Make it possible to query GrXPFactory for dst texture without GrPipelineAnalysis.

Change-Id: I8c140eb4e3e5f2d21ecbf8f8f3c8533dc7f50e7c
Reviewed-on: https://skia-review.googlesource.com/7316
Commit-Queue: Brian Salomon <bsalomon@google.com>
Reviewed-by: Greg Daniel <egdaniel@google.com>

3 files changed, 25 insertions, 8 deletions

diff --git a/include/gpu/GrXferProcessor.h b/include/gpu/GrXferProcessor.h
index 17cd2c7bf3..353c682f96 100644
--- a/include/gpu/GrXferProcessor.h
+++ b/include/gpu/GrXferProcessor.h
@@ -307,6 +307,16 @@ GR_MAKE_BITFIELD_OPS(GrXferProcessor::OptFlags);
 class GrXPFactory {
 public:
     typedef GrXferProcessor::DstTexture DstTexture;
+
+    /** Describes known properties of a draw's color input to the GrXferProcessor. */
+    enum class ColorType { kUnknown, kOpaqueConstant, kConstant, kOpaque };
+
+    /**
+     * Indicates whether a draw's coverage input to the GrXferProcessor is solid, single channel
+     * or LCD (four channel coverage).
+     */
+    enum class CoverageType { kNone, kSingleChannel, kLCD };
+
     GrXferProcessor* createXferProcessor(const GrPipelineAnalysis&,
                                          bool hasMixedSamples,
                                          const DstTexture*,
@@ -329,24 +339,33 @@ public:
     virtual void getInvariantBlendedColor(const GrProcOptInfo& colorPOI,
                                           InvariantBlendedColor*) const = 0;
 
-    bool willNeedDstTexture(const GrCaps& caps, const GrPipelineAnalysis&) const;
+    bool willNeedDstTexture(const GrCaps& caps, const GrPipelineAnalysis& analysis) const;
 
 protected:
     constexpr GrXPFactory() {}
 
+    static bool ColorTypeIsOpaque(ColorType type) {
+        return ColorType::kOpaqueConstant == type || ColorType::kOpaque == type;
+    }
+
+    static bool ColorTypeIsConstant(ColorType type) {
+        return ColorType::kOpaqueConstant == type || ColorType::kConstant == type;
+    }
+
 private:
     virtual GrXferProcessor* onCreateXferProcessor(const GrCaps& caps,
                                                    const GrPipelineAnalysis&,
                                                    bool hasMixedSamples,
                                                    const DstTexture*) const = 0;
 
-    bool willReadDstColor(const GrCaps&, const GrPipelineAnalysis&) const;
+    bool willReadDstColor(const GrCaps& caps, const GrPipelineAnalysis& analysis) const;
 
     /**
      *  Returns true if the XP generated by this factory will explicitly read dst in the fragment
-     *  shader.
+     *  shader. This will not be called for draws that read from PLS since the dst color is always
+     *  available in such draws.
      */
-    virtual bool onWillReadDstColor(const GrCaps&, const GrPipelineAnalysis&) const = 0;
+    virtual bool willReadDstColor(const GrCaps&, ColorType, CoverageType) const = 0;
 };
 #if defined(__GNUC__) || defined(__clang)
 #pragma GCC diagnostic pop
diff --git a/include/gpu/effects/GrCoverageSetOpXP.h b/include/gpu/effects/GrCoverageSetOpXP.h
index ca71abc4e0..385cad865e 100644
--- a/include/gpu/effects/GrCoverageSetOpXP.h
+++ b/include/gpu/effects/GrCoverageSetOpXP.h
@@ -40,9 +40,7 @@ private:
                                            bool hasMixedSamples,
                                            const DstTexture*) const override;
 
-    bool onWillReadDstColor(const GrCaps&, const GrPipelineAnalysis&) const override {
-        return false;
-    }
+    bool willReadDstColor(const GrCaps&, ColorType, CoverageType) const override { return false; }
 
     GR_DECLARE_XP_FACTORY_TEST;
 
diff --git a/include/gpu/effects/GrPorterDuffXferProcessor.h b/include/gpu/effects/GrPorterDuffXferProcessor.h
index ca14275926..028cac65c8 100644
--- a/include/gpu/effects/GrPorterDuffXferProcessor.h
+++ b/include/gpu/effects/GrPorterDuffXferProcessor.h
@@ -63,7 +63,7 @@ private:
                                            bool hasMixedSamples,
                                            const DstTexture*) const override;
 
-    bool onWillReadDstColor(const GrCaps&, const GrPipelineAnalysis&) const override;
+    bool willReadDstColor(const GrCaps&, ColorType, CoverageType) const override;
 
     GR_DECLARE_XP_FACTORY_TEST;
     static void TestGetXPOutputTypes(const GrXferProcessor*, int* outPrimary, int* outSecondary);