Simplify transformed box tracing.

Avoid calling AngleVectors twice, transpose rotation matrix instead.
Add convenience functions.

2 files changed, 37 insertions, 25 deletions

diff --git a/inc/shared/shared.h b/inc/shared/shared.h
index 22024e4..761bfb8 100644
--- a/inc/shared/shared.h
+++ b/inc/shared/shared.h
@@ -267,6 +267,33 @@ static inline void AnglesToAxis(vec3_t angles, vec3_t axis[3])
     VectorInverse(axis[1]);
 }
 
+static inline void TransposeAxis(vec3_t axis[3])
+{
+    vec_t temp;
+
+    temp = axis[0][1];
+    axis[0][1] = axis[1][0];
+    axis[1][0] = temp;
+
+    temp = axis[0][2];
+    axis[0][2] = axis[2][0];
+    axis[2][0] = temp;
+
+    temp = axis[1][2];
+    axis[1][2] = axis[2][1];
+    axis[2][1] = temp;
+}
+
+static inline void RotatePoint(vec3_t point, vec3_t axis[3])
+{
+    vec3_t temp;
+
+    VectorCopy(point, temp);
+    point[0] = DotProduct(temp, axis[0]);
+    point[1] = DotProduct(temp, axis[1]);
+    point[2] = DotProduct(temp, axis[2]);
+}
+
 static inline unsigned npot32(unsigned k)
 {
     if (k == 0)
diff --git a/src/common/cmodel.c b/src/common/cmodel.c
index 71c836f..5c75708 100644
--- a/src/common/cmodel.c
+++ b/src/common/cmodel.c
@@ -782,9 +782,7 @@ void CM_TransformedBoxTrace(trace_t *trace, vec3_t start, vec3_t end,
                             vec3_t origin, vec3_t angles)
 {
     vec3_t      start_l, end_l;
-    vec3_t      a;
-    vec3_t      forward, right, up;
-    vec3_t      temp;
+    vec3_t      axis[3];
     qboolean    rotated;
 
     // subtract origin offset
@@ -799,36 +797,23 @@ void CM_TransformedBoxTrace(trace_t *trace, vec3_t start, vec3_t end,
         rotated = qfalse;
 
     if (rotated) {
-        AngleVectors(angles, forward, right, up);
-
-        VectorCopy(start_l, temp);
-        start_l[0] = DotProduct(temp, forward);
-        start_l[1] = -DotProduct(temp, right);
-        start_l[2] = DotProduct(temp, up);
-
-        VectorCopy(end_l, temp);
-        end_l[0] = DotProduct(temp, forward);
-        end_l[1] = -DotProduct(temp, right);
-        end_l[2] = DotProduct(temp, up);
+        AnglesToAxis(angles, axis);
+        RotatePoint(start_l, axis);
+        RotatePoint(end_l, axis);
     }
 
     // sweep the box through the model
     CM_BoxTrace(trace, start_l, end_l, mins, maxs, headnode, brushmask);
 
+    // rotate plane normal into the worlds frame of reference
     if (rotated && trace->fraction != 1.0) {
-        // FIXME: figure out how to do this with existing angles
-        VectorNegate(angles, a);
-        AngleVectors(a, forward, right, up);
-
-        VectorCopy(trace->plane.normal, temp);
-        trace->plane.normal[0] = DotProduct(temp, forward);
-        trace->plane.normal[1] = -DotProduct(temp, right);
-        trace->plane.normal[2] = DotProduct(temp, up);
+        TransposeAxis(axis);
+        RotatePoint(trace->plane.normal, axis);
     }
 
-    trace->endpos[0] = start[0] + trace->fraction * (end[0] - start[0]);
-    trace->endpos[1] = start[1] + trace->fraction * (end[1] - start[1]);
-    trace->endpos[2] = start[2] + trace->fraction * (end[2] - start[2]);
+    // FIXME: offset plane distance?
+
+    LerpVector(start, end, trace->fraction, trace->endpos);
 }
 
 void CM_ClipEntity(trace_t *dst, const trace_t *src, struct edict_s *ent)