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I am creating an editor of sorts that allow you to create 3D voxel models. I just got started and have ran into a few errors. Here is what it is producing:

enter image description here

I think the problem has to do with the way I am handling my vertex format (VertexPositionNormalColor) shader or the way either of them are written:

    struct VertexPositionNormalColor {
        Vector3 position;
        Vector3 normal;

        Color color;

        public readonly static VertexDeclaration VertexDeclaration = new VertexDeclaration(
            new VertexElement(0, VertexElementFormat.Vector3, VertexElementUsage.Position, 0),
            new VertexElement(sizeof(float) * 3, VertexElementFormat.Vector3, VertexElementUsage.Normal, 1),
            new VertexElement(sizeof(float) * 6, VertexElementFormat.Vector4, VertexElementUsage.Color, 0)

        public VertexPositionNormalColor(Vector3 position, Vector3 normal, Color color) {
            this.position = position;
            this.normal = normal;
            this.color = color;

Shader code:

struct ColoredVertexToPixel  {
    float4 Position     : POSITION;
    float4 Color        : COLOR0;

struct ColoredPixelToFrame  {
    float4 Color        : COLOR0;

ColoredVertexToPixel ColoredVertexShader(float4 inPosition : POSITION, float3 inNormal : NORMAL, float4 inColor : COLOR0)  {
    ColoredVertexToPixel Output = (ColoredVertexToPixel)0;

    float4 worldPos = mul(inPosition, World);
    float4 viewPos = mul(worldPos, View);

    Output.Position = mul(viewPos, Projection);
    Output.Color = inColor;

    // TODO: Implement basic lighting

    return Output;

ColoredPixelToFrame ColoredPixelShader(ColoredVertexToPixel PSIn)  {
    ColoredPixelToFrame Output = (ColoredPixelToFrame)0;

    Output.Color = PSIn.Color;

    return Output;

technique ColoredBlock  {
    pass Pass0  {
        VertexShader = compile vs_2_0 ColoredVertexShader();
        PixelShader = compile ps_2_0 ColoredPixelShader();

I also tryed the object creation code in another project with a different effect file and vertex format and it worked fine. This is defiantly a shader/vertex format error as I set each vertex with the exact same color, so maybe the color and position data in the shader is getting with each other?

Any ideas?


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up vote 3 down vote accepted

First, and since you are using only one normal channel, I would change the UsageIndex of your VertexElementUsage.Normal from 1 to 0.

And for your color channel, your vertex buffer is expecting a VertexElementFormat.Vector4, that is, 4 float components. The type used for colors in XNA is a special 32-bit encoded value, so change it to VertexElementFormat.Color.

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