////////////////////////////////
//~ Transient buffer types

Struct(GPU_SubmittedResourceNode)
{
    GPU_SubmittedResourceNode *next;

    /* Set during transient upload */
    GPU_Resource *resource;

    /* Set during transient reset */
    i64 fence_target;  /* Once the buffer's queue reaches the target, the resource can be freed or reused */
};

Struct(GPU_TransientBuffer)
{
    GPU_QueueKind queue_kind;
    u32 element_size;

    GPU_SubmittedResourceNode *uploaded;
    GPU_SubmittedResourceNode *first_submitted;
    GPU_SubmittedResourceNode *last_submitted;
    u32 max_in_flight;
};


////////////////////////////////
//~ State types

Struct(GPU_SharedUtilState)
{
    /* Common shared resources */
    GPU_Resource *pt_sampler;
    GPU_Resource *quad_indices;
    GPU_Resource *noise;

    /* Transient buffer pool */
    Mutex submitted_transient_buffers_mutex;
    GPU_SubmittedResourceNode *first_free_submitted_transient_buffer;
} extern GPU_shared_util_state;

////////////////////////////////
//~ Startup

void GPU_StartupUtils(void);

////////////////////////////////
//~ Common resource helpers

GPU_Resource *GPU_GetCommonPointSampler(void);
GPU_Resource *GPU_GetCommonQuadIndices(void);
GPU_Resource *GPU_GetCommonNoise(void);

////////////////////////////////
//~ Transient buffer operations

GPU_TransientBuffer GPU_AcquireTransientBuffer(GPU_QueueKind queue_kind, u32 element_size);
void GPU_ReleaseTransientBuffer(GPU_TransientBuffer *tbuff);

GPU_Resource *GPU_UploadTransientBuffer(GPU_TransientBuffer *tbuff, void *src, u64 src_size);
GPU_Resource *GPU_UploadTransientBufferFromArena(GPU_TransientBuffer *tbuff, Arena *arena);
void GPU_ResetTransientBuffer(GPU_TransientBuffer *tbuff, i64 queue_fence_target);