ddraw: Fix offscreen flag handling in TransformVertices.

dlls/ddraw/tests/ddraw1.c

@@ -9362,12 +9362,7 @@ static void test_transform_vertices(void)
     }
 
     /* Finally try to figure out how the DWORD dwOffscreen works.
-     * Apparently no vertex is offscreen with clipping off,
-     * and with clipping on the offscreen flag is set if only one vertex
-     * is transformed, and this vertex is offscreen.
-     *
-     * FIXME: This is wrong. It might be the logical AND of all
-     * output clip flags. */
+     * It is a logical AND of the vertices' dwFlags members. */
     vp_data = vp_template;
     vp_data.dwWidth = 5;
     vp_data.dwHeight = 5;
@@ -9387,17 +9382,38 @@ static void test_transform_vertices(void)
             &transformdata, D3DTRANSFORM_CLIPPED, &offscreen);
     ok(SUCCEEDED(hr), "Failed to transform vertices, hr %#x.\n", hr);
     ok(offscreen == (D3DCLIP_RIGHT | D3DCLIP_TOP), "Offscreen is %x.\n", offscreen);
-
+    offscreen = 0xdeadbeef;
     hr = IDirect3DViewport_TransformVertices(viewport, 2,
             &transformdata, D3DTRANSFORM_CLIPPED, &offscreen);
     ok(SUCCEEDED(hr), "Failed to transform vertices, hr %#x.\n", hr);
-    todo_wine ok(offscreen == (D3DCLIP_RIGHT | D3DCLIP_TOP), "Offscreen is %x.\n", offscreen);
+    ok(offscreen == (D3DCLIP_RIGHT | D3DCLIP_TOP), "Offscreen is %x.\n", offscreen);
+    hr = IDirect3DViewport_TransformVertices(viewport, 3,
+            &transformdata, D3DTRANSFORM_CLIPPED, &offscreen);
+    ok(SUCCEEDED(hr), "Failed to transform vertices, hr %#x.\n", hr);
+    ok(!offscreen, "Offscreen is %x.\n", offscreen);
+
+    transformdata.lpIn = cliptest + 1;
+    hr = IDirect3DViewport_TransformVertices(viewport, 1,
+            &transformdata, D3DTRANSFORM_CLIPPED, &offscreen);
+    ok(SUCCEEDED(hr), "Failed to transform vertices, hr %#x.\n", hr);
+    ok(offscreen == (D3DCLIP_BACK | D3DCLIP_RIGHT | D3DCLIP_TOP), "Offscreen is %x.\n", offscreen);
 
     transformdata.lpIn = cliptest + 2;
     hr = IDirect3DViewport_TransformVertices(viewport, 1,
             &transformdata, D3DTRANSFORM_CLIPPED, &offscreen);
     ok(SUCCEEDED(hr), "Failed to transform vertices, hr %#x.\n", hr);
     ok(offscreen == (D3DCLIP_BOTTOM | D3DCLIP_LEFT), "Offscreen is %x.\n", offscreen);
+    offscreen = 0xdeadbeef;
+    hr = IDirect3DViewport_TransformVertices(viewport, 2,
+            &transformdata, D3DTRANSFORM_CLIPPED, &offscreen);
+    ok(SUCCEEDED(hr), "Failed to transform vertices, hr %#x.\n", hr);
+    ok(offscreen == (D3DCLIP_BOTTOM | D3DCLIP_LEFT), "Offscreen is %x.\n", offscreen);
+
+    transformdata.lpIn = cliptest + 3;
+    hr = IDirect3DViewport_TransformVertices(viewport, 1,
+            &transformdata, D3DTRANSFORM_CLIPPED, &offscreen);
+    ok(SUCCEEDED(hr), "Failed to transform vertices, hr %#x.\n", hr);
+    ok(offscreen == (D3DCLIP_FRONT | D3DCLIP_BOTTOM | D3DCLIP_LEFT), "Offscreen is %x.\n", offscreen);
 
     transformdata.lpIn = offscreentest;
     transformdata.dwInSize = sizeof(offscreentest[0]);

dlls/ddraw/viewport.c

@@ -372,8 +372,8 @@ static HRESULT WINAPI d3d_viewport_SetViewport(IDirect3DViewport3 *iface, D3DVIE
  *  dwVertexCount: The number of vertices to be transformed
  *  lpData: Pointer to the vertex data
  *  dwFlags: D3DTRANSFORM_CLIPPED or D3DTRANSFORM_UNCLIPPED
- *  lpOffScreen: Set to the clipping plane clipping the vertex, if only one
- *               vertex is transformed and clipping is on. 0 otherwise
+ *  offscreen: Logical AND of the planes that clipped the vertices if clipping
+ *          is on. 0 if clipping is off.
  *
  * Returns:
  *  D3D_OK on success
@@ -391,7 +391,7 @@ struct transform_vertices_vertex
 };
 
 static HRESULT WINAPI d3d_viewport_TransformVertices(IDirect3DViewport3 *iface,
-        DWORD dwVertexCount, D3DTRANSFORMDATA *lpData, DWORD dwFlags, DWORD *lpOffScreen)
+        DWORD dwVertexCount, D3DTRANSFORMDATA *lpData, DWORD dwFlags, DWORD *offscreen)
 {
     struct d3d_viewport *viewport = impl_from_IDirect3DViewport3(iface);
     D3DVIEWPORT vp = viewport->viewports.vp1;
@@ -401,8 +401,8 @@ static HRESULT WINAPI d3d_viewport_TransformVertices(IDirect3DViewport3 *iface,
     unsigned int i;
     D3DHVERTEX *outH;
 
-    TRACE("iface %p, vertex_count %u, vertex_data %p, flags %#x, clip_plane %p.\n",
-            iface, dwVertexCount, lpData, dwFlags, lpOffScreen);
+    TRACE("iface %p, vertex_count %u, vertex_data %p, flags %#x, offscreen %p.\n",
+            iface, dwVertexCount, lpData, dwFlags, offscreen);
 
     /* Tests on windows show that Windows crashes when this occurs,
      * so don't return the (intuitive) return value
@@ -428,6 +428,12 @@ static HRESULT WINAPI d3d_viewport_TransformVertices(IDirect3DViewport3 *iface,
     multiply_matrix(&mat, &view_mat, &world_mat);
     multiply_matrix(&mat, &viewport->active_device->legacy_projection, &mat);
 
+    /* The pointer is not tested against NULL on Windows. */
+    if (dwFlags & D3DTRANSFORM_CLIPPED)
+        *offscreen = ~0U;
+    else
+        *offscreen = 0;
+
     outH = lpData->lpHOut;
     for(i = 0; i < dwVertexCount; i++)
     {
@@ -460,6 +466,8 @@ static HRESULT WINAPI d3d_viewport_TransformVertices(IDirect3DViewport3 *iface,
             if(z > 1.0)
                 outH[i].dwFlags |= D3DCLIP_BACK;
 
+            *offscreen &= outH[i].dwFlags;
+
             if(outH[i].dwFlags)
             {
                 /* Looks like native just drops the vertex, leaves whatever data
@@ -485,22 +493,6 @@ static HRESULT WINAPI d3d_viewport_TransformVertices(IDirect3DViewport3 *iface,
         out->payload = in->payload;
     }
 
-    /* According to the d3d test, the offscreen flag is set only
-     * if exactly one vertex is transformed. It's not documented,
-     * but the test shows that the lpOffscreen flag is set to the
-     * flag combination of clipping planes that clips the vertex.
-     *
-     * If clipping is requested, Windows assumes that the offscreen
-     * param is a valid pointer.
-     */
-    if(dwVertexCount == 1 && dwFlags & D3DTRANSFORM_CLIPPED)
-    {
-        *lpOffScreen = outH[0].dwFlags;
-    }
-    else if(*lpOffScreen)
-    {
-        *lpOffScreen = 0;
-    }
     wined3d_mutex_unlock();
 
     TRACE("All done\n");