Stuff

float4x4 WorldViewProj : WORLDVIEWPROJECTION;
texture ParticleTexture : TEXTURE;

struct VS_INPUT
{
	float4 position : POSITION0;
	float2 texCoord : TEXCOORD0;
	float4 color : COLOR0;
	float  pointSize : PSIZE0;
};

struct VS_OUTPUT
{
	float4 position : POSITION0;
	float2 texCoord : TEXCOORD0;
	float4 color : COLOR0;
	float  pointSize : PSIZE;
};

sampler ParticleSampler = sampler_state
{
	Texture = <ParticleTexture>;
};

VS_OUTPUT VertexShader( VS_INPUT input )
{
	VS_OUTPUT output = (VS_OUTPUT)0;
	
	output.position = mul( input.position , WorldViewProj);
	output.texCoord = input.texCoord;
	output.color = input.color;
	output.pointSize = input.pointSize;
	
	return output;
}

float4 PixelShader( VS_OUTPUT input ) : COLOR0
{
	float4 texColor = tex2D( ParticleSampler , input.texCoord );
	
	float4 color = texColor * input.color;

	return color;
}

technique PointSpriteTechnique
{
    pass P0
    {
        vertexShader = compile vs_2_0 VertexShader();
        pixelShader = compile ps_2_0 PixelShader();
    }
}