PipelineResourceSignatureWebGPUImpl.hpp

/*
 *  Copyright 2023-2026 Diligent Graphics LLC
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
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 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
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 *
 *  In no event and under no legal theory, whether in tort (including negligence),
 *  contract, or otherwise, unless required by applicable law (such as deliberate
 *  and grossly negligent acts) or agreed to in writing, shall any Contributor be
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 */

#pragma once

/// \file
/// Declaration of Diligent::PipelineResourceSignatureWebGPUImpl class

#include <array>
#include <memory>

#include "EngineWebGPUImplTraits.hpp"
#include "PipelineResourceSignatureBase.hpp"

// ShaderResourceCacheWebGPU, ShaderVariableManagerWebGPU, and ShaderResourceBindingWebGPUImpl
// are required by PipelineResourceSignatureBase
#include "ShaderResourceCacheWebGPU.hpp"
#include "ShaderVariableManagerWebGPU.hpp"
#include "ShaderResourceBindingWebGPUImpl.hpp"

#include "PipelineResourceAttribsWebGPU.hpp"
#include "WebGPUObjectWrappers.hpp"
#include "SamplerWebGPUImpl.hpp"

namespace Diligent
{

struct WGSLShaderResourceAttribs;
class DeviceContextWebGPUImpl;
class BufferWebGPUImpl;

struct ImmutableSamplerAttribsWebGPU
{
public:
    Uint32 BindGroup    = ~0u;
    Uint32 BindingIndex = ~0u;
    Uint32 CacheOffset  = 0; // Offset in the SRB resource cache
    Uint32 ArraySize    = 1;

    ImmutableSamplerAttribsWebGPU() noexcept {}

    bool IsAllocated() const { return BindingIndex != ~0u; }
};
ASSERT_SIZEOF(ImmutableSamplerAttribsWebGPU, 16, "The struct is used in serialization and must be tightly packed");

/// Inline constant buffer attributes for WebGPU backend.
/// Similar to Vulkan's InlineConstantBufferAttribsVk.
struct InlineConstantBufferAttribsWebGPU
{
    Uint32 BindGroup    = 0; // Bind group index (similar to Vulkan's DescrSet)
    Uint32 CacheOffset  = 0; // Offset within bind group (similar to Vulkan's SRBCacheOffset)
    Uint32 NumConstants = 0; // Number of 32-bit constants (= ResDesc.ArraySize)

    // Shared dynamic UBO created in the Signature.
    // All SRBs reference this same buffer to reduce memory usage.
    RefCntAutoPtr<BufferWebGPUImpl> pBuffer;
};

struct PipelineResourceSignatureInternalDataWebGPU : PipelineResourceSignatureInternalData<PipelineResourceAttribsWebGPU, ImmutableSamplerAttribsWebGPU>
{
    PipelineResourceSignatureInternalDataWebGPU() noexcept = default;

    explicit PipelineResourceSignatureInternalDataWebGPU(const PipelineResourceSignatureInternalData& InternalData) noexcept :
        PipelineResourceSignatureInternalData{InternalData}
    {}
};

/// Implementation of the Diligent::PipelineResourceSignatureWebGPUImpl class
class PipelineResourceSignatureWebGPUImpl final : public PipelineResourceSignatureBase<EngineWebGPUImplTraits>
{
public:
    using TPipelineResourceSignatureBase = PipelineResourceSignatureBase<EngineWebGPUImplTraits>;

    using ResourceAttribs = TPipelineResourceSignatureBase::PipelineResourceAttribsType;

    // Bind group identifier (this is not the bind group index in the layout!)
    enum BIND_GROUP_ID : size_t
    {
        // Static/mutable variables bind group id
        BIND_GROUP_ID_STATIC_MUTABLE = 0,

        // Dynamic variables bind group id
        BIND_GROUP_ID_DYNAMIC,

        BIND_GROUP_ID_NUM_GROUPS
    };

    // Static/mutable and dynamic bind groups
    static constexpr Uint32 MAX_BIND_GROUPS = BIND_GROUP_ID_NUM_GROUPS;

    static_assert(ResourceAttribs::MaxBindGroups >= MAX_BIND_GROUPS, "Not enough bits to store bind group index");

    PipelineResourceSignatureWebGPUImpl(IReferenceCounters*                  pRefCounters,
                                        RenderDeviceWebGPUImpl*              pDevice,
                                        const PipelineResourceSignatureDesc& Desc,
                                        SHADER_TYPE                          ShaderStages      = SHADER_TYPE_UNKNOWN,
                                        bool                                 bIsDeviceInternal = false);

    PipelineResourceSignatureWebGPUImpl(IReferenceCounters*                                pRefCounters,
                                        RenderDeviceWebGPUImpl*                            pDevice,
                                        const PipelineResourceSignatureDesc&               Desc,
                                        const PipelineResourceSignatureInternalDataWebGPU& InternalData);

    ~PipelineResourceSignatureWebGPUImpl();

    Uint32 GetNumBindGroups() const
    {
        static_assert(BIND_GROUP_ID_NUM_GROUPS == 2, "Please update this method with new bind group id");
        return (HasBindGroup(BIND_GROUP_ID_STATIC_MUTABLE) ? 1 : 0) + (HasBindGroup(BIND_GROUP_ID_DYNAMIC) ? 1 : 0);
    }

    WGPUBindGroupLayout GetWGPUBindGroupLayout(BIND_GROUP_ID GroupId);

    bool   HasBindGroup(BIND_GROUP_ID GroupId) const { return m_BindGroupSizes[GroupId] != ~0u && m_BindGroupSizes[GroupId] > 0; }
    Uint32 GetBindGroupSize(BIND_GROUP_ID GroupId) const { return m_BindGroupSizes[GroupId]; }
    Uint32 GetDynamicOffsetCount(BIND_GROUP_ID GroupId) const { return m_DynamicOffsetCounts[GroupId]; }
    Uint32 GetDynamicUniformBufferCount() const { return m_DynamicUniformBufferCount; }
    Uint32 GetDynamicStorageBufferCount() const { return m_DynamicStorageBufferCount; }

    void InitSRBResourceCache(ShaderResourceCacheWebGPU& ResourceCache);

    void CopyStaticResources(ShaderResourceCacheWebGPU& ResourceCache) const;
    // Make the base class method visible
    using TPipelineResourceSignatureBase::CopyStaticResources;

    // Updates inline constant buffers before draw/dispatch.
    // Must be called when SRB is stale or DRAW_FLAG_INLINE_CONSTANTS_INTACT is not set.
    void UpdateInlineConstantBuffers(const ShaderResourceCacheWebGPU& ResourceCache,
                                     DeviceContextWebGPUImpl*         pCtx) const;

    // Returns the bind group index in the resource cache
    template <BIND_GROUP_ID GroupId>
    Uint32 GetBindGroupIndex() const;

#ifdef DILIGENT_DEVELOPMENT
    /// Verifies committed resource using the WGSL resource attributes from the PSO.
    bool DvpValidateCommittedResource(const DeviceContextWebGPUImpl*   pDeviceCtx,
                                      const WGSLShaderResourceAttribs& WGSLAttribs,
                                      Uint32                           ResIndex,
                                      const ShaderResourceCacheWebGPU& ResourceCache,
                                      const char*                      ShaderName,
                                      const char*                      PSOName) const;
    bool DvpValidateImmutableSampler(const WGSLShaderResourceAttribs& WGSLAttribs,
                                     Uint32                           ImtblSamIndex,
                                     const ShaderResourceCacheWebGPU& ResourceCache,
                                     const char*                      ShaderName,
                                     const char*                      PSOName) const;
#endif

private:
    void CreateBindGroupLayouts(bool IsSerialized);

    // Resource cache group identifier
    enum CACHE_GROUP : size_t
    {
        CACHE_GROUP_DYN_UB = 0,         // Uniform buffer with dynamic offset
        CACHE_GROUP_DYN_SB,             // Storage buffer with dynamic offset
        CACHE_GROUP_OTHER,              // Other resource type
        CACHE_GROUP_COUNT_PER_VAR_TYPE, // Cache group count per shader variable type

        CACHE_GROUP_DYN_UB_STAT_VAR = CACHE_GROUP_DYN_UB, // Uniform buffer with dynamic offset, static variable
        CACHE_GROUP_DYN_SB_STAT_VAR = CACHE_GROUP_DYN_SB, // Storage buffer with dynamic offset, static variable
        CACHE_GROUP_OTHER_STAT_VAR  = CACHE_GROUP_OTHER,  // Other resource type, static variable

        CACHE_GROUP_DYN_UB_DYN_VAR, // Uniform buffer with dynamic offset, dynamic variable
        CACHE_GROUP_DYN_SB_DYN_VAR, // Storage buffer with dynamic offset, dynamic variable
        CACHE_GROUP_OTHER_DYN_VAR,  // Other resource type, dynamic variable

        CACHE_GROUP_COUNT
    };
    static_assert(CACHE_GROUP_COUNT == CACHE_GROUP_COUNT_PER_VAR_TYPE * MAX_BIND_GROUPS, "Inconsistent cache group count");

    using CacheOffsetsType = std::array<Uint32, CACHE_GROUP_COUNT>; // [Dynamic UBs, Dynamic SBs, Other] x [bind group]
    using BindingCountType = std::array<Uint32, CACHE_GROUP_COUNT>; // [Dynamic UBs, Dynamic SBs, Other] x [bind group]

    static inline CACHE_GROUP   GetResourceCacheGroup(const PipelineResourceDesc& Res);
    static inline BIND_GROUP_ID VarTypeToBindGroupId(SHADER_RESOURCE_VARIABLE_TYPE VarType);

private:
    struct WGPUBindGroupLayoutsCreateInfo;
    std::unique_ptr<WGPUBindGroupLayoutsCreateInfo> m_BindGroupLayoutsCreateInfo;

    std::array<WebGPUBindGroupLayoutWrapper, BIND_GROUP_ID_NUM_GROUPS> m_wgpuBindGroupLayouts;

    // Bind group sizes indexed by the group index in the layout (not BIND_GROUP_ID!)
    std::array<Uint32, MAX_BIND_GROUPS> m_BindGroupSizes = {~0U, ~0U};

    // The total number of uniform and storage buffers with dynamic offsets in each bind group.
    std::array<Uint32, MAX_BIND_GROUPS> m_DynamicOffsetCounts = {0, 0};

    // The total number of uniform buffers with dynamic offsets in both bind groups,
    // accounting for array size.
    Uint16 m_DynamicUniformBufferCount = 0;
    // The total number storage buffers with dynamic offsets in both bind groups,
    // accounting for array size.
    Uint16 m_DynamicStorageBufferCount = 0;
};

template <> Uint32 PipelineResourceSignatureWebGPUImpl::GetBindGroupIndex<PipelineResourceSignatureWebGPUImpl::BIND_GROUP_ID_STATIC_MUTABLE>() const;
template <> Uint32 PipelineResourceSignatureWebGPUImpl::GetBindGroupIndex<PipelineResourceSignatureWebGPUImpl::BIND_GROUP_ID_DYNAMIC>() const;

} // namespace Diligent