update

misc/bdebug.bat

@@ -1,2 +1,2 @@
 call build || exit /b %errorlevel%
-devenv .\build\handmade.exe
+devenv .\build\handmade_win32.exe

misc/brun.bat

@@ -1,2 +1,2 @@
 call build || exit /b %errorlevel%
-.\build\handmade.exe
+.\build\handmade_win32.exe

misc/build.bat

@@ -1,9 +1,9 @@
 @echo off
 if NOT EXIST .\build mkdir .\build
-pushd .\build
-cl ^
+
+set commonLinkerFlags= -opt:ref user32.lib Gdi32.lib winmm.lib                         
+set commonCompilerFlags=^
     -MT                                                             %= Make sure the C runtime library is statically linked =%^
-    -Fmwin32_handmade.map                                           %= Create a map file =%^
     -Gm-                                                            %= Turns off incremently building =%^
     -nologo                                                         %= No one cares you made the compiler Microsoft =%^
     -Oi                                                             %= Always use intrinsics  =%^
@@ -12,10 +12,12 @@ cl ^
     -WX -W4 -wd4201 -wd4100 -wd4189                                 %= Compiler warnings, -WX warnings as errors, -W4 warning level 4, -wdXXXX disable warning XXXX =%^
     -DHANDMADE_INTERNAL=1 -DHANDMADE_SLOW=1 -DHANDMADE_WIN32=1      %= Custom #defines =%^
     -FC                                                             %= Full path of source code file in diagnostics =%^
-    -Zi                                                             %= Generate debugger info =%^
-    -Fe:handmade.exe ..\src\win32_handmade.cpp                      %= Output filename, input filename =%^
-    user32.lib Gdi32.lib winmm.lib                                  %= Linked libraries =%^
-    /link -subsystem:windows,5.1                                    %= Linker stuff =%
+    -Zi                                                             %= Generate debugger info =%
+
+pushd .\build
+
+cl %commonCompilerFlags% -Fe:handmade.dll ..\src\handmade.cpp -Fmhandmade.map /link /DLL /EXPORT:gameGetSoundSamples /EXPORT:gameUpdateAndRender
+cl %commonCompilerFlags% -Fe:handmade_win32.exe ..\src\win32_handmade.cpp -Fmwin32_handmade.map /link %commonLinkerFlags%
 popd
 exit /b
 

src/handmade.cpp

@@ -2,16 +2,6 @@
 
 #define PI32 3.141592653589f
 
-void debug_printf(wchar_t* format, ...) { 
-    size_t bufsize = wcslen(format)*10;
-    wchar_t *output = (wchar_t*)malloc(bufsize);
-    va_list list;
-    va_start(list, format);
-    vswprintf(output, bufsize, format, list);
-    OutputDebugStringW(output);
-    free(output);
-}
-
 internal void outputSineSound(GameSoundOutputBuffer *soundBuffer, GameState *state) {
     int16 toneVolume = 3000;
     int wavePeriod = soundBuffer->samplesPerSecond/state->toneHz;
@@ -34,23 +24,25 @@ internal void renderWeirdGradient(GameOffscreenBuffer *buffer, int xOffset, int
         for (int x = 0; x < buffer->width; x++) {
             uint8 blue = (uint8)(x + xOffset);
             uint8 green = (uint8)(y + yOffset);
-            *pixel++ = (green << 8) | blue;
+            *pixel++ = (green << 16) | blue;
         }
         row += pitch;
     }
 }
 
-internal void gameUpdateAndRender(GameMemory *memory, GameOffscreenBuffer *videoBuf, GameInput *input) {
+extern "C" GAME_UPDATE_AND_RENDER(gameUpdateAndRender) {
     Assert(sizeof(GameState) <= memory->permanentStorageSize);
 
     GameState *state = (GameState*)memory->permanentStorage;
 
     if (!memory->isInitialised) {
-        //DebugReadFileResult bmpMem = DEBUG_platformReadEntireFile(__FILE__);
-        //if (bmpMem.contents) {
-        //    DEBUG_platformWriteEntireFile("c:/source/repos/handmade/src/test.cpp", bmpMem.contentsSize, bmpMem.contents);
-        //    DEBUG_platformFreeFileMemory(bmpMem.contents);
-        //}
+        DebugReadFileResult bmpMem = memory->debugReadEntireFile(__FILE__);
+        if (bmpMem.contents) {
+            if (false) {
+                memory->debugWriteEntireFile("c:/source/repos/handmade/src/test.cpp", bmpMem.contentsSize, bmpMem.contents);
+            }
+            memory->debugFreeFileMemory(bmpMem.contents);
+        }
 
         state->toneHz = 440;
         state->tSine = 0;
@@ -70,8 +62,6 @@ internal void gameUpdateAndRender(GameMemory *memory, GameOffscreenBuffer *video
             } else if (controllerInput->stickLeft.endedDown) {
                 state->toneHz = 440 - 128;
                 state->greenOffset += 10;
-            } else {
-                //state->toneHz = 440;
             }
             if (controllerInput->stickUp.endedDown) {
                 state->blueOffset += 10;
@@ -84,6 +74,14 @@ internal void gameUpdateAndRender(GameMemory *memory, GameOffscreenBuffer *video
     renderWeirdGradient(videoBuf, state->greenOffset, state->blueOffset);
 }
 
-internal void gameGetSoundSamples(GameMemory *memory, GameSoundOutputBuffer *soundBuf) {
+extern "C" GAME_GET_SOUND_SAMPLES(gameGetSoundSamples) {
     outputSineSound(soundBuf, (GameState*)memory->permanentStorage);
 }
+
+#if HANDMADE_WIN32
+#include "windows.h"
+
+BOOL DllMain() {
+    return TRUE;
+}
+#endif

src/handmade.h

@@ -64,6 +64,28 @@ inline uint32 safeTruncateUInt64(uint64 val) {
     return (uint32)val;
 }
 
+// === Platform to game services ===
+#if HANDMADE_INTERNAL
+
+struct DebugReadFileResult {
+    uint32 contentsSize;
+    void *contents;
+};
+
+#define DEBUG_PLATFORM_READ_ENTIRE_FILE(name) DebugReadFileResult name(char *filename)
+typedef DEBUG_PLATFORM_READ_ENTIRE_FILE(DebugPlatformReadEntireFileFn);
+
+#define DEBUG_PLATFORM_FREE_FILE_MEMORY(name) void name(void *fileMemory)
+typedef DEBUG_PLATFORM_FREE_FILE_MEMORY(DebugPlatformFreeFileMemoryFn);
+
+#define DEBUG_PLATFORM_WRITE_ENTIRE_FILE(name) bool32 name(char *filename, uint32 memorySize, void *memory)
+typedef DEBUG_PLATFORM_WRITE_ENTIRE_FILE(DebugPlatformWriteEntireFileFn);
+
+#define DEBUG_PLATFORM_PRINTF(name) void name(wchar_t* format, ...)
+typedef DEBUG_PLATFORM_PRINTF(DebugPrintfFn);
+
+#endif
+
 // Game to platform layer services
 struct GameSoundOutputBuffer {
     int samplesPerSecond;
@@ -111,10 +133,17 @@ struct GameInput {
 
 struct GameMemory {
     bool32 isInitialised;
+
     uint64 permanentStorageSize;
     void *permanentStorage; // required to be initialised to zero at startup 
+
     uint64 transientStorageSize;
     void *transientStorage; // required to be initialised to zero at startup 
+
+    DebugPlatformReadEntireFileFn *debugReadEntireFile;
+    DebugPlatformFreeFileMemoryFn *debugFreeFileMemory;
+    DebugPlatformWriteEntireFileFn *debugWriteEntireFile;
+    DebugPrintfFn *debug_printf;
 };
 
 struct GameState {
@@ -125,22 +154,11 @@ struct GameState {
 };
 
 // === Game to platform services ===
-internal void gameUpdateAndRender(GameMemory *memory, GameInput *input, GameOffscreenBuffer *videoBuf);
-internal void gameGetSoundSamples(GameMemory *memory, GameSoundOutputBuffer *soundBuf);
-
-// === Platform to game services ===
-#if HANDMADE_INTERNAL
-
-struct DebugReadFileResult {
-    uint32 contentsSize;
-    void *contents;
-};
-
-DebugReadFileResult DEBUG_platformReadEntireFile(char *filename);
-void DEBUG_platformFreeFileMemory(void *memory);
-bool32 DEBUG_platformWriteEntireFile(char *filename, uint32 memorySize, void *memory);
-void debug_printf(wchar_t* format, ...);
-
-#endif
 
+#define GAME_UPDATE_AND_RENDER(name) void name(GameMemory *memory, GameOffscreenBuffer *videoBuf, GameInput *input)
+typedef GAME_UPDATE_AND_RENDER(GameUpdateAndRenderFn);
+GAME_UPDATE_AND_RENDER(gameUpdateAndRenderStub) {}
 
+#define GAME_GET_SOUND_SAMPLES(name) void name(GameMemory *memory, GameSoundOutputBuffer *soundBuf)
+typedef GAME_GET_SOUND_SAMPLES(GameGetSoundSamplesFn);
+GAME_GET_SOUND_SAMPLES(gameGetSoundSamplesStub) {}

src/win32_handmade.cpp

@@ -4,8 +4,8 @@
 #include <dsound.h>
 
 // Local imports
+#include "handmade.h"
 #include "win32_handmade.h"
-#include "handmade.cpp"
 
 global ATOM HH_CTRLW;
 global bool globalRunning;
@@ -31,13 +31,23 @@ typedef HRESULT WINAPI DirectSoundCreateFn(LPCGUID pcGuidDevice, LPDIRECTSOUND *
 
 #define stackAlloc(size, type) (type*)_alloca(size*sizeof(type))
 
-void DEBUG_platformFreeFileMemory(void *fileMemory) {
+DEBUG_PLATFORM_PRINTF(debug_printf) { 
+    size_t bufsize = wcslen(format)*10;
+    wchar_t *output = (wchar_t*)malloc(bufsize);
+    va_list list;
+    va_start(list, format);
+    vswprintf(output, bufsize, format, list);
+    OutputDebugStringW(output);
+    free(output);
+}
+
+DEBUG_PLATFORM_FREE_FILE_MEMORY(debugFreeFileMemory) {
     if (fileMemory) {
         VirtualFree(fileMemory, NULL, MEM_RELEASE);
     }
 }
 
-DebugReadFileResult DEBUG_platformReadEntireFile(char *filename) {
+DEBUG_PLATFORM_READ_ENTIRE_FILE(debugReadEntireFile) {
     DebugReadFileResult result = {};
     HANDLE fileHandle = CreateFileA(filename, GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, NULL, NULL);
     if (fileHandle != INVALID_HANDLE_VALUE) {
@@ -50,7 +60,7 @@ DebugReadFileResult DEBUG_platformReadEntireFile(char *filename) {
                 if (ReadFile(fileHandle, result.contents, (DWORD)fileSize.QuadPart, &bytesRead, NULL) && (fileSize32 == (uint32)bytesRead)) {
                     result.contentsSize = fileSize32;
                 } else {
-                    DEBUG_platformFreeFileMemory(result.contents);
+                    debugFreeFileMemory(result.contents);
                     result.contents = NULL;
                     // logging
                 }
@@ -68,7 +78,7 @@ DebugReadFileResult DEBUG_platformReadEntireFile(char *filename) {
     return result;
 }
 
-bool32 DEBUG_platformWriteEntireFile(char *filename, uint32 memorySize, void *memory) {
+DEBUG_PLATFORM_WRITE_ENTIRE_FILE(debugWriteEntireFile) {
     bool32 result = false;
     HANDLE fileHandle = CreateFileA(filename, GENERIC_WRITE, FILE_SHARE_READ, NULL, CREATE_ALWAYS, NULL, NULL);
     if (fileHandle != INVALID_HANDLE_VALUE) {
@@ -128,6 +138,42 @@ internal void win32DrawBufferInWindow(Win32OffscreenBuffer *buffer, HWND window)
     );
 }
 
+struct Win32GameCode {
+    HMODULE gameCodeLib;
+    GameUpdateAndRenderFn *updateAndRender;
+    GameGetSoundSamplesFn *getSoundSamples;
+    bool isValid;
+};
+
+internal Win32GameCode win32LoadGameCode() {
+    Win32GameCode result = {};
+
+    CopyFile("handmade.dll", "handmade_temp.dll", FALSE);
+    HMODULE gameCodeLib = LoadLibrary("handmade_temp.dll");
+    result.gameCodeLib = gameCodeLib;
+
+    if (gameCodeLib) {
+        result.updateAndRender = (GameUpdateAndRenderFn *)GetProcAddress(result.gameCodeLib, "gameUpdateAndRender");
+        result.getSoundSamples = (GameGetSoundSamplesFn *)GetProcAddress(result.gameCodeLib, "gameGetSoundSamples");
+        result.isValid = (result.updateAndRender && result.getSoundSamples);
+    }
+    if (!result.isValid) {
+        result.getSoundSamples = gameGetSoundSamplesStub;
+        result.updateAndRender = gameUpdateAndRenderStub;
+    }
+
+    return result;
+}
+
+internal void win32UnloadGameCode(Win32GameCode *gameCode) {
+    if (gameCode->gameCodeLib) {
+        FreeLibrary(gameCode->gameCodeLib);
+    }
+    gameCode->isValid = false;
+    gameCode->getSoundSamples = gameGetSoundSamplesStub;
+    gameCode->updateAndRender = gameUpdateAndRenderStub;
+}
+
 internal void win32LoadXInput() {
     HMODULE xInputLib = LoadLibrary("xinput1_4.dll");
     if (!xInputLib) {
@@ -472,6 +518,10 @@ int APIENTRY WinMain(HINSTANCE instance, HINSTANCE prevInstance, PSTR commandLin
             GameMemory gameMemory = {};
             gameMemory.permanentStorageSize = Megabytes(64);
             gameMemory.transientStorageSize = Gigabytes((uint64)4);
+            gameMemory.debugFreeFileMemory = debugFreeFileMemory;
+            gameMemory.debugWriteEntireFile = debugWriteEntireFile;
+            gameMemory.debugReadEntireFile = debugReadEntireFile;
+            gameMemory.debug_printf = debug_printf;
 
             uint64 totalSize = gameMemory.permanentStorageSize + gameMemory.transientStorageSize;
             gameMemory.permanentStorage = VirtualAlloc(baseAddress, totalSize, MEM_RESERVE | MEM_COMMIT, PAGE_READWRITE);
@@ -484,12 +534,23 @@ int APIENTRY WinMain(HINSTANCE instance, HINSTANCE prevInstance, PSTR commandLin
             LARGE_INTEGER lastWorkCounter = win32GetWallClock();
             LARGE_INTEGER flipWallClock = win32GetWallClock();
 
-            int64 lastCycleCount = __rdtsc();
 
             DWORD audioLatencyBytes = 0;
             real32 audioLatencySeconds = 0;
+            bool soundIsValid = false;
+
+            Win32GameCode game = win32LoadGameCode();
+            uint32 loadCounter = 0;
 
+            int64 lastCycleCount = __rdtsc();
             while (globalRunning) {
+                if (loadCounter++ > 60) {
+                    win32UnloadGameCode(&game);
+                    game = win32LoadGameCode();
+                    loadCounter = 0;
+                    // TODO(dledda): handmade hero episode 22 (from the beginning)
+                }
+
                 GameControllerInput *oldKeyboardController = &oldInput->controllers[0];
                 GameControllerInput *newKeyboardController = &newInput->controllers[0];
                 GameControllerInput zeroController = {};
@@ -566,11 +627,10 @@ int APIENTRY WinMain(HINSTANCE instance, HINSTANCE prevInstance, PSTR commandLin
                 videoBuffer.memory = globalBackBuffer.memory;
                 videoBuffer.width = globalBackBuffer.width;
                 videoBuffer.height = globalBackBuffer.height;
-                gameUpdateAndRender(&gameMemory, &videoBuffer, newInput);
+                game.updateAndRender(&gameMemory, &videoBuffer, newInput);
 
                 DWORD playCursor = 0;
                 DWORD writeCursor = 0;
-                bool soundIsValid = false;
 
                 if (SUCCEEDED(globalSecondaryBuffer->GetCurrentPosition(&playCursor, &writeCursor))) {
                     if (!soundIsValid) {
@@ -579,17 +639,17 @@ int APIENTRY WinMain(HINSTANCE instance, HINSTANCE prevInstance, PSTR commandLin
                     }
                     DWORD byteToLock = (soundOutput.runningSampleIndex*soundOutput.bytesPerSample) % soundOutput.secondaryBufferSize;
 
-                    // TODO(dledda): episode 20 ~2:00, something's wrong though, gotta sort it out.  
-
                     DWORD expectedSoundBytesPerFrame = (soundOutput.samplesPerSecond * soundOutput.bytesPerSample) / gameUpdateHz;
                     DWORD expectedFrameBoundaryByte = playCursor + expectedSoundBytesPerFrame;
+
                     DWORD safeWriteCursor = writeCursor;
                     if (safeWriteCursor < playCursor) {
                         safeWriteCursor += soundOutput.secondaryBufferSize;
                     }
                     Assert(safeWriteCursor >= playCursor);
-                    safeWriteCursor += soundOutput.safetyBytes + 2000;
-                    bool audioIsLowLatency = safeWriteCursor >= expectedFrameBoundaryByte;
+                    safeWriteCursor += soundOutput.safetyBytes;
+
+                    bool audioIsLowLatency = safeWriteCursor < expectedFrameBoundaryByte;
 
                     DWORD targetCursor = 0;
                     if (audioIsLowLatency) {
@@ -610,7 +670,7 @@ int APIENTRY WinMain(HINSTANCE instance, HINSTANCE prevInstance, PSTR commandLin
                     soundBuffer.samplesPerSecond = soundOutput.samplesPerSecond;
                     soundBuffer.sampleCount = bytesToWrite / soundOutput.bytesPerSample;
                     soundBuffer.samples = samples;
-                    gameGetSoundSamples(&gameMemory, &soundBuffer);
+                    game.getSoundSamples(&gameMemory, &soundBuffer);
 #if HANDMADE_INTERNAL
                     Assert(debugTimeMarkerIndex < ArrayCount(debugMarkers));