From 5346d16aba69324852a0d0844a41bb33d167ac54 Mon Sep 17 00:00:00 2001
From: Brandon Dyck <brandon@dyck.us>
Date: Wed, 24 Nov 2021 18:11:43 -0700
Subject: [PATCH] Added timers

---
 lib/minifb/src/minifb.zig | 37 ++++++++++++++++++++++
 src/main.zig              | 64 +++++++++++++++++++++------------------
 2 files changed, 71 insertions(+), 30 deletions(-)

diff --git a/lib/minifb/src/minifb.zig b/lib/minifb/src/minifb.zig
index 48e9093..e31f2ef 100644
--- a/lib/minifb/src/minifb.zig
+++ b/lib/minifb/src/minifb.zig
@@ -63,3 +63,40 @@ test "set and get target FPS" {
         try std.testing.expectEqual(fps, getTargetFPS());
     }
 }
+
+pub const Timer = struct {
+    ctimer: *minifb_c.mfb_timer,
+
+    pub fn init() !Timer {
+        const ctimer: ?*minifb_c.mfb_timer = minifb_c.mfb_timer_create();
+        if (ctimer) |value| {
+            return Timer {.ctimer=value};
+        } else {
+            return error.ItBroke;
+        }
+    }
+
+    pub fn deinit(self: Timer) void {
+        minifb_c.mfb_timer_destroy(self.ctimer);
+    }
+
+    pub fn reset(self: Timer) void {
+        minifb_c.mfb_timer_reset(self.ctimer);
+    }
+
+    pub fn now(self: Timer) f64 {
+        return minifb_c.mfb_timer_now(self.ctimer);
+    }
+
+    pub fn delta(self: Timer) f64 {
+        return minifb_c.mfb_timer_delta(self.ctimer);
+    }
+
+    pub fn getFrequency() f64 {
+        return minifb_c.mfb_timer_get_frequency();
+    }
+
+    pub fn getResolution() f64 {
+        return minifb_c.mfb_timer_get_resolution();
+    }
+};
\ No newline at end of file
diff --git a/src/main.zig b/src/main.zig
index 03bb199..14b84a6 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -16,14 +16,33 @@ const Coords = struct {
 };
 
 const State = struct {
-    bgValue: u8,
-    increasing: bool,
-};
+    period: f64,
+    bgValue: u8 = 0,
+    increasing: bool = true,
+    timer: mfb.Timer,
 
-fn render(buf: Buffer, state: State) void {
-    buf.drawRectangle(.{.x=0,.y=0}, .{.x=Width, .y=Height}, grey(state.bgValue));
-    buf.drawRectangle(.{.x=Width/3, .y=Height/3}, .{.x=2*Width/3, .y=2*Height/3}, mfb.rgb(255,0,0));
-}
+    pub fn init(period: f64) !State {
+        const timer = try mfb.Timer.init();
+        return State{
+            .period=period,
+            .timer=timer,
+        };
+    }
+
+    pub fn deinit(self: State) void {
+        self.timer.deinit();
+    }
+
+    pub fn render(self: State, buf: Buffer) void {
+        var bgValue = @rem(self.timer.now(), self.period) / self.period * 512;
+        if (bgValue >= 256) {
+            bgValue = 512 - bgValue;
+        }
+
+        buf.drawRectangle(.{.x=0,.y=0}, .{.x=Width, .y=Height}, grey(@floatToInt(u8, bgValue)));
+        buf.drawRectangle(.{.x=Width/3, .y=Height/3}, .{.x=2*Width/3, .y=2*Height/3}, mfb.rgb(255,0,0));
+    }
+};
 
 const Buffer = struct {
     alloc: *std.mem.Allocator,
@@ -31,7 +50,7 @@ const Buffer = struct {
     width: u32,
     height: u32,
 
-    pub fn init(alloc: *std.mem.Allocator, width: u32, height: u32) anyerror!Buffer {
+    pub fn init(alloc: *std.mem.Allocator, width: u32, height: u32) !Buffer {
         const slice = try alloc.alloc(u32, width*height);
         return Buffer {
             .alloc=alloc,
@@ -73,38 +92,23 @@ const Buffer = struct {
     }
 };
 
-pub fn main() anyerror!void {
+pub fn main() !void {
     var gp_allocator = std.heap.GeneralPurposeAllocator(.{}){};
     const alloc = &gp_allocator.allocator;
 
     std.log.info("All your codebase are belong to us.", .{});
     var win = mfb.Window.open("Hello minifb-zig", Width, Height) catch unreachable;
-    mfb.setTargetFPS(60);
+    mfb.setTargetFPS(7);
+
+    var state = try State.init(3);
+    defer state.deinit();
 
-    var state = State {
-        .increasing=true,
-        .bgValue=0,
-    };
     var buf = try Buffer.init(alloc, Width, Height);
     defer buf.deinit();
 
-    render(buf, state);
+    state.render(buf);
     while (win.waitSync()) {
-        if (state.increasing) {
-            if (state.bgValue < 255) {
-                state.bgValue += 1;
-            } else {
-                state.increasing = false;
-            }
-        } else {
-            if (state.bgValue > 0) {
-                state.bgValue -= 1;
-            } else {
-                state.increasing = true;
-            }
-        }
-
-        render(buf, state);
+        state.render(buf);
         // TODO Handle mfb state
         _ = win.update(buf.slice) catch unreachable;
     }