From 5429c5fac19bc4e019ed13fdbff85a0dd2bc5892 Mon Sep 17 00:00:00 2001
From: Pablo Rodriguez <prodriguez@noreply.git.rodlop.net>
Date: Thu, 28 Nov 2024 04:08:37 -0500
Subject: [PATCH] implemented DisplaySDL

---
 CMakeLists.txt  |  2 +-
 DisplaySDL.cpp  | 77 +++++++++++++++++++++++++++++++++++++++++++++++++
 DisplaySDL.hpp  | 18 ++++++++++++
 Peripherals.hpp |  6 ++--
 main.cpp        | 15 +++++++++-
 5 files changed, 114 insertions(+), 4 deletions(-)
 create mode 100644 DisplaySDL.cpp
 create mode 100644 DisplaySDL.hpp

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 1187052..b0b5ee0 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -5,5 +5,5 @@ SET(CMAKE_BUILD_TYPE Debug)
 add_subdirectory(submodules/sdl2)
 
 SET(CMAKE_EXPORT_COMPILE_COMMANDS ON)
-add_executable(chocochip8 main.cpp Interpreter.cpp BuzzerSDL.cpp)
+add_executable(chocochip8 main.cpp Interpreter.cpp DisplaySDL.cpp BuzzerSDL.cpp)
 target_link_libraries(chocochip8 SDL2::SDL2-static)
diff --git a/DisplaySDL.cpp b/DisplaySDL.cpp
new file mode 100644
index 0000000..9303a6e
--- /dev/null
+++ b/DisplaySDL.cpp
@@ -0,0 +1,77 @@
+#include "DisplaySDL.hpp"
+
+#include <stdexcept>
+
+DisplaySDL::DisplaySDL(int w, int h, uint32_t fgColor, uint32_t bgColor) {
+  // Create SDL Window
+  mpWindow = SDL_CreateWindow(
+    "ChocoChip-8",
+    SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED,
+    w, h,
+    0
+  );
+  if(mpWindow == NULL) {
+    throw std::runtime_error(SDL_GetError());
+  }
+
+  // Convert our foreground/background colors to the format expected by SDL
+  SDL_PixelFormat *fmt = SDL_AllocFormat(SDL_GetWindowPixelFormat(mpWindow));
+  mFgColor = SDL_MapRGB(
+      fmt,
+      (fgColor & 0x00FF0000) >> 16,
+      (fgColor & 0x0000FF00) >> 8,
+      (fgColor & 0x000000FF)
+  );
+  mBgColor = SDL_MapRGB(
+      fmt,
+      (bgColor & 0x00FF0000) >> 16,
+      (bgColor & 0x0000FF00) >> 8,
+      (bgColor & 0x000000FF)
+  );
+  SDL_FreeFormat(fmt);
+};
+
+DisplaySDL::~DisplaySDL() {
+  SDL_DestroyWindow(mpWindow);
+}
+
+void DisplaySDL::updateWindow() const {
+  SDL_Surface *pSurface = SDL_GetWindowSurface(mpWindow);
+  SDL_LockSurface(pSurface);
+
+  int fx, fy; // ChocoChip8 Framebuffer coordinates
+  int sx, sy; // SDL Surface coordinates
+  int lx, ly; // Last-used ChocoChip8 Framebuffer coordinates
+  Uint32 lc;  // Last-used SDL color
+  
+  // Fill the entire SDL surface, one pixel at a time
+  lx = -1;
+  ly = -1;
+  for(sy = 0; sy < pSurface->h; sy++) {
+    for(sx = 0; sx < pSurface->w; sx++) {
+      // Map SDL surface coordinates to Chocochip8 Framebuffer coordinates
+      fx = sx * (double(chocochip8::gcWidth) / pSurface->w);
+      fy = sy * (double(chocochip8::gcHeight) / pSurface->h);
+
+      // Reuse color if this screen pixel maps to the same ChocoChip8 pixel as the last
+      if(fx != lx || fy != ly) {
+        lx = fx;
+        ly = ly;
+        // Read Chocochip8 Framebuffer and choose appropriate color,
+        // note that the MSB of an scanline's bitset is the leftmost pixel.
+        lc = (mpFramebuffer->at(fy)[(chocochip8::gcWidth - 1) - fx] ? mFgColor : mBgColor);
+      }
+
+      // Convert (x, y) indexes into SDL Surface pixel array index
+      Uint32 *pPixel = static_cast<Uint32*>(static_cast<void*>(
+          static_cast<char*>(pSurface->pixels)
+          + sy * pSurface->pitch
+          + sx * pSurface->format->BytesPerPixel
+      ));
+      *pPixel = lc;
+    }
+  }
+
+  SDL_UnlockSurface(pSurface);
+  SDL_UpdateWindowSurface(mpWindow);
+}
diff --git a/DisplaySDL.hpp b/DisplaySDL.hpp
new file mode 100644
index 0000000..6f88350
--- /dev/null
+++ b/DisplaySDL.hpp
@@ -0,0 +1,18 @@
+#pragma once
+
+#include "Peripherals.hpp"
+
+#include <cstdint>
+#include <SDL2/SDL_video.h>
+
+class DisplaySDL : public chocochip8::Display {
+public:
+  DisplaySDL(int w, int h, uint32_t fgCol, uint32_t bgCol);
+  ~DisplaySDL() override;
+  void updateWindow() const;
+
+private:
+  SDL_Window *mpWindow;
+  Uint32 mFgColor;
+  Uint32 mBgColor;
+};
diff --git a/Peripherals.hpp b/Peripherals.hpp
index b69c3ef..7ed23a7 100644
--- a/Peripherals.hpp
+++ b/Peripherals.hpp
@@ -6,8 +6,10 @@
 
 namespace chocochip8 {
 
-  using Scanline = std::bitset<128>;
-  using Framebuffer = std::array<Scanline, 64>;
+  constexpr size_t gcWidth = 128;
+  constexpr size_t gcHeight = 64;
+  using Scanline = std::bitset<gcWidth>;
+  using Framebuffer = std::array<Scanline, gcHeight>;
 
   enum class Key {
     KEY_0, KEY_1, KEY_2, KEY_3,
diff --git a/main.cpp b/main.cpp
index 766ed8b..2b1513b 100644
--- a/main.cpp
+++ b/main.cpp
@@ -2,6 +2,8 @@
 #include <SDL2/SDL.h>
 
 #include "BuzzerSDL.hpp"
+#include "DisplaySDL.hpp"
+#include "Peripherals.hpp"
 
 int main(int argc, char* args[]) {
   if (SDL_Init(SDL_INIT_EVERYTHING) < 0) {
@@ -9,11 +11,22 @@ int main(int argc, char* args[]) {
     return 1;
   }
 
+  class DisplayTest : public DisplaySDL {
+  public:
+    DisplayTest() : DisplaySDL(1280, 640, 0xff0000, 0x00ff00) {
+      for(int i = 0; i < chocochip8::gcHeight; i+=2) {
+        mpFramebuffer->at(i).set();
+      }
+    }
+  };
+
   BuzzerSDL buzzer(440);
-  buzzer.on();
+  //buzzer.on();
+  DisplayTest display;
 
   SDL_Event event;
   while(SDL_WaitEvent(&event) && event.type != SDL_QUIT) {
+    display.updateWindow();
   }
   
   buzzer.off();