Code (main.cpp)
#include <windows.h>
#include <stdint.h>
#include <wchar.h>
typedef uint32_t u32;
int running = 1;
int client_width = 640;
int client_height = 640;
float player_x;
float player_y;
float d_player_x;
float d_player_y;
int moving_left;
int moving_right;
int moving_up;
int moving_down;
int tile_size = 25;
void* memory;
BITMAPINFO bitmap_info;
float target_seconds_per_frame = 1.0f / 120.0f;
LARGE_INTEGER frequency;
float get_seconds_per_frame(LARGE_INTEGER start_counter,
LARGE_INTEGER end_counter)
{
return ((float)(end_counter.QuadPart - start_counter.QuadPart) / (float)frequency.QuadPart);
}
void clear_screen(u32 color)
{
u32 *pixel = (u32 *)memory;
for(int pixel_number = 0;
pixel_number < client_width * client_height;
++pixel_number)
{
*pixel++ = color;
}
}
void draw_rectangle(int rec_x,
int rec_y,
int rec_width,
int rec_height,
u32 color)
{
u32 *pixel = (u32 *)memory;
pixel += rec_y * client_width + rec_x;
for(int y = 0;
y < rec_height;
++y)
{
for(int x = 0;
x < rec_width;
++x)
{
*pixel++ = color;
}
pixel += client_width - rec_width;
}
}
LRESULT CALLBACK
WindowProc(HWND window,
UINT message,
WPARAM w_param,
LPARAM l_param)
{
LRESULT result;
switch(message)
{
case WM_CLOSE:
{
running = 0;
} break;
case WM_KEYUP:
{
switch(w_param)
{
case VK_RIGHT:
{
moving_right = 0;
} break;
case VK_LEFT:
{
moving_left = 0;
} break;
case VK_UP:
{
moving_up = 0;
} break;
case VK_DOWN:
{
moving_down = 0;
} break;
}
} break;
case WM_KEYDOWN:
{
switch(w_param)
{
case VK_RIGHT:
{
if(!moving_right) moving_right = 1;
} break;
case VK_LEFT:
{
if(!moving_left) moving_left = 1;
} break;
case VK_UP:
{
if(!moving_up) moving_up = 1;
} break;
case VK_DOWN:
{
if(!moving_down) moving_down = 1;
} break;
}
} break;
default:
{
result = DefWindowProc(window,
message,
w_param,
l_param);
} break;
}
return result;
}
int WINAPI
wWinMain(HINSTANCE instance,
HINSTANCE prev_instance,
PWSTR cmd_line,
int cmd_show)
{
WNDCLASS window_class = {0};
wchar_t class_name[] = L"GameWindowClass";
window_class.lpfnWndProc = WindowProc;
window_class.hInstance = instance;
window_class.lpszClassName = class_name;
window_class.hCursor = LoadCursor(0,
IDC_CROSS
);
RECT window_rect;
window_rect.left = 0;
window_rect.top = 0;
window_rect.right = client_width;
window_rect.bottom = client_height;
AdjustWindowRectEx(&window_rect,
WS_OVERLAPPEDWINDOW,
0,0
);
int window_width = window_rect.right - window_rect.left;
int window_height = window_rect.bottom - window_rect.top;
int screen_width = GetSystemMetrics(SM_CXSCREEN);
int screen_height = GetSystemMetrics(SM_CYSCREEN);
int window_x = (screen_width / 2) - (window_width / 2);
int window_y = (screen_height / 2) - (window_height / 2);
RegisterClass(&window_class);
HWND window = CreateWindowEx(0,
class_name,
L"Game",
WS_OVERLAPPEDWINDOW|WS_VISIBLE,
window_x,
window_y,
window_width,
window_height,
0,
0,
instance,
0);
memory = VirtualAlloc(0,
client_width * client_height * 4,
MEM_RESERVE|MEM_COMMIT,
PAGE_READWRITE
);
bitmap_info.bmiHeader.biSize = sizeof(bitmap_info.bmiHeader);
bitmap_info.bmiHeader.biWidth = client_width;
bitmap_info.bmiHeader.biHeight = client_height;
bitmap_info.bmiHeader.biPlanes = 1;
bitmap_info.bmiHeader.biBitCount = 32;
bitmap_info.bmiHeader.biCompression = BI_RGB;
HDC hdc = GetDC(window);
LARGE_INTEGER start_counter, end_counter, counts, fps, ms;
QueryPerformanceCounter(&start_counter);
QueryPerformanceFrequency(&frequency);
while(running)
{
MSG message;
while(PeekMessage(&message, window, 0, 0, PM_REMOVE))
{
TranslateMessage(&message);
DispatchMessage(&message);
}
QueryPerformanceCounter(&end_counter);
float seconds_per_frame = get_seconds_per_frame(start_counter,
end_counter);
if(seconds_per_frame < target_seconds_per_frame)
{
DWORD sleep_ms;
sleep_ms = (DWORD)(1000 * (target_seconds_per_frame - seconds_per_frame));
Sleep(sleep_ms);
while(seconds_per_frame < target_seconds_per_frame)
{
QueryPerformanceCounter(&end_counter);
seconds_per_frame = get_seconds_per_frame(start_counter,
end_counter);
}
}
QueryPerformanceCounter(&end_counter);
seconds_per_frame = get_seconds_per_frame(start_counter,
end_counter);
start_counter = end_counter;
float dt = seconds_per_frame;
float speed = 250.0f;
if(moving_right) d_player_x = 1.0f;
if(moving_left) d_player_x = -1.0f;
if(moving_up) d_player_y = 1.0f;
if(moving_down) d_player_y = -1.0f;
d_player_x *= speed;
d_player_y *= speed;
if(d_player_x != 0.0f && d_player_y != 0.0f)
{
d_player_x *= 0.707f;
d_player_y *= 0.707f;
}
player_x += dt * d_player_x;
player_y += dt * d_player_y;
d_player_x = 0.0f;
d_player_y = 0.0f;
clear_screen(0x111111);
draw_rectangle(100, 100, 50, 50, 0x222222);
draw_rectangle(150, 150, 25, 25, 0x333333);
draw_rectangle(175, 175, 15, 15, 0x444444);
draw_rectangle(player_x,
player_y,
tile_size,
tile_size,
0xff00f7);
StretchDIBits(hdc,
0,
0,
client_width,
client_height,
0,
0,
client_width,
client_height,
memory,
&bitmap_info,
DIB_RGB_COLORS,
SRCCOPY
);
wchar_t buf[100];
swprintf_s(buf, sizeof(buf),
L"%0.4f\n\n",
seconds_per_frame);
OutputDebugString(buf);
}
return 0;
}
Build script (build.bat)
@echo off
cl main.cpp /Fegame.exe ^
/Zi /nologo ^
/DUNICODE /D_UNICODE ^
user32.lib gdi32.lib
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