From 4abf87e2783828ef59071e229f2ba5b7fbe62c0d Mon Sep 17 00:00:00 2001
From: Selim Mustafaev <selim@fastmail.fm>
Date: Thu, 24 Aug 2023 00:15:05 +0300
Subject: [PATCH] Adding PPU stub class

---
 CMakeLists.txt |  2 +-
 src/Nes.cpp    |  5 ++++-
 src/Nes.h      |  3 +++
 src/Ppu.cpp    | 26 ++++++++++++++++++++++++++
 src/Ppu.h      | 24 ++++++++++++++++++++++++
 5 files changed, 58 insertions(+), 2 deletions(-)
 create mode 100644 src/Ppu.cpp
 create mode 100644 src/Ppu.h

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 1851550..350a802 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -16,7 +16,7 @@ add_executable(nes
         src/Mapper/Mapper.cpp
         src/Mapper/Mapper.h
         src/Mapper/Mapper0.cpp
-        src/Mapper/Mapper0.h)
+        src/Mapper/Mapper0.h src/Ppu.cpp src/Ppu.h)
 
 find_package(SDL2 CONFIG REQUIRED)
 target_link_libraries(nes PRIVATE SDL2::SDL2)
\ No newline at end of file
diff --git a/src/Nes.cpp b/src/Nes.cpp
index a7bfb0b..c00c28c 100644
--- a/src/Nes.cpp
+++ b/src/Nes.cpp
@@ -29,7 +29,10 @@ namespace nes {
 
         size_t ticks = 0;
         while (ticks <= 15000) {
-            _cpu->tick();
+            _ppu->tick();
+            if(ticks % 3 == 0) {
+                _cpu->tick();
+            }
             ticks++;
         }
 
diff --git a/src/Nes.h b/src/Nes.h
index 8b245b5..8f607f9 100644
--- a/src/Nes.h
+++ b/src/Nes.h
@@ -7,6 +7,8 @@
 
 #include "Cpu.h"
 #include "Cartridge.h"
+#include "Ppu.h"
+
 #include <filesystem>
 #include <optional>
 
@@ -22,6 +24,7 @@ namespace nes {
 
     private:
         std::unique_ptr<Cpu> _cpu;
+        std::shared_ptr<Ppu> _ppu;
         std::shared_ptr<Cartridge> _cartridge;
     };
 
diff --git a/src/Ppu.cpp b/src/Ppu.cpp
new file mode 100644
index 0000000..6592ab3
--- /dev/null
+++ b/src/Ppu.cpp
@@ -0,0 +1,26 @@
+//
+// Created by selim on 8/22/23.
+//
+
+#include "Ppu.h"
+
+namespace nes {
+
+    Ppu::Ppu(): _column{}, _scanline{} {
+
+    }
+
+    void Ppu::tick() {
+
+
+        _column++;
+        if(_column >= 341) {
+            _column = 0;
+            _scanline++;
+
+            if(_scanline >= 261) {
+                _scanline = -1;
+            }
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/Ppu.h b/src/Ppu.h
new file mode 100644
index 0000000..b00cdfa
--- /dev/null
+++ b/src/Ppu.h
@@ -0,0 +1,24 @@
+//
+// Created by selim on 8/22/23.
+//
+
+#ifndef NES_PPU_H
+#define NES_PPU_H
+
+#include <cstdint>
+
+namespace nes {
+
+    class Ppu {
+    public:
+        Ppu();
+        void tick();
+
+    private:
+        int16_t _column;
+        int16_t _scanline;
+    };
+
+}
+
+#endif //NES_PPU_H