EM_Task/TraceInsights/Private/Insights/ViewModels/TimingViewDrawHelper.h

// Copyright Epic Games, Inc. All Rights Reserved.

#pragma once

#include "CoreMinimal.h"
#include "Fonts/SlateFontInfo.h"
#include "Math/Color.h"

// Insights
#include "Insights/ViewModels/TimingEventsTrack.h"  // for ITimingEventsTrackDrawStateBuilder
#include "Insights/ViewModels/ITimingViewDrawHelper.h"

////////////////////////////////////////////////////////////////////////////////////////////////////

struct FSlateBrush;
struct FDrawContext;

class ITimingTrackDrawContext;
class FTimingEventsTrack;
class FTimingTrackViewport;

enum class EDrawEventMode : uint32;

struct FTimingViewLayout;

////////////////////////////////////////////////////////////////////////////////////////////////////

struct FTimingEventsTrackDrawState
{
    struct FBoxPrimitive
    {
        int32 Depth;
        float X;
        float W;
        FLinearColor Color;
    };

    struct FTextPrimitive
    {
        int32 Depth;
        float X;
        FString Text;
        bool bWhite;
    };

    FTimingEventsTrackDrawState()
        : Boxes(), InsideBoxes(), Borders(), Texts(), NumLanes(0), NumEvents(0), NumMergedBoxes(0)
    {
    }

    void Reset()
    {
        Boxes.Reset();
        InsideBoxes.Reset();
        Borders.Reset();
        Texts.Reset();
        NumLanes       = 0;
        NumEvents      = 0;
        NumMergedBoxes = 0;
    }

    int32 GetNumLanes() const { return NumLanes; }

    int32 GetNumEvents() const { return NumEvents; }
    int32 GetNumMergedBoxes() const { return NumMergedBoxes; }
    int32 GetTotalNumBoxes() const { return Boxes.Num() + InsideBoxes.Num(); }

    TArray<FBoxPrimitive> Boxes;
    TArray<FBoxPrimitive> InsideBoxes;
    TArray<FBoxPrimitive> Borders;
    TArray<FTextPrimitive> Texts;

    int32 NumLanes;

    // Debug stats.
    int32 NumEvents;
    int32 NumMergedBoxes;
};

////////////////////////////////////////////////////////////////////////////////////////////////////

class FTimingEventsTrackDrawStateBuilder: public ITimingEventsTrackDrawStateBuilder
{
private:
    struct FBoxData
    {
        float X1;
        float X2;
        uint32 Color;
        FLinearColor LinearColor;

        FBoxData(): X1(0.0f), X2(0.0f), Color(0) {}
        void Reset()
        {
            X1    = 0.0f;
            X2    = 0.0f;
            Color = 0;
        }
    };

public:
    explicit FTimingEventsTrackDrawStateBuilder(FTimingEventsTrackDrawState& InState, const FTimingTrackViewport& InViewport);
    virtual ~FTimingEventsTrackDrawStateBuilder() {}

    /**
     * Non-copyable
     */
    FTimingEventsTrackDrawStateBuilder(const FTimingEventsTrackDrawStateBuilder&)            = delete;
    FTimingEventsTrackDrawStateBuilder& operator=(const FTimingEventsTrackDrawStateBuilder&) = delete;

    const FTimingTrackViewport& GetViewport() const { return Viewport; }

    virtual void AddEvent(double InEventStartTime, double InEventEndTime, uint32 InEventDepth, const TCHAR* InEventName, uint64 InEventType = 0, uint32 InEventColor = 0) override;
    virtual void AddEvent(double InEventStartTime, double InEventEndTime, uint32 InEventDepth, uint32 InEventColor, GetEventNameCallback InGetEventNameCallback) override;
    void Flush();

    int32 GetMaxDepth() const { return MaxDepth; }

    static void AppendDurationToEventName(FString& InOutEventName, const double InDuration);

private:
    void FlushBox(const FBoxData& Box, const int32 Depth);

private:
    FTimingEventsTrackDrawState& DrawState;  // cached draw state to build
    const FTimingTrackViewport& Viewport;

    int32 MaxDepth;

    TArray<float> LastEventX2;  // X2 value for last event on each depth
    TArray<FBoxData> LastBox;

    const FSlateFontInfo EventFont;
};

////////////////////////////////////////////////////////////////////////////////////////////////////

class FTimingViewDrawHelper final: public ITimingViewDrawHelper
{
private:
    enum class EDrawLayer : int32
    {
        EventBorder,
        EventFill,
        EventText,
        EventHighlight,
        HeaderBackground,
        HeaderText,

        Count,
    };
    static int32 ToInt32(EDrawLayer Layer) { return static_cast<int32>(Layer); }

public:
    explicit FTimingViewDrawHelper(const FDrawContext& InDrawContext, const FTimingTrackViewport& InViewport);
    ~FTimingViewDrawHelper();

    /**
     * Non-copyable
     */
    FTimingViewDrawHelper(const FTimingViewDrawHelper&)            = delete;
    FTimingViewDrawHelper& operator=(const FTimingViewDrawHelper&) = delete;

    // ITimingViewDrawHelper interface
    virtual const FSlateBrush* GetWhiteBrush() const override { return WhiteBrush; }
    virtual const FSlateFontInfo& GetEventFont() const override { return EventFont; }
    virtual FLinearColor GetEdgeColor() const override { return EdgeColor; }
    virtual FLinearColor GetTrackNameTextColor(const FBaseTimingTrack& Track) const override;
    virtual int32 GetHeaderBackgroundLayerId() const override { return ReservedLayerId + ToInt32(EDrawLayer::HeaderBackground); }
    virtual int32 GetHeaderTextLayerId() const override { return ReservedLayerId + ToInt32(EDrawLayer::HeaderText); }

    const FDrawContext& GetDrawContext() const { return DrawContext; }
    const FTimingTrackViewport& GetViewport() const { return Viewport; }

    void DrawBackground() const;

    //////////////////////////////////////////////////

    void BeginDrawTracks() const;

    // OffsetY = 1.0f is for the top horizontal line (which separates the timelines) added by DrawTrackHeader.
    void DrawEvents(const FTimingEventsTrackDrawState& DrawState, const FTimingEventsTrack& Track, const float OffsetY = 1.0f) const;

    void DrawFadedEvents(const FTimingEventsTrackDrawState& DrawState, const FTimingEventsTrack& Track, const float OffsetY = 1.0f, const float Opacity = 0.1f) const;

    void DrawMarkers(const FTimingEventsTrackDrawState& DrawState, float LineY, float LineH, float Opacity) const;

    void DrawTrackHeader(const FBaseTimingTrack& Track) const;
    void DrawTrackHeader(const FBaseTimingTrack& Track, const int32 HeaderLayerId, const int32 HeaderTextLayerId) const;

    void EndDrawTracks() const;

    //////////////////////////////////////////////////

    void DrawTimingEventHighlight(double StartTime, double EndTime, float Y, EDrawEventMode Mode) const;

    int32 GetNumEvents() const { return NumEvents; }
    int32 GetNumMergedBoxes() const { return NumMergedBoxes; }
    int32 GetNumDrawBoxes() const { return NumDrawBoxes; }
    int32 GetNumDrawBorders() const { return NumDrawBorders; }
    int32 GetNumDrawTexts() const { return NumDrawTexts; }

private:
    const FDrawContext& DrawContext;
    const FTimingTrackViewport& Viewport;

    const FSlateBrush* WhiteBrush;
    const FSlateBrush* EventBorderBrush;
    const FSlateBrush* HoveredEventBorderBrush;
    const FSlateBrush* SelectedEventBorderBrush;
    const FSlateBrush* BackgroundAreaBrush;
    const FLinearColor ValidAreaColor;
    const FLinearColor InvalidAreaColor;
    const FLinearColor EdgeColor;
    const FSlateFontInfo EventFont;

    mutable int32 ReservedLayerId;

    mutable float ValidAreaX;
    mutable float ValidAreaW;

    mutable int32 NumEvents;
    mutable int32 NumMergedBoxes;
    mutable int32 NumDrawBoxes;
    mutable int32 NumDrawBorders;
    mutable int32 NumDrawTexts;
};

////////////////////////////////////////////////////////////////////////////////////////////////////