model_brush: slightly change bih math

diff --git a/model_brush.c b/model_brush.c
index b911682791493e5233866a2c5d1518e6b0c81dda..69082e61b8fdb7723b2a2ba7aa3297b56f68e703 100644 (file)
--- a/model_brush.c
+++ b/model_brush.c
@@ -7124,8 +7124,10 @@ void Mod_CollisionBIH_TraceBrush(model_t *model, const frameblend_t *frameblend,
        trace->skipmaterialflagsmask = skipmaterialflagsmask;
 
        // calculate tracebox-like parameters for efficient culling
-       VectorMAM(0.5f, thisbrush_start->mins, 0.5f, thisbrush_start->maxs, start);
-       VectorMAM(0.5f, thisbrush_end->mins, 0.5f, thisbrush_end->maxs, end);
+       VectorAdd(thisbrush_start->mins, thisbrush_start->maxs, start);
+       VectorAdd(thisbrush_end->mins, thisbrush_end->maxs, end);
+       VectorM(0.5f, start, start);
+       VectorM(0.5f, end, end);
        VectorSubtract(thisbrush_start->mins, start, startmins);
        VectorSubtract(thisbrush_start->maxs, start, startmaxs);
        VectorSubtract(thisbrush_end->mins, end, endmins);
@@ -7167,10 +7169,10 @@ void Mod_CollisionBIH_TraceBrush(model_t *model, const frameblend_t *frameblend,
                                continue;
                        // recurse children of the split
                        axis = node->type - BIH_SPLITX;
-                       d1 = node->backmax - nodestart[axis] - mins[axis];
-                       d2 = node->backmax - nodeend[axis] - mins[axis];
-                       d3 = nodestart[axis] - node->frontmin + maxs[axis];
-                       d4 = nodeend[axis] - node->frontmin + maxs[axis];
+                       d1 = node->backmax - mins[axis] - nodestart[axis];
+                       d2 = node->backmax - mins[axis] - nodeend[axis];
+                       d3 = nodestart[axis] - (node->frontmin - maxs[axis]);
+                       d4 = nodeend[axis] - (node->frontmin - maxs[axis]);
                        f = 1.f / (nodeend[axis] - nodestart[axis]);
                        switch((d1 < 0) | ((d2 < 0) << 1) | ((d3 < 0) << 2) | ((d4 < 0) << 3))
                        {