XNA 4.0奇怪的顏色錯誤

Question

我有問題用XNA繪製地形，特別是顏色（它發生在VertexPositionColorNormal和VertexPositionTextureNormal）。我的代碼如下：

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; 
} 

而這種代碼繪製地形：

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，結果是很奇怪的，因爲你可以在下面的圖片看到：

Terrain laterally

Terrain bottom

顏色是漸變f rom黃色到白色（黃色向上，白色向下）。不過，如果我使用效果文件從Riemers教程（從3D系列1 effects.fx），一切都是正確的，因爲你可以在這裏看到：

Terrain good laterally

Terrain good bottom

如果你願意，你可以在此處看到效果代碼：Effects file

因此問題：有人知道BasicEffect在這裏發生了什麼嗎？我想使用Riemers文件（一切似乎都正確），但我需要使用透明度，BasicEffect對象爲我提供了alpha屬性，這對於我所需要的是非常完美的。

PD：同樣的問題發生帶紋理的地形，使用VertexPositionNormalTexture

Answer 1

望着圖片，變色似乎是一個很不錯的圈，從平行光。我會嘗試刪除BasicEffect示例中使用的DirectionalLight0屬性設置，然後查看是否更正了變色。