float depth = 0.4; //apparent depth of the texture

	float numsteps = 300.0; //large but just to reduce aliasing in the stub
	float stepsize = 1.0/numsteps; 

	float3 rayPos = float3(texCoords, 0.0f); //entry point for the ray

/* The following direction I'm iffy about, it works when z is larger than 1.6 making the relief map look correct. This is reflecting about the tangent plane I believe... */
	float3 rayDir = -vEyeVector/vEyeVector.z; //direction for the ray
	rayDir.z = 1.0f/depth;
	rayDir = normalize(rayDir);

	float3 rayEnd = rayPos + rayDir/rayDir.z; //ray hits the bottom boundary
	float delta = length(rayPos-rayEnd)/numsteps;

	float3 lastPos = rayPos;

	for (int i = 0; i < numsteps; i++) {
		float height = tex2D(heightmapTexture, rayPos.xy).r;
		if (rayPos.z > height)
			break;		
		lastPos = rayPos;
		rayPos += delta*rayDir;
	}