1 files changed, 91 insertions, 0 deletions
diff --git a/src/win95/zbuffer.c b/src/win95/zbuffer.c
new file mode 100644
index 0000000..b33ea85
--- /dev/null
+++ b/src/win95/zbuffer.c
@@ -0,0 +1,91 @@
+/***************************************************************************/
+/*                           Creation of Z-Buffer                          */
+/***************************************************************************/
+/*
+ * D3DAppICreateZBuffer
+ * Create a Z-Buffer of the appropriate depth and attach it to the back
+ * buffer.
+ */
+BOOL
+D3DAppICreateZBuffer(int w, int h, int driver)
+{
+    DDSURFACEDESC ddsd;
+    DWORD devDepth;
+    /*
+     * Release any Z-Buffer that might be around just in case.
+     */
+    RELEASE(d3dappi.lpZBuffer);
+    
+    /*
+     * If this driver does not do z-buffering, don't create a z-buffer
+     */
+    if (!d3dappi.Driver[driver].bDoesZBuffer)
+        return TRUE;
+
+    memset(&ddsd, 0 ,sizeof(DDSURFACEDESC));
+    ddsd.dwSize = sizeof( ddsd );
+    ddsd.dwFlags = DDSD_WIDTH | DDSD_HEIGHT | DDSD_CAPS |
+                   DDSD_ZBUFFERBITDEPTH;
+    ddsd.ddsCaps.dwCaps = DDSCAPS_ZBUFFER;
+    ddsd.dwHeight = h;
+    ddsd.dwWidth = w;
+    /*
+     * If this is a hardware D3D driver, the Z-Buffer MUST end up in video
+     * memory.  Otherwise, it MUST end up in system memory.
+     */
+    if (d3dappi.Driver[driver].bIsHardware)
+        ddsd.ddsCaps.dwCaps |= DDSCAPS_VIDEOMEMORY;
+    else
+        ddsd.ddsCaps.dwCaps |= DDSCAPS_SYSTEMMEMORY;
+    /*
+     * Get the Z buffer bit depth from this driver's D3D device description
+     */
+    devDepth = d3dappi.Driver[driver].Desc.dwDeviceZBufferBitDepth;
+    if (devDepth & DDBD_32)
+        ddsd.dwZBufferBitDepth = 32;
+    else if (devDepth & DDBD_24)
+        ddsd.dwZBufferBitDepth = 24;
+    else if (devDepth & DDBD_16)
+        ddsd.dwZBufferBitDepth = 16;
+    else if (devDepth & DDBD_8)
+        ddsd.dwZBufferBitDepth = 8;
+    else {
+        D3DAppISetErrorString("Unsupported Z-buffer depth requested by device.\n");
+        return FALSE;
+    }
+    LastError = d3dappi.lpDD->lpVtbl->CreateSurface(d3dappi.lpDD, &ddsd,
+                                                    &d3dappi.lpZBuffer,
+                                                    NULL);
+    if(LastError != DD_OK) {
+        D3DAppISetErrorString("CreateSurface for Z-buffer failed.\n%s",
+                              D3DAppErrorToString(LastError));
+        goto exit_with_error;
+    }
+    /*
+     * Attach the Z-buffer to the back buffer so D3D will find it
+     */
+    LastError =
+       d3dappi.lpBackBuffer->lpVtbl->AddAttachedSurface(d3dappi.lpBackBuffer,
+                                                        d3dappi.lpZBuffer);
+    if(LastError != DD_OK) {
+        D3DAppISetErrorString("AddAttachedBuffer failed for Z-Buffer.\n%s",
+                              D3DAppErrorToString(LastError));
+        goto exit_with_error;
+    }
+    /*
+     * Find out if it ended up in video memory (FYI).
+     */
+    LastError = D3DAppIGetSurfDesc(&ddsd, d3dappi.lpZBuffer);
+    if (LastError != DD_OK) {
+        D3DAppISetErrorString("Failed to get surface description of Z buffer.\n%s",
+                              D3DAppErrorToString(LastError));
+        goto exit_with_error;
+    }
+    d3dappi.bZBufferInVideo =
+                  (ddsd.ddsCaps.dwCaps & DDSCAPS_VIDEOMEMORY) ? TRUE : FALSE;
+    return TRUE;
+
+exit_with_error:
+    RELEASE(d3dappi.lpZBuffer);
+    return FALSE;
+}