1 files changed, 89 insertions, 0 deletions
diff --git a/src/deps/skia/include/private/SkSLSampleUsage.h b/src/deps/skia/include/private/SkSLSampleUsage.h
new file mode 100644
index 000000000..a8d67a025
--- /dev/null
+++ b/src/deps/skia/include/private/SkSLSampleUsage.h
@@ -0,0 +1,89 @@
+/*
+ * Copyright 2020 Google LLC
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkSLSampleUsage_DEFINED
+#define SkSLSampleUsage_DEFINED
+
+#include "include/core/SkTypes.h"
+
+#include <string>
+
+namespace SkSL {
+
+/**
+ * Represents all of the ways that a fragment processor is sampled by its parent.
+ */
+class SampleUsage {
+public:
+    enum class Kind {
+        // Child is never sampled
+        kNone,
+        // Child is only sampled at the same coordinates as the parent
+        kPassThrough,
+        // Child is sampled with a matrix whose value is uniform
+        kUniformMatrix,
+        // Child is sampled with sk_FragCoord.xy
+        kFragCoord,
+        // Child is sampled using explicit coordinates
+        kExplicit,
+    };
+
+    // Make a SampleUsage that corresponds to no sampling of the child at all
+    SampleUsage() = default;
+
+    SampleUsage(Kind kind, bool hasPerspective) : fKind(kind), fHasPerspective(hasPerspective) {
+        if (kind != Kind::kUniformMatrix) {
+            SkASSERT(!fHasPerspective);
+        }
+    }
+
+    // Child is sampled with a matrix whose value is uniform. The name is fixed.
+    static SampleUsage UniformMatrix(bool hasPerspective) {
+        return SampleUsage(Kind::kUniformMatrix, hasPerspective);
+    }
+
+    static SampleUsage Explicit() {
+        return SampleUsage(Kind::kExplicit, false);
+    }
+
+    static SampleUsage PassThrough() {
+        return SampleUsage(Kind::kPassThrough, false);
+    }
+
+    static SampleUsage FragCoord() { return SampleUsage(Kind::kFragCoord, false); }
+
+    bool operator==(const SampleUsage& that) const {
+        return fKind == that.fKind && fHasPerspective == that.fHasPerspective;
+    }
+
+    bool operator!=(const SampleUsage& that) const { return !(*this == that); }
+
+    // Arbitrary name used by all uniform sampling matrices
+    static const char* MatrixUniformName() { return "matrix"; }
+
+    SampleUsage merge(const SampleUsage& other);
+
+    Kind kind() const { return fKind; }
+
+    bool hasPerspective() const { return fHasPerspective; }
+
+    bool isSampled()       const { return fKind != Kind::kNone; }
+    bool isPassThrough()   const { return fKind == Kind::kPassThrough; }
+    bool isExplicit()      const { return fKind == Kind::kExplicit; }
+    bool isUniformMatrix() const { return fKind == Kind::kUniformMatrix; }
+    bool isFragCoord()     const { return fKind == Kind::kFragCoord; }
+
+    std::string constructor() const;
+
+private:
+    Kind fKind = Kind::kNone;
+    bool fHasPerspective = false;  // Only valid if fKind is kUniformMatrix
+};
+
+}  // namespace SkSL
+
+#endif