3

几天来，我一直在 XNA 的一个项目上工作。该应用程序的主要思想是有一个可以单独翻转的平面彩色瓷砖网格。我遇到的问题是我无法真正弄清楚如何围绕瓷砖单个中心轴进行翻转旋转。

现在发生的事情是图块围绕世界轴而不是它自己的轴旋转。

每个图块由一组顶点组成，这些顶点在 3D 世界中创建一个二维正方形。

我很确定问题与我弄乱了矩阵有关。

以下是每个单独图块的代码：

public Tile(Vector3 position, int size, Matrix world)
    {
        this.position = position;
        this.size = size;
        this.world = world;

        vertices = new VertexPositionColor[6];

        for (int i = 0; i < vertices.Length; i++)
            vertices[i].Position = position;

        vertices[0].Position += new Vector3(0, 0, 0);
        vertices[0].Color = Color.Pink;
        vertices[1].Position += new Vector3(0, size, 0);
        vertices[1].Color = Color.Yellow;
        vertices[2].Position += new Vector3(0, size, size);
        vertices[2].Color = Color.Green;

        vertices[3].Position += new Vector3(0, size, size);
        vertices[3].Color = Color.Green;
        vertices[4].Position += new Vector3(0, 0f, size);
        vertices[4].Color = Color.Blue;
        vertices[5].Position += new Vector3(0, 0, 0);
        vertices[5].Color = Color.Blue;
    }

    public VertexPositionColor[] Vertices
    {
        get{ return Functions.TransformVertices((VertexPositionColor[])vertices.Clone(), GetMatrix()); }
    }

    private Matrix GetMatrix()
    {
        return Matrix.CreateRotationZ(rot);
    }


    private void TransformVertices(Matrix matrix)
    {
        for (int i = 0; i < vertices.Length; i++)
            vertices[i].Position = Vector3.Transform(vertices[i].Position, matrix);
    }

这是绘图方法：

protected override void Draw( GameTime gameTime)
    {
        GraphicsDevice.Clear(Color.CornflowerBlue);

        RasterizerState rasterizerState = new RasterizerState();
        rasterizerState.CullMode = CullMode.None;
        GraphicsDevice.RasterizerState = rasterizerState;
        viewMatrix = Matrix.CreateLookAt(cameraPos, new Vector3(0, 0, 0), Vector3.Up);

        effect.CurrentTechnique = effect.Techniques["ColoredNoShading"];
        effect.Parameters["xView"].SetValue(viewMatrix);
        effect.Parameters["xProjection"].SetValue(projectionMatrix);

        Vector3 rotAxis = new Vector3(0, 0, 1);
        rotAxis.Normalize();
        worldMatrix = Matrix.Identity;
        effect.Parameters["xWorld"].SetValue(worldMatrix);

        foreach (EffectPass pass in effect.CurrentTechnique.Passes)
        {
            pass.Apply();

            foreach(Tile tile in tiles)
                GraphicsDevice.DrawUserPrimitives(PrimitiveType.TriangleList, tile.Vertices, 0, 2, VertexPositionColor.VertexDeclaration);
        }

        base.Draw(gameTime);
    }

如果有帮助，我可以将整个源代码发送给您。任何帮助都是无价的！

4

1 回答 1

6

要围绕自己的轴旋转 Tile：

(1) Transform the tile back to the origin.
(2) Perform rotation.
(3) Transform back to original position.
于 2013-08-26T14:34:31.390 回答