d3dx8: Implement D3DXVec2CCW with a test.

dlls/d3dx8/tests/math.c

@@ -32,6 +32,18 @@ static void D3X8Vector2Test(void)
     u.x=3.0f; u.y=4.0f;
     v.x=-7.0f; v.y=9.0f;
 
+/*_______________D3DXVec2CCW__________________________*/
+   expected = 55.0f;
+   got = D3DXVec2CCW(&u,&v);
+   ok(fabs( got - expected ) < admitted_error, "Expected: %f, Got: %f\n", expected, got);
+   /* Tests the case NULL */
+    expected=0.0f;
+    got = D3DXVec2CCW(NULL,&v);
+    ok(fabs( got - expected ) < admitted_error, "Expected: %f, Got: %f\n", expected, got);
+    expected=0.0f;
+    got = D3DXVec2CCW(NULL,NULL);
+    ok(fabs( got - expected ) < admitted_error, "Expected: %f, Got: %f\n", expected, got);
+
 /*_______________D3DXVec2Dot__________________________*/
    expected = 15.0f;
    got = D3DXVec2Dot(&u,&v);

include/d3dx8math.h

@@ -58,6 +58,7 @@ typedef struct D3DXCOLOR
     FLOAT r, g, b, a;
 } D3DXCOLOR, *LPD3DXCOLOR;
 
+FLOAT D3DXVec2CCW(CONST D3DXVECTOR2 *pv1, CONST D3DXVECTOR2 *pv2);
 FLOAT D3DXVec2Dot(CONST D3DXVECTOR2 *pv1, CONST D3DXVECTOR2 *pv2);
 FLOAT D3DXVec2Length(CONST D3DXVECTOR2 *pv);
 FLOAT D3DXVec2LengthSq(CONST D3DXVECTOR2 *pv);

include/d3dx8math.inl

@@ -19,6 +19,12 @@
 #ifndef __D3DX8MATH_INL__
 #define __D3DX8MATH_INL__
 
+extern inline FLOAT D3DXVec2CCW(CONST D3DXVECTOR2 *pv1, CONST D3DXVECTOR2 *pv2)
+{
+    if ( !pv1 || !pv2) return 0.0f;
+    return ( (pv1->x) * (pv2->y) - (pv1->y) * (pv2->x) );
+}
+
 extern inline FLOAT D3DXVec2Dot(CONST D3DXVECTOR2 *pv1, CONST D3DXVECTOR2 *pv2)
 {
     if ( !pv1 || !pv2) return 0.0f;