OpenRCT2/src/openrct2-ui/drawing/engines/opengl/OpenGLDrawingEngine.cpp

/*****************************************************************************
 * Copyright (c) 2014-2020 OpenRCT2 developers
 *
 * For a complete list of all authors, please refer to contributors.md
 * Interested in contributing? Visit https://github.com/OpenRCT2/OpenRCT2
 *
 * OpenRCT2 is licensed under the GNU General Public License version 3.
 *****************************************************************************/

#ifndef DISABLE_OPENGL

#    include "../DrawingEngineFactory.hpp"
#    include "ApplyPaletteShader.h"
#    include "DrawCommands.h"
#    include "DrawLineShader.h"
#    include "DrawRectShader.h"
#    include "GLSLTypes.h"
#    include "OpenGLAPI.h"
#    include "OpenGLFramebuffer.h"
#    include "SwapFramebuffer.h"
#    include "TextureCache.h"
#    include "TransparencyDepth.h"

#    include <SDL.h>
#    include <algorithm>
#    include <cmath>
#    include <openrct2-ui/interface/Window.h>
#    include <openrct2/Intro.h>
#    include <openrct2/config/Config.h>
#    include <openrct2/core/Console.hpp>
#    include <openrct2/drawing/Drawing.h>
#    include <openrct2/drawing/IDrawingContext.h>
#    include <openrct2/drawing/IDrawingEngine.h>
#    include <openrct2/drawing/LightFX.h>
#    include <openrct2/drawing/Weather.h>
#    include <openrct2/interface/Screenshot.h>
#    include <openrct2/ui/UiContext.h>
#    include <openrct2/util/Util.h>
#    include <openrct2/world/Climate.h>
#    include <unordered_map>

using namespace OpenRCT2;
using namespace OpenRCT2::Drawing;
using namespace OpenRCT2::Ui;

struct OpenGLVersion
{
    GLint Major;
    GLint Minor;
};

constexpr OpenGLVersion OPENGL_MINIMUM_REQUIRED_VERSION = { 3, 3 };

class OpenGLDrawingEngine;

class OpenGLDrawingContext final : public IDrawingContext
{
private:
    OpenGLDrawingEngine* _engine = nullptr;
    ApplyTransparencyShader* _applyTransparencyShader = nullptr;
    DrawLineShader* _drawLineShader = nullptr;
    DrawRectShader* _drawRectShader = nullptr;
    SwapFramebuffer* _swapFramebuffer = nullptr;

    TextureCache* _textureCache = nullptr;

    int32_t _offsetX = 0;
    int32_t _offsetY = 0;
    int32_t _clipLeft = 0;
    int32_t _clipTop = 0;
    int32_t _clipRight = 0;
    int32_t _clipBottom = 0;
    ScreenCoordsXY _spriteOffset;

    int32_t _drawCount = 0;

    struct
    {
        LineCommandBatch lines;
        RectCommandBatch rects;
        RectCommandBatch transparent;
    } _commandBuffers;

public:
    explicit OpenGLDrawingContext(OpenGLDrawingEngine* engine);
    ~OpenGLDrawingContext() override;

    IDrawingEngine* GetEngine() override;
    TextureCache* GetTextureCache() const
    {
        return _textureCache;
    }
    const OpenGLFramebuffer& GetFinalFramebuffer() const
    {
        return _swapFramebuffer->GetFinalFramebuffer();
    }

    void Initialise();
    void Resize(int32_t width, int32_t height);
    void ResetPalette();
    void StartNewDraw();

    void Clear(rct_drawpixelinfo* dpi, uint8_t paletteIndex) override;
    void FillRect(rct_drawpixelinfo* dpi, uint32_t colour, int32_t x, int32_t y, int32_t w, int32_t h) override;
    void FilterRect(
        rct_drawpixelinfo* dpi, FilterPaletteID palette, int32_t left, int32_t top, int32_t right, int32_t bottom) override;
    void DrawLine(rct_drawpixelinfo* dpi, uint32_t colour, const ScreenLine& line) override;
    void DrawSprite(rct_drawpixelinfo* dpi, ImageId imageId, int32_t x, int32_t y) override;
    void DrawSpriteRawMasked(rct_drawpixelinfo* dpi, int32_t x, int32_t y, ImageId maskImage, ImageId colourImage) override;
    void DrawSpriteSolid(rct_drawpixelinfo* dpi, uint32_t image, int32_t x, int32_t y, uint8_t colour) override;
    void DrawGlyph(rct_drawpixelinfo* dpi, uint32_t image, int32_t x, int32_t y, const PaletteMap& palette) override;
    void DrawBitmap(
        rct_drawpixelinfo* dpi, uint32_t image, const void* pixels, int32_t width, int32_t height, int32_t x,
        int32_t y) override;

    void FlushCommandBuffers();

    void FlushLines();
    void FlushRectangles();
    void HandleTransparency();
    void CalculcateClipping(rct_drawpixelinfo* dpi);
};

class OpenGLWeatherDrawer final : public IWeatherDrawer
{
    OpenGLDrawingContext* _drawingContext;

public:
    explicit OpenGLWeatherDrawer(OpenGLDrawingContext* drawingContext)
        : _drawingContext(drawingContext)
    {
    }

    virtual void Draw(
        rct_drawpixelinfo* dpi, int32_t x, int32_t y, int32_t width, int32_t height, int32_t xStart, int32_t yStart,
        const uint8_t* weatherpattern) override
    {
        const uint8_t* pattern = weatherpattern;
        auto patternXSpace = *pattern++;
        auto patternYSpace = *pattern++;

        uint8_t patternStartXOffset = xStart % patternXSpace;
        uint8_t patternStartYOffset = yStart % patternYSpace;

        uint32_t pixelOffset = (dpi->pitch + dpi->width) * y + x;
        uint8_t patternYPos = patternStartYOffset % patternYSpace;

        for (; height != 0; height--)
        {
            auto patternX = pattern[patternYPos * 2];
            if (patternX != 0xFF)
            {
                uint32_t finalPixelOffset = width + pixelOffset;

                uint32_t xPixelOffset = pixelOffset;
                xPixelOffset += (static_cast<uint8_t>(patternX - patternStartXOffset)) % patternXSpace;

                auto patternPixel = pattern[patternYPos * 2 + 1];
                for (; xPixelOffset < finalPixelOffset; xPixelOffset += patternXSpace)
                {
                    int32_t pixelX = xPixelOffset % dpi->width;
                    int32_t pixelY = (xPixelOffset / dpi->width) % dpi->height;

                    _drawingContext->DrawLine(dpi, patternPixel, { { pixelX, pixelY }, { pixelX + 1, pixelY + 1 } });
                }
            }

            pixelOffset += dpi->pitch + dpi->width;
            patternYPos++;
            patternYPos %= patternYSpace;
        }
    }
};

class OpenGLDrawingEngine final : public IDrawingEngine
{
private:
    std::shared_ptr<IUiContext> const _uiContext;
    SDL_Window* _window = nullptr;
    SDL_GLContext _context = nullptr;

    uint32_t _width = 0;
    uint32_t _height = 0;
    uint32_t _pitch = 0;
    size_t _bitsSize = 0;
    uint8_t* _bits = nullptr;

    rct_drawpixelinfo _bitsDPI = {};

    OpenGLDrawingContext* _drawingContext;

    ApplyPaletteShader* _applyPaletteShader = nullptr;
    OpenGLFramebuffer* _screenFramebuffer = nullptr;
    OpenGLFramebuffer* _scaleFramebuffer = nullptr;
    OpenGLFramebuffer* _smoothScaleFramebuffer = nullptr;
    OpenGLWeatherDrawer _weatherDrawer;

public:
    SDL_Color Palette[256];
    vec4 GLPalette[256];

    explicit OpenGLDrawingEngine(const std::shared_ptr<IUiContext>& uiContext)
        : _uiContext(uiContext)
        , _drawingContext(new OpenGLDrawingContext(this))
        , _weatherDrawer(_drawingContext)
    {
        _window = static_cast<SDL_Window*>(_uiContext->GetWindow());
        _bitsDPI.DrawingEngine = this;
#    ifdef __ENABLE_LIGHTFX__
        lightfx_set_available(false);
#    endif
    }

    ~OpenGLDrawingEngine() override
    {
        delete _applyPaletteShader;
        delete _screenFramebuffer;

        delete _drawingContext;
        delete[] _bits;

        SDL_GL_DeleteContext(_context);
    }

    void Initialise() override
    {
        OpenGLVersion requiredVersion = OPENGL_MINIMUM_REQUIRED_VERSION;
        SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
        SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, requiredVersion.Major);
        SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, requiredVersion.Minor);

        _context = SDL_GL_CreateContext(_window);
        if (_context == nullptr)
        {
            char szRequiredVersion[32];
            snprintf(szRequiredVersion, 32, "OpenGL %d.%d", requiredVersion.Major, requiredVersion.Minor);
            throw std::runtime_error(std::string(szRequiredVersion) + std::string(" not available."));
        }
        SDL_GL_MakeCurrent(_window, _context);

        if (!OpenGLAPI::Initialise())
        {
            throw std::runtime_error("Unable to initialise OpenGL.");
        }

        _drawingContext->Initialise();

        _applyPaletteShader = new ApplyPaletteShader();
    }

    void Resize(uint32_t width, uint32_t height) override
    {
        ConfigureBits(width, height, width);
        ConfigureCanvas();
        _drawingContext->Resize(width, height);
    }

    void SetPalette(const GamePalette& palette) override
    {
        for (int32_t i = 0; i < 256; i++)
        {
            SDL_Color colour;
            colour.r = palette[i].Red;
            colour.g = palette[i].Green;
            colour.b = palette[i].Blue;
            colour.a = i == 0 ? 0 : 255;

            Palette[i] = colour;
            GLPalette[i] = {
                colour.r / 255.0f,
                colour.g / 255.0f,
                colour.b / 255.0f,
                colour.a / 255.0f,
            };
        }

        _applyPaletteShader->Use();
        _applyPaletteShader->SetPalette(GLPalette);
        _drawingContext->ResetPalette();
    }

    void SetVSync(bool vsync) override
    {
        SDL_GL_SetSwapInterval(vsync);
    }

    void Invalidate(int32_t left, int32_t top, int32_t right, int32_t bottom) override
    {
    }

    void BeginDraw() override
    {
        assert(_screenFramebuffer != nullptr);

        _drawingContext->StartNewDraw();
        _drawingContext->CalculcateClipping(&_bitsDPI);
    }

    void EndDraw() override
    {
        _drawingContext->FlushCommandBuffers();

        glDisable(GL_DEPTH_TEST);
        if (_scaleFramebuffer != nullptr)
        {
            // Render to intermediary RGB buffer for GL_LINEAR
            _scaleFramebuffer->Bind();
        }
        else
        {
            _screenFramebuffer->Bind();
        }

        _applyPaletteShader->Use();
        _applyPaletteShader->SetTexture(_drawingContext->GetFinalFramebuffer().GetTexture());
        _applyPaletteShader->Draw();

        if (_smoothScaleFramebuffer != nullptr)
        {
            _smoothScaleFramebuffer->Copy(*_scaleFramebuffer, GL_NEAREST);
            _screenFramebuffer->Copy(*_smoothScaleFramebuffer, GL_LINEAR);
        }
        else if (_scaleFramebuffer != nullptr)
        {
            _screenFramebuffer->Copy(*_scaleFramebuffer, GL_LINEAR);
        }

        CheckGLError();
        Display();
    }

    void PaintWindows() override
    {
        _drawingContext->CalculcateClipping(&_bitsDPI);

        window_update_all_viewports();
        window_draw_all(&_bitsDPI, 0, 0, _width, _height);
    }

    void PaintWeather() override
    {
        _drawingContext->CalculcateClipping(&_bitsDPI);

        DrawWeather(&_bitsDPI, &_weatherDrawer);
    }

    std::string Screenshot() override
    {
        const OpenGLFramebuffer& framebuffer = _drawingContext->GetFinalFramebuffer();
        framebuffer.Bind();
        framebuffer.GetPixels(_bitsDPI);
        std::string result = screenshot_dump_png(&_bitsDPI);
        return result;
    }

    void CopyRect(int32_t x, int32_t y, int32_t width, int32_t height, int32_t dx, int32_t dy) override
    {
        // Not applicable for this engine
    }

    IDrawingContext* GetDrawingContext() override
    {
        return _drawingContext;
    }

    rct_drawpixelinfo* GetDrawingPixelInfo() override
    {
        return &_bitsDPI;
    }

    DRAWING_ENGINE_FLAGS GetFlags() override
    {
        return DEF_NONE;
    }

    void InvalidateImage(uint32_t image) override
    {
        _drawingContext->GetTextureCache()->InvalidateImage(image);
    }

    rct_drawpixelinfo* GetDPI()
    {
        return &_bitsDPI;
    }

private:
    static OpenGLVersion GetOpenGLVersion()
    {
        CheckGLError(); // Clear Any Errors
        OpenGLVersion version = { 0, 0 };
        glGetIntegerv(GL_MAJOR_VERSION, &version.Major);
        if (glGetError() != GL_NO_ERROR)
            return { 0, 0 };
        glGetIntegerv(GL_MINOR_VERSION, &version.Minor);
        if (glGetError() != GL_NO_ERROR)
            return { 0, 0 };
        return version;
    }

    void ConfigureBits(uint32_t width, uint32_t height, uint32_t pitch)
    {
        size_t newBitsSize = pitch * height;
        uint8_t* newBits = new uint8_t[newBitsSize];
        if (_bits == nullptr)
        {
            std::fill_n(newBits, newBitsSize, 0);
        }
        else
        {
            if (_pitch == pitch)
            {
                std::copy_n(_bits, std::min(_bitsSize, newBitsSize), newBits);
            }
            else
            {
                uint8_t* src = _bits;
                uint8_t* dst = newBits;

                uint32_t minWidth = std::min(_width, width);
                uint32_t minHeight = std::min(_height, height);
                for (uint32_t y = 0; y < minHeight; y++)
                {
                    std::copy_n(src, minWidth, dst);
                    if (pitch - minWidth > 0)
                    {
                        std::fill_n(dst + minWidth, pitch - minWidth, 0);
                    }
                    src += _pitch;
                    dst += pitch;
                }
            }
            delete[] _bits;
        }

        _bits = newBits;
        _bitsSize = newBitsSize;
        _width = width;
        _height = height;
        _pitch = pitch;

        rct_drawpixelinfo* dpi = &_bitsDPI;
        dpi->bits = _bits;
        dpi->x = 0;
        dpi->y = 0;
        dpi->width = width;
        dpi->height = height;
        dpi->pitch = _pitch - width;
    }

    void ConfigureCanvas()
    {
        // Re-create screen framebuffer
        delete _screenFramebuffer;
        _screenFramebuffer = new OpenGLFramebuffer(_window);

        if (_scaleFramebuffer != nullptr)
        {
            delete _scaleFramebuffer;
            _scaleFramebuffer = nullptr;
        }
        if (_smoothScaleFramebuffer != nullptr)
        {
            delete _smoothScaleFramebuffer;
            _smoothScaleFramebuffer = nullptr;
        }
        if (GetContext()->GetUiContext()->GetScaleQuality() != ScaleQuality::NearestNeighbour)
        {
            _scaleFramebuffer = new OpenGLFramebuffer(_width, _height, false, false);
        }
        if (GetContext()->GetUiContext()->GetScaleQuality() == ScaleQuality::SmoothNearestNeighbour)
        {
            uint32_t scale = std::ceil(gConfigGeneral.window_scale);
            _smoothScaleFramebuffer = new OpenGLFramebuffer(_width * scale, _height * scale, false, false);
        }
    }

    void Display()
    {
        SDL_GL_SwapWindow(_window);
    }
};

std::unique_ptr<IDrawingEngine> OpenRCT2::Ui::CreateOpenGLDrawingEngine(const std::shared_ptr<IUiContext>& uiContext)
{
    return std::make_unique<OpenGLDrawingEngine>(uiContext);
}

OpenGLDrawingContext::OpenGLDrawingContext(OpenGLDrawingEngine* engine)
{
    _engine = engine;
}

OpenGLDrawingContext::~OpenGLDrawingContext()
{
    delete _applyTransparencyShader;
    delete _drawLineShader;
    delete _drawRectShader;
    delete _swapFramebuffer;

    delete _textureCache;
}

IDrawingEngine* OpenGLDrawingContext::GetEngine()
{
    return _engine;
}

void OpenGLDrawingContext::Initialise()
{
    _textureCache = new TextureCache();
    _applyTransparencyShader = new ApplyTransparencyShader();
    _drawRectShader = new DrawRectShader();
    _drawLineShader = new DrawLineShader();
}

void OpenGLDrawingContext::Resize(int32_t width, int32_t height)
{
    _commandBuffers.lines.clear();
    _commandBuffers.rects.clear();

    _drawRectShader->Use();
    _drawRectShader->SetScreenSize(width, height);
    _drawLineShader->Use();
    _drawLineShader->SetScreenSize(width, height);

    // Re-create canvas framebuffer
    delete _swapFramebuffer;
    _swapFramebuffer = new SwapFramebuffer(width, height);
}

void OpenGLDrawingContext::ResetPalette()
{
    // FlushCommandBuffers();
}

void OpenGLDrawingContext::StartNewDraw()
{
    _drawCount = 0;
    _swapFramebuffer->Clear();
}

void OpenGLDrawingContext::Clear(rct_drawpixelinfo* dpi, uint8_t paletteIndex)
{
    CalculcateClipping(dpi);

    FillRect(dpi, paletteIndex, _clipLeft - _offsetX, _clipTop - _offsetY, _clipRight - _offsetX, _clipBottom - _offsetY);
}

void OpenGLDrawingContext::FillRect(
    rct_drawpixelinfo* dpi, uint32_t colour, int32_t left, int32_t top, int32_t right, int32_t bottom)
{
    CalculcateClipping(dpi);

    left += _offsetX;
    top += _offsetY;
    right += _offsetX;
    bottom += _offsetY;

    DrawRectCommand& command = _commandBuffers.rects.allocate();

    command.clip = { _clipLeft, _clipTop, _clipRight, _clipBottom };
    command.texColourAtlas = 0;
    command.texColourBounds = { 0.0f, 0.0f, 0.0f, 0.0f };
    command.texMaskAtlas = 0;
    command.texMaskBounds = { 0.0f, 0.0f, 0.0f, 0.0f };
    command.palettes = { 0, 0, 0 };
    command.colour = colour & 0xFF;
    command.bounds = { left, top, right + 1, bottom + 1 };
    command.flags = DrawRectCommand::FLAG_NO_TEXTURE;
    command.depth = _drawCount++;

    if (colour & 0x1000000)
    {
        // cross-pattern
        command.flags |= DrawRectCommand::FLAG_CROSS_HATCH;
    }
    else if (colour & 0x2000000)
    {
        assert(false);
        // Should be FilterRect
    }
}

void OpenGLDrawingContext::FilterRect(
    rct_drawpixelinfo* dpi, FilterPaletteID palette, int32_t left, int32_t top, int32_t right, int32_t bottom)
{
    CalculcateClipping(dpi);

    left += _offsetX;
    top += _offsetY;
    right += _offsetX;
    bottom += _offsetY;

    DrawRectCommand& command = _commandBuffers.transparent.allocate();

    command.clip = { _clipLeft, _clipTop, _clipRight, _clipBottom };
    command.texColourAtlas = 0;
    command.texColourBounds = { 0.0f, 0.0f, 0.0f, 0.0f };
    command.texMaskAtlas = 0;
    command.texMaskBounds = { 0.0f, 0.0f, 0.0f, 0.0f };
    command.palettes = { 0, 0, 0 };
    command.colour = TextureCache::PaletteToY(palette);
    command.bounds = { left, top, right + 1, bottom + 1 };
    command.flags = DrawRectCommand::FLAG_NO_TEXTURE;
    command.depth = _drawCount++;
}

void OpenGLDrawingContext::DrawLine(rct_drawpixelinfo* dpi, uint32_t colour, const ScreenLine& line)
{
    CalculcateClipping(dpi);

    DrawLineCommand& command = _commandBuffers.lines.allocate();

    command.clip = { _clipLeft, _clipTop, _clipRight, _clipBottom };
    command.bounds = { line.GetX1() + _offsetX, line.GetY1() + _offsetY, line.GetX2() + _offsetX, line.GetY2() + _offsetY };
    command.colour = colour & 0xFF;
    command.depth = _drawCount++;
}

void OpenGLDrawingContext::DrawSprite(rct_drawpixelinfo* dpi, ImageId imageId, int32_t x, int32_t y)
{
    CalculcateClipping(dpi);

    auto g1Element = gfx_get_g1_element(imageId);
    if (g1Element == nullptr)
    {
        return;
    }

    if (dpi->zoom_level > ZoomLevel{ 0 })
    {
        if (g1Element->flags & G1_FLAG_HAS_ZOOM_SPRITE)
        {
            rct_drawpixelinfo zoomedDPI;
            zoomedDPI.bits = dpi->bits;
            zoomedDPI.x = dpi->x >> 1;
            zoomedDPI.y = dpi->y >> 1;
            zoomedDPI.height = dpi->height >> 1;
            zoomedDPI.width = dpi->width >> 1;
            zoomedDPI.pitch = dpi->pitch;
            zoomedDPI.zoom_level = dpi->zoom_level - 1;
            DrawSprite(&zoomedDPI, imageId.WithIndex(imageId.GetIndex() - g1Element->zoomed_offset), x >> 1, y >> 1);
            return;
        }
        if (g1Element->flags & G1_FLAG_NO_ZOOM_DRAW)
        {
            return;
        }
    }

    int32_t left = x + g1Element->x_offset;
    int32_t top = y + g1Element->y_offset;

    int32_t zoom_mask;
    if (dpi->zoom_level >= ZoomLevel{ 0 })
        zoom_mask = 0xFFFFFFFF * dpi->zoom_level;
    else
        zoom_mask = 0xFFFFFFFF;
    if (dpi->zoom_level != ZoomLevel{ 0 } && (g1Element->flags & G1_FLAG_RLE_COMPRESSION))
    {
        top -= ~zoom_mask;
    }

    if (!(g1Element->flags & G1_FLAG_RLE_COMPRESSION))
    {
        top &= zoom_mask;
        left += ~zoom_mask;
    }

    left &= zoom_mask;

    int32_t right = left + g1Element->width;
    int32_t bottom = top + g1Element->height;

    if (dpi->zoom_level != ZoomLevel{ 0 } && (g1Element->flags & G1_FLAG_RLE_COMPRESSION))
    {
        bottom += top & ~zoom_mask;
    }

    if (left > right)
    {
        std::swap(left, right);
    }
    if (top > bottom)
    {
        std::swap(top, bottom);
    }

    left -= dpi->x;
    top -= dpi->y;
    right -= dpi->x;
    bottom -= dpi->y;

    left = left / dpi->zoom_level;
    top = top / dpi->zoom_level;
    right = right / dpi->zoom_level;
    bottom = bottom / dpi->zoom_level;

    left += _spriteOffset.x;
    top += _spriteOffset.y;
    right += _spriteOffset.x;
    bottom += _spriteOffset.y;

    const auto texture = _textureCache->GetOrLoadImageTexture(imageId);

    int paletteCount;
    ivec3 palettes{};
    bool special = false;
    if (imageId.HasSecondary())
    {
        palettes.x = TextureCache::PaletteToY(static_cast<FilterPaletteID>(imageId.GetPrimary()));
        palettes.y = TextureCache::PaletteToY(static_cast<FilterPaletteID>(imageId.GetSecondary()));
        if (!imageId.HasTertiary())
        {
            paletteCount = 2;
        }
        else
        {
            paletteCount = 3;
            palettes.z = TextureCache::PaletteToY(static_cast<FilterPaletteID>(imageId.GetTertiary()));
        }
    }
    else if (imageId.IsRemap() || imageId.IsBlended())
    {
        paletteCount = 1;
        FilterPaletteID palette = static_cast<FilterPaletteID>(imageId.GetRemap());
        palettes.x = TextureCache::PaletteToY(palette);
        if (palette == FilterPaletteID::PaletteWater)
        {
            special = true;
        }
    }
    else
    {
        paletteCount = 0;
    }

    if (special || imageId.IsBlended())
    {
        DrawRectCommand& command = _commandBuffers.transparent.allocate();

        command.clip = { _clipLeft, _clipTop, _clipRight, _clipBottom };
        command.texColourAtlas = texture.index;
        command.texColourBounds = texture.normalizedBounds;
        command.texMaskAtlas = texture.index;
        command.texMaskBounds = texture.normalizedBounds;
        command.palettes = palettes;
        command.colour = palettes.x - (special ? 1 : 0);
        command.bounds = { left, top, right, bottom };
        command.flags = special ? 0 : DrawRectCommand::FLAG_NO_TEXTURE | DrawRectCommand::FLAG_MASK;
        command.depth = _drawCount++;
    }
    else
    {
        DrawRectCommand& command = _commandBuffers.rects.allocate();

        command.clip = { _clipLeft, _clipTop, _clipRight, _clipBottom };
        command.texColourAtlas = texture.index;
        command.texColourBounds = texture.normalizedBounds;
        command.texMaskAtlas = 0;
        command.texMaskBounds = { 0.0f, 0.0f, 0.0f, 0.0f };
        command.palettes = palettes;
        command.colour = 0;
        command.bounds = { left, top, right, bottom };
        command.flags = paletteCount;
        command.depth = _drawCount++;
    }
}

void OpenGLDrawingContext::DrawSpriteRawMasked(
    rct_drawpixelinfo* dpi, int32_t x, int32_t y, ImageId maskImage, ImageId colourImage)
{
    CalculcateClipping(dpi);

    auto g1ElementMask = gfx_get_g1_element(maskImage);
    auto g1ElementColour = gfx_get_g1_element(colourImage);
    if (g1ElementMask == nullptr || g1ElementColour == nullptr)
    {
        return;
    }

    const auto textureMask = _textureCache->GetOrLoadImageTexture(maskImage);
    const auto textureColour = _textureCache->GetOrLoadImageTexture(colourImage);

    int32_t drawOffsetX = g1ElementMask->x_offset;
    int32_t drawOffsetY = g1ElementMask->y_offset;
    int32_t drawWidth = std::min(g1ElementMask->width, g1ElementColour->width);
    int32_t drawHeight = std::min(g1ElementMask->height, g1ElementColour->height);

    int32_t left = x + drawOffsetX;
    int32_t top = y + drawOffsetY;
    int32_t right = left + drawWidth;
    int32_t bottom = top + drawHeight;

    if (left > right)
    {
        std::swap(left, right);
    }
    if (top > bottom)
    {
        std::swap(top, bottom);
    }

    left -= dpi->x;
    top -= dpi->y;
    right -= dpi->x;
    bottom -= dpi->y;

    left = left / dpi->zoom_level;
    top = top / dpi->zoom_level;
    right = right / dpi->zoom_level;
    bottom = bottom / dpi->zoom_level;

    left += _spriteOffset.x;
    top += _spriteOffset.y;
    right += _spriteOffset.x;
    bottom += _spriteOffset.y;

    DrawRectCommand& command = _commandBuffers.rects.allocate();

    command.clip = { _clipLeft, _clipTop, _clipRight, _clipBottom };
    command.texColourAtlas = textureColour.index;
    command.texColourBounds = textureColour.normalizedBounds;
    command.texMaskAtlas = textureMask.index;
    command.texMaskBounds = textureMask.normalizedBounds;
    command.palettes = { 0, 0, 0 };
    command.flags = DrawRectCommand::FLAG_MASK;
    command.colour = 0;
    command.bounds = { left, top, right, bottom };
    command.depth = _drawCount++;
}

void OpenGLDrawingContext::DrawSpriteSolid(rct_drawpixelinfo* dpi, uint32_t image, int32_t x, int32_t y, uint8_t colour)
{
    CalculcateClipping(dpi);

    assert((colour & 0xFF) > 0u);

    int32_t g1Id = image & 0x7FFFF;
    auto g1Element = gfx_get_g1_element(g1Id);
    if (g1Element == nullptr)
    {
        return;
    }

    const auto texture = _textureCache->GetOrLoadImageTexture(ImageId::FromUInt32(image));

    int32_t drawOffsetX = g1Element->x_offset;
    int32_t drawOffsetY = g1Element->y_offset;
    int32_t drawWidth = static_cast<uint16_t>(g1Element->width);
    int32_t drawHeight = static_cast<uint16_t>(g1Element->height);

    int32_t left = x + drawOffsetX;
    int32_t top = y + drawOffsetY;
    int32_t right = left + drawWidth;
    int32_t bottom = top + drawHeight;

    if (left > right)
    {
        std::swap(left, right);
    }
    if (top > bottom)
    {
        std::swap(top, bottom);
    }

    left += _offsetX;
    top += _offsetY;
    right += _offsetX;
    bottom += _offsetY;

    DrawRectCommand& command = _commandBuffers.rects.allocate();

    command.clip = { _clipLeft, _clipTop, _clipRight, _clipBottom };
    command.texColourAtlas = 0;
    command.texColourBounds = { 0.0f, 0.0f, 0.0f, 0.0f };
    command.texMaskAtlas = texture.index;
    command.texMaskBounds = texture.normalizedBounds;
    command.palettes = { 0, 0, 0 };
    command.flags = DrawRectCommand::FLAG_NO_TEXTURE | DrawRectCommand::FLAG_MASK;
    command.colour = colour & 0xFF;
    command.bounds = { left, top, right, bottom };
    command.depth = _drawCount++;
}

void OpenGLDrawingContext::DrawGlyph(rct_drawpixelinfo* dpi, uint32_t image, int32_t x, int32_t y, const PaletteMap& palette)
{
    CalculcateClipping(dpi);

    auto g1Element = gfx_get_g1_element(image & 0x7FFFF);
    if (g1Element == nullptr)
    {
        return;
    }

    const auto texture = _textureCache->GetOrLoadGlyphTexture(ImageId::FromUInt32(image), palette);

    int32_t left = x + g1Element->x_offset;
    int32_t top = y + g1Element->y_offset;
    int32_t right = left + static_cast<uint16_t>(g1Element->width);
    int32_t bottom = top + static_cast<uint16_t>(g1Element->height);

    if (left > right)
    {
        std::swap(left, right);
    }
    if (top > bottom)
    {
        std::swap(top, bottom);
    }

    left -= dpi->x;
    top -= dpi->y;
    right -= dpi->x;
    bottom -= dpi->y;

    left = left / dpi->zoom_level;
    top = top / dpi->zoom_level;
    right = right / dpi->zoom_level;
    bottom = bottom / dpi->zoom_level;

    left += _spriteOffset.x;
    top += _spriteOffset.y;
    right += _spriteOffset.x;
    bottom += _spriteOffset.y;

    DrawRectCommand& command = _commandBuffers.rects.allocate();

    command.clip = { _clipLeft, _clipTop, _clipRight, _clipBottom };
    command.texColourAtlas = texture.index;
    command.texColourBounds = texture.normalizedBounds;
    command.texMaskAtlas = 0;
    command.texMaskBounds = { 0.0f, 0.0f, 0.0f, 0.0f };
    command.palettes = { 0, 0, 0 };
    command.flags = 0;
    command.colour = 0;
    command.bounds = { left, top, right, bottom };
    command.depth = _drawCount++;
}

void OpenGLDrawingContext::DrawBitmap(
    rct_drawpixelinfo* dpi, uint32_t image, const void* pixels, int32_t width, int32_t height, int32_t x, int32_t y)
{
    CalculcateClipping(dpi);

    const auto texture = _textureCache->GetOrLoadBitmapTexture(image, pixels, width, height);

    int32_t drawOffsetX = 0;
    int32_t drawOffsetY = 0;
    int32_t drawWidth = static_cast<uint16_t>(width);
    int32_t drawHeight = static_cast<uint16_t>(height);

    int32_t left = x + drawOffsetX;
    int32_t top = y + drawOffsetY;
    int32_t right = left + drawWidth;
    int32_t bottom = top + drawHeight;

    if (left > right)
    {
        std::swap(left, right);
    }
    if (top > bottom)
    {
        std::swap(top, bottom);
    }

    left += _offsetX;
    top += _offsetY;
    right += _offsetX;
    bottom += _offsetY;

    DrawRectCommand& command = _commandBuffers.rects.allocate();

    command.clip = { _clipLeft, _clipTop, _clipRight, _clipBottom };
    command.texColourAtlas = texture.index;
    command.texColourBounds = texture.normalizedBounds;
    command.texMaskAtlas = 0;
    command.texMaskBounds = { 0.0f, 0.0f, 0.0f, 0.0f };
    command.palettes = { 0, 0, 0 };
    command.flags = 0;
    command.colour = 0;
    command.bounds = { left, top, right, bottom };
    command.depth = _drawCount++;
}

void OpenGLDrawingContext::FlushCommandBuffers()
{
    glEnable(GL_DEPTH_TEST);
    glDepthFunc(GL_LESS);

    _swapFramebuffer->BindOpaque();
    _drawRectShader->Use();
    _drawRectShader->DisablePeeling();

    FlushLines();
    FlushRectangles();

    HandleTransparency();
}

void OpenGLDrawingContext::FlushLines()
{
    if (_commandBuffers.lines.empty())
        return;

    _drawLineShader->Use();
    _drawLineShader->DrawInstances(_commandBuffers.lines);

    _commandBuffers.lines.clear();
}

void OpenGLDrawingContext::FlushRectangles()
{
    if (_commandBuffers.rects.empty())
        return;

    OpenGLAPI::SetTexture(0, GL_TEXTURE_2D_ARRAY, _textureCache->GetAtlasesTexture());
    OpenGLAPI::SetTexture(1, GL_TEXTURE_2D, _textureCache->GetPaletteTexture());

    _drawRectShader->Use();
    _drawRectShader->SetInstances(_commandBuffers.rects);
    _drawRectShader->DrawInstances();

    _commandBuffers.rects.clear();
}

void OpenGLDrawingContext::HandleTransparency()
{
    if (_commandBuffers.transparent.empty())
    {
        return;
    }

    _drawRectShader->Use();
    _drawRectShader->SetInstances(_commandBuffers.transparent);

    int32_t max_depth = MaxTransparencyDepth(_commandBuffers.transparent);
    for (int32_t i = 0; i < max_depth; ++i)
    {
        _swapFramebuffer->BindTransparent();

        glEnable(GL_DEPTH_TEST);
        glDepthFunc(GL_GREATER);
        _drawRectShader->Use();

        if (i > 0)
        {
            _drawRectShader->EnablePeeling(_swapFramebuffer->GetBackDepthTexture());
        }

        OpenGLAPI::SetTexture(0, GL_TEXTURE_2D_ARRAY, _textureCache->GetAtlasesTexture());
        OpenGLAPI::SetTexture(1, GL_TEXTURE_2D, _textureCache->GetPaletteTexture());

        _drawRectShader->Use();
        _drawRectShader->DrawInstances();
        _swapFramebuffer->ApplyTransparency(*_applyTransparencyShader, _textureCache->GetPaletteTexture());
    }

    _commandBuffers.transparent.clear();
}

void OpenGLDrawingContext::CalculcateClipping(rct_drawpixelinfo* dpi)
{
    auto screenDPI = _engine->GetDPI();
    auto bytesPerRow = screenDPI->GetBytesPerRow();
    auto bitsOffset = static_cast<size_t>(dpi->bits - screenDPI->bits);
#    ifndef NDEBUG
    auto bitsSize = static_cast<size_t>(screenDPI->height) * bytesPerRow;
    assert(bitsOffset < bitsSize);
#    endif

    _clipLeft = static_cast<int32_t>(bitsOffset % bytesPerRow) + dpi->remX;
    _clipTop = static_cast<int32_t>(bitsOffset / bytesPerRow) + dpi->remY;
    _clipRight = _clipLeft + (dpi->width / dpi->zoom_level);
    _clipBottom = _clipTop + (dpi->height / dpi->zoom_level);
    _offsetX = _clipLeft - dpi->x;
    _offsetY = _clipTop - dpi->y;
    _spriteOffset.x = _clipLeft - dpi->remX;
    _spriteOffset.y = _clipTop - dpi->remY;
}

#endif /* DISABLE_OPENGL */