Question

我为每个世界，视图和投影变换都有一个SlimDX矩阵。根据{{3}}，投影变换将坐标保留在（-1,1）^ 3立方体中。

我认为通过将相对于渲染目标的鼠标位置转换为投影空间（即将其缩放到（-1,1）范围并将其固定在z轴上的-1）然后应用反转的世界观投影。

以下代码显示了我的尝试。我的测试是运行应用程序并使用鼠标滚轮放大和缩小，看看打印的X坐标是否改变，同时将鼠标光标保持在窗口的左边缘 - 它不会在某处出现错误。

form.MouseMove += (obj, eargs) =>
        {
            SlimDX.Matrix worldview = SlimDX.Matrix.Multiply(SlimDX.Matrix.Identity, viewMatrix);
            SlimDX.Matrix worldviewprojection = SlimDX.Matrix.Multiply(worldview, projectionMatrix);
            worldviewprojection.Invert();

            var pointX = (float)((2.0 * ((float)eargs.Location.X) / (float)form.Width) - 1.0f);
            var pointY = (float)((2.0 * (((float)eargs.Location.Y) / (float)form.Height)) - 1.0f) * -1.0f;
            var mouseInProjectionSpace = new Vector4(pointX, pointY, -1.0f, 1.0f);
            var mouseInWorldSpace = Vector4.Transform(mouseInProjectionSpace, worldviewprojection);
            Console.WriteLine(mouseInWorldSpace);
        };

        form.MouseWheel += (_, __) =>
            {
                if (__.Delta > 0)
                    cam.Z /= 2.0f;
                else
                    cam.Z *= 2.0f;
                viewMatrix = GetView(cam);
                Console.WriteLine("zzz="+cam.Z);
            };

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Answer 1

你的z错了，因为在投影空间z是0（近平面）到1（远平面）

所以它确实：

Vector2 mouse = //Normalized as -1 to 1 (as you did)
Vector3 orig = new Vector3(mouse.X,mouse.Y,0.0f);
Vector3 far = new Vector3(mouse.X,mouse.Y,1.0f);

//This gets mouse position on near plane
Vector3 origin = Vector3.TransformCoordinate(orig,worldviewprojectioninverse);

//This gets mouse position on far plane
Vector3 posfar = Vector3.TransformCoordinate(far,worldviewprojectioninverse);

如何将鼠标转换为世界坐标？

1 个答案: