dTriColliderCommon.h: macro replaced with inline functions

Thanks to Im-Dex. Imported from commit:
Im-dex/xray-162@98f5477

Author: Xottab-DUTY

src/xrPhysics/tri-colliderknoopc/dTriColliderCommon.h

@@ -1,3 +1,4 @@
+#pragma once
 #ifndef D_TRI_COLLIDER_COMMON
 #define D_TRI_COLLIDER_COMMON
 
@@ -7,11 +8,21 @@
 
 extern xr_vector<flags8> gl_cl_tries_state;
 
-// extern xr_vector<int>::iterator		I,E,B				;
+// NOTE: stride is sizeof(dContact) * N, where N is [0, ...)
+inline dContactGeom* CONTACT(dContactGeom* ptr, const int stride)
+{
+    const size_t count = stride / sizeof(dContact);
+    dContact* contact = (dContact*)(uintptr_t(ptr) - uintptr_t(offsetof(dContact, geom)));
+    return &contact[count].geom;
+}
+
+inline dSurfaceParameters* SURFACE(dContactGeom* ptr, const int stride)
+{
+    const size_t count = stride / sizeof(dContact);
+    dContact* contact = (dContact*)(uintptr_t(ptr) - uintptr_t(offsetof(dContact, geom)));
+    return &contact[count].surface;
+}
 
-#define CONTACT(Ptr, Stride) ((dContactGeom*)(((char*)Ptr) + (Stride)))
-//#define SURFACE(Ptr, Stride) ((dSurfaceParameters*)(((char*)Ptr) + (Stride - sizeof(dSurfaceParameters))))
-#define SURFACE(Ptr, Stride) ((dSurfaceParameters*) (((char*)Ptr) + (Stride - offsetof(dContact, geom) + offsetof(dContact, surface))))
 #define NUMC_MASK (0xffff)
 
 #define M_SIN_PI_3 REAL(0.8660254037844386467637231707529362)