src/dawn/native/BindingInfo.h

// Copyright 2020 The Dawn & Tint Authors
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#ifndef SRC_DAWN_NATIVE_BINDINGINFO_H_
#define SRC_DAWN_NATIVE_BINDINGINFO_H_

#include <cstdint>
#include <variant>
#include <vector>

#include "dawn/common/Constants.h"
#include "dawn/common/Ref.h"
#include "dawn/common/ityp_array.h"
#include "dawn/native/Error.h"
#include "dawn/native/Format.h"
#include "dawn/native/IntegerTypes.h"
#include "dawn/native/PerStage.h"

#include "dawn/native/dawn_platform.h"

namespace dawn::native {

// Not a real WebGPU limit, but used to optimize parts of Dawn which expect valid usage of the
// API. There should never be more bindings than the max per stage, for each stage.
static constexpr uint32_t kMaxBindingsPerPipelineLayout =
    3 * (kMaxSampledTexturesPerShaderStage + kMaxSamplersPerShaderStage +
         kMaxStorageBuffersPerShaderStage + kMaxStorageTexturesPerShaderStage +
         kMaxUniformBuffersPerShaderStage);

static constexpr BindingIndex kMaxBindingsPerPipelineLayoutTyped =
    BindingIndex(kMaxBindingsPerPipelineLayout);

// TODO(enga): Figure out a good number for this.
static constexpr uint32_t kMaxOptimalBindingsPerGroup = 32;

enum class BindingInfoType {
    Buffer,
    Sampler,
    Texture,
    StorageTexture,
    ExternalTexture,
    StaticSampler
};

struct StaticSamplerHolderBindingLayout {
    Ref<SamplerBase> sampler;
};

// A mirror of wgpu::BufferBindingLayout for use inside dawn::native.
struct BufferBindingInfo {
    BufferBindingInfo();
    explicit BufferBindingInfo(const BufferBindingLayout& apiLayout);

    wgpu::BufferBindingType type;
    uint64_t minBindingSize;

    // Always false in shader reflection.
    bool hasDynamicOffset = false;
};

// A mirror of wgpu::TextureBindingLayout for use inside dawn::native.
struct TextureBindingInfo {
    TextureBindingInfo();
    explicit TextureBindingInfo(const TextureBindingLayout& apiLayout);

    // For shader reflection UnfilterableFloat is never used and the sample type is Float for any
    // texture_Nd<f32>.
    wgpu::TextureSampleType sampleType;
    wgpu::TextureViewDimension viewDimension;
    bool multisampled;
};

// A mirror of wgpu::StorageTextureBindingLayout for use inside dawn::native.
struct StorageTextureBindingInfo {
    StorageTextureBindingInfo();
    explicit StorageTextureBindingInfo(const StorageTextureBindingLayout& apiLayout);

    wgpu::TextureFormat format;
    wgpu::TextureViewDimension viewDimension;
    wgpu::StorageTextureAccess access;
};

// A mirror of wgpu::ExternalTextureBindingLayout for use inside dawn::native.
struct ExternalTextureBindingInfo {};

struct BindingInfo {
    BindingNumber binding;
    wgpu::ShaderStage visibility;

    std::variant<BufferBindingInfo,
                 SamplerBindingLayout,
                 TextureBindingInfo,
                 StorageTextureBindingInfo,
                 StaticSamplerHolderBindingLayout>
        bindingLayout;
};

BindingInfoType GetBindingInfoType(const BindingInfo& bindingInfo);

struct BindingSlot {
    BindGroupIndex group;
    BindingNumber binding;
};

struct PerStageBindingCounts {
    uint32_t sampledTextureCount;
    uint32_t samplerCount;
    uint32_t storageBufferCount;
    uint32_t storageTextureCount;
    uint32_t uniformBufferCount;
    uint32_t externalTextureCount;
    uint32_t staticSamplerCount;
};

struct BindingCounts {
    uint32_t totalCount;
    uint32_t bufferCount;
    uint32_t unverifiedBufferCount;  // Buffers with minimum buffer size unspecified
    uint32_t dynamicUniformBufferCount;
    uint32_t dynamicStorageBufferCount;
    uint32_t staticSamplerCount;
    PerStage<PerStageBindingCounts> perStage;
};

struct CombinedLimits;

void IncrementBindingCounts(BindingCounts* bindingCounts,
                            const UnpackedPtr<BindGroupLayoutEntry>& entry);
void AccumulateBindingCounts(BindingCounts* bindingCounts, const BindingCounts& rhs);
MaybeError ValidateBindingCounts(const CombinedLimits& limits, const BindingCounts& bindingCounts);

// For buffer size validation
using RequiredBufferSizes = PerBindGroup<std::vector<uint64_t>>;

}  // namespace dawn::native

#endif  // SRC_DAWN_NATIVE_BINDINGINFO_H_