Trove Debug Draw

Installation

Refer to Trove Readme for installation instructions.

Overview

Trove Debug Draw is a GPU-persistent burst-compatible debug line/mesh drawer.

How it works

Trove Debug Draw uses BatchRenderGroup. Make sure your project is compatible with BRG by consulting this page: https://docs.unity3d.com/6000.0/Documentation/Manual/batch-renderer-group-getting-started.html

In this package, you create DebugDrawGroups representing collections of GPU-persistent lines and triangles. If you don't change any DebugDrawGroups, data will not have to be re-uploaded to the GPU, which will enable drawing lots of debug shapes at high performance.

Creating a DebugDrawGroup

Each system that wants to debug draw can store its own DebugDrawGroup. Systems are also responsible for allocating these DebugDrawGroups by using the AllocateDebugDrawGroup function of the DebugDrawSingleton.

Once a DebugDrawGroup is created, drawing is done by simply calling the various Draw(...) functions of the DebugDrawGroup.

You should not call Draw(...) every frame if things are not changing. Once Draw(...) is called, the debug drawer will keep drawing that thing until the DebugDrawGroup is cleared.

partial struct TestDebugDrawSystem : ISystem
{
    private DebugDrawGroup _debugDrawGroup;
    
    public void OnCreate(ref SystemState state)
    {
        state.RequireForUpdate<DebugDrawSingleton>();
    }

    [BurstCompile]
    public void OnUpdate(ref SystemState state)
    {
        // Allocate the DebugDrawGroup if not created
        if (!_debugDrawGroup.IsCreated)
        {
            ref DebugDrawSingleton debugDrawSingleton = ref SystemAPI.GetSingletonRW<DebugDrawSingleton>().ValueRW;
            _debugDrawGroup = debugDrawSingleton.AllocateDebugDrawGroup();

            // On start, draw some shapes. These shapes will be drawn every frame until we clear the group
            _debugDrawGroup.DrawLine(start, end, color);
            _debugDrawGroup.DrawBox(start, quaternion.identity, extents, color);
        }

        // Since the DebugDrawGroup is GPU-persistent, we must manually clear it when we want to stop drawing (or when we want to update the things that this group is drawing)
        if((float)SystemAPI.Time.ElapsedTime > 5f)
        {
            _debugDrawGroup.Clear();
        }
    }
}

DebugDrawGroup can be passed to jobs, but can't be written to in parallel. For parallel writing, it is recommended to write debuf draw events to a NativeStream first, and then have a single-thread job that reads this stream and writes it to the DebugDrawGroup.