gfx_pipeline_SDF_vulkan.hpp

// Copyright Take Vos 2020-2021.
// Distributed under the Boost Software License, Version 1.0.
// (See accompanying file LICENSE_1_0.txt or copy at https://www.boost.org/LICENSE_1_0.txt)
 
#pragma once
 
#include "gfx_pipeline_vulkan.hpp"
#include "../container/module.hpp"
#include "../font/font.hpp"
#include "../macros.hpp"
#include <vma/vk_mem_alloc.h>
#include <span>
 
namespace hi { inline namespace v1 {

class gfx_pipeline_SDF : public gfx_pipeline {
public:
    struct vertex {
        sfloat_rgb32 position;

        sfloat_rgba32 clippingRectangle;

        sfloat_rgb32 textureCoord;

        sfloat_rgba16 color;
 
        vertex(point3 position, aarectangle clippingRectangle, point3 textureCoord, hi::color color) noexcept :
            position(position), clippingRectangle(clippingRectangle), textureCoord(textureCoord), color(color)
        {
        }
 
        static vk::VertexInputBindingDescription inputBindingDescription()
        {
            return {0, sizeof(vertex), vk::VertexInputRate::eVertex};
        }
 
        static std::vector<vk::VertexInputAttributeDescription> inputAttributeDescriptions()
        {
            return {
                {0, 0, vk::Format::eR32G32B32Sfloat, offsetof(vertex, position)},
                {1, 0, vk::Format::eR32G32B32A32Sfloat, offsetof(vertex, clippingRectangle)},
                {2, 0, vk::Format::eR32G32B32Sfloat, offsetof(vertex, textureCoord)},
                {3, 0, vk::Format::eR16G16B16A16Sfloat, offsetof(vertex, color)}};
        }
    };
 
    struct push_constants {
        sfloat_rg32 window_extent = extent2{0.0, 0.0};
        sfloat_rg32 viewport_scale = scale2{0.0, 0.0};
        sfloat_rg32 red_subpixel_offset = vector2{0.0, 0.0};
        sfloat_rg32 blue_subpixel_offset = vector2{0.0, 0.0};
        VkBool32 has_subpixels = false;
 
        static std::vector<vk::PushConstantRange> pushConstantRanges()
        {
            return {{vk::ShaderStageFlagBits::eVertex | vk::ShaderStageFlagBits::eFragment, 0, sizeof(push_constants)}};
        }
    };
 
    struct specialization_constants {
        float sdf_r8maxDistance;
        float atlasImageWidth;
 
        [[nodiscard]] vk::SpecializationInfo specializationInfo(std::vector<vk::SpecializationMapEntry>& entries) const noexcept
        {
            return {narrow_cast<uint32_t>(ssize(entries)), entries.data(), sizeof(specialization_constants), this};
        }
 
        [[nodiscard]] static std::vector<vk::SpecializationMapEntry> specializationConstantMapEntries() noexcept
        {
            return {
                {0, offsetof(specialization_constants, sdf_r8maxDistance), sizeof(sdf_r8maxDistance)},
                {1, offsetof(specialization_constants, atlasImageWidth), sizeof(atlasImageWidth)},
            };
        }
    };
 
    struct texture_map {
        vk::Image image;
        VmaAllocation allocation = {};
        vk::ImageView view;
        hi::pixmap_span<sdf_r8> pixmap;
        vk::ImageLayout layout = vk::ImageLayout::eUndefined;
 
        void transitionLayout(const gfx_device& device, vk::Format format, vk::ImageLayout nextLayout);
    };
 
    struct device_shared {
        // Studies in China have shown that literate individuals know and use between 3,000 and 4,000 characters.
        // Handle up to 7 * 7 * 128 == 6321 characters with a 16 x 1024 x 1024, 16 x 1 MByte
        //
        // For latin characters we can store about 7 * 12 == 84 characters in a single image, which is enough
        // for the full alpha numeric range that an application will use.
 
        constexpr static int atlasImageWidth = 256; // 7-12 characters, of 34 pixels wide.
        constexpr static int atlasImageHeight = 256; // 7 characters, of 34 pixels height.
        static_assert(atlasImageWidth == atlasImageHeight, "needed for fwidth(textureCoord)");
 
        constexpr static int atlasMaximumNrImages = 128; // 128 * 49 characters.
        constexpr static int stagingImageWidth = 64; // One 'em' is 28 pixels, with edges 34 pixels.
        constexpr static int stagingImageHeight = 64;
 
        constexpr static float atlasTextureCoordinateMultiplier = 1.0f / atlasImageWidth;
        constexpr static float drawfontSize = 28.0f;
        constexpr static float drawBorder = sdf_r8::max_distance;
        constexpr static float scaledDrawBorder = drawBorder / drawfontSize;
 
        gfx_device const& device;
 
        vk::ShaderModule vertexShaderModule;
        vk::ShaderModule fragmentShaderModule;
 
        specialization_constants specializationConstants;
        std::vector<vk::SpecializationMapEntry> fragmentShaderSpecializationMapEntries;
        vk::SpecializationInfo fragmentShaderSpecializationInfo;
        std::vector<vk::PipelineShaderStageCreateInfo> shaderStages;
 
        texture_map stagingTexture;
        std::vector<texture_map> atlasTextures;
 
        std::array<vk::DescriptorImageInfo, atlasMaximumNrImages> atlasDescriptorImageInfos;
        vk::Sampler atlasSampler;
        vk::DescriptorImageInfo atlasSamplerDescriptorImageInfo;
 
        point3 atlas_allocation_position = {};
        int atlasAllocationMaxHeight = 0;
 
        device_shared(gfx_device const& device);
        ~device_shared();
 
        device_shared(device_shared const&) = delete;
        device_shared& operator=(device_shared const&) = delete;
        device_shared(device_shared&&) = delete;
        device_shared& operator=(device_shared&&) = delete;

        void destroy(gfx_device const *vulkanDevice);

        [[nodiscard]] glyph_atlas_info allocate_rect(extent2 draw_extent, scale2 draw_scale) noexcept;
 
        void drawInCommandBuffer(vk::CommandBuffer const& commandBuffer);

        void uploadStagingPixmapToAtlas(glyph_atlas_info const& location);

        void prepareStagingPixmapForDrawing();

        void prepare_atlas_for_rendering();

        bool place_vertices(
            vector_span<vertex>& vertices,
            aarectangle const& clipping_rectangle,
            quad const& box,
            hi::font const& font,
            glyph_id glyph,
            quad_color colors) noexcept;
 
    private:
        void buildShaders();
        void teardownShaders(gfx_device const *vulkanDevice);
        void addAtlasImage();
        void buildAtlas();
        void teardownAtlas(gfx_device const *vulkanDevice);
        void add_glyph_to_atlas(hi::font const& font, glyph_id glyph, glyph_atlas_info& info) noexcept;

        hi_force_inline std::pair<glyph_atlas_info const *, bool>
        get_glyph_from_atlas(hi::font const& font, glyph_id glyph) noexcept
        {
            auto& info = font.atlas_info(glyph);
 
            if (info) [[likely]] {
                return {&info, false};
 
            } else {
                add_glyph_to_atlas(font, glyph, info);
                return {&info, true};
            }
        }
    };
 
    vector_span<vertex> vertexBufferData;
 
    ~gfx_pipeline_SDF() = default;
    gfx_pipeline_SDF(const gfx_pipeline_SDF&) = delete;
    gfx_pipeline_SDF& operator=(const gfx_pipeline_SDF&) = delete;
    gfx_pipeline_SDF(gfx_pipeline_SDF&&) = delete;
    gfx_pipeline_SDF& operator=(gfx_pipeline_SDF&&) = delete;
 
    gfx_pipeline_SDF(gfx_surface *surface) : gfx_pipeline(surface) {}
 
    void draw_in_command_buffer(vk::CommandBuffer commandBuffer, draw_context const& context) override;
 
private:
    push_constants pushConstants;
    int numberOfAtlasImagesInDescriptor = 0;
 
    vk::Buffer vertexBuffer;
    VmaAllocation vertexBufferAllocation;
 
    [[nodiscard]] std::vector<vk::PipelineShaderStageCreateInfo> createShaderStages() const override;
    [[nodiscard]] std::vector<vk::DescriptorSetLayoutBinding> createDescriptorSetLayoutBindings() const override;
    [[nodiscard]] std::vector<vk::WriteDescriptorSet> createWriteDescriptorSet() const override;
    [[nodiscard]] size_t getDescriptorSetVersion() const override;
    [[nodiscard]] std::vector<vk::PushConstantRange> createPushConstantRanges() const override;
    [[nodiscard]] vk::VertexInputBindingDescription createVertexInputBindingDescription() const override;
    [[nodiscard]] std::vector<vk::VertexInputAttributeDescription> createVertexInputAttributeDescriptions() const override;
    [[nodiscard]] std::vector<vk::PipelineColorBlendAttachmentState> getPipelineColorBlendAttachmentStates() const override;
 
private:
    void build_vertex_buffers() override;
    void teardown_vertex_buffers() override;
};
 
}} // namespace hi