layout(lines, invocations=2) in;
layout(line_strip, max_vertices=2) out;
in int gl_InvocationID;
out vec4 fcolor;
in vec4 fca[];
uniform mat4 mvp;

void main(){
	if(gl_in[0].gl_Position.x > 0)
		return;	
	if(gl_InvocationID == 1){
		gl_Position = mvp * gl_in[0].gl_Position;
		fcolor = fca[0];
		EmitVertex();
		gl_Position = mvp * gl_in[1].gl_Position;
		fcolor = fca[1];
		EmitVertex();
		EndPrimitive();
	} else {
		gl_Position = mvp * gl_in[0].gl_Position + vec4(2, 0, 0, 0);
		fcolor = vec4(1, .2, .6, 1);
		EmitVertex();
		gl_Position = mvp * gl_in[1].gl_Position + vec4(2, 0, 0, 0);
		fcolor = vec4(1, .2, .6, 1);
		EmitVertex();
		EndPrimitive();
	}

}
in vec3 coord3d;
uniform mat4 mvp;
uniform float wind;
out vec4 fca;

void main(void) {
	float xdisp = coord3d.x;
	float zdisp = coord3d.z;
	if(coord3d.y > -2){
		xdisp += (coord3d.y+2)/5.0 * wind;
	}
	gl_Position = vec4(xdisp, coord3d.y, zdisp, 1.0);
	if(coord3d.y > 0)
		fca = vec4(0, .6, .2, 1);
	else
		fca = vec4(.5, .6, 0, 1);
}