uniform float cameraWidth;
uniform vec3 variables; //particle size, life left to start fade out, and size increase over age.

void main()
{           
	vec4 worldPos;
	// Set the front color to the color passed through with glColor*f 
	gl_FrontColor = gl_Color;
	
	gl_FrontColor.a = gl_Vertex.z / variables.y;

	gl_PointSize = variables.x / cameraWidth;
	
	worldPos = gl_Vertex;
	worldPos.z = 0.0;
	
	gl_Position = gl_ModelViewProjectionMatrix * worldPos;
}