From a9c30f6236af36f6c428b0b10dd4d48a21c70733 Mon Sep 17 00:00:00 2001
From: Julien Dessaux
Date: Sun, 14 Aug 2022 15:36:59 +0200
Subject: Implement left and right movements

---
 src/brothers.zig | 52 +++++++++++++++++++++++++++++++++++++++++++---------
 src/game.zig     | 15 +++++++++++++--
 src/main.zig     | 29 ++++++++++++++++++++---------
 3 files changed, 76 insertions(+), 20 deletions(-)

diff --git a/src/brothers.zig b/src/brothers.zig
index b221ddc..cf78988 100644
--- a/src/brothers.zig
+++ b/src/brothers.zig
@@ -8,6 +8,8 @@ pub const Side = enum(u1) {
 
 const startingX = [2]f64{ 15, 60 };
 const colors = [2]spoon.Attribute.Colour{ .blue, .red };
+const leftLimit = [2]f64{ 1, 40 };
+const rightLimit = [2]f64{ 33, 74 }; // (38, 79) minus a brother's width
 
 pub const Brother = struct {
     side: Side,
@@ -15,15 +17,7 @@ pub const Brother = struct {
     y: f64,
     dx: f64,
     dy: f64,
-    pub fn reset(self: *Brother, side: ?Side) void {
-        if (side) |s| {
-            self.side = s;
-        }
-        self.x = startingX[@enumToInt(self.side)];
-        self.y = 17;
-        self.dx = 0;
-        self.dy = 0;
-    }
+    moveDuration: u64,
     pub fn draw(self: Brother, rc: *spoon.Term.RenderContext) !void {
         try rc.setAttribute(.{ .fg = colors[@enumToInt(self.side)] });
         var iter = std.mem.split(u8, brother, "\n");
@@ -34,6 +28,46 @@ pub const Brother = struct {
             _ = try rc.buffer.writer().write(line);
         }
     }
+    pub fn moveLeft(self: *Brother) void {
+        self.dx -= 5 / (1000 / 60.0);
+        self.moveDuration = 24;
+    }
+    pub fn moveRight(self: *Brother) void {
+        self.dx += 5 / (1000 / 60.0);
+        self.moveDuration = 24;
+    }
+    pub fn step(self: *Brother) void {
+        const x = self.x + self.dx;
+        const ll = leftLimit[@enumToInt(self.side)];
+        const rl = rightLimit[@enumToInt(self.side)];
+        if (x < ll) {
+            self.x = ll;
+            self.dx = 0;
+            self.moveDuration = 0;
+        } else if (x > rl) {
+            self.x = rl;
+            self.dx = 0;
+            self.moveDuration = 0;
+        } else {
+            self.x = x;
+            if (self.moveDuration > 0) {
+                self.moveDuration -= 1;
+                if (self.moveDuration == 0) {
+                    self.dx = 0;
+                }
+            }
+        }
+    }
+    pub fn reset(self: *Brother, side: ?Side) void {
+        if (side) |s| {
+            self.side = s;
+        }
+        self.x = startingX[@enumToInt(self.side)];
+        self.y = 17;
+        self.dx = 0;
+        self.dy = 0;
+        self.moveDuration = 0;
+    }
 };
 
 const brother =
diff --git a/src/game.zig b/src/game.zig
index fc64001..97c2c80 100644
--- a/src/game.zig
+++ b/src/game.zig
@@ -6,17 +6,28 @@ const playfield = @import("playfield.zig");
 
 pub const Game = struct {
     brothers: [2]brothers.Brother = undefined,
-    character: ?brothers.Side = undefined,
+    side: brothers.Side = undefined,
     pub fn draw(self: Game, rc: *spoon.Term.RenderContext) !void {
         try playfield.draw(rc);
         try self.brothers[0].draw(rc);
         try self.brothers[1].draw(rc);
     }
-    pub fn reset(self: *Game) void {
+    pub fn moveLeft(self: *Game) void {
+        self.brothers[@enumToInt(self.side)].moveLeft();
+    }
+    pub fn moveRight(self: *Game) void {
+        self.brothers[@enumToInt(self.side)].moveRight();
+    }
+    pub fn reset(self: *Game, side: brothers.Side) void {
+        self.side = side;
         self.resetRound();
     }
     pub fn resetRound(self: *Game) void {
         self.brothers[0].reset(brothers.Side.left);
         self.brothers[1].reset(brothers.Side.right);
     }
+    pub fn step(self: *Game) void {
+        self.brothers[0].step();
+        self.brothers[1].step();
+    }
 };
diff --git a/src/main.zig b/src/main.zig
index cec8688..120e926 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -33,21 +33,32 @@ pub fn main() !void {
     try term.fetchSize();
     try term.setWindowTitle("Grenade Brothers", .{});
 
-    gs.reset();
+    gs.reset(.left);
     try renderAll();
 
     var buf: [16]u8 = undefined;
     while (!done) {
-        _ = try std.os.poll(&fds, 100);
-
-        const read = try term.readInput(&buf);
-        var it = spoon.inputParser(buf[0..read]);
-        while (it.next()) |in| {
-            if (in.eqlDescription("escape") or in.eqlDescription("q")) {
-                done = true;
-                break;
+        // TODO We need to measure how long it took before a key was hit so that we can adjust the timeout on the next loop
+        // otherwise we will get inconsistent ticks for movement steps
+        const timeout = try std.os.poll(&fds, @floatToInt(u64, 1000 / 60.0));
+
+        if (timeout > 0) { // if timeout if not 0 then some fds we are polling have events for us
+            const read = try term.readInput(&buf);
+            var it = spoon.inputParser(buf[0..read]);
+            while (it.next()) |in| {
+                if (in.eqlDescription("escape") or in.eqlDescription("q")) {
+                    done = true;
+                    break;
+                } else if (in.eqlDescription("arrow-left") or in.eqlDescription("a")) {
+                    gs.moveLeft();
+                } else if (in.eqlDescription("arrow-right") or in.eqlDescription("d")) {
+                    gs.moveRight();
+                }
             }
+        } else {
+            gs.step();
         }
+        try renderAll();
     }
 }
 
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