Properly reset emulator state on program start

This doesn't change anything functionally, it just makes the screen black before you load a ROM.

src/emu.cpp

@@ -4,6 +4,34 @@
 #include <iostream>
 #include <array>
 
+void EmulatorState::reset() {
+    for (int i = 0; i < 4096; i++)
+        memory[i] = 0;
+
+    PC = program_begin;
+
+    for (int i = 0; i < 12; i++)
+        stack[i] = 0;
+
+    stack_pointer = 0;
+
+    I = 0;
+
+    for (int i = 0; i < 16; i++)
+        v[i] = 0;
+
+    delay_timer = 0;
+    sound_timer = 0;
+
+    for (int y = 0; y < screen_height; y++) {
+        for (int x = 0; x < screen_width; x++) {
+          pixels[to_coord(x, y)] = 0;
+        }
+    }
+
+    draw_dirty = true;
+}
+
 typedef void (*cpu_func)(const uint16_t opcode);
 
 void null_func(const uint16_t opcode) {

src/emu.hpp

@@ -13,33 +13,7 @@ inline int to_coord(int x, int y) {
 }
 
 struct EmulatorState {
-    void reset() {
+    void reset();
-        for(int i = 0; i < 4096; i++)
-            memory[i] = 0;
-        
-        PC = program_begin;
-        
-        for(int i = 0; i < 12; i++)
-            stack[i] = 0;
-        
-        stack_pointer = 0;
-        
-        I = 0;
-        
-        for(int i = 0; i < 16; i++)
-            v[i] = 0;
-        
-        delay_timer = 0;
-        sound_timer = 0;
-        
-        for(int y = 0; y < screen_height; y++) {
-            for(int x = 0; x < screen_width; x++) {
-                pixels[to_coord(x, y)] = 0;
-            }
-        }
-        
-        draw_dirty = true;
-    }
     
     uint8_t memory[4096] = {};
     uint16_t PC = program_begin;

src/main.cpp

@@ -208,6 +208,8 @@ int main(int argc, char* argv[]) {
     SDL_GL_MakeCurrent(window, gl_context);
     SDL_GL_SetSwapInterval(1);
 
+    state.reset();
+
     gladLoadGL();
     setup_gfx();