C# XNA顶点法线计算不适用于立方体
我有一个函数,可以计算大多数基本体的顶点法线。但它似乎无法处理立方体 当我尝试使用漫反射光着色器时,它会给出这样的结果(右侧相同) 这是我计算法线的代码:C# XNA顶点法线计算不适用于立方体,c#,3d,xna,cube,vertex,C#,3d,Xna,Cube,Vertex,我有一个函数,可以计算大多数基本体的顶点法线。但它似乎无法处理立方体 当我尝试使用漫反射光着色器时,它会给出这样的结果(右侧相同) 这是我计算法线的代码: public virtual void GenerateNormals() { for (int i = 0; i < vertices.Length; i++) vertices[i].Normal = new Vector3(0, 0, 0); for (int i
public virtual void GenerateNormals()
{
for (int i = 0; i < vertices.Length; i++)
vertices[i].Normal = new Vector3(0, 0, 0);
for (int i = 0; i < indices.Length / 3; i++)
{
Vector3 firstvec = vertices[indices[i * 3 + 1]].Position - vertices[indices[i * 3]].Position;
Vector3 secondvec = vertices[indices[i * 3]].Position - vertices[indices[i * 3 + 2]].Position;
Vector3 normal = Vector3.Cross(firstvec, secondvec);
normal.Normalize();
vertices[indices[i * 3]].Normal += normal;
vertices[indices[i * 3 + 1]].Normal += normal;
vertices[indices[i * 3 + 2]].Normal += normal;
}
for (int i = 0; i < vertices.Length; i++)
if (vertices[i].Normal != Vector3.Zero) vertices[i].Normal.Normalize();
}
指数如下:
Vector3[] vectors = new Vector3[8];
vectors[0] = new Vector3(-1, 1, -1);
vectors[1] = new Vector3(1, 1, -1);
vectors[2] = new Vector3(-1, 1, 1);
vectors[3] = new Vector3(1, 1, 1);
vectors[4] = new Vector3(-1, -1, -1);
vectors[5] = new Vector3(1, -1, -1);
vectors[6] = new Vector3(-1, -1, 1);
vectors[7] = new Vector3(1, -1, 1);
vertices = new VertexPositionNormalColored[24];
//Top
vertices[0].Position = vectors[0];
vertices[0].Color = TopColor;
vertices[1].Position = vectors[1];
vertices[1].Color = TopColor;
vertices[2].Position = vectors[2];
vertices[2].Color = TopColor;
vertices[3].Position = vectors[3];
vertices[3].Color = TopColor;
//Bottom
vertices[4].Position = vectors[4];
vertices[4].Color = BottomColor;
vertices[5].Position = vectors[5];
vertices[5].Color = BottomColor;
vertices[6].Position = vectors[6];
vertices[6].Color = BottomColor;
vertices[7].Position = vectors[7];
vertices[7].Color = BottomColor;
//Left
vertices[8].Position = vectors[2];
vertices[8].Color = LeftColor;
vertices[9].Position = vectors[0];
vertices[9].Color = LeftColor;
vertices[10].Position = vectors[6];
vertices[10].Color = LeftColor;
vertices[11].Position = vectors[4];
vertices[11].Color = LeftColor;
//Right
vertices[12].Position = vectors[3];
vertices[12].Color = RightColor;
vertices[13].Position = vectors[1];
vertices[13].Color = RightColor;
vertices[14].Position = vectors[7];
vertices[14].Color = RightColor;
vertices[15].Position = vectors[5];
vertices[15].Color = RightColor;
//Back
vertices[16].Position = vectors[0];
vertices[16].Color = BackColor;
vertices[17].Position = vectors[1];
vertices[17].Color = BackColor;
vertices[18].Position = vectors[4];
vertices[18].Color = BackColor;
vertices[19].Position = vectors[5];
vertices[19].Color = BackColor;
//Front
vertices[20].Position = vectors[2];
vertices[20].Color = FrontColor;
vertices[21].Position = vectors[3];
vertices[21].Color = FrontColor;
vertices[22].Position = vectors[6];
vertices[22].Color = FrontColor;
vertices[23].Position = vectors[7];
vertices[23].Color = FrontColor;
indices = new int[36];
//Top
indices[0] = 0;
indices[1] = 1;
indices[2] = 2;
indices[3] = 2;
indices[4] = 3;
indices[5] = 1;
//Back
indices[6] = 16;
indices[7] = 17;
indices[8] = 18;
indices[9] = 18;
indices[10] = 19;
indices[11] = 17;
//Left
indices[12] = 8;
indices[13] = 9;
indices[14] = 10;
indices[15] = 10;
indices[16] = 11;
indices[17] = 9;
//Front
indices[18] = 20;
indices[19] = 21;
indices[20] = 22;
indices[21] = 22;
indices[22] = 23;
indices[23] = 21;
//Right
indices[24] = 12;
indices[25] = 13;
indices[26] = 14;
indices[27] = 14;
indices[28] = 15;
indices[29] = 13;
//Bottom
indices[30] = 4;
indices[31] = 5;
indices[32] = 6;
indices[33] = 6;
indices[34] = 7;
indices[35] = 5;
我希望专家能帮我找到解决办法。提前谢谢 Hmm,看起来您正在计算(和求和)某些顶点的法线两次(因为您正在遍历索引数组,并且每个面重用一些顶点)。但是法线应该是相同的,并且规格化应该去掉这一点。我怀疑计算出的法线在第一次移动时朝一个方向移动,然后在下一次移动时朝相反方向移动,从而导致法线为(0,0,0)
尝试跳过索引数组并直接遍历顶点数组,只计算每个顶点的法线一次。由于两个不同三角形中的顶点顺序不同,因此会得到此结果 在右手系统中,第一个三角形
{(-1,1,-1),(1,1,-1),(-1,1)}
按顺时针顺序排列,而第二个三角形{(-1,1,1),(1,1,-1)}
按逆时针顺序排列
这些三角形的法线将具有不同的方向。我使用标记数组来获得更平滑的结果。我在网上查过,所以这不成问题。啊,我明白了。不过,我看不出在这种情况下有什么区别,因为只有共享顶点的三角形彼此完全平行。我知道,但我不仅对立方体使用这种方法,而且对其他形状也使用这种方法。我知道会是这样的。现在这个问题的解决方案来了。就像试着去做,直到它变好。我想我会在扑杀的帮助下解决它。无论如何,谢谢你的回答!现在我知道立方体是问题所在,而不是我计算法线的方式。