X-Git-Url: http://git.xonotic.org/?a=blobdiff_plain;f=collision.c;h=30f4d7662acdae19488a51c9d22811a30c4c901f;hb=8269574f33908230c65305a5683d5362cb3ffbf2;hp=2306aded1529a7164634408b482c09a9888776e0;hpb=5fe25e4d5947e5f1c6f5a5d802bd26c7232c6aa8;p=xonotic%2Fdarkplaces.git

diff --git a/collision.c b/collision.c
index 2306aded..30f4d766 100644
--- a/collision.c
+++ b/collision.c
@@ -2,7 +2,7 @@
 #include "quakedef.h"
 #include "polygon.h"
 
-#define COLLISION_SNAPSCALE (32.0f)
+#define COLLISION_SNAPSCALE (8.0f)
 #define COLLISION_SNAP (1.0f / COLLISION_SNAPSCALE)
 
 cvar_t collision_impactnudge = {0, "collision_impactnudge", "0.03125"};
@@ -11,287 +11,6 @@ cvar_t collision_endnudge = {0, "collision_endnudge", "0"};
 cvar_t collision_enternudge = {0, "collision_enternudge", "0"};
 cvar_t collision_leavenudge = {0, "collision_leavenudge", "0"};
 
-#if 0
-typedef struct
-{
-	// the hull we're tracing through
-	const hull_t *hull;
-
-	// the trace structure to fill in
-	trace_t *trace;
-
-	// start and end of the trace (in model space)
-	double start[3];
-	double end[3];
-
-	// end - start
-	double dist[3];
-
-	// overrides the CONTENTS_SOLID in the box bsp tree
-	int boxsupercontents;
-}
-RecursiveHullCheckTraceInfo_t;
-
-#define HULLCHECKSTATE_EMPTY 0
-#define HULLCHECKSTATE_SOLID 1
-#define HULLCHECKSTATE_DONE 2
-
-static int RecursiveHullCheck(RecursiveHullCheckTraceInfo_t *t, int num, double p1f, double p2f, double p1[3], double p2[3])
-{
-	// status variables, these don't need to be saved on the stack when
-	// recursing...  but are because this should be thread-safe
-	// (note: tracing against a bbox is not thread-safe, yet)
-	int ret;
-	mplane_t *plane;
-	double t1, t2;
-
-	// variables that need to be stored on the stack when recursing
-	dclipnode_t *node;
-	int side;
-	double midf, mid[3];
-
-	// LordHavoc: a goto!  everyone flee in terror... :)
-loc0:
-	// check for empty
-	if (num < 0)
-	{
-		num = Mod_Q1BSP_SuperContentsFromNativeContents(NULL, num);
-		if (!t->trace->startfound)
-		{
-			t->trace->startfound = true;
-			t->trace->startsupercontents |= num;
-		}
-		if (num & SUPERCONTENTS_LIQUIDSMASK)
-			t->trace->inwater = true;
-		if (num == 0)
-			t->trace->inopen = true;
-		if (num & t->trace->hitsupercontentsmask)
-		{
-			// if the first leaf is solid, set startsolid
-			if (t->trace->allsolid)
-				t->trace->startsolid = true;
-#if COLLISIONPARANOID >= 3
-			Con_Print("S");
-#endif
-			return HULLCHECKSTATE_SOLID;
-		}
-		else
-		{
-			t->trace->allsolid = false;
-#if COLLISIONPARANOID >= 3
-			Con_Print("E");
-#endif
-			return HULLCHECKSTATE_EMPTY;
-		}
-	}
-
-	// find the point distances
-	node = t->hull->clipnodes + num;
-
-	plane = t->hull->planes + node->planenum;
-	if (plane->type < 3)
-	{
-		t1 = p1[plane->type] - plane->dist;
-		t2 = p2[plane->type] - plane->dist;
-	}
-	else
-	{
-		t1 = DotProduct (plane->normal, p1) - plane->dist;
-		t2 = DotProduct (plane->normal, p2) - plane->dist;
-	}
-
-	if (t1 < 0)
-	{
-		if (t2 < 0)
-		{
-#if COLLISIONPARANOID >= 3
-			Con_Print("<");
-#endif
-			num = node->children[1];
-			goto loc0;
-		}
-		side = 1;
-	}
-	else
-	{
-		if (t2 >= 0)
-		{
-#if COLLISIONPARANOID >= 3
-			Con_Print(">");
-#endif
-			num = node->children[0];
-			goto loc0;
-		}
-		side = 0;
-	}
-
-	// the line intersects, find intersection point
-	// LordHavoc: this uses the original trace for maximum accuracy
-#if COLLISIONPARANOID >= 3
-	Con_Print("M");
-#endif
-	if (plane->type < 3)
-	{
-		t1 = t->start[plane->type] - plane->dist;
-		t2 = t->end[plane->type] - plane->dist;
-	}
-	else
-	{
-		t1 = DotProduct (plane->normal, t->start) - plane->dist;
-		t2 = DotProduct (plane->normal, t->end) - plane->dist;
-	}
-
-	midf = t1 / (t1 - t2);
-	midf = bound(p1f, midf, p2f);
-	VectorMA(t->start, midf, t->dist, mid);
-
-	// recurse both sides, front side first
-	ret = RecursiveHullCheck (t, node->children[side], p1f, midf, p1, mid);
-	// if this side is not empty, return what it is (solid or done)
-	if (ret != HULLCHECKSTATE_EMPTY)
-		return ret;
-
-	ret = RecursiveHullCheck (t, node->children[side ^ 1], midf, p2f, mid, p2);
-	// if other side is not solid, return what it is (empty or done)
-	if (ret != HULLCHECKSTATE_SOLID)
-		return ret;
-
-	// front is air and back is solid, this is the impact point...
-	if (side)
-	{
-		t->trace->plane.dist = -plane->dist;
-		VectorNegate (plane->normal, t->trace->plane.normal);
-	}
-	else
-	{
-		t->trace->plane.dist = plane->dist;
-		VectorCopy (plane->normal, t->trace->plane.normal);
-	}
-
-	// calculate the true fraction
-	t1 = DotProduct(t->trace->plane.normal, t->start) - t->trace->plane.dist - collision_startnudge.value;
-	t2 = DotProduct(t->trace->plane.normal, t->end) - t->trace->plane.dist - collision_endnudge.value;
-	midf = t1 / (t1 - t2);
-	t->trace->realfraction = bound(0, midf, 1);
-
-	// calculate the return fraction which is nudged off the surface a bit
-	midf = (t1 - collision_impactnudge.value) / (t1 - t2);
-	t->trace->fraction = bound(0, midf, 1);
-
-#if COLLISIONPARANOID >= 3
-	Con_Print("D");
-#endif
-	return HULLCHECKSTATE_DONE;
-}
-
-#if 0
-// used if start and end are the same
-static void RecursiveHullCheckPoint (RecursiveHullCheckTraceInfo_t *t, int num)
-{
-	// If you can read this, you understand BSP trees
-	while (num >= 0)
-		num = t->hull->clipnodes[num].children[((t->hull->planes[t->hull->clipnodes[num].planenum].type < 3) ? (t->start[t->hull->planes[t->hull->clipnodes[num].planenum].type]) : (DotProduct(t->hull->planes[t->hull->clipnodes[num].planenum].normal, t->start))) < t->hull->planes[t->hull->clipnodes[num].planenum].dist];
-
-	// check for empty
-	t->trace->endcontents = num;
-	if (t->trace->thiscontents)
-	{
-		if (num == t->trace->thiscontents)
-			t->trace->allsolid = false;
-		else
-		{
-			// if the first leaf is solid, set startsolid
-			if (t->trace->allsolid)
-				t->trace->startsolid = true;
-		}
-	}
-	else
-	{
-		if (num != CONTENTS_SOLID)
-		{
-			t->trace->allsolid = false;
-			if (num == CONTENTS_EMPTY)
-				t->trace->inopen = true;
-			else
-				t->trace->inwater = true;
-		}
-		else
-		{
-			// if the first leaf is solid, set startsolid
-			if (t->trace->allsolid)
-				t->trace->startsolid = true;
-		}
-	}
-}
-#endif
-
-static hull_t box_hull;
-static dclipnode_t box_clipnodes[6];
-static mplane_t box_planes[6];
-
-void Mod_Q1BSP_Collision_Init (void)
-{
-	int		i;
-	int		side;
-
-	//Set up the planes and clipnodes so that the six floats of a bounding box
-	//can just be stored out and get a proper hull_t structure.
-
-	box_hull.clipnodes = box_clipnodes;
-	box_hull.planes = box_planes;
-	box_hull.firstclipnode = 0;
-	box_hull.lastclipnode = 5;
-
-	for (i = 0;i < 6;i++)
-	{
-		box_clipnodes[i].planenum = i;
-
-		side = i&1;
-
-		box_clipnodes[i].children[side] = CONTENTS_EMPTY;
-		if (i != 5)
-			box_clipnodes[i].children[side^1] = i + 1;
-		else
-			box_clipnodes[i].children[side^1] = CONTENTS_SOLID;
-
-		box_planes[i].type = i>>1;
-		box_planes[i].normal[i>>1] = 1;
-	}
-}
-
-void Collision_ClipTrace_Box(trace_t *trace, const vec3_t cmins, const vec3_t cmaxs, const vec3_t start, const vec3_t mins, const vec3_t maxs, const vec3_t end, int hitsupercontentsmask, int boxsupercontents)
-{
-	RecursiveHullCheckTraceInfo_t rhc;
-	// fill in a default trace
-	memset(&rhc, 0, sizeof(rhc));
-	memset(trace, 0, sizeof(trace_t));
-	//To keep everything totally uniform, bounding boxes are turned into small
-	//BSP trees instead of being compared directly.
-	// create a temp hull from bounding box sizes
-	box_planes[0].dist = cmaxs[0] - mins[0];
-	box_planes[1].dist = cmins[0] - maxs[0];
-	box_planes[2].dist = cmaxs[1] - mins[1];
-	box_planes[3].dist = cmins[1] - maxs[1];
-	box_planes[4].dist = cmaxs[2] - mins[2];
-	box_planes[5].dist = cmins[2] - maxs[2];
-	// trace a line through the generated clipping hull
-	rhc.boxsupercontents = boxsupercontents;
-	rhc.hull = &box_hull;
-	rhc.trace = trace;
-	rhc.trace->hitsupercontentsmask = hitsupercontentsmask;
-	rhc.trace->fraction = 1;
-	rhc.trace->realfraction = 1;
-	rhc.trace->allsolid = true;
-	VectorCopy(start, rhc.start);
-	VectorCopy(end, rhc.end);
-	VectorSubtract(rhc.end, rhc.start, rhc.dist);
-	Mod_Q1BSP_RecursiveHullCheck(&rhc, rhc.hull->firstclipnode, 0, 1, rhc.start, rhc.end);
-	VectorMA(rhc.start, rhc.trace->fraction, rhc.dist, rhc.trace->endpos);
-	if (rhc.trace->startsupercontents)
-		rhc.trace->startsupercontents = boxsupercontents;
-}
-#endif
-
 void Collision_Init (void)
 {
 	Cvar_RegisterVariable(&collision_impactnudge);
@@ -449,7 +168,7 @@ colbrushf_t *Collision_NewBrushFromPlanes(mempool_t *mempool, int numoriginalpla
 		// check if there are too many and skip the brush
 		if (numplanesbuf >= maxplanesbuf)
 		{
-			Con_Print("Mod_Q3BSP_LoadBrushes: failed to build collision brush: too many planes for buffer\n");
+			Con_Print("Collision_NewBrushFromPlanes: failed to build collision brush: too many planes for buffer\n");
 			return NULL;
 		}
 
@@ -620,6 +339,7 @@ void Collision_CalcPlanesForPolygonBrushFloat(colbrushf_t *brush)
 	float edge0[3], edge1[3], edge2[3], normal[3], dist, bestdist;
 	colpointf_t *p, *p2;
 
+	// FIXME: these probably don't actually need to be normalized if the collision code does not care
 	if (brush->numpoints == 3)
 	{
 		// optimized triangle case
@@ -791,7 +511,7 @@ colbrushf_t *Collision_AllocBrushFromPermanentPolygonFloat(mempool_t *mempool, i
 	brush->numplanes = numpoints + 2;
 	brush->planes = (void *)(brush + 1);
 	brush->points = (colpointf_t *)points;
-	Host_Error("Collision_AllocBrushFromPermanentPolygonFloat: FIXME: this code needs to be updated to generate a mesh...\n");
+	Sys_Error("Collision_AllocBrushFromPermanentPolygonFloat: FIXME: this code needs to be updated to generate a mesh...\n");
 	return brush;
 }
 
@@ -799,7 +519,7 @@ colbrushf_t *Collision_AllocBrushFromPermanentPolygonFloat(mempool_t *mempool, i
 void Collision_TraceBrushBrushFloat(trace_t *trace, const colbrushf_t *thisbrush_start, const colbrushf_t *thisbrush_end, const colbrushf_t *thatbrush_start, const colbrushf_t *thatbrush_end)
 {
 	int nplane, nplane2, fstartsolid, fendsolid, brushsolid;
-	float enterfrac, leavefrac, d1, d2, f, move, imove, newimpactnormal[3], enterfrac2;
+	float enterfrac, leavefrac, d1, d2, f, imove, newimpactnormal[3], enterfrac2;
 	const colplanef_t *startplane, *endplane;
 
 	enterfrac = -1;
@@ -825,7 +545,7 @@ void Collision_TraceBrushBrushFloat(trace_t *trace, const colbrushf_t *thisbrush
 					return;
 				}
 				f = furthestplanedist_float(startplane->normal, thisbrush_start->points, thisbrush_start->numpoints);
-				if (fabs(f - startplane->dist) > 0.01f)
+				if (fabs(f - startplane->dist) > 0.125f)
 					Con_Printf("startplane->dist %f != calculated %f (thisbrush_start)\n", startplane->dist, f);
 			}
 			d1 = nearestplanedist_float(startplane->normal, thisbrush_start->points, thisbrush_start->numpoints) - furthestplanedist_float(startplane->normal, thatbrush_start->points, thatbrush_start->numpoints) - collision_startnudge.value;
@@ -844,7 +564,7 @@ void Collision_TraceBrushBrushFloat(trace_t *trace, const colbrushf_t *thisbrush
 					return;
 				}
 				f = furthestplanedist_float(startplane->normal, thatbrush_start->points, thatbrush_start->numpoints);
-				if (fabs(f - startplane->dist) > 0.01f)
+				if (fabs(f - startplane->dist) > 0.125f)
 					Con_Printf("startplane->dist %f != calculated %f (thatbrush_start)\n", startplane->dist, f);
 			}
 			d1 = nearestplanedist_float(startplane->normal, thisbrush_start->points, thisbrush_start->numpoints) - startplane->dist - collision_startnudge.value;
@@ -852,46 +572,38 @@ void Collision_TraceBrushBrushFloat(trace_t *trace, const colbrushf_t *thisbrush
 		}
 		//Con_Printf("%c%i: d1 = %f, d2 = %f, d1 / (d1 - d2) = %f\n", nplane2 != nplane ? 'b' : 'a', nplane2, d1, d2, d1 / (d1 - d2));
 
-		move = d1 - d2;
-		if (move > 0)
+		if(d1 > d2)
 		{
 			// moving into brush
-			if (d2 > collision_enternudge.value)
+			if(d2 > 0)
 				return;
-			if (d1 < 0)
-				continue;
-			// enter
-			fstartsolid = false;
-			imove = 1 / move;
-			f = (d1 - collision_enternudge.value) * imove;
-			f = bound(0, f, 1);
-			if (enterfrac < f)
+			if(d1 > 0)
 			{
-				enterfrac = f;
-				enterfrac2 = f - collision_impactnudge.value * imove;
-				enterfrac2 = bound(0, enterfrac2, 1);
-				VectorLerp(startplane->normal, enterfrac, endplane->normal, newimpactnormal);
+				// enter
+				fstartsolid = false;
+				imove = 1 / (d1 - d2);
+				f = (d1 - collision_enternudge.value) * imove;
+				if (enterfrac < f)
+				{
+					enterfrac = f;
+					enterfrac2 = f - collision_impactnudge.value * imove;
+					VectorLerp(startplane->normal, enterfrac, endplane->normal, newimpactnormal);
+				}
 			}
 		}
-		else if (move < 0)
-		{
-			// moving out of brush
-			if (d1 > collision_leavenudge.value)
-				return;
-			if (d2 < 0)
-				continue;
-			// leave
-			fendsolid = false;
-			f = (d1 + collision_leavenudge.value) / move;
-			f = bound(0, f, 1);
-			if (leavefrac > f)
-				leavefrac = f;
-		}
 		else
 		{
-			// sliding along plane
-			if (d1 > 0)
+			// moving out of brush
+			if(d1 > 0)
 				return;
+			if(d2 > 0)
+			{
+				// leave
+				fendsolid = false;
+				f = (d1 + collision_leavenudge.value) / (d1 - d2);
+				if (leavefrac > f)
+					leavefrac = f;
+			}
 		}
 	}
 
@@ -947,7 +659,7 @@ void Collision_TraceBrushBrushFloat(trace_t *trace, const colbrushf_t *thisbrush
 void Collision_TraceLineBrushFloat(trace_t *trace, const vec3_t linestart, const vec3_t lineend, const colbrushf_t *thatbrush_start, const colbrushf_t *thatbrush_end)
 {
 	int nplane, fstartsolid, fendsolid, brushsolid;
-	float enterfrac, leavefrac, d1, d2, f, move, imove, newimpactnormal[3], enterfrac2;
+	float enterfrac, leavefrac, d1, d2, f, imove, newimpactnormal[3], enterfrac2;
 	const colplanef_t *startplane, *endplane;
 
 	enterfrac = -1;
@@ -973,42 +685,43 @@ void Collision_TraceLineBrushFloat(trace_t *trace, const vec3_t linestart, const
 			if (thatbrush_start->numpoints)
 			{
 				f = furthestplanedist_float(startplane->normal, thatbrush_start->points, thatbrush_start->numpoints);
-				if (fabs(f - startplane->dist) > 0.01f)
+				if (fabs(f - startplane->dist) > 0.125f)
 					Con_Printf("startplane->dist %f != calculated %f\n", startplane->dist, f);
 			}
 		}
 
-		move = d1 - d2;
-		if (move > 0)
+		if (d1 > d2)
 		{
 			// moving into brush
-			if (d2 >= 0)
+			if (d2 > 0)
 				return;
-			if (d1 <= 0)
-				continue;
-			// enter
-			fstartsolid = false;
-			imove = 1 / move;
-			f = (d1 - collision_enternudge.value) * imove;
-			if (enterfrac < f)
+			if (d1 > 0)
 			{
-				enterfrac = f;
-				enterfrac2 = f - collision_impactnudge.value * imove;
-				VectorLerp(startplane->normal, enterfrac, endplane->normal, newimpactnormal);
+				// enter
+				fstartsolid = false;
+				imove = 1 / (d1 - d2);
+				f = (d1 - collision_enternudge.value) * imove;
+				if (enterfrac < f)
+				{
+					enterfrac = f;
+					enterfrac2 = f - collision_impactnudge.value * imove;
+					VectorLerp(startplane->normal, enterfrac, endplane->normal, newimpactnormal);
+				}
 			}
 		}
 		else
 		{
 			// moving out of brush
-			if (d1 >= 0)
+			if (d1 > 0)
 				return;
-			if (d2 <= 0)
-				continue;
-			// leave
-			fendsolid = false;
-			f = (d1 - collision_leavenudge.value) / move;
-			if (leavefrac > f)
-				leavefrac = f;
+			if (d2 > 0)
+			{
+				// leave
+				fendsolid = false;
+				f = (d1 + collision_leavenudge.value) / (d1 - d2);
+				if (leavefrac > f)
+					leavefrac = f;
+			}
 		}
 	}
 
@@ -1267,6 +980,7 @@ colbrushf_t *Collision_BrushForBox(const matrix4x4_t *matrix, const vec3_t mins,
 	colbrushf_t *brush;
 	if (brushforbox_brush[0].numpoints == 0)
 		Collision_InitBrushForBox();
+	// FIXME: these probably don't actually need to be normalized if the collision code does not care
 	if (VectorCompare(mins, maxs))
 	{
 		// point brush
@@ -1411,7 +1125,18 @@ float Collision_ClipTrace_Line_Sphere(double *linestart, double *lineend, double
 
 void Collision_TraceLineTriangleFloat(trace_t *trace, const vec3_t linestart, const vec3_t lineend, const float *point0, const float *point1, const float *point2)
 {
-	float d1, d2, d, f, fnudged, impact[3], edgenormal[3], faceplanenormal[3], faceplanedist, edge[3];
+#if 1
+	// more optimized
+	float d1, d2, d, f, impact[3], edgenormal[3], faceplanenormal[3], faceplanedist, faceplanenormallength2, edge01[3], edge21[3], edge02[3];
+
+	// this function executes:
+	// 32 ops when line starts behind triangle
+	// 38 ops when line ends infront of triangle
+	// 43 ops when line fraction is already closer than this triangle
+	// 72 ops when line is outside edge 01
+	// 92 ops when line is outside edge 21
+	// 115 ops when line is outside edge 02
+	// 123 ops when line impacts triangle and updates trace results
 
 	// this code is designed for clockwise triangles, conversion to
 	// counterclockwise would require swapping some things around...
@@ -1419,23 +1144,122 @@ void Collision_TraceLineTriangleFloat(trace_t *trace, const vec3_t linestart, co
 	// function when calling it than it is to rewire the internals.
 
 	// calculate the faceplanenormal of the triangle, this represents the front side
-	TriangleNormal(point0, point1, point2, faceplanenormal);
+	// 15 ops
+	VectorSubtract(point0, point1, edge01);
+	VectorSubtract(point2, point1, edge21);
+	CrossProduct(edge01, edge21, faceplanenormal);
 	// there's no point in processing a degenerate triangle (GIGO - Garbage In, Garbage Out)
-	if (DotProduct(faceplanenormal, faceplanenormal) < 0.0001f)
+	// 6 ops
+	faceplanenormallength2 = DotProduct(faceplanenormal, faceplanenormal);
+	if (faceplanenormallength2 < 0.0001f)
 		return;
-	// normalize the normal
-	VectorNormalize(faceplanenormal);
 	// calculate the distance
+	// 5 ops
 	faceplanedist = DotProduct(point0, faceplanenormal);
 
+	// if start point is on the back side there is no collision
+	// (we don't care about traces going through the triangle the wrong way)
+
 	// calculate the start distance
+	// 6 ops
+	d1 = DotProduct(faceplanenormal, linestart);
+	if (d1 <= faceplanedist)
+		return;
+
+	// calculate the end distance
+	// 6 ops
+	d2 = DotProduct(faceplanenormal, lineend);
+	// if both are in front, there is no collision
+	if (d2 >= faceplanedist)
+		return;
+
+	// from here on we know d1 is >= 0 and d2 is < 0
+	// this means the line starts infront and ends behind, passing through it
+
+	// calculate the recipricol of the distance delta,
+	// so we can use it multiple times cheaply (instead of division)
+	// 2 ops
+	d = 1.0f / (d1 - d2);
+	// calculate the impact fraction by taking the start distance (> 0)
+	// and subtracting the face plane distance (this is the distance of the
+	// triangle along that same normal)
+	// then multiply by the recipricol distance delta
+	// 2 ops
+	f = (d1 - faceplanedist) * d;
+	// skip out if this impact is further away than previous ones
+	// 1 ops
+	if (f > trace->realfraction)
+		return;
+	// calculate the perfect impact point for classification of insidedness
+	// 9 ops
+	impact[0] = linestart[0] + f * (lineend[0] - linestart[0]);
+	impact[1] = linestart[1] + f * (lineend[1] - linestart[1]);
+	impact[2] = linestart[2] + f * (lineend[2] - linestart[2]);
+
+	// calculate the edge normal and reject if impact is outside triangle
+	// (an edge normal faces away from the triangle, to get the desired normal
+	//  a crossproduct with the faceplanenormal is used, and because of the way
+	// the insidedness comparison is written it does not need to be normalized)
+
+	// first use the two edges from the triangle plane math
+	// the other edge only gets calculated if the point survives that long
+
+	// 20 ops
+	CrossProduct(edge01, faceplanenormal, edgenormal);
+	if (DotProduct(impact, edgenormal) > DotProduct(point1, edgenormal))
+		return;
+
+	// 20 ops
+	CrossProduct(faceplanenormal, edge21, edgenormal);
+	if (DotProduct(impact, edgenormal) > DotProduct(point2, edgenormal))
+		return;
+
+	// 23 ops
+	VectorSubtract(point0, point2, edge02);
+	CrossProduct(faceplanenormal, edge02, edgenormal);
+	if (DotProduct(impact, edgenormal) > DotProduct(point0, edgenormal))
+		return;
+
+	// 8 ops (rare)
+
+	// store the new trace fraction
+	trace->realfraction = f;
+
+	// calculate a nudged fraction to keep it out of the surface
+	// (the main fraction remains perfect)
+	trace->fraction = f - collision_impactnudge.value * d;
+
+	// store the new trace plane (because collisions only happen from
+	// the front this is always simply the triangle normal, never flipped)
+	d = 1.0 / sqrt(faceplanenormallength2);
+	VectorScale(faceplanenormal, d, trace->plane.normal);
+	trace->plane.dist = faceplanedist * d;
+#else
+	float d1, d2, d, f, fnudged, impact[3], edgenormal[3], faceplanenormal[3], faceplanedist, edge[3];
+
+	// this code is designed for clockwise triangles, conversion to
+	// counterclockwise would require swapping some things around...
+	// it is easier to simply swap the point0 and point2 parameters to this
+	// function when calling it than it is to rewire the internals.
+
+	// calculate the unnormalized faceplanenormal of the triangle,
+	// this represents the front side
+	TriangleNormal(point0, point1, point2, faceplanenormal);
+	// there's no point in processing a degenerate triangle
+	// (GIGO - Garbage In, Garbage Out)
+	if (DotProduct(faceplanenormal, faceplanenormal) < 0.0001f)
+		return;
+	// calculate the unnormalized distance
+	faceplanedist = DotProduct(point0, faceplanenormal);
+
+	// calculate the unnormalized start distance
 	d1 = DotProduct(faceplanenormal, linestart) - faceplanedist;
 	// if start point is on the back side there is no collision
 	// (we don't care about traces going through the triangle the wrong way)
-	if (d1 < 0)
+	if (d1 <= 0)
 		return;
 
-	// calculate the end distance
+	// calculate the unnormalized end distance
 	d2 = DotProduct(faceplanenormal, lineend) - faceplanedist;
 	// if both are in front, there is no collision
 	if (d2 >= 0)
@@ -1464,7 +1288,7 @@ void Collision_TraceLineTriangleFloat(trace_t *trace, const vec3_t linestart, co
 	// (an edge normal faces away from the triangle, to get the desired normal
 	//  a crossproduct with the faceplanenormal is used, and because of the way
 	// the insidedness comparison is written it does not need to be normalized)
-	
+
 	VectorSubtract(point2, point0, edge);
 	CrossProduct(edge, faceplanenormal, edgenormal);
 	if (DotProduct(impact, edgenormal) > DotProduct(point0, edgenormal))
@@ -1483,9 +1307,19 @@ void Collision_TraceLineTriangleFloat(trace_t *trace, const vec3_t linestart, co
 	// store the new trace fraction
 	trace->realfraction = bound(0, f, 1);
 
+	// store the new trace plane (because collisions only happen from
+	// the front this is always simply the triangle normal, never flipped)
+	VectorNormalize(faceplanenormal);
+	VectorCopy(faceplanenormal, trace->plane.normal);
+	trace->plane.dist = DotProduct(point0, faceplanenormal);
+
+	// calculate the normalized start and end distances
+	d1 = DotProduct(trace->plane.normal, linestart) - trace->plane.dist;
+	d2 = DotProduct(trace->plane.normal, lineend) - trace->plane.dist;
+
 	// calculate a nudged fraction to keep it out of the surface
 	// (the main fraction remains perfect)
-	fnudged = (d1 - collision_impactnudge.value) * d;
+	fnudged = (d1 - collision_impactnudge.value) / (d1 - d2);
 	trace->fraction = bound(0, fnudged, 1);
 
 	// store the new trace endpos
@@ -1493,11 +1327,7 @@ void Collision_TraceLineTriangleFloat(trace_t *trace, const vec3_t linestart, co
 	//trace->endpos[0] = linestart[0] + fnudged * (lineend[0] - linestart[0]);
 	//trace->endpos[1] = linestart[1] + fnudged * (lineend[1] - linestart[1]);
 	//trace->endpos[2] = linestart[2] + fnudged * (lineend[2] - linestart[2]);
-
-	// store the new trace plane (because collisions only happen from
-	// the front this is always simply the triangle normal, never flipped)
-	VectorCopy(faceplanenormal, trace->plane.normal);
-	trace->plane.dist = faceplanedist;
+#endif
 }
 
 typedef struct colbspnode_s