UPBGE: Fix gl_Color.

gl_Color is set as the vertex color of the first color layer,
this was broken by the addressu sage of RAS_DisplayArrayLayout::colors
instead of RAS_DisplayArrayLayout::colors[0].

Fix issue #784.

source/gameengine/Rasterizer/RAS_OpenGLRasterizer/RAS_StorageVao.cpp

@@ -56,7 +56,7 @@ RAS_StorageVao::RAS_StorageVao(const RAS_DisplayArrayLayout &layout, RAS_Display
 	glNormalPointer(GL_FLOAT, 0, (const void *)layout.normal);
 
 	glEnableClientState(GL_COLOR_ARRAY);
-	glColorPointer(4, GL_UNSIGNED_BYTE, 0, (const void *)layout.colors);
+	glColorPointer(4, GL_UNSIGNED_BYTE, 0, (const void *)layout.colors[0]);
 
 	for (const RAS_AttributeArray::Attrib& attrib : attribList) {
 		const RAS_AttributeArray::AttribType type = attrib.m_type;