void main_vertex
(
   float4 position : POSITION,
   out float4 oPosition : POSITION,
   uniform float4x4 modelViewProj,
   float2 tex : TEXCOORD,
   out float2 oTex : TEXCOORD
)
{
   oPosition = mul(modelViewProj, position);
   oTex = tex;
}

float4 main_fragment (float2 tex : TEXCOORD) : COLOR
{
   return float4(tex, 0.0, 1.0);
}

