d3dx8: Only the points in the positive ray are taken in account in D3DXSphereBoundProbe.

dlls/d3dx8/mesh.c

@@ -27,13 +27,14 @@ WINE_DEFAULT_DEBUG_CHANNEL(d3dx);
 BOOL WINAPI D3DXSphereBoundProbe(CONST D3DXVECTOR3 *pcenter, FLOAT radius, CONST D3DXVECTOR3 *prayposition, CONST D3DXVECTOR3 *praydirection)
 {
     D3DXVECTOR3 difference;
-    FLOAT a, b, c;
+    FLOAT a, b, c, d;
 
     a = D3DXVec3LengthSq(praydirection);
     if (!D3DXVec3Subtract(&difference, prayposition, pcenter)) return FALSE;
     b = D3DXVec3Dot(&difference, praydirection);
     c = D3DXVec3LengthSq(&difference) - radius * radius;
+    d = b * b - a * c;
 
-    if ( b * b - a * c <= 0.0f ) return FALSE;
+    if ( ( d <= 0.0f ) || ( sqrt(d) <= b ) ) return FALSE;
     return TRUE;
 }

dlls/d3dx8/tests/mesh.c

@@ -36,6 +36,10 @@ static void D3DXBoundProbeTest(void)
     result = D3DXSphereBoundProbe(&center, radius, &rayposition, &raydirection);
     ok(result == TRUE, "expected TRUE, received FALSE\n");
 
+    rayposition.x = 45.0f; rayposition.y = -75.0f; rayposition.z = 49.0f;
+    result = D3DXSphereBoundProbe(&center, radius, &rayposition, &raydirection);
+    ok(result == FALSE, "expected FALSE, received TRUE\n");
+
     rayposition.x = 5.0f; rayposition.y = 7.0f; rayposition.z = 9.0f;
     result = D3DXSphereBoundProbe(&center, radius, &rayposition, &raydirection);
     ok(result == FALSE, "expected FALSE, received TRUE\n");