我正在尝试计算世界空间中的视锥角。我已经通过使用 FOV 并使用平面的宽度/高度和一些矢量数学来实现它
但是，许多示例只是说明您可以将像 (1,1,1) 这样的 NDC 角乘以反 viewProjection 矩阵。但是当我这样做时，我会得到一些不同的结果。这是我现在用来测试的代码：
float nearHeight = 2 * tan(mFOV / 2) * mNear;
float nearWidth = mNear * mRatio;
float farHeight = 2 * tan(mFOV / 2) * mFar;
float farWidth = mFar * mRatio;
glm::vec3 fc = mPos + mFront * mFar;
glm::vec3 nc = mPos + mFront * mNear;
mFrustum.frustumCorners[0] = fc + (mUp * farHeight / 2.0f) - (mRight * farWidth / 2.0f);
mFrustum.frustumCorners[1] = fc + (mUp * farHeight / 2.0f) + (mRight * farWidth / 2.0f);
mFrustum.frustumCorners[2] = fc - (mUp * farHeight / 2.0f) - (mRight * farWidth / 2.0f);
mFrustum.frustumCorners[3] = fc - (mUp * farHeight / 2.0f) + (mRight * farWidth / 2.0f);
mFrustum.frustumCorners[4] = nc + (mUp * nearHeight / 2.0f) - (mRight * nearWidth / 2.0f);
mFrustum.frustumCorners[5] = nc + (mUp * nearHeight / 2.0f) + (mRight * nearWidth / 2.0f);
mFrustum.frustumCorners[6] = nc - (mUp * nearHeight / 2.0f) - (mRight * nearWidth / 2.0f);
mFrustum.frustumCorners[7] = nc - (mUp * nearHeight / 2.0f) + (mRight * nearWidth / 2.0f);
glm::vec4 test(1.0f, 1.0f, 1.0f,1.0f);
glm::vec4 test2(-1.0f, -1.0f, -1.0f, 1.0f);
glm::mat4 testingMatrix = glm::inverse(mProjectionMatrix * getViewMatrix());
test = testingMatrix*test;
test2 = testingMatrix*test2;
test2.x /= test2.w;
test2.y /= test2.w;
test2.z /= test2.w;
test.x /= test.w;
test.y /= test.w;
test.z /= test.w;
现在，这两个结果都给出了 [near,far] = [1, 10000] 的准确 z 值，但是 x 值相差很大，而 y 值几乎相同。我只是想知道哪种方式最准确？
逆视图投影
定期计算
