomon, 2015-04-22 13:42:56]

https://codereview.chromium.org/1049143002/diff/40001/include/gpu/GrXferProce...
File include/gpu/GrXferProcessor.h (right):

https://codereview.chromium.org/1049143002/diff/40001/include/gpu/GrXferProce...
include/gpu/GrXferProcessor.h:135: blendInfo->fSrcBlend = kOne_GrBlendCoeff;
My only suggestion is to move this code into a reset() or setDefault() function
on BlendInfo and call that here.

Also, looks like you got changes from another CL mixed into here (adding blend
barrier GL stuff).

Otherwise, lgtm.

[Chris Dalton, 2015-04-23 06:58:20]

This takes the barrier stuff out and adds the reset() method to BlendInfo.

I'll leave it open a bit longer in case you wanted to take another look before
it gets committed.

[bsalomon, 2015-04-23 14:46:08]

On 2015/04/23 06:58:20, Chris Dalton wrote:
> This takes the barrier stuff out and adds the reset() method to BlendInfo.
> 
> I'll leave it open a bit longer in case you wanted to take another look before
> it gets committed.

lgtm

[Chris Dalton, 2015-04-23 16:03:12]

The CQ bit was checked by cdalton@nvidia.com

[Chris Dalton, 2015-04-23 16:03:12]

The patchset sent to the CQ was uploaded after l-g-t-m from
markkilgard@gmail.com
Link to the patchset: https://codereview.chromium.org/1049143002/#ps100001
(title: "Undo accidental upload of chrome change")

[commit-bot: I haz the power, 2015-04-23 16:03:31]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1049143002/100001

[commit-bot: I haz the power, 2015-04-23 16:03:34]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-04-23 16:03:34]

Failed to apply patch for include/gpu/GrXferProcessor.h:
While running git apply --index -3 -p1;
  error: patch failed: include/gpu/GrXferProcessor.h:141
  error: repository lacks the necessary blob to fall back on 3-way merge.
  error: include/gpu/GrXferProcessor.h: patch does not apply

Patch:       include/gpu/GrXferProcessor.h
Index: include/gpu/GrXferProcessor.h
diff --git a/include/gpu/GrXferProcessor.h b/include/gpu/GrXferProcessor.h
index
636a6627e81e73ecea6f493f9d288a3eb00c4a3a..539406e622724f995e11548710adee2b90d09bd2
100644
--- a/include/gpu/GrXferProcessor.h
+++ b/include/gpu/GrXferProcessor.h
@@ -141,7 +141,12 @@ public:
                                      GrXferBarrierType* outBarrierType) const;
 
     struct BlendInfo {
-        BlendInfo() : fWriteColor(true) {}
+        void reset() {
+            fSrcBlend = kOne_GrBlendCoeff;
+            fDstBlend = kZero_GrBlendCoeff;
+            fBlendConstant = 0;
+            fWriteColor = true;
+        }
 
         GrBlendCoeff fSrcBlend;
         GrBlendCoeff fDstBlend;
@@ -149,7 +154,10 @@ public:
         bool         fWriteColor;
     };
 
-    virtual void getBlendInfo(BlendInfo* blendInfo) const = 0;
+    void getBlendInfo(BlendInfo* blendInfo) const {
+        blendInfo->reset();
+        this->onGetBlendInfo(blendInfo);
+    }
 
     bool willReadDstColor() const { return fWillReadDstColor; }
 
@@ -210,6 +218,13 @@ private:
     virtual void onGetGLProcessorKey(const GrGLCaps& caps,
                                      GrProcessorKeyBuilder* b) const = 0;
 
+    /**
+     * Retrieves the hardware blend state required by this Xfer processor. The
BlendInfo struct
+     * comes initialized to default values, so the Xfer processor only needs to
set the state it
+     * needs. It may not even need to override this method at all.
+     */
+    virtual void onGetBlendInfo(BlendInfo*) const {}
+
     virtual bool onIsEqual(const GrXferProcessor&) const = 0;
 
     bool                    fWillReadDstColor;

[Chris Dalton, 2015-04-23 16:39:49]

The CQ bit was checked by cdalton@nvidia.com

[Chris Dalton, 2015-04-23 16:39:50]

The patchset sent to the CQ was uploaded after l-g-t-m from
markkilgard@gmail.com, bsalomon@google.com
Link to the patchset: https://codereview.chromium.org/1049143002/#ps120001
(title: "rebase")

[commit-bot: I haz the power, 2015-04-23 16:40:13]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1049143002/120001

[commit-bot: I haz the power, 2015-04-23 16:40:27]

Committed patchset #7 (id:120001) as
https://skia.googlesource.com/skia/+/f4f2b442228ca188cfb6b44ee3faa86773bb9db3