imgui_layer_helpers_internal.h

#pragma once
 
#include <volk.h>
 
#include <map>
#include <vector>
 
namespace pixelbullet::application_layers_internal
{
struct SampledImageTextureKey
{
    VkImageView image_view = VK_NULL_HANDLE;
    VkSampler sampler = VK_NULL_HANDLE;
 
    bool operator<(const SampledImageTextureKey& other) const noexcept
    {
        if (image_view != other.image_view)
        {
            return image_view < other.image_view;
        }
 
        return sampler < other.sampler;
    }
};
 
inline bool IsValidSampledImageTextureKey(const SampledImageTextureKey& key) noexcept
{
    return key.image_view != VK_NULL_HANDLE && key.sampler != VK_NULL_HANDLE;
}
 
template <typename CacheMap, typename CreateFn>
inline VkDescriptorSet GetOrCreateSampledImageTextureDescriptor(CacheMap& cache, const SampledImageTextureKey& key,
                                                                CreateFn&& create_descriptor)
{
    if (!IsValidSampledImageTextureKey(key))
    {
        return VK_NULL_HANDLE;
    }
 
    if (const auto it = cache.find(key); it != cache.end())
    {
        return it->second;
    }
 
    const VkDescriptorSet descriptor_set = create_descriptor(key.sampler, key.image_view);
    if (descriptor_set == VK_NULL_HANDLE)
    {
        return VK_NULL_HANDLE;
    }
 
    cache.emplace(key, descriptor_set);
    return descriptor_set;
}
 
template <typename CacheMap, typename DestroyFn>
inline void ClearSampledImageTextureDescriptors(CacheMap& cache, DestroyFn&& destroy_descriptor)
{
    for (const auto& [key, descriptor_set] : cache)
    {
        destroy_descriptor(descriptor_set);
    }
 
    cache.clear();
}
 
inline bool RequiresTextureCacheRebuild(const std::vector<VkDescriptorSet>& descriptor_sets, const std::vector<VkImageView>& cached_views,
                                        const std::vector<VkSampler>& cached_samplers, const std::vector<VkImageView>& current_views,
                                        const std::vector<VkSampler>& current_samplers) noexcept
{
    if (descriptor_sets.size() != current_views.size() || current_views.size() != current_samplers.size() ||
        cached_views.size() != current_views.size() || cached_samplers.size() != current_samplers.size())
    {
        return true;
    }
 
    for (std::size_t image_index = 0; image_index < current_views.size(); ++image_index)
    {
        if (cached_views[image_index] != current_views[image_index] || cached_samplers[image_index] != current_samplers[image_index])
        {
            return true;
        }
    }
 
    return false;
}
} // namespace pixelbullet::application_layers_internal