screenshots in .bmp format without libpng

src/main.c

@@ -36,9 +36,7 @@ void mouse_lock();
 void mouse_unlock();
 
 /* from screenshot.c */
-#ifdef HAVE_LIBPNG
 BOOL screenshot(struct IDirectDrawSurfaceImpl *);
-#endif
 
 IDirectDrawImpl *ddraw = NULL;
 
@@ -761,7 +759,7 @@ LRESULT CALLBACK WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
                     return 0;
                 }
             }
-#ifdef HAVE_LIBPNG
+
             if(wParam == VK_CONTROL || wParam == ddraw->screenshotKey)
             {
                 if(GetAsyncKeyState(VK_CONTROL) & 0x8000 && GetAsyncKeyState(ddraw->screenshotKey) & 0x8000)
@@ -770,16 +768,13 @@ LRESULT CALLBACK WndProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
                     return 0;
                 }
             }
-#endif
             break;
 
-#ifdef HAVE_LIBPNG
         case WM_KEYUP:
             if (wParam == VK_SNAPSHOT)
                 screenshot(ddraw->primary);
 
             break;
-#endif
             
 
         /* button up messages reactivate cursor lock */

src/screenshot.c

@@ -13,9 +13,6 @@
  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
-
-#ifdef HAVE_LIBPNG
-
 #include <windows.h>
 #include <stdio.h>
 #include <ctype.h>
@@ -24,6 +21,102 @@
 #include "palette.h"
 #include "surface.h"
 
+#ifndef HAVE_LIBPNG
+
+//https://docs.microsoft.com/en-us/windows/desktop/gdi/storing-an-image
+
+BOOL screenshot(struct IDirectDrawSurfaceImpl *src)
+{
+    HANDLE hf;                 // file handle  
+    BITMAPFILEHEADER hdr;       // bitmap file-header  
+    PBITMAPINFOHEADER pbih;     // bitmap info-header  
+    LPBYTE lpBits;              // memory pointer  
+    DWORD dwTotal;              // total count of bytes  
+    DWORD cb;                   // incremental count of bytes  
+    BYTE *hp;                   // byte pointer  
+    DWORD dwTmp;
+    int i;
+    char title[128];
+    char filename[128];
+    char str_time[64];
+    time_t t = time(NULL);
+    BOOL result = TRUE;
+
+    strncpy(title, ddraw->title, sizeof(ddraw->title));
+
+    for (i = 0; i<strlen(title); i++) {
+        if (title[i] == ' ')
+        {
+            title[i] = '_';
+        }
+        else
+        {
+            title[i] = tolower(title[i]);
+        }
+    }
+
+    strftime(str_time, 64, "%Y-%m-%d-%H_%M_%S", localtime(&t));
+    _snprintf(filename, 128, "%s-%s.bmp", title, str_time);
+
+    pbih = (PBITMAPINFOHEADER)src->bmi;
+    lpBits = (LPBYTE)src->surface;
+
+    if (!lpBits)
+        return FALSE;
+
+    // Create the .BMP file.  
+    hf = CreateFile(filename,
+        GENERIC_READ | GENERIC_WRITE,
+        (DWORD)0,
+        NULL,
+        CREATE_ALWAYS,
+        FILE_ATTRIBUTE_NORMAL,
+        (HANDLE)NULL);
+
+    if (hf == INVALID_HANDLE_VALUE)
+        return FALSE;
+
+    hdr.bfType = 0x4d42;        // 0x42 = "B" 0x4d = "M"  
+                                // Compute the size of the entire file.  
+    hdr.bfSize = (DWORD)(sizeof(BITMAPFILEHEADER) +
+        pbih->biSize + pbih->biClrUsed
+        * sizeof(RGBQUAD) + pbih->biSizeImage);
+    hdr.bfReserved1 = 0;
+    hdr.bfReserved2 = 0;
+
+    // Compute the offset to the array of color indices.  
+    hdr.bfOffBits = (DWORD) sizeof(BITMAPFILEHEADER) +
+        pbih->biSize + pbih->biClrUsed
+        * sizeof(RGBQUAD);
+
+    // Copy the BITMAPFILEHEADER into the .BMP file.  
+    if (!WriteFile(hf, (LPVOID)&hdr, sizeof(BITMAPFILEHEADER),
+        (LPDWORD)&dwTmp, NULL))
+    {
+        result = FALSE;
+    }
+
+    // Copy the BITMAPINFOHEADER and RGBQUAD array into the file.  
+    if (!WriteFile(hf, (LPVOID)pbih, sizeof(BITMAPINFOHEADER)
+        + pbih->biClrUsed * sizeof(RGBQUAD),
+        (LPDWORD)&dwTmp, (NULL)))
+        result = FALSE;
+
+    // Copy the array of color indices into the .BMP file.  
+    dwTotal = cb = pbih->biSizeImage;
+    hp = lpBits;
+    if (!WriteFile(hf, (LPSTR)hp, (int)cb, (LPDWORD)&dwTmp, NULL))
+        result = FALSE;
+
+    // Close the .BMP file.  
+    if (!CloseHandle(hf))
+        result = FALSE;
+
+    return result;
+}
+
+#else
+
 #include <png.h>
 
 BOOL screenshot(struct IDirectDrawSurfaceImpl *src)

src/surface.c

@@ -560,6 +560,12 @@ HRESULT __stdcall ddraw_CreateSurface(IDirectDrawImpl *This, LPDDSURFACEDESC lpD
         Surface->bmi->bmiHeader.biBitCount = Surface->bpp;
         Surface->bmi->bmiHeader.biCompression = BI_RGB;
 
+        WORD cClrBits = (WORD)(Surface->bmi->bmiHeader.biPlanes * Surface->bmi->bmiHeader.biBitCount);
+        if (cClrBits < 24)
+            Surface->bmi->bmiHeader.biClrUsed = (1 << cClrBits);
+
+        Surface->bmi->bmiHeader.biSizeImage = ((Surface->width * cClrBits + 31) & ~31) / 8 * Surface->height;
+
         int i;
         for (i = 0; i < 256; i++)
         {