d3dx8: Implement D3DXPlaneColorSubtract.

dlls/d3dx8/tests/math.c

@@ -108,6 +108,18 @@ static void D3DXColorTest(void)
     ok(funcpointer == NULL, "Expected: %p, Got: %p\n", NULL, funcpointer);
     funcpointer = D3DXColorScale(NULL,NULL,scale);
     ok(funcpointer == NULL, "Expected: %p, Got: %p\n", NULL, funcpointer);
+
+/*_______________D3DXColorSubtract_______________*/
+    expected.r = -0.1f; expected.g = 0.25f; expected.b = -0.35f, expected.a = 0.82f;
+    D3DXColorSubtract(&got,&color,&color2);
+    expect_color(expected,got);
+    /* Test the NULL case */
+    funcpointer = D3DXColorSubtract(&got,NULL,&color2);
+    ok(funcpointer == NULL, "Expected: %p, Got: %p\n", NULL, funcpointer);
+    funcpointer = D3DXColorSubtract(NULL,NULL,&color2);
+    ok(funcpointer == NULL, "Expected: %p, Got: %p\n", NULL, funcpointer);
+    funcpointer = D3DXColorSubtract(NULL,NULL,NULL);
+    ok(funcpointer == NULL, "Expected: %p, Got: %p\n", NULL, funcpointer);
 }
 
 static void D3DXPlaneTest(void)

include/d3dx8math.inl

@@ -71,6 +71,16 @@ static inline D3DXCOLOR* D3DXColorScale(D3DXCOLOR *pout, CONST D3DXCOLOR *pc, FL
     return pout;
 }
 
+static inline D3DXCOLOR* D3DXColorSubtract(D3DXCOLOR *pout, CONST D3DXCOLOR *pc1, CONST D3DXCOLOR *pc2)
+{
+    if ( !pout || !pc1 || !pc2 ) return NULL;
+    pout->r = (pc1->r) - (pc2->r);
+    pout->g = (pc1->g) - (pc2->g);
+    pout->b = (pc1->b) - (pc2->b);
+    pout->a = (pc1->a) - (pc2->a);
+    return pout;
+}
+
 /*_______________D3DXVECTOR2________________________*/
 
 static inline D3DXVECTOR2* D3DXVec2Add(D3DXVECTOR2 *pout, CONST D3DXVECTOR2 *pv1, CONST D3DXVECTOR2 *pv2)