unity3d 圖形吧 之 場景中畫圓
阿新 • • 發佈：2019-02-12
先看一下效果：
區別就是一個2d一個3d.
2d就不介紹了，相對簡單一些，對於3d的內容，我們先來看一看數學中的一個題和答案，這樣就很容易理解程式了。
這樣就好辦了！ 直接看下面幾個指令碼吧。
using UnityEngine; using System.Collections; using SunGuangDong.Math; [ExecuteInEditMode] public class DrawCircleMono : MonoBehaviour { private Vector3 m_Normal ; // Use this for initialization void Start () { m_Normal = new Vector3 (0, 1, 0); } void OnDrawGizmos() { Circle2d circle2 = new Circle2d(transform.position, 5); DrawCircle(ref circle2, Color.red); Vector3 center = new Vector3 (transform.position.x, transform.position.y + 0.2f, transform.position.z); Circle3d circle3 = new Circle3d(ref center,ref m_Normal, 5); DrawCircle (circle3, Color.red, 40); } protected void DrawCircle(ref Circle2d circle, Color color) { int count = 40; float delta = 2f * Mathf.PI / count; Vector3 prev = circle.Eval(0); Color tempColor = Gizmos.color; Gizmos.color = color; for (int i = 1; i <= count; ++i) { Vector3 curr = circle.Eval(i * delta); Gizmos.DrawLine(prev, curr); prev = curr; } Gizmos.color = tempColor; } protected void DrawCircle(Vector2 center, float radius, Color color) { Circle2d circle = new Circle2d(ref center, radius); int count = 40; float delta = 2f * Mathf.PI / count; Vector3 prev = circle.Eval(0); Color tempColor = Gizmos.color; Gizmos.color = color; for (int i = 1; i <= count; ++i) { Vector3 curr = circle.Eval(i * delta); Gizmos.DrawLine(prev, curr); prev = curr; } Gizmos.color = tempColor; } protected void DrawCircle(Circle3d circle, Color color, int count = 20) { float delta = 2f * Mathf.PI / count; Vector3 prev = circle.Eval(0); Color tempColor = Gizmos.color; Gizmos.color = color; for (int i = 1; i <= count; ++i) { Vector3 curr = circle.Eval(i * delta); Gizmos.DrawLine(prev, curr); prev = curr; } Gizmos.color = tempColor; } }
上面這個指令碼在 掛到場景中的任意物件上，如Cube
namespace SunGuangDong.Math { using System; using System.Collections.Generic; using System.Runtime.InteropServices; using UnityEngine; [StructLayout(LayoutKind.Sequential)] public struct Circle2d { public Vector2 Center; public float Radius; public Circle2d(ref Vector2 center, float radius) { this.Center = center; this.Radius = radius; } public Circle2d(Vector2 center, float radius) { this.Center = center; this.Radius = radius; } public float CalcPerimeter() { return (6.283185f * this.Radius); } public float CalcArea() { return ((3.141593f * this.Radius) * this.Radius); } public Vector2 Eval(float t) { return new Vector2(this.Center.x + (this.Radius * Mathf.Cos(t)), this.Center.y + (this.Radius * Mathf.Sin(t))); } public Vector2 Eval(float t, float radius) { return new Vector2(this.Center.x + (radius * Mathf.Cos(t)), this.Center.y + (radius * Mathf.Sin(t))); } public bool Contains(ref Vector2 point) { Vector2 vector = point - this.Center; return (vector.magnitude <= (this.Radius * this.Radius)); } public bool Contains(Vector2 point) { Vector2 vector = point - this.Center; return (vector.magnitude <= (this.Radius * this.Radius)); } public void Include(ref Circle2d circle) { Vector2 vector = circle.Center - this.Center; float num = vector.magnitude; float num2 = circle.Radius - this.Radius; float num3 = num2 * num2; if (num3 >= num) { if (num2 >= 0f) { this = circle; } } else { float num4 = Mathf.Sqrt(num); if (num4 > 1E-05f) { float num5 = (num4 + num2) / (2f * num4); this.Center += (Vector2) (num5 * vector); } this.Radius = 0.5f * ((num4 + this.Radius) + circle.Radius); } } public void Include(Circle2d circle) { this.Include(ref circle); } } }
namespace SunGuangDong.Math { using System; using System.Runtime.InteropServices; using UnityEngine; [StructLayout(LayoutKind.Sequential)] public struct Circle3d { public Vector3 Center; public Vector3 Axis0; public Vector3 Axis1; public Vector3 Normal; public float Radius; public Circle3d(ref Vector3 center, ref Vector3 normal, float radius) { this.Center = center; this.Normal = normal; Vector3ex.CreateOrthonormalBasis(out this.Axis0, out this.Axis1, ref this.Normal); this.Radius = radius; } public Circle3d(Vector3 center, Vector3 normal, float radius) { this.Center = center; this.Normal = normal; Vector3ex.CreateOrthonormalBasis(out this.Axis0, out this.Axis1, ref this.Normal); this.Radius = radius; } public float CalcPerimeter() { return (6.283185f * this.Radius); } public float CalcArea() { return ((3.141593f * this.Radius) * this.Radius); } public Vector3 Eval(float t) { return (this.Center + ((Vector3) (this.Radius * ((Mathf.Cos(t) * this.Axis0) + (Mathf.Sin(t) * this.Axis1))))); } public Vector3 Eval(float t, float radius) { return (this.Center + ((Vector3) (radius * ((Mathf.Cos(t) * this.Axis0) + (Mathf.Sin(t) * this.Axis1))))); } } }
namespace SunGuangDong.Math
{
using System;
using System.Collections.Generic;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;
using UnityEngine;
public static class Vector3ex
{
public static readonly Vector3 Zero = new Vector3(0f, 0f, 0f);
public static void CreateOrthonormalBasis(out Vector3 u, out Vector3 v, ref Vector3 w)
{
if (Mathf.Abs(w.x) >= Mathf.Abs(w.y))
{
float num = Mathfex.InvSqrt((w.x * w.x) + (w.z * w.z));
u.x = -w.z * num;
u.y = 0f;
u.z = w.x * num;
v.x = w.y * u.z;
v.y = (w.z * u.x) - (w.x * u.z);
v.z = -w.y * u.x;
}
else
{
float num2 = Mathfex.InvSqrt((w.y * w.y) + (w.z * w.z));
u.x = 0f;
u.y = w.z * num2;
u.z = -w.y * num2;
v.x = (w.y * u.z) - (w.z * u.y);
v.y = -w.x * u.z;
v.z = w.x * u.y;
}
}
}
}namespace SunGuangDong.Math
{
using System;
using System.Runtime.InteropServices;
using UnityEngine;
public static class Mathfex
{
public const float Pi = 3.141593f;
public static float InvSqrt(float value)
{
if (value != 0f)
{
return (1f / Mathf.Sqrt(value));
}
return 0f;
}
}
}
最後附上一些其他圖片吧。
