OTHERARSYSTEM.md

如何使用自己的AR定位系统

此项涉及代码与工程的重构,建议备份好当前数据

Note:
使用自己的AR定位系统,需要继承ISlamGenerator并重写相应方法,详情可参考
Project/Plugins/SpaceTarget/Source/SpaceTarget/Private/ARKitSlamGenerator.h
Project/Plugins/SpaceTarget/Source/SpaceTarget/Private/ARCoreSlamGenerator.h

示例代码:

UCLASS(BlueprintType, Blueprintable, Category = "4DMR-SpaceTarget")
class AARKitSlamGenerator : public AActor, public ISlamGenerator
{
	GENERATED_BODY()
	......
public:
	/*get slam current camera intrinsics interface,you need to overwrite it.*/
	virtual bool GetCameraIntrinsics(FCameraIntrisics& ci) override;
	/*get slam current pose interface,you need to overwrite it.*/
	virtual bool GetCameraPose(FCameraPose& cp) override;
	/*set slam current pose interface*/
	virtual void SetCameraPose(FTransform cp) override;
	/*get slam tracking state.you need to overwrite it.*/
	virtual bool GetTrackingStatus(FXRTrackingState& ts) override;
	/*get slam tracking texture which type is RGBA8888,you need to overwrite it*/
	virtual bool GetCameraTexture(FCameraTexture& ct) override;
	......
}

• 移除相关ARKit,ARCore的内容 1.删除 .../Plugins/SpaceTarget/SpaceTarget.uplugin 内对ARKit与ARCore的插件引用,同时确保项目的(SPTest.uplugin)没有此引用

2.删除 .../Plugins/SpaceTarget/Source/SpaceTarget/SpaceTarget.Build.cs 对ARKit与ARCore插件的引用

3.删除调用文件 删除 .../Plugins/SpaceTarget/Source/SpaceTarget/Public/ 目录以下文件:

ARCoreSlamGenerator.h

ARKitSlamGenerator.h

删除 .../Plugins/SpaceTarget/Source/SpaceTarget/Private/ 目录以下文件:

ARCoreSlamGenerator.cpp

ARKitSlamGenerator.cpp

4.修改SpaceTarget Content/SpaceTargetActor蓝图内容,将slam修改为自定义继承自ISlamGenearator的类

5.删除 SpaceTargetPawn 蓝图中定义 Start AR Session ,改用您的AR启动函数

完成后,右键项目启动文件,重新Generate一次项目即可使用自定义的AR定位

---

图像坐标校正

由于每个AR系统的生成的图像与UE4坐标轴匹配都不相同,故需要在 FCameraTexture.direction 中指定图像旋转方向

enum class FImageDirection : uint8
{
	
	LEFT = 2,
	RIGHT = 3,
	UP = 0,
	DOWN = 1
};

• AR显示的正常画面:

• 示例:ARKit与ARCore图像:

以ARKit ARCore为例:图像向左旋转了-90度,所以设置为:

 ct.direction = FImageDirection::LEFT;

• 在SpaceTarget中我们约定图片朝向为:

以此得出正确的朝向关系

void USpaceTargetSubsystem::FixImageAixs(FImageDirection dir, ImageAixs& tempaix)
{
	switch (dir)
	{
	case FImageDirection::LEFT:
		tempaix.X = FString("-z");
		tempaix.Y = FString("-y");
		tempaix.Z = FString("x");
		break;
	case FImageDirection::RIGHT:
		tempaix.X = FString("z");
		tempaix.Y = FString("y");
		tempaix.Z = FString("x");
		break;
	case FImageDirection::UP:
		tempaix.X = FString("y");
		tempaix.Y = FString("-z");
		tempaix.Z = FString("x");
		break;
	case FImageDirection::DOWN:
		tempaix.X = FString("-y");
		tempaix.Y = FString("z");
		tempaix.Z = FString("x");
		break;
	}
}