From f8477714ae8bf1df0819877e4c544cb5608f0188 Mon Sep 17 00:00:00 2001
From: Rekai Musuka <rekai@musuka.dev>
Date: Fri, 10 Mar 2023 02:27:31 -0600
Subject: [PATCH] feat: implement resetting

---
 src/core/Bus.zig         |  2 +-
 src/core/apu.zig         | 18 ++++++++++++------
 src/core/ppu.zig         | 20 ++++++++++++++++++++
 src/core/ppu/Oam.zig     |  4 ++++
 src/core/ppu/Palette.zig |  4 ++++
 src/core/ppu/Vram.zig    |  4 ++++
 src/util.zig             |  8 ++++++--
 7 files changed, 51 insertions(+), 9 deletions(-)

diff --git a/src/core/Bus.zig b/src/core/Bus.zig
index 0c2d3a8..22b0b31 100644
--- a/src/core/Bus.zig
+++ b/src/core/Bus.zig
@@ -104,7 +104,7 @@ pub fn deinit(self: *Self) void {
 
 pub fn reset(self: *Self) void {
     self.bios.reset();
-    // TODO: deinit ppu
+    self.ppu.reset();
     self.apu.reset();
     self.iwram.reset();
     self.ewram.reset();
diff --git a/src/core/apu.zig b/src/core/apu.zig
index 89204f9..a93ad0b 100644
--- a/src/core/apu.zig
+++ b/src/core/apu.zig
@@ -278,16 +278,20 @@ pub const Apu = struct {
             .is_buffer_full = false,
         };
 
-        sched.push(.SampleAudio, apu.interval());
-        sched.push(.{ .ApuChannel = 0 }, @import("apu/signal/Square.zig").interval);
-        sched.push(.{ .ApuChannel = 1 }, @import("apu/signal/Square.zig").interval);
-        sched.push(.{ .ApuChannel = 2 }, @import("apu/signal/Wave.zig").interval);
-        sched.push(.{ .ApuChannel = 3 }, @import("apu/signal/Lfsr.zig").interval);
-        sched.push(.FrameSequencer, FrameSequencer.interval);
+        Self.initEvents(apu.sched, apu.interval());
 
         return apu;
     }
 
+    fn initEvents(scheduler: *Scheduler, apu_interval: u64) void {
+        scheduler.push(.SampleAudio, apu_interval);
+        scheduler.push(.{ .ApuChannel = 0 }, @import("apu/signal/Square.zig").interval);
+        scheduler.push(.{ .ApuChannel = 1 }, @import("apu/signal/Square.zig").interval);
+        scheduler.push(.{ .ApuChannel = 2 }, @import("apu/signal/Wave.zig").interval);
+        scheduler.push(.{ .ApuChannel = 3 }, @import("apu/signal/Lfsr.zig").interval);
+        scheduler.push(.FrameSequencer, FrameSequencer.interval);
+    }
+
     /// Used when resetting the emulator
     pub fn reset(self: *Self) void {
         // FIXME: These reset functions are meant to emulate obscure APU behaviour. Write proper emu reset fns
@@ -306,6 +310,8 @@ pub const Apu = struct {
 
         self.sampling_cycle = 0;
         self.fs.reset();
+
+        Self.initEvents(self.sched, self.interval());
     }
 
     /// Emulates the reset behaviour of the APU
diff --git a/src/core/ppu.zig b/src/core/ppu.zig
index a6da4a9..35cb7ad 100644
--- a/src/core/ppu.zig
+++ b/src/core/ppu.zig
@@ -290,6 +290,26 @@ pub const Ppu = struct {
         };
     }
 
+    pub fn reset(self: *Self) void {
+        self.sched.push(.Draw, 240 * 4);
+
+        self.vram.reset();
+        self.palette.reset();
+        self.oam.reset();
+        self.framebuf.reset();
+
+        self.win = Window.init();
+        self.bg = [_]Background{Background.init()} ** 4;
+        self.aff_bg = [_]AffineBackground{AffineBackground.init()} ** 2;
+        self.bld = Blend.create();
+        self.dispcnt = .{ .raw = 0x0000 };
+        self.dispstat = .{ .raw = 0x0000 };
+        self.vcount = .{ .raw = 0x0000 };
+
+        self.scanline.reset();
+        std.mem.set(?Sprite, self.scanline_sprites, null);
+    }
+
     pub fn deinit(self: *Self) void {
         self.allocator.destroy(self.scanline_sprites);
         self.framebuf.deinit();
diff --git a/src/core/ppu/Oam.zig b/src/core/ppu/Oam.zig
index 2e0a78d..f09c0ff 100644
--- a/src/core/ppu/Oam.zig
+++ b/src/core/ppu/Oam.zig
@@ -34,6 +34,10 @@ pub fn init(allocator: Allocator) !Self {
     return Self{ .buf = buf, .allocator = allocator };
 }
 
+pub fn reset(self: *Self) void {
+    std.mem.set(u8, self.buf, 0);
+}
+
 pub fn deinit(self: *Self) void {
     self.allocator.free(self.buf);
     self.* = undefined;
diff --git a/src/core/ppu/Palette.zig b/src/core/ppu/Palette.zig
index d23978a..9e6f36a 100644
--- a/src/core/ppu/Palette.zig
+++ b/src/core/ppu/Palette.zig
@@ -37,6 +37,10 @@ pub fn init(allocator: Allocator) !Self {
     return Self{ .buf = buf, .allocator = allocator };
 }
 
+pub fn reset(self: *Self) void {
+    std.mem.set(u8, self.buf, 0);
+}
+
 pub fn deinit(self: *Self) void {
     self.allocator.free(self.buf);
     self.* = undefined;
diff --git a/src/core/ppu/Vram.zig b/src/core/ppu/Vram.zig
index f599212..f148dc7 100644
--- a/src/core/ppu/Vram.zig
+++ b/src/core/ppu/Vram.zig
@@ -45,6 +45,10 @@ pub fn init(allocator: Allocator) !Self {
     return Self{ .buf = buf, .allocator = allocator };
 }
 
+pub fn reset(self: *Self) void {
+    std.mem.set(u8, self.buf, 0);
+}
+
 pub fn deinit(self: *Self) void {
     self.allocator.free(self.buf);
     self.* = undefined;
diff --git a/src/util.zig b/src/util.zig
index db49131..276a658 100644
--- a/src/util.zig
+++ b/src/util.zig
@@ -251,7 +251,7 @@ pub const FrameBuffer = struct {
 
     layers: [2][]u8,
     buf: []u8,
-    current: u1,
+    current: u1 = 0,
 
     allocator: Allocator,
 
@@ -266,12 +266,16 @@ pub const FrameBuffer = struct {
             // Front and Back Framebuffers
             .layers = [_][]u8{ buf[0..][0..len], buf[len..][0..len] },
             .buf = buf,
-            .current = 0,
 
             .allocator = allocator,
         };
     }
 
+    pub fn reset(self: *Self) void {
+        std.mem.set(u8, self.buf, 0);
+        self.current = 0;
+    }
+
     pub fn deinit(self: *Self) void {
         self.allocator.free(self.buf);
         self.* = undefined;