| 1 | /* |
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| 2 | * Copyright 2020 Google LLC |
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| 3 | * |
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| 4 | * Use of this source code is governed by a BSD-style license that can be |
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| 5 | * found in the LICENSE file. |
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| 6 | */ |
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| 7 | |
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| 8 | #ifndef SkSLSampleUsage_DEFINED |
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| 9 | #define SkSLSampleUsage_DEFINED |
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| 10 | |
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| 11 | #include "include/core/SkTypes.h" |
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| 12 | |
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| 13 | namespace SkSL { |
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| 14 | |
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| 15 | /** |
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| 16 | * Represents all of the ways that a fragment processor is sampled by its parent. |
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| 17 | */ |
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| 18 | class SampleUsage { |
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| 19 | public: |
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| 20 | enum class Kind { |
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| 21 | // Child is never sampled |
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| 22 | kNone, |
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| 23 | // Child is only sampled at the same coordinates as the parent |
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| 24 | kPassThrough, |
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| 25 | // Child is sampled with a matrix whose value is uniform |
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| 26 | kUniformMatrix, |
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| 27 | // Child is sampled with sk_FragCoord.xy |
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| 28 | kFragCoord, |
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| 29 | // Child is sampled using explicit coordinates |
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| 30 | kExplicit, |
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| 31 | }; |
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| 32 | |
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| 33 | // Make a SampleUsage that corresponds to no sampling of the child at all |
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| 34 | SampleUsage() = default; |
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| 35 | |
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| 36 | SampleUsage(Kind kind, bool hasPerspective) : fKind(kind), fHasPerspective(hasPerspective) { |
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| 37 | if (kind != Kind::kUniformMatrix) { |
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| 38 | SkASSERT(!fHasPerspective); |
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| 39 | } |
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| 40 | } |
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| 41 | |
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| 42 | // Child is sampled with a matrix whose value is uniform. The name is fixed. |
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| 43 | static SampleUsage UniformMatrix(bool hasPerspective) { |
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| 44 | return SampleUsage(Kind::kUniformMatrix, hasPerspective); |
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| 45 | } |
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| 46 | |
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| 47 | static SampleUsage Explicit() { |
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| 48 | return SampleUsage(Kind::kExplicit, false); |
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| 49 | } |
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| 50 | |
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| 51 | static SampleUsage PassThrough() { |
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| 52 | return SampleUsage(Kind::kPassThrough, false); |
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| 53 | } |
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| 54 | |
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| 55 | static SampleUsage FragCoord() { return SampleUsage(Kind::kFragCoord, false); } |
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| 56 | |
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| 57 | bool operator==(const SampleUsage& that) const { |
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| 58 | return fKind == that.fKind && fHasPerspective == that.fHasPerspective; |
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| 59 | } |
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| 60 | |
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| 61 | bool operator!=(const SampleUsage& that) const { return !(*this == that); } |
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| 62 | |
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| 63 | // Arbitrary name used by all uniform sampling matrices |
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| 64 | static const char* MatrixUniformName() { return "matrix" ; } |
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| 65 | |
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| 66 | SampleUsage merge(const SampleUsage& other); |
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| 67 | |
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| 68 | Kind kind() const { return fKind; } |
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| 69 | |
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| 70 | bool hasPerspective() const { return fHasPerspective; } |
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| 71 | |
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| 72 | bool isSampled() const { return fKind != Kind::kNone; } |
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| 73 | bool isPassThrough() const { return fKind == Kind::kPassThrough; } |
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| 74 | bool isExplicit() const { return fKind == Kind::kExplicit; } |
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| 75 | bool isUniformMatrix() const { return fKind == Kind::kUniformMatrix; } |
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| 76 | bool isFragCoord() const { return fKind == Kind::kFragCoord; } |
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| 77 | |
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| 78 | private: |
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| 79 | Kind fKind = Kind::kNone; |
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| 80 | bool fHasPerspective = false; // Only valid if fKind is kUniformMatrix |
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| 81 | }; |
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| 82 | |
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| 83 | } // namespace SkSL |
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| 84 | |
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| 85 | #endif |
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| 86 | |
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