重心插值算法
/// <summary>
/// 獲取三角形內(nèi)某點(diǎn)的顏色
/// </summary>
/// <param name="triangles">三角形頂點(diǎn)位置列表</param>
/// <param name="trianglesColor">三角形頂點(diǎn)顏色列表</param>
/// <param name="pointPosition">三角形內(nèi)某位置</param>
/// <returns></returns>
public Color GetTriangleBarycenterColor(Vector3[] triangles, Color[] trianglesColor, Vector3 pointPosition)
{
var A = triangles[0];
var B = triangles[1];
var C = triangles[2];
float a = (-(pointPosition.x - B.x) * (C.y - B.y) + (pointPosition.y - B.y) * (C.x - B.x)) / (-(A.x - B.x) * (C.y - B.y) + (A.y - B.y) * (C.x - B.x));
float b = (-(pointPosition.x - C.x) * (A.y - C.y) + (pointPosition.y - C.y) * (A.x - C.x)) / (-(B.x - C.x) * (A.x - C.y) + (B.y - C.y) * (A.x - C.x));
float c = 1 - a - b;
//Debug.LogError($"a : {a} b :趋箩 c:{c}");
Color colorA = trianglesColor[0];
Color colorB = trianglesColor[1];
Color colorC = trianglesColor[2];
return colorA * a + colorB * b + colorC * c;
}
/// <summary>
/// 頂點(diǎn)是否位于三角形內(nèi)
/// </summary>
/// <param name="point">頂點(diǎn)位置</param>
/// <param name="triangles">三角形頂點(diǎn)</param>
/// <returns></returns>
private bool IsPointInTriangle(Vector3 point, Vector3[] triangles)
{
var A = triangles[0];
var B = triangles[1];
var C = triangles[2];
var v0 = C - A;
var v1 = B - A;
var v2 = point - A;
float dot00 = Vector3.Dot(v0, v0);
float dot01 = Vector3.Dot(v0, v1);
float dot02 = Vector3.Dot(v0, v2);
float dot11 = Vector3.Dot(v1, v1);
float dot12 = Vector3.Dot(v1, v2);
float inverDeno = 1 / (dot00 * dot11 - dot01 * dot01);
float u = (dot11 * dot02 - dot01 * dot12) * inverDeno;
if (u < 0 || u > 1) // if u out of range, return directly
{
return false;
}
float v = (dot00 * dot12 - dot01 * dot02) * inverDeno;
if (v < 0 || v > 1) // if v out of range, return directly
{
return false;
}
return u + v <= 1;
}
