有两种转换：
1.使用6个正方形组成的CubeMap。
这种比较简单，排版好就行：
2.全景图转成CubeMap。
借鉴Unity商店里面的插件：PanoramaToCubemap
可以直接将鱼眼那种的全景贴图转为CubeMap。
需要注意的是这两种转换后，得到的贴图都存在水平或者垂直方向的翻转问题。
完整代码：
using UnityEngine; public static class CubeMapAndTexture2D { /// <summary> /// 使用6平面贴图得到CubeMap /// </summary> /// <param name="tempTex"></param> /// <returns></returns> public static Cubemap GetCubeMapByCubeTexture2D(Texture2D tempTex) { tempTex = FlipPixels(tempTex, false, true); int everyW = (int)(tempTex.width / 4f); int everyH = (int)(tempTex.height / 3f); int cubeMapSize = Mathf.Min(everyW, everyH); Cubemap cubemap = new Cubemap(cubeMapSize, TextureFormat.RGB24, false); cubemap.SetPixels(tempTex.GetPixels(cubeMapSize, 0, cubeMapSize, cubeMapSize), CubemapFace.PositiveY); cubemap.SetPixels(tempTex.GetPixels(0, cubeMapSize, cubeMapSize, cubeMapSize), CubemapFace.NegativeX); cubemap.SetPixels(tempTex.GetPixels(cubeMapSize, cubeMapSize, cubeMapSize, cubeMapSize), CubemapFace.PositiveZ); cubemap.SetPixels(tempTex.GetPixels(2 * cubeMapSize, cubeMapSize, cubeMapSize, cubeMapSize), CubemapFace.PositiveX); cubemap.SetPixels(tempTex.GetPixels(3 * cubeMapSize, cubeMapSize, cubeMapSize, cubeMapSize), CubemapFace.NegativeZ); cubemap.SetPixels(tempTex.GetPixels(cubeMapSize, 2 * cubeMapSize, cubeMapSize, cubeMapSize), CubemapFace.NegativeY); cubemap.Apply(); return cubemap; } /// <summary> /// 使用Panorado全景图获取CubeMap /// </summary> /// <param name="tempTex"></param> /// <returns></returns> public static Cubemap GetCubeMapByPanoradoTexture2D(Texture2D tempTex) { int everyW = (int)(tempTex.width / 4f); int everyH = (int)(tempTex.height / 3f); int cubeMapSize = Mathf.Min(everyW, everyH); Cubemap cubemap = new Cubemap(cubeMapSize, TextureFormat.RGB24, false); cubemap.SetPixels(CreateCubemapTexture(tempTex, cubeMapSize, 0).GetPixels(), CubemapFace.PositiveZ); cubemap.SetPixels(CreateCubemapTexture(tempTex, cubeMapSize, 1).GetPixels(), CubemapFace.NegativeZ); cubemap.SetPixels(CreateCubemapTexture(tempTex, cubeMapSize, 2).GetPixels(), CubemapFace.NegativeX); cubemap.SetPixels(CreateCubemapTexture(tempTex, cubeMapSize, 3).GetPixels(), CubemapFace.PositiveX); cubemap.SetPixels(CreateCubemapTexture(tempTex, cubeMapSize, 4).GetPixels(), CubemapFace.PositiveY); cubemap.SetPixels(CreateCubemapTexture(tempTex, cubeMapSize, 5).GetPixels(), CubemapFace.NegativeY); cubemap.Apply(); return cubemap; } static Texture2D CreateCubemapTexture(Texture2D m_srcTexture, int texSize, int faceIndex, string fileName = null) { Texture2D tex = new Texture2D(texSize, texSize, TextureFormat.RGB24, false); Vector3[] vDirA = new Vector3[4]; if (faceIndex == 0) { vDirA[0] = new Vector3(-1.0f, -1.0f, -1.0f); vDirA[1] = new Vector3(1.0f, -1.0f, -1.0f); vDirA[2] = new Vector3(-1.0f, 1.0f, -1.0f); vDirA[3] = new Vector3(1.0f, 1.0f, -1.0f); } if (faceIndex == 1) { vDirA[0] = new Vector3(1.0f, -1.0f, 1.0f); vDirA[1] = new Vector3(-1.0f, -1.0f, 1.0f); vDirA[2] = new Vector3(1.0f, 1.0f, 1.0f); vDirA[3] = new Vector3(-1.0f, 1.0f, 1.0f); } if (faceIndex == 2) { vDirA[0] = new Vector3(1.0f, -1.0f, -1.0f); vDirA[1] = new Vector3(1.0f, -1.0f, 1.0f); vDirA[2] = new Vector3(1.0f, 1.0f, -1.0f); vDirA[3] = new Vector3(1.0f, 1.0f, 1.0f); } if (faceIndex == 3) { vDirA[0] = new Vector3(-1.0f, -1.0f, 1.0f); vDirA[1] = new Vector3(-1.0f, -1.0f, -1.0f); vDirA[2] = new Vector3(-1.0f, 1.0f, 1.0f); vDirA[3] = new Vector3(-1.0f, 1.0f, -1.0f); } if (faceIndex == 4) { vDirA[0] = new Vector3(-1.0f, 1.0f, -1.0f); vDirA[1] = new Vector3(1.0f, 1.0f, -1.0f); vDirA[2] = new Vector3(-1.0f, 1.0f, 1.0f); vDirA[3] = new Vector3(1.0f, 1.0f, 1.0f); } if (faceIndex == 5) { vDirA[0] = new Vector3(-1.0f, -1.0f, 1.0f); vDirA[1] = new Vector3(1.0f, -1.0f, 1.0f); vDirA[2] = new Vector3(-1.0f, -1.0f, -1.0f); vDirA[3] = new Vector3(1.0f, -1.0f, -1.0f); } Vector3 rotDX1 = (vDirA[1] - vDirA[0]) / (float)texSize; Vector3 rotDX2 = (vDirA[3] - vDirA[2]) / (float)texSize; float dy = 1.0f / (float)texSize; float fy = 0.0f; Color[] cols = new Color[texSize]; for (int y = 0; y < texSize; y++) { Vector3 xv1 = vDirA[0]; Vector3 xv2 = vDirA[2]; for (int x = 0; x < texSize; x++) { Vector3 v = ((xv2 - xv1) * fy) + xv1; v.Normalize(); cols[x] = CalcProjectionSpherical(m_srcTexture, v); xv1 += rotDX1; xv2 += rotDX2; } tex.SetPixels(0, y, texSize, 1, cols); fy += dy; } tex.wrapMode = TextureWrapMode.Clamp; // 在cubemap的情况下，如果不在wrapMode上Clapp的话，就会看到边界。 tex.Apply(); tex = FlipPixels(tex, true, true); return tex; } static Color CalcProjectionSpherical(Texture2D m_srcTexture, Vector3 vDir) { float theta = Mathf.Atan2(vDir.z, vDir.x); // -π ～ +π（水平方向旋转）. float phi = Mathf.Acos(vDir.y); // 0 ～ +π（垂直方向旋转）. while (theta < -Mathf.PI) theta += Mathf.PI + Mathf.PI; while (theta > Mathf.PI) theta -= Mathf.PI + Mathf.PI; float dx = theta / Mathf.PI; // -1.0 ～ +1.0. float dy = phi / Mathf.PI; // 0.0 ～ +1.0. dx = dx * 0.5f + 0.5f; int px = (int)(dx * (float)m_srcTexture.width); if (px < 0) px = 0; if (px >= m_srcTexture.width) px = m_srcTexture.width - 1; int py = (int)(dy * (float)m_srcTexture.height); if (py < 0) py = 0; if (py >= m_srcTexture.height) py = m_srcTexture.height - 1; Color col = m_srcTexture.GetPixel(px, m_srcTexture.height - py - 1); return col; } /// <summary> /// 水平/垂直反转帖图象素 /// </summary> /// <param name="texture"></param> /// <param name="flipX"></param> /// <param name="flipY"></param> /// <returns></returns> public static Texture2D FlipPixels(Texture2D texture, bool flipX, bool flipY) { if (!flipX && !flipY) { return texture; } if (flipX) { for (int i = 0; i < texture.width / 2; i++) { for (int j = 0; j < texture.height; j++) { Color tempC = texture.GetPixel(i, j); texture.SetPixel(i, j, texture.GetPixel(texture.width - 1 - i, j)); texture.SetPixel(texture.width - 1 - i, j, tempC); } } } if (flipY) { for (int i = 0; i < texture.width; i++) { for (int j = 0; j < texture.height / 2; j++) { Color tempC = texture.GetPixel(i, j); texture.SetPixel(i, j, texture.GetPixel(i, texture.height - 1 - j)); texture.SetPixel(i, texture.height - 1 - j, tempC); } } } texture.Apply(); return texture; } /// <summary> /// 将CubeMap转为普通贴图 /// </summary> /// <param name="cubemap"></param> /// <returns></returns> public static Texture2D GetTexture2DByCubeMap(Cubemap cubemap) { int everyW = cubemap.width; int everyH = cubemap.height; Texture2D texture2D = new Texture2D(everyW * 4, everyH * 3); texture2D.SetPixels(everyW, 0, everyW, everyH, cubemap.GetPixels(CubemapFace.PositiveY)); texture2D.SetPixels(0, everyH, everyW, everyH, cubemap.GetPixels(CubemapFace.NegativeX)); texture2D.SetPixels(everyW, everyH, everyW, everyH, cubemap.GetPixels(CubemapFace.PositiveZ)); texture2D.SetPixels(2 * everyW, everyH, everyW, everyH, cubemap.GetPixels(CubemapFace.PositiveX)); texture2D.SetPixels(3 * everyW, everyH, everyW, everyH, cubemap.GetPixels(CubemapFace.NegativeZ)); texture2D.SetPixels(everyW, 2 * everyH, everyW, everyH, cubemap.GetPixels(CubemapFace.NegativeY)); texture2D.Apply(); texture2D = FlipPixels(texture2D, false, true); return texture2D; } }
就这样！
拜拜~