Device.h

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/* Copyright (C) 2023 Wildfire Games.
 * This file is part of 0 A.D.
 *
 * 0 A.D. is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 *
 * 0 A.D. is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with 0 A.D.  If not, see <http://www.gnu.org/licenses/>.
 */

#ifndef INCLUDED_RENDERER_BACKEND_GL_DEVICE
#define INCLUDED_RENDERER_BACKEND_GL_DEVICE

#include "renderer/backend/Format.h"
#include "renderer/backend/gl/Buffer.h"
#include "renderer/backend/gl/DeviceForward.h"
#include "renderer/backend/gl/Framebuffer.h"
#include "renderer/backend/gl/ShaderProgram.h"
#include "renderer/backend/gl/Texture.h"
#include "renderer/backend/IDevice.h"
#include "scriptinterface/ScriptForward.h"

#include <memory>
#include <string>
#include <tuple>
#include <unordered_map>
#include <vector>

typedef struct SDL_Window SDL_Window;
typedef void* SDL_GLContext;

namespace Renderer
{

namespace Backend
{

namespace GL
{

class CDeviceCommandContext;

class CDevice final : public IDevice
{
public:
    ~CDevice() override;

    /**
     * Creates the GL device and the GL context for the window if it presents.
     */
    static std::unique_ptr<IDevice> Create(SDL_Window* window, const bool arb);

    Backend GetBackend() const override { return m_ARB ? Backend::GL_ARB : Backend::GL; }

    const std::string& GetName() const override { return m_Name; }
    const std::string& GetVersion() const override { return m_Version; }
    const std::string& GetDriverInformation() const override { return m_DriverInformation; }
    const std::vector<std::string>& GetExtensions() const override { return m_Extensions; }

    void Report(const ScriptRequest& rq, JS::HandleValue settings) override;

    std::unique_ptr<IDeviceCommandContext> CreateCommandContext() override;

    std::unique_ptr<IGraphicsPipelineState> CreateGraphicsPipelineState(
        const SGraphicsPipelineStateDesc& pipelineStateDesc) override;

    std::unique_ptr<IVertexInputLayout> CreateVertexInputLayout(
        const PS::span<const SVertexAttributeFormat> attributes) override;

    CDeviceCommandContext* GetActiveCommandContext() { return m_ActiveCommandContext; }

    std::unique_ptr<ITexture> CreateTexture(
        const char* name, const ITexture::Type type, const uint32_t usage,
        const Format format, const uint32_t width, const uint32_t height,
        const Sampler::Desc& defaultSamplerDesc, const uint32_t MIPLevelCount, const uint32_t sampleCount) override;

    std::unique_ptr<ITexture> CreateTexture2D(
        const char* name, const uint32_t usage,
        const Format format, const uint32_t width, const uint32_t height,
        const Sampler::Desc& defaultSamplerDesc, const uint32_t MIPLevelCount = 1, const uint32_t sampleCount = 1) override;

    std::unique_ptr<IFramebuffer> CreateFramebuffer(
        const char* name, SColorAttachment* colorAttachment,
        SDepthStencilAttachment* depthStencilAttachment) override;

    std::unique_ptr<IBuffer> CreateBuffer(
        const char* name, const IBuffer::Type type, const uint32_t size, const bool dynamic) override;

    std::unique_ptr<IShaderProgram> CreateShaderProgram(
        const CStr& name, const CShaderDefines& defines) override;

    bool AcquireNextBackbuffer() override;

    IFramebuffer* GetCurrentBackbuffer(
        const AttachmentLoadOp colorAttachmentLoadOp,
        const AttachmentStoreOp colorAttachmentStoreOp,
        const AttachmentLoadOp depthStencilAttachmentLoadOp,
        const AttachmentStoreOp depthStencilAttachmentStoreOp) override;

    void Present() override;

    void OnWindowResize(const uint32_t width, const uint32_t height) override;

    bool UseFramebufferInvalidating() const { return m_UseFramebufferInvalidating; }

    bool IsTextureFormatSupported(const Format format) const override;

    bool IsFramebufferFormatSupported(const Format format) const override;

    Format GetPreferredDepthStencilFormat(
        const uint32_t usage, const bool depth, const bool stencil) const override;

    const Capabilities& GetCapabilities() const override { return m_Capabilities; }

private:
    CDevice();

    SDL_Window* m_Window = nullptr;
    SDL_GLContext m_Context = nullptr;
    int m_SurfaceDrawableWidth = 0, m_SurfaceDrawableHeight = 0;

    bool m_ARB = false;

    std::string m_Name;
    std::string m_Version;
    std::string m_DriverInformation;
    std::vector<std::string> m_Extensions;

    // GL can have the only one command context at once.
    // TODO: remove as soon as we have no GL code outside backend, currently
    // it's used only as a helper for transition.
    CDeviceCommandContext* m_ActiveCommandContext = nullptr;

    using BackbufferKey = std::tuple<
        AttachmentLoadOp, AttachmentStoreOp,
        AttachmentLoadOp, AttachmentStoreOp>;
    struct BackbufferKeyHash
    {
        size_t operator()(const BackbufferKey& key) const;
    };
    // We use std::unordered_map to avoid storing sizes of Attachment*Op
    // enumerations. If it becomes a performance issue we'll replace it
    // by an array.
    std::unordered_map<
        BackbufferKey, std::unique_ptr<CFramebuffer>, BackbufferKeyHash> m_Backbuffers;
    bool m_BackbufferAcquired = false;
    bool m_UseFramebufferInvalidating = false;

    Capabilities m_Capabilities{};
};

} // namespace GL

} // namespace Backend

} // namespace Renderer

#endif // INCLUDED_RENDERER_BACKEND_GL_DEVICE