From c33068d831ee2c1129509e0c751d8726beb2736d Mon Sep 17 00:00:00 2001
From: Rekai Musuka <rekai@musuka.dev>
Date: Fri, 21 Oct 2022 05:11:51 -0300
Subject: [PATCH] fix: allocate framebuf on heap

---
 src/main.zig | 13 ++++---------
 src/ppu.zig  | 14 ++++++++++++++
 2 files changed, 18 insertions(+), 9 deletions(-)

diff --git a/src/main.zig b/src/main.zig
index 79667ae..0a5a83c 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -6,6 +6,8 @@ const Bus = @import("Bus.zig");
 const Arm7tdmi = @import("cpu.zig").Arm7tdmi;
 const Scheduler = @import("scheduler.zig").Scheduler;
 
+const buf_pitch = @import("ppu.zig").buf_pitch;
+
 pub fn main() anyerror!void {
     // Allocator for Emulator + CLI Aruments
     var gpa = std.heap.GeneralPurposeAllocator(.{}){};
@@ -57,14 +59,6 @@ pub fn main() anyerror!void {
     const texture = SDL.SDL_CreateTexture(renderer, SDL.SDL_PIXELFORMAT_BGR555, SDL.SDL_TEXTUREACCESS_STREAMING, 240, 160) orelse sdlPanic();
     defer SDL.SDL_DestroyTexture(texture);
 
-    const buf_pitch = 240 * @sizeOf(u16);
-    const buf_len = buf_pitch * 160;
-    var white: [buf_len]u8 = [_]u8{ 0xFF, 0x7F } ** (buf_len / 2);
-
-    var white_heap = try alloc.alloc(u8, buf_len);
-    for (white) |b, i| white_heap[i] = b;
-    defer alloc.free(white_heap);
-
     emu_loop: while (true) {
         emu.runFrame(&scheduler, &cpu, &bus);
 
@@ -76,7 +70,8 @@ pub fn main() anyerror!void {
             else => {},
         }
 
-        _ = SDL.SDL_UpdateTexture(texture, null, &white_heap, buf_pitch);
+        const buf_ptr = bus.ppu.frame_buf.ptr;
+        _ = SDL.SDL_UpdateTexture(texture, null, buf_ptr, buf_pitch);
         _ = SDL.SDL_RenderCopy(renderer, texture, null, null);
         SDL.SDL_RenderPresent(renderer);
     }
diff --git a/src/ppu.zig b/src/ppu.zig
index f197568..86c22b5 100644
--- a/src/ppu.zig
+++ b/src/ppu.zig
@@ -4,24 +4,38 @@ const EventKind = @import("scheduler.zig").EventKind;
 const Scheduler = @import("scheduler.zig").Scheduler;
 
 const Allocator = std.mem.Allocator;
+const width = 240;
+const height = 160;
+pub const buf_pitch = width * @sizeOf(u16);
+const buf_len = buf_pitch * height;
 
 pub const Ppu = struct {
     vram: Vram,
     palette: Palette,
     sched: *Scheduler,
+    frame_buf: []u8,
+    alloc: Allocator,
 
     pub fn init(alloc: Allocator, sched: *Scheduler) !@This() {
         // Queue first Hblank
         sched.push(.{ .kind = .HBlank, .tick = sched.tick + 240 * 4 });
 
+        // Initialize the Frame Buffer to white
+        const white_buf: [buf_len]u8 = [_]u8{ 0xFF, 0x7F } ** (buf_len / 2);
+        const frame_buf = try alloc.alloc(u8, buf_len);
+        std.mem.copy(u8, frame_buf, &white_buf);
+
         return @This(){
             .vram = try Vram.init(alloc),
             .palette = try Palette.init(alloc),
             .sched = sched,
+            .frame_buf = frame_buf,
+            .alloc = alloc,
         };
     }
 
     pub fn deinit(self: @This()) void {
+        self.alloc.free(self.frame_buf);
         self.vram.deinit();
         self.palette.deinit();
     }