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const std = @import("std");
const utils = @import("utils.zig");
const w4 = @import("wasm4.zig");
pub const Ball = struct {
// position of the top left corner
x: f64,
y: f64,
vx: f64,
vy: f64,
pub fn draw(self: Ball) void {
var y = @floatToInt(u8, std.math.round(self.y));
var x = @floatToInt(u8, std.math.round(self.x));
w4.DRAW_COLORS.* = 0x2400;
w4.blit(&ball, x, y, ball_width, ball_height, ball_flags);
}
pub fn resetRound(self: *Ball, side: utils.side) void {
self.x = @intToFloat(f64, utils.startingX[@enumToInt(side)] + 4);
self.y = 160 - 32 - 8;
self.vx = 0;
self.vy = -250;
}
pub fn update(self: *Ball) void {
self.vy += utils.gravity;
self.x += self.vx * utils.frequency;
self.y += self.vy * utils.frequency;
// collisions handling
if (self.x < 0) { // left wall
self.vx = -self.vx * utils.bounce;
self.x = 0;
}
if (self.x >= 160 - ball_width) { // right wall
self.vx = -self.vx * utils.bounce;
self.x = 160 - ball_width - 1;
}
if (self.y < 0) { // ceiling
self.vy = -self.vy * utils.bounce;
self.y = 0;
}
if (self.y >= 160 - ball_height) { // floor
self.vy = 0;
self.y = 160 - ball_height;
}
// Net collision
var x1: f64 = 78 - ball_width;
var x2: f64 = 82;
var y1: f64 = 100 - ball_height;
var y2: f64 = 160;
if (self.x >= x1 and self.x < x2 and self.y >= y1 and self.y < y2) {
if (self.vx > 0) {
self.x = x1;
} else {
self.x = x2;
}
self.vx = -self.vx;
}
// TODO collision with top of the net?
}
};
//----- Sprite ----------------------------------------------------------------
pub const ball_width = 8;
pub const ball_height = 8;
const ball_flags = 1; // BLIT_2BPP
const ball = [16]u8{ 0x1a, 0xa4, 0x6f, 0xf9, 0xbf, 0xae, 0xbf, 0xae, 0xbf, 0xfe, 0xbf, 0xfe, 0x6f, 0xf9, 0x1a, 0xa4 };
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