Move DstCopy on gpu into the GrXferProcessor.

src/gpu/GrXferProcessor.cpp

Index: src/gpu/GrXferProcessor.cpp
diff --git a/src/gpu/GrXferProcessor.cpp b/src/gpu/GrXferProcessor.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..e2d714208f525129ae9aa8984e8f0bd77dfe88d7
--- /dev/null
+++ b/src/gpu/GrXferProcessor.cpp
@@ -0,0 +1,74 @@
+/*
+ * Copyright 2015 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "GrXferProcessor.h"
+#include "gl/GrGLCaps.h"
+
+// Interpretation of DstReadKey when generating code
+enum {
+    kNoDstRead_DstReadKey           = 0,
+    kYesDstRead_DstReadKeyBit       = 0x1, // Set if we read the dst.
+    kDstCopyRead_DstReadKeyBit      = 0x2, // Set if we use a dst-copy-read.
+    kTopLeftOrigin_DstReadKeyBit    = 0x4, // Set if dst-copy origin is top-left.

[bsalomon, 2015/01/30 14:59:15]

canonicalize on always tl or bl?

[egdaniel, 2015/02/03 16:47:44]

Done.

+};
+
+///////////////////////////////////////////////////////////////////////////////
+
+GrXferProcessor::GrXferProcessor() : fWillReadDstColor(false), fDstReadKey(kNoDstRead_DstReadKey) {
+}
+
+GrXferProcessor::GrXferProcessor(const GrDeviceCoordTexture* dstCopy, int32_t dstReadKey)
+    : fWillReadDstColor(false)
+    , fDstReadKey(dstReadKey) {
+    if (dstCopy && dstCopy->texture()) {
+        SkASSERT(kDstCopyRead_DstReadKeyBit & fDstReadKey);
+        fDstCopy.reset(dstCopy->texture());
+        fOffset = dstCopy->offset();
+        this->addTextureAccess(&fDstCopy);
+    }
+}
+
+void GrXferProcessor::getGLProcessorKey(const GrGLCaps& caps, GrProcessorKeyBuilder* b) const {
+    b->add32(fDstReadKey);
+    this->onGetGLProcessorKey(caps, b);
+}
+
+bool GrXferProcessor::hasDstCopy() const {
+    return (kDstCopyRead_DstReadKeyBit & fDstReadKey);
+}
+
+bool GrXferProcessor::dstCopyIsTopDown() const {
+    return (kTopLeftOrigin_DstReadKeyBit & fDstReadKey);
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+GrXferProcessor* GrXPFactory::createXferProcessor(const GrProcOptInfo& colorPOI,
+                                                  const GrProcOptInfo& coveragePOI,
+                                                  const GrDeviceCoordTexture* dstCopy,
+                                                  const GrDrawTargetCaps& caps) const {
+    int32_t dstReadKey;
+    if (this->willReadDst()) {
+        dstReadKey = kYesDstRead_DstReadKeyBit;
+        if (!caps.dstReadInShaderSupport()) {
+            SkASSERT(dstCopy->texture());
+            dstReadKey |= kDstCopyRead_DstReadKeyBit;
+            if (kTopLeft_GrSurfaceOrigin == dstCopy->texture()->origin()) {
+                dstReadKey |= kTopLeftOrigin_DstReadKeyBit;
+            }
+        }
+    } else {
+        dstReadKey = kNoDstRead_DstReadKey;
+
+    }
+    return this->onCreateXferProcessor(colorPOI, coveragePOI, dstCopy, dstReadKey);
+}
+
+bool GrXPFactory::willNeedDstCopy(const GrDrawTargetCaps& caps) const {
+    return (this->willReadDst() && !caps.dstReadInShaderSupport());
+}
+