precision highp float;
attribute vec3 land;
attribute vec2 landnormal;
uniform float rot;
uniform float world_x;
uniform float world_y;
uniform mat4 MV;
uniform mat4 P;
varying vec2 worldxy;
varying mat4 pre;
varying vec2 norm;
void main() {
	norm = landnormal;
	mat2 rotate = mat2(
		cos(rot), -sin(rot),
		sin(rot), cos(rot)
	);
	worldxy = vec2(world_x, world_y);
	pre = P * MV;
	vec2 local = (land.xy - worldxy) * rotate;
	float z_scale = 0.5;
	// clamp so that everything becomes orthographic once we move away
	float xoff = clamp(land.z * local.x * z_scale, -0.5, 0.5);
	float yoff = clamp(land.z * local.y * z_scale, -0.5, 0.5);
	gl_Position = P * MV * vec4(local.xy - vec2(xoff, yoff), land.z, 1.0);
}