KeyV2/src/dishes.scad

include <libraries/geodesic_sphere.scad>
include <shapes.scad>
//geodesic looks much better, but runs very slow for anything above a 2u
geodesic=false;

//dish selector
module  dish(width, height, depth, inverted) {
		if($dish_type == "cylindrical"){
			cylindrical_dish(width, height, depth, inverted);
		}
		else if ($dish_type == "spherical") {
			spherical_dish(width, height, depth, inverted);
		}
		else if ($dish_type == "sideways cylindrical"){
			sideways_cylindrical_dish(width, height, depth, inverted);
		}
		else if ($dish_type == "old spherical") {
			old_spherical_dish(width, height, depth, inverted);
		} else {
			// else no dish, "no dish" is the value
			// switchted to actually diffing a cube here due to (hopeful) changes to stems being differenced from the dish instead of the inside
			translate([0,0,500]) cube([width, height, 1000], center=true);
		}
}

module cylindrical_dish(width, height, depth, inverted){
	// .5 has problems starting around 3u
	$fa=.25;
	/* we do some funky math here
	 * basically you want to have the dish "dig in" to the keycap x millimeters
	 * in order to do that you have to solve a small (2d) system of equations
	 * where the chord of the spherical cross section of the dish is
	 * the width of the keycap.
	 */
	// the distance you have to move the dish so it digs in depth millimeters
	chord_length = (pow(width, 2) - 4 * pow(depth, 2)) / (8 * depth);
	//the radius of the dish
	rad = (pow(width, 2) + 4 * pow(depth, 2)) / (8 * depth);
  direction = inverted ? -1 : 1;

  translate([0,0, chord_length * direction]){
    rotate([90, 0, 0]) cylinder(h=height + 20, r=rad, center=true);
  }
}

module sideways_cylindrical_dish(width, height, depth, inverted){
	$fa=1;
	chord_length = (pow(height, 2) - 4 * pow(depth, 2)) / (8 * depth);
	rad = (pow(height, 2) + 4 * pow(depth, 2)) / (8 * depth);

  direction = inverted ? -1 : 1;

	translate([0,0, chord_length * direction]){
		// cylinder is rendered facing up, so we rotate it on the y axis first
		rotate([0,90,0]) cylinder(h = width + 20,r=rad, center=true); // +20 for fudge factor
	}
}

module spherical_dish(width, height, depth, inverted){

	//same thing as the cylindrical dish here, but we need the corners to just touch - so we have to find the hypotenuse of the top
	chord = pow((pow(width,2) + pow(height, 2)),0.5); //getting diagonal of the top

	// the distance you have to move the dish up so it digs in depth millimeters
	chord_length = (pow(chord, 2) - 4 * pow(depth, 2)) / (8 * depth);
	//the radius of the dish
	rad = (pow(chord, 2) + 4 * pow(depth, 2)) / (8 * depth);
  direction = inverted ? -1 : 1;

	translate([0,0,0 * direction]){
		if (geodesic){
			$fa=20;
			scale([chord/2/depth, chord/2/depth]) {
				geodesic_sphere(r=depth);
			}
		} else {
			$fa=7;
			// rotate 1 because the bottom of the sphere looks like trash.
			scale([chord/2/depth, chord/2/depth]) {
				geodesic_sphere(r=depth);
			}
		}
  }
}

//the older, 'more accurate', and MUCH slower spherical dish.
// generates the largest sphere possible that still contains the chord we are looking for
// much more graduated curvature at an immense cost
module old_spherical_dish(width, height, depth, inverted){

	//same thing as the cylindrical dish here, but we need the corners to just touch - so we have to find the hypotenuse of the top
	chord = pow((pow(width,2) + pow(height, 2)),0.5); //getting diagonal of the top

	// the distance you have to move the dish up so it digs in depth millimeters
	chord_length = (pow(chord, 2) - 4 * pow(depth, 2)) / (8 * depth);
	//the radius of the dish
	rad = (pow(chord, 2) + 4 * pow(depth, 2)) / (8 * depth);
  direction = inverted ? -1 : 1;

	translate([0,0,chord_length * direction]){
		if (geodesic){
			$fa=7;
			geodesic_sphere(r=rad);
		} else {
			$fa=1;
			// rotate 1 because the bottom of the sphere looks like trash
			sphere(r=rad);
		}
	}
}