Begin raymarcher example and math module, fixing parsing bugs

examples/drawing_to_screen_using_windows_api.kl

@@ -59,7 +59,7 @@ WinMain :: (hInstance: HINSTANCE, hPrevInstance: HINSTANCE, lpCmdLine: LPSTR, nS
 
   arena: Arena.Arena
 
-  window_name := StringToString16(&arena, "Have a wonderful day! 豈 更 車 賈 滑 串 句 龜 ")
+  window_name := StringToString16(&arena, "Have a wonderful day! 你好世界 ")
   w := WNDCLASSW{
     lpfnWndProc   = WindowProc,
     hInstance     = hInstance,

examples/raymarcher.kl

@@ -0,0 +1,164 @@
+#import "math.kl"
+
+Epsilon :: 0.00001
+Screen  :  *U32
+X       :   S64
+Y       :   S64
+
+SphereSDF :: (pos: Vec3): F32
+  result := Vec3_Length(pos) - 1.0
+  return result
+
+Raymarcher_Update :: ()
+  up := Vec3{0, 1, 0}
+  forward := Vec3{0, 0, -1}
+  side := Vec3_Normalize(Vec3_Cross(forward, up))
+
+  bug := Vec3_Dot(side, forward, d, e)
+  Xf := 1 / X->F32
+  Yf := 1 / Y->F32
+  ratio := X->F32 / Y->F32
+  for y := 0, y < Y, y+=1
+      for x := 0, x < X, x+=1
+        uv := Vec3{x->F32 * Xf * 2 - 1, y->F32 * Yf * 2 - 1, 1.0}
+        uv.x *= ratio
+        dir := Vec3_Normalize(Vec3{Vec3_Dot(side, uv), Vec3_Dot(up, uv), Vec3_Dot(forward, uv)})
+        pos := Vec3{0, 0, 5}
+
+        t: F32
+        end: F32 = 100.0
+        hit := true
+        for i := 0, i < 255, i+=1
+          p := Vec3_Add(pos, Vec3_MulF32(dir, t))
+
+          distance := SphereSDF(p)
+          if distance < Epsilon
+            break
+
+          t += distance
+          if distance >= end
+            hit = false
+            break
+
+        if hit
+          Screen[x + y*X] = Vec3_ConvertToARGB({1, uv.y, 0})
+
+
+
+
+/////////////////////////////////////
+//
+// Windows specific code
+//
+
+#import "base.kl"
+#import "arena.kl"
+#import "os_windows.kl"
+#import "kernel32.kl"
+#import "gdi32.kl"
+#import "user32.kl"
+#import "winmm.kl"
+
+Windows_Bitmap :: struct
+  size: Vec2I
+  data: *U32
+  hdc: HDC
+  dib: HBITMAP
+
+CreateBitmap :: (size: Vec2I, bottom_up: Bool = true): Windows_Bitmap
+  result: Windows_Bitmap = {size = size}
+  if bottom_up == false
+    result.size.y = -result.size.y
+
+  header_size: U32 = SizeOf(BITMAPINFOHEADER)
+  Assert(header_size == 40)
+  bminfo := BITMAPINFO{
+    BITMAPINFOHEADER{
+      biSize          = header_size,
+      biWidth         = size.x->LONG,
+      biHeight        = size.y->LONG,
+      biPlanes        = 1,
+      biBitCount      = 32,
+      biCompression   = BI_RGB,
+      biXPelsPerMeter = 1,
+      biYPelsPerMeter = 1,
+    }
+  }
+
+  hdc := GetDC(0)
+  result.dib = CreateDIBSection(hdc, &bminfo, DIB_RGB_COLORS, (&result.data)->**void, 0, 0)
+  result.hdc = CreateCompatibleDC(hdc)
+  return result
+
+
+AppIsRunning := true
+WindowProc :: (hwnd: HWND, msg: UINT, wparam: WPARAM, lparam: LPARAM): LRESULT
+  if msg == WM_DESTROY
+    PostQuitMessage(0)
+    AppIsRunning = false
+    return 0
+  else;; return DefWindowProcW(hwnd, msg, wparam, lparam)
+
+WinMain :: (hInstance: HINSTANCE, hPrevInstance: HINSTANCE, lpCmdLine: LPSTR, nShowCmd: int): int
+  if good_scheduling := false, timeBeginPeriod(1) == TIMERR_NOERROR
+    good_scheduling = true
+
+  arena: Arena
+
+  window_name := StringToString16(&arena, "Have a wonderful day! 你好世界 ")
+  w := WNDCLASSW{
+    lpfnWndProc   = WindowProc,
+    hInstance     = hInstance,
+    lpszClassName = window_name.str,
+  }
+  Assert(RegisterClassW(&w) != 0)
+
+  screen_size: Vec2I = {1280, 720}
+  window := CreateWindowExW(
+    dwExStyle = 0, hWndParent = 0, hMenu = 0, lpParam = 0,
+    X = CW_USEDEFAULT, Y = CW_USEDEFAULT, nWidth = screen_size.x->int, nHeight = screen_size.y->int,
+    lpClassName = window_name.str,
+    lpWindowName = window_name.str,
+    dwStyle = WS_OVERLAPPEDWINDOW,
+    hInstance = hInstance
+  )
+  Assert(window != 0)
+  ShowWindow(window, nShowCmd)
+
+  window_dc := GetDC(window)
+  bitmap := CreateBitmap(screen_size)
+
+  requested_time_per_frame := 1.0 / 60.0
+  frame_start_time := Time()
+  frame_number: S64
+  total_time: F64
+  for AppIsRunning
+    msg: MSG
+    for PeekMessageW(&msg, window, 0, 0, PM_REMOVE) > 0
+      TranslateMessage(&msg)
+      DispatchMessageW(&msg)
+
+    Screen = bitmap.data; X = bitmap.size.x; Y = bitmap.size.y
+    Raymarcher_Update()
+
+
+    SelectObject(bitmap.hdc, bitmap.dib)
+    BitBlt(window_dc, 0, 0, (bitmap.size.x)->int, (bitmap.size.y)->int, bitmap.hdc, 0, 0, SRCCOPY)
+
+
+    frame_time := Time() - frame_start_time
+    if frame_time < requested_time_per_frame
+      if good_scheduling
+        time_to_sleep := (requested_time_per_frame - frame_time) * 1000
+        if time_to_sleep > 0
+          time_to_sleep_dword := time_to_sleep->DWORD
+          // @check if time_to_sleep_dword truncates down
+          Sleep(time_to_sleep_dword)
+
+        new_frame_time := Time()
+        for new_frame_time < requested_time_per_frame
+          new_frame_time = Time() - frame_start_time
+
+        frame_time = new_frame_time
+        frame_number += 1
+        total_time += frame_time