HLSL/GLSL Example 4

struct Joint
{
    float4x4 local;
    uint parentIndex;
};

cbuffer Constants
{
    float4x4 g_WorldViewProj;
    Joint g_Joints[255];
    uint count;
};

struct PSInput
{
    float4 Pos : SV_POSITION;
};

[maxvertexcount(256)]
void main(
    line PSInput points[2],
    inout LineStream< PSInput > stream
)
{
    PSInput v[2];

    uint i, j;
    for (i = 0; i < count; ++i)
    {
        j = g_Joints[i].parentIndex;
        if (j != 255)
        {
            v[0].Pos = mul(float4(g_Joints[i].local[0][3], g_Joints[i].local[1][3], g_Joints[i].local[2][3], g_Joints[i].local[3][3]), g_WorldViewProj);
            v[1].Pos = mul(float4(g_Joints[j].local[0][3], g_Joints[j].local[1][3], g_Joints[j].local[2][3], g_Joints[j].local[3][3]), g_WorldViewProj);
            stream.Append(v[0]); //EmitVertex
            stream.Append(v[1]); //EmitVertex
            stream.RestartStrip(); //EndPrimitive
        }
        else
        {
            v[0].Pos = mul(float4(g_Joints[i].local[0][3], g_Joints[i].local[1][3], g_Joints[i].local[2][3], g_Joints[i].local[3][3]), g_WorldViewProj);
            v[1].Pos = mul(float4(g_Joints[i].local[0][3], g_Joints[i].local[1][3], g_Joints[i].local[2][3], g_Joints[i].local[3][3]) + float4(0.0, 1.0, 0.0, 0.0), g_WorldViewProj);
            stream.Append(v[0]); //EmitVertex
            stream.Append(v[1]); //EmitVertex
            stream.RestartStrip(); //EndPrimitive
        }
    }


}