shader_type canvas_item;

uniform ivec2 location;
uniform ivec2 dimension = ivec2(1,1);

uniform float ground_height = 3000.;
uniform float cell_height = 300.;
uniform int num_cells = 60;

varying vec2 world_position;

void vertex()
{
    world_position = (MODEL_MATRIX * vec4(VERTEX, 0.0, 1.0)).xy;
}

void fragment() {
	float radius = sqrt(world_position.x * world_position.x + world_position.y * world_position.y);
	float angle = atan(world_position.y, world_position.x);

	float sample_y = 1. - ((radius - ground_height) / cell_height - float( location.y)) / float(dimension.y);
	float sample_x = mod(fract(angle / TAU + 1.) * float(num_cells) - float(location.x) + float(num_cells), float(num_cells)) / float(dimension.x);

	if(sample_y > 1. || sample_y < 0. || sample_x > 1. || sample_x < 0.) {
		discard;
	}
	COLOR = texture(TEXTURE, vec2(sample_x, sample_y));

}

//void light() {
//	// Called for every pixel for every light affecting the CanvasItem.
//	// Uncomment to replace the default light processing function with this one.
//}