DeviceCommandContext.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_DEVICECOMMANDCONTEXT
#define INCLUDED_RENDERER_BACKEND_GL_DEVICECOMMANDCONTEXT

#include "lib/ogl.h"
#include "ps/containers/Span.h"
#include "renderer/backend/Format.h"
#include "renderer/backend/gl/Buffer.h"
#include "renderer/backend/IDeviceCommandContext.h"
#include "renderer/backend/PipelineState.h"

#include <array>
#include <cstdint>
#include <functional>
#include <memory>
#include <optional>
#include <utility>

namespace Renderer
{

namespace Backend
{

namespace GL
{

class CDevice;
class CFramebuffer;
class CShaderProgram;
class CTexture;

class CDeviceCommandContext final : public IDeviceCommandContext
{
public:
    ~CDeviceCommandContext();

    IDevice* GetDevice() override;

    void SetGraphicsPipelineState(const SGraphicsPipelineStateDesc& pipelineState);

    void SetGraphicsPipelineState(IGraphicsPipelineState* pipelineState) override;

    void BlitFramebuffer(IFramebuffer* destinationFramebuffer, IFramebuffer* sourceFramebuffer) override;

    void BeginFramebufferPass(IFramebuffer* framebuffer) override;
    void EndFramebufferPass() override;
    void ClearFramebuffer(const bool color, const bool depth, const bool stencil) override;
    void ReadbackFramebufferSync(
        const uint32_t x, const uint32_t y, const uint32_t width, const uint32_t height,
        void* data) override;

    void UploadTexture(ITexture* texture, const Format dataFormat,
        const void* data, const size_t dataSize,
        const uint32_t level = 0, const uint32_t layer = 0) override;
    void UploadTextureRegion(ITexture* texture, const Format dataFormat,
        const void* data, const size_t dataSize,
        const uint32_t xOffset, const uint32_t yOffset,
        const uint32_t width, const uint32_t height,
        const uint32_t level = 0, const uint32_t layer = 0) override;

    using UploadBufferFunction = std::function<void(u8*)>;
    void UploadBuffer(IBuffer* buffer, const void* data, const uint32_t dataSize) override;
    void UploadBuffer(IBuffer* buffer, const UploadBufferFunction& uploadFunction) override;
    void UploadBufferRegion(
        IBuffer* buffer, const void* data, const uint32_t dataOffset, const uint32_t dataSize) override;
    void UploadBufferRegion(
        IBuffer* buffer, const uint32_t dataOffset, const uint32_t dataSize,
        const UploadBufferFunction& uploadFunction) override;

    void SetScissors(const uint32_t scissorCount, const Rect* scissors) override;
    void SetViewports(const uint32_t viewportCount, const Rect* viewports) override;

    void SetVertexInputLayout(
        IVertexInputLayout* vertexInputLayout) override;

    void SetVertexBuffer(
        const uint32_t bindingSlot, IBuffer* buffer, const uint32_t offset) override;
    void SetVertexBufferData(
        const uint32_t bindingSlot, const void* data, const uint32_t dataSize) override;

    void SetIndexBuffer(IBuffer* buffer) override;
    void SetIndexBufferData(const void* data, const uint32_t dataSize) override;

    void BeginPass() override;
    void EndPass() override;

    void Draw(const uint32_t firstVertex, const uint32_t vertexCount) override;
    void DrawIndexed(
        const uint32_t firstIndex, const uint32_t indexCount, const int32_t vertexOffset) override;
    void DrawInstanced(
        const uint32_t firstVertex, const uint32_t vertexCount,
        const uint32_t firstInstance, const uint32_t instanceCount) override;
    void DrawIndexedInstanced(
        const uint32_t firstIndex, const uint32_t indexCount,
        const uint32_t firstInstance, const uint32_t instanceCount,
        const int32_t vertexOffset) override;
    void DrawIndexedInRange(
        const uint32_t firstIndex, const uint32_t indexCount,
        const uint32_t start, const uint32_t end) override;

    void SetTexture(const int32_t bindingSlot, ITexture* texture) override;

    void SetUniform(
        const int32_t bindingSlot,
        const float value) override;
    void SetUniform(
        const int32_t bindingSlot,
        const float valueX, const float valueY) override;
    void SetUniform(
        const int32_t bindingSlot,
        const float valueX, const float valueY,
        const float valueZ) override;
    void SetUniform(
        const int32_t bindingSlot,
        const float valueX, const float valueY,
        const float valueZ, const float valueW) override;
    void SetUniform(
        const int32_t bindingSlot, PS::span<const float> values) override;

    void BeginScopedLabel(const char* name) override;
    void EndScopedLabel() override;

    void Flush() override;

    // We need to know when to invalidate our texture bind cache.
    void OnTextureDestroy(CTexture* texture);

private:
    friend class CDevice;
    friend class CTexture;

    static std::unique_ptr<CDeviceCommandContext> Create(CDevice* device);

    CDeviceCommandContext(CDevice* device);

    void ResetStates();

    void SetGraphicsPipelineStateImpl(
        const SGraphicsPipelineStateDesc& pipelineStateDesc, const bool force);

    void BindTexture(const uint32_t unit, const GLenum target, const GLuint handle);
    void BindBuffer(const IBuffer::Type type, CBuffer* buffer);

    CDevice* m_Device = nullptr;

    SGraphicsPipelineStateDesc m_GraphicsPipelineStateDesc{};
    CFramebuffer* m_Framebuffer = nullptr;
    CShaderProgram* m_ShaderProgram = nullptr;
    uint32_t m_ScissorCount = 0;
    // GL2.1 doesn't support more than 1 scissor.
    std::array<Rect, 1> m_Scissors;

    uint32_t m_ScopedLabelDepth = 0;

    CBuffer* m_VertexBuffer = nullptr;
    CBuffer* m_IndexBuffer = nullptr;
    const void* m_IndexBufferData = nullptr;

    bool m_InsideFramebufferPass = false;
    bool m_InsidePass = false;

    uint32_t m_ActiveTextureUnit = 0;
    struct BindUnit
    {
        GLenum target;
        GLuint handle;
    };
    std::array<BindUnit, 16> m_BoundTextures;
    class ScopedBind
    {
    public:
        ScopedBind(CDeviceCommandContext* deviceCommandContext,
            const GLenum target, const GLuint handle);

        ~ScopedBind();
    private:
        CDeviceCommandContext* m_DeviceCommandContext = nullptr;
        BindUnit m_OldBindUnit;
        uint32_t m_ActiveTextureUnit = 0;
    };

    using BoundBuffer = std::pair<GLenum, GLuint>;
    std::array<BoundBuffer, 2> m_BoundBuffers;
    class ScopedBufferBind
    {
    public:
        ScopedBufferBind(
            CDeviceCommandContext* deviceCommandContext, CBuffer* buffer);

        ~ScopedBufferBind();
    private:
        CDeviceCommandContext* m_DeviceCommandContext = nullptr;
        size_t m_CacheIndex = 0;
    };

    struct VertexAttributeFormat
    {
        Format format;
        uint32_t offset;
        uint32_t stride;
        VertexAttributeRate rate;
        uint32_t bindingSlot;

        bool active;
        bool initialized;
    };
    std::array<
        VertexAttributeFormat,
        static_cast<size_t>(VertexAttributeStream::UV7) + 1> m_VertexAttributeFormat;
};

} // namespace GL

} // namespace Backend

} // namespace Renderer

#endif // INCLUDED_RENDERER_BACKEND_GL_DEVICECOMMANDCONTEXT