public static Matrix4x4 GenerateJitteredProjectionMatrixFromOriginal()

in unity/Assets/PostProcessingV2/Runtime/Utils/RuntimeUtilities.cs [428:489]
47 lines of code
1 McCabe index (conditional complexity)

        public static Matrix4x4 GenerateJitteredProjectionMatrixFromOriginal(PostProcessRenderContext context, Matrix4x4 origProj, Vector2 jitter)
        {
#if UNITY_2017_2_OR_NEWER
            var planes = origProj.decomposeProjection;

            float vertFov = Math.Abs(planes.top) + Math.Abs(planes.bottom);
            float horizFov = Math.Abs(planes.left) + Math.Abs(planes.right);

            var planeJitter = new Vector2(jitter.x * horizFov / context.screenWidth,
                                          jitter.y * vertFov / context.screenHeight);

            planes.left += planeJitter.x;
            planes.right += planeJitter.x;
            planes.top += planeJitter.y;
            planes.bottom += planeJitter.y;

            var jitteredMatrix = Matrix4x4.Frustum(planes);

            return jitteredMatrix;
#else
            var rTan = (1.0f + origProj[0, 2]) / origProj[0, 0];
            var lTan = (-1.0f + origProj[0, 2]) / origProj[0, 0];

            var tTan = (1.0f + origProj[1, 2]) / origProj[1, 1];
            var bTan = (-1.0f + origProj[1, 2]) / origProj[1, 1];

            float tanVertFov = Math.Abs(tTan) + Math.Abs(bTan);
            float tanHorizFov = Math.Abs(lTan) + Math.Abs(rTan);

            jitter.x *= tanHorizFov / context.screenWidth;
            jitter.y *= tanVertFov / context.screenHeight;

            float left = jitter.x + lTan;
            float right = jitter.x + rTan;
            float top = jitter.y + tTan;
            float bottom = jitter.y + bTan;

            var jitteredMatrix = new Matrix4x4();

            jitteredMatrix[0, 0] = 2f / (right - left);
            jitteredMatrix[0, 1] = 0f;
            jitteredMatrix[0, 2] = (right + left) / (right - left);
            jitteredMatrix[0, 3] = 0f;

            jitteredMatrix[1, 0] = 0f;
            jitteredMatrix[1, 1] = 2f / (top - bottom);
            jitteredMatrix[1, 2] = (top + bottom) / (top - bottom);
            jitteredMatrix[1, 3] = 0f;

            jitteredMatrix[2, 0] = 0f;
            jitteredMatrix[2, 1] = 0f;
            jitteredMatrix[2, 2] = origProj[2, 2];
            jitteredMatrix[2, 3] = origProj[2, 3];

            jitteredMatrix[3, 0] = 0f;
            jitteredMatrix[3, 1] = 0f;
            jitteredMatrix[3, 2] = -1f;
            jitteredMatrix[3, 3] = 0f;

            return jitteredMatrix;
#endif
        }