瑞金网站建设推广,哪里免费做网站,中学网站建设方案,北京网站维护在上一篇UE5.5 PCGFrameWork使用入门-CSDN博客 大致介绍了UE5 PCG框架的基本使用.
本篇探索PCGFrame的高级应用--GPU点云。也就是利用GPU HLSL编程对点云进行操纵#xff0c;可以大幅度提升点云生成效率。
目前在UE5 PCG框架中#xff0c;点云GPU的应用大致分为三类: Point…在上一篇UE5.5 PCGFrameWork使用入门-CSDN博客 大致介绍了UE5 PCG框架的基本使用.
本篇探索PCGFrame的高级应用--GPU点云。也就是利用GPU HLSL编程对点云进行操纵可以大幅度提升点云生成效率。
目前在UE5 PCG框架中点云GPU的应用大致分为三类: PointGenerator, PointProcessor, Custom GPU节点
三种模式下是同一个节点只是选择模式GPU变量预声明GPU函数等存在一些差别。 SourceEditor
SourceEditor可以打开相应模式下的GPU可以看到预先声明变量和各种公用函数。 PointGenerator
预先生成的点云函数和变量
预生成数量
预定义生成点云的数量, 在GPU HLSL NumPoints和ElementIndex 输入声明(Input Declartions)
由节点的输入类型和名字动态决定来生成相应输入函数可以用来在GPU获取点云地形纹理等数据类型有下面几种 比如增加一个点云输入和地形数据输入 预先生成输入代码: 下面具体分析每种类型输入的相应简单使用
点云输入
InPosition名的点云输入 /*** INPUT DATA FUNCTIONS ***/uint InPosition_GetNumData();
uint InPosition_GetNumElements();
uint InPosition_GetNumElements(uint DataIndex);// Valid types: bool, int, float, float2, float3, float4, Rotator (float3), Quat (float4), Transform (float4x4), StringKey (int), Name (uint2)type InPosition_Gettype(uint DataIndex, uint ElementIndex, int AttributeId);
type InPosition_Gettype(uint DataIndex, uint ElementIndex, AttributeName);/*** INPUT POINT DATA FUNCTIONS ***/float3 InPosition_GetPosition(uint DataIndex, uint ElementIndex);
float4 InPosition_GetRotation(uint DataIndex, uint ElementIndex);
float3 InPosition_GetScale(uint DataIndex, uint ElementIndex);
float3 InPosition_GetBoundsMin(uint DataIndex, uint ElementIndex);
float3 InPosition_GetBoundsMax(uint DataIndex, uint ElementIndex);
float4 InPosition_GetColor(uint DataIndex, uint ElementIndex);
float InPosition_GetDensity(uint DataIndex, uint ElementIndex);
int InPosition_GetSeed(uint DataIndex, uint ElementIndex);
float InPosition_GetSteepness(uint DataIndex, uint ElementIndex);
float4x4 InPosition_GetPointTransform(uint DataIndex, uint ElementIndex);
bool InPosition_IsPointRemoved(uint DataIndex, uint ElementIndex);
这里暂时不清楚NumData意义可以确定的并不是点云数量
这里的Type代表你获取数据的类型, 而ElementIndex代码第N个点云DataIndex暂时推荐都使用0.
InPosition_GetNumElements
获取输入点云的数量
InPosition_Gettype
这里是获取第N个点云的相应属性, 这里有两种方法
[1]通过属性序号来获取
type InPosition_Gettype(uint DataIndex, uint ElementIndex, int AttributeId);
案例: 获取输入的第2个点云的位置Position的AttributeId为0
float3 Position InPosition_GetFloat3(0, 1, 0);
[2]一种是通过属性名字来获取
type InPosition_Gettype(uint DataIndex, uint ElementIndex, AttributeName);
案例: 获取输入的第2个点云的位置Position的名字为$Position, 注意单引号和$字符前缀
否则会报语法错误.当然类型映射措辞和属性名字不存在也会报语法错误. float3 Position InPosition_GetFloat3(0, 0, $Position);
InPosition_GetXXX
这里比较容易理解直接获取点云各种属性(位置缩放旋转Color, Bound等等)。
float3 InPosition_GetPosition(uint DataIndex, uint ElementIndex);
float4 InPosition_GetRotation(uint DataIndex, uint ElementIndex);
float3 InPosition_GetScale(uint DataIndex, uint ElementIndex);
float3 InPosition_GetBoundsMin(uint DataIndex, uint ElementIndex);
float3 InPosition_GetBoundsMax(uint DataIndex, uint ElementIndex);
float4 InPosition_GetColor(uint DataIndex, uint ElementIndex);
float InPosition_GetDensity(uint DataIndex, uint ElementIndex);
int InPosition_GetSeed(uint DataIndex, uint ElementIndex);
float InPosition_GetSteepness(uint DataIndex, uint ElementIndex);
float4x4 InPosition_GetPointTransform(uint DataIndex, uint ElementIndex);
bool InPosition_IsPointRemoved(uint DataIndex, uint ElementIndex);
地形输入
Landscape名的地形输入 float Landscape_GetHeight(float3 WorldPos);
float3 Landscape_GetNormal(float3 WorldPos);
这里不用解释太多就是根据WorldPos采样地形的高度和法线等属性
纹理输入
“Texture”名的纹理输入 float2 Texture_GetTexCoords(float2 WorldPos, float2 Min, float2 Max);
float4 Texture_Sample(uint DataIndex, float2 TexCoords);// Computes sample coordinates of the WorldPos relative to the texture datas bounds.float4
Texture_SampleWorldPos(uint DataIndex, float2 WorldPos);
案例: 在一个PCG Volume的Grid2D点云设置相应的纹理值为点云缩放
float3 Min GetComponentBoundsMin(); // World-space
float3 Max GetComponentBoundsMax(); // World-space
float3 InPosition CreateGrid2D(ElementIndex, NumPoints, Min, Max);
float2 UV Texture_GetTexCoords(float2(InPosition.x, InPosition.y), Min, Max);
float4 SampleValue Texture_Sample(0, UV);
Out_SetScale(Out_DataIndex, ElementIndex, float3(SampleValue.x, SampleValue.x, SampleValue.x));
Out_SetPosition(Out_DataIndex, ElementIndex, InPosition);AttributeSet 输出函数(Output Declarations)
/*** OUTPUT DATA FUNCTIONS ***/// Valid types: bool, int, float, float2, float3, float4, Rotator (float3), Quat (float4), Transform (float4x4), StringKey (int), Name (uint2)void Out_Settype(uint DataIndex, uint ElementIndex, int AttributeId, type Value);
void Out_Settype(uint DataIndex, uint ElementIndex, AttributeName, type Value);/*** OUTPUT POINT DATA FUNCTIONS ***/void Out_InitializePoint(uint DataIndex, uint ElementIndex);
void Out_CopyElementFrom_input pin(uint TargetDataIndex, uint TargetElementIndex, uint SourceDataIndex, uint SourceElementIndex);
bool Out_RemovePoint(uint DataIndex, uint ElementIndex);void Out_SetPosition(uint DataIndex, uint ElementIndex, float3 Position);
void Out_SetRotation(uint DataIndex, uint ElementIndex, float4 Rotation);
void Out_SetScale(uint DataIndex, uint ElementIndex, float3 Scale);
void Out_SetBoundsMin(uint DataIndex, uint ElementIndex, float3 BoundsMin);
void Out_SetBoundsMax(uint DataIndex, uint ElementIndex, float3 BoundsMax);
void Out_SetColor(uint DataIndex, uint ElementIndex, float4 Color);
void Out_SetDensity(uint DataIndex, uint ElementIndex, float Density);
void Out_SetSeed(uint DataIndex, uint ElementIndex, int Seed);
void Out_SetSteepness(uint DataIndex, uint ElementIndex, float Steepness);
void Out_SetPointTransform(uint DataIndex, uint ElementIndex, float4x4 Transform);
设置输出点云数据的各种函数(虽然Ouput引脚支持各种类型暂时只发现只有Point类型可以输出)
这里和上面的输入函数用法基本一致。主要解释一个特殊函数:
Out_RemovePoint(Out_DataIndex, ElementIndex);
这个函数用于移除某个ElementIndex的点云
代码例子: 移除ElementIndex为3的整数倍的点云
if(ElementIndex % 3 0)Out_RemovePoint(Out_DataIndex, ElementIndex);
辅助函数(Helper Declarations)
/*** HELPER FUNCTIONS ***/int3 GetNumThreads();
uint GetThreadCountMultiplier();// Returns false if thread has no data to operate on.
// Valid pins: InPosition, Landscape, Texture, Out
bool pin_GetThreadData(uint ThreadIndex, out uint OutDataIndex, out uint OutElementIndex);float3 GetComponentBoundsMin(); // World-space
float3 GetComponentBoundsMax();
uint GetSeed();float FRand(inout uint Seed); // Returns random float between 0 and 1.
uint ComputeSeed(uint A, uint B);
uint ComputeSeed(uint A, uint B, uint C);
uint ComputeSeedFromPosition(float3 Position);// Returns the position of the Nth point in a 2D or 3D grid with the given constraints.
float3 CreateGrid2D(int ElementIndex, int NumPoints, float3 Min, float3 Max);
float3 CreateGrid2D(int ElementIndex, int NumPoints, int NumRows, float3 Min, float3 Max);
float3 CreateGrid3D(int ElementIndex, int NumPoints, float3 Min, float3 Max);
float3 CreateGrid3D(int ElementIndex, int NumPoints, int NumRows, int NumCols, float3 Min, float3 Max);
GetComponentBoundsMin和GetComponentBoundsMax
获取PCG Volume的BoundMin, BoundMax 随机函数
uint GetSeed();float FRand(inout uint Seed); // Returns random float between 0 and 1.
uint ComputeSeed(uint A, uint B);
uint ComputeSeed(uint A, uint B, uint C);
uint ComputeSeedFromPosition(float3 Position);
和随机种子和随机值密切相关的一组函数非常常见的配套函数.
GetSeed函数获取的种子来自节点面板: 创建Grid点云函数
// Returns the position of the Nth point in a 2D or 3D grid with the given constraints.
float3 CreateGrid2D(int ElementIndex, int NumPoints, float3 Min, float3 Max);
float3 CreateGrid2D(int ElementIndex, int NumPoints, int NumRows, float3 Min, float3 Max);
float3 CreateGrid3D(int ElementIndex, int NumPoints, float3 Min, float3 Max);
float3 CreateGrid3D(int ElementIndex, int NumPoints, int NumRows, int NumCols, float3 Min, float3 Max);
一组可以让用户快速创建Grid(2D或者3D)点云的函数
演示一个案例: 创建400个 行数为10的Grid 2D点云
使用
float3 CreateGrid2D(int ElementIndex, int NumPoints, int NumRows, float3 Min, float3 Max); 完整代码:
float3 Min GetComponentBoundsMin(); // World-space
float3 Max GetComponentBoundsMax(); // World-space
float3 InPosition CreateGrid2D(ElementIndex, NumPoints, 10, Min, Max);
Out_SetPosition(Out_DataIndex, ElementIndex, InPosition);演示效果: 自定义函数(ShaderFunction) 用户自定义函数如何生成各种分形点云各种自定义几何形状分布的点云等等
演示Demo: 生成一个以某点位置为中心的贴地形点云圆圈 GPU代码相关
Shader Function
/** CUSTOM SHADER FUNCTIONS **/float3 CreateCircle2D(uint ElementIndex, int NumPoints, float3 Center, float Radius)
{// 计算角度均匀分布float Angle 2 * 3.14159265358979323846 * ElementIndex / NumPoints;// 极坐标转笛卡尔坐标float X Center.x Radius * cos(Angle);float Z Center.y Radius * sin(Angle);return float3(X, Z, 0);
}
Shader Source
float3 InPosition InPosition_GetFloat3(0, 0, 0);
float3 Position CreateCircle2D(ElementIndex, NumPoints, InPosition, 3000.0);
float Height Landscape_GetHeight(Position);
Position.z Height;
Out_SetPosition(Out_DataIndex, ElementIndex, Position);
运行Demo效果
跟随PCG Actor移动的贴地点云圆圈 PointProcessor和Custom
目前看PointProcessor和Custom像PointGenerator除了无法预定义点云数量, 暂时看不出什么和PointGenerator存在什么区别 参考资料
[1]PCG: Advanced Topics New Features in UE 5.5 | Unreal Fest 2024
[2]Unreal Engine 5.5 - Compute Shaders With PCG Introduction (Height Thresholding in HLSL)
[3]Unreal Engine 5.5 - PCG Compute Introduction (Fractals in HLSL)
[4]Directx11入门教程四十八之小议ComputeShader_dx11 dispatch-CSDN博客
