opentk pitch 旋转使形状变形 [英] opentk pitch rotation deforms the shape

问题描述

我在 c# 中使用 opentk 来渲染 3d 表面并旋转它.偏航工作正常，但俯仰旋转(将对象向相机倾斜)会导致表面变形.

I'm using opentk in c# to render a 3d surface and rotate it. The yaw works fine, but the pitch rotation (tilting the object towards the camera) causes the surface to deform.

左边的图像是我渲染的，它变形了，右边的是正确的.请注意，当音高为零时，它看起来非常好.这是我的代码的要点:

The image on the left is what I'm rendering which is deformed and the one one the right is correct. Note that when the pitch is zero, it looks perfectly fine. Here is the gist of my code:

private void glControl1_Paint(object sender, PaintEventArgs e)
{
    GL.Clear(ClearBufferMask.ColorBufferBit | ClearBufferMask.DepthBufferBit);
    Matrix4 perspective = Matrix4.CreatePerspectiveFieldOfView(1.0f, aspect_ratio, 1.0f, 10000.0f); //Setup Perspective [fovy, aspect, zNear, zFar]
    Matrix4 lookat = Matrix4.LookAt(eye_pos.X, eye_pos.Y, eye_pos.Z, 0, 0, 0, 0, 0, 1); //Setup camera   [eyeX, eyeY, eyeZ, targetX, targetY, targetZ, upX, upY, upZ)]

    GL.MatrixMode(MatrixMode.Projection); //Load Perspective
    GL.LoadIdentity();
    GL.Viewport(0, 0, this.ClientSize.Width, this.ClientSize.Height);
    GL.LoadMatrix(ref perspective);
    GL.MatrixMode(MatrixMode.Modelview); //Load Camera
    GL.LoadIdentity();
    GL.LoadMatrix(ref lookat);
    GL.Viewport(0, 0, glControl1.Width, glControl1.Height); //Size of window
    GL.Enable(EnableCap.DepthTest); //Enable correct Z Drawings
    GL.DepthFunc(DepthFunction.Less); //Enable correct Z Drawings

    //Rotating
    Vector2 xy_view_vector = new Vector2(eye_pos.X, eye_pos.Y);
    xy_view_vector.Normalize();
    Vector2 fold_vec = xy_view_vector.PerpendicularLeft; // this is the line over which you'd tilt the view forward towards the camera
    GL.Rotate((float)numericUpDown2.Value, fold_vec.X, fold_vec.Y, 0.0f);// pitch (tilt forward)
    GL.Rotate((float)numericUpDown1.Value, 0.0f, 0.0f, 1.0f);// yaw rotation - about z


    // axes
    GL.Begin(PrimitiveType.Lines);
    GL.Color3(Color.White);
    GL.Vertex3(-10, 0, 0);
    GL.Vertex3(10, 0, 0);
    GL.Vertex3(0, -10, 0);
    GL.Vertex3(0, 10, 0);
    GL.Vertex3(0, 0, -10);
    GL.Vertex3(0, 0, 10);
    GL.End();

    int i2, j2;
    float z1, z2, z3, z4;
    GL.Begin(PrimitiveType.Quads);
    for (int i = 0; i < data.x.Count - 2; i++)
    {
        for (int j = 0; j < data.y.Count - 2; j++)
        {
            i2 = i + 1;
            j2 = j + 1;
            z1 = data.z[i.ToString() + "," + j.ToString()];
            z2 = data.z[i2.ToString() + "," + j.ToString()];
            z3 = data.z[i2.ToString() + "," + j2.ToString()];
            z4 = data.z[i.ToString() + "," + j2.ToString()];
            GL.Color4(color_map.GetColor((z1 + z3) / 2, data.minz, data.maxz, opacity));

            GL.Vertex3(new Vector3(data.x[i], data.y[j], z1));
            GL.Vertex3(new Vector3(data.x[i2], data.y[j], z2));
            GL.Vertex3(new Vector3(data.x[i2], data.y[j2], z3));
            GL.Vertex3(new Vector3(data.x[i], data.y[j2], z4));
        }
    }
    GL.End();

    GraphicsContext.CurrentContext.VSync = true; //Caps frame rate as to not over run GPU
    glControl1.SwapBuffers(); //Takes from the 'GL' and puts into control
}

我想知道是否有人知道为什么会发生这种情况.拥有一个简单的俯仰/偏航旋转示例会有所帮助 - 因此，如果您知道可以提供帮助的 opentk 示例，我会很高兴将其链接起来.

I was wondering if anyone has a clue as to why this is happening. Having a simple pitch/yaw rotation sample would help - so if you know an opentk sample that can help, I'd appreciate linking it.

推荐答案

我不能确切地告诉你你做错了什么，但我可以粘贴我用来围绕原点的对象旋转相机的代码:

I can not tell you exactly what you are doing wrong, but I can paste the code which I use to rotate the camera around an object at the origin:

void SetupPerspective()
{
    var aspectRatio = Width / (float)Height;
    Projection = Matrix4.CreatePerspectiveFieldOfView(MathHelper.PiOver4, aspectRatio, 0.1f, 10);
    ModelView = Matrix4.Identity;
    // apply camera transform
    Camera.ApplyCamera(ref ModelView);
}

void ApplyCamera(ref Matrix4 modelView)
{
    modelView = Matrix4.CreateRotationY(Yaw)
        * Matrix4.CreateRotationX(Pitch)
        * Matrix4.CreateRotationZ(Roll)
        * Matrix4.CreateTranslation(-Position)
        * modelView;
}

我不使用固定功能管道，但您可以像已经在做的那样设置生成的 Projection 和 ModelView 矩阵.

I don't use the fixed-function pipeline but you could set the resulting Projection and ModelView matrices just like you're already doing it.

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