colors - XNA 4.0 奇怪的颜色错误

Question

我在使用 XNA 绘制地形时遇到问题，特别是颜色（VertexPositionColorNormal 和 VertexPositionTextureNormal 会发生这种情况）。我的代码如下：

public BasicEffect GetEffectForColoredTerrain()
{
    this.coloredTerrainEffect.EnableDefaultLighting();
    this.coloredTerrainEffect.SpecularPower = 0.01f; //Power of the light
    this.coloredTerrainEffect.AmbientLightColor = new Vector3(0.1f, 0.1f, 0.1f); //Color of the light when it reflects on a surface
    this.coloredTerrainEffect.EmissiveColor = new Vector3(1, 0, 0);
    this.coloredTerrainEffect.DirectionalLight0.Enabled = true; //Enable directional light
    this.coloredTerrainEffect.DirectionalLight0.DiffuseColor = (new Vector3(0.2f, 0.2f, 0.2f)); //Diffuse color
    this.coloredTerrainEffect.DirectionalLight0.SpecularColor = (new Vector3(0.2f, 0.2f, 0.2f)); //Specular color
    this.coloredTerrainEffect.DirectionalLight0.Direction = Vector3.Normalize(new Vector3(1, -1f, 1)); //Direction where the light comes from.
    this.coloredTerrainEffect.View = Camera.GetInstance().GetViewMatrix();
    this.coloredTerrainEffect.Projection = Camera.GetInstance().GetProjectionMatrix();
    this.coloredTerrainEffect.Alpha = (float)((float)Configuration.GetInstance().TerrainOpacity / (float)100);
    this.coloredTerrainEffect.VertexColorEnabled = true;

    return this.coloredTerrainEffect;
}

而这个绘制地形的代码：

RasterizerState rs = new RasterizerState();
rs.CullMode = CullMode.None;
WorldContent.CommonGraphicsDevice.RasterizerState = rs;
//Restore things that SpriteBatch can have overriden
WorldContent.CommonGraphicsDevice.BlendState = BlendState.AlphaBlend;
WorldContent.CommonGraphicsDevice.DepthStencilState = DepthStencilState.Default;
WorldContent.CommonGraphicsDevice.SamplerStates[0] = SamplerState.LinearClamp;

BasicEffect shader = ShadersHandler.GetInstance().GetEffectForColoredTerrain();
foreach (EffectPass pass in shader.CurrentTechnique.Passes)
{
    pass.Apply();
    WorldContent.CommonGraphicsDevice.Indices = indexBufferVertices;
    WorldContent.CommonGraphicsDevice.SetVertexBuffer(vertexBufferVertices);
    WorldContent.CommonGraphicsDevice.DrawIndexedPrimitives(PrimitiveType.TriangleList, 0, 0, vertexPositionColorNormalList.Length, 0, indicesVertices.Length / 3);
}

然而，结果真的很奇怪，如下图所示：

横向地形

地形底部

颜色是从黄色到白色的渐变（黄色向上，白色向下）。但是，如果我使用 Riemers 教程中的效果文件（3D 系列 1 中的 effects.fx），一切都是正确的，如您在此处看到的：

横向地形好

地形好底

如果您愿意，可以在此处查看效果代码：效果文件

所以问题：有谁知道BasicEffect在这里发生了什么？我想使用 Riemers 文件（一切似乎都正确），但我需要使用透明度，并且 BasicEffect 对象为我提供了 alpha 属性，这非常适合我正在寻找的东西。

PD：纹理地形也会出现同样的问题，使用 VertexPositionNormalTexture