]> de.git.xonotic.org Git - xonotic/darkplaces.git/blobdiff - collision.c
Removed collision_prefernudgedfraction cvar and trace.realfraction field, this has...
[xonotic/darkplaces.git] / collision.c
index af0758f50fb196d5c9914ba9402b43fde49c933e..e574773b1fb7d6a72069277d6c5a87d210902d0d 100644 (file)
@@ -14,14 +14,13 @@ cvar_t collision_startnudge = {0, "collision_startnudge", "0", "how much to bias
 cvar_t collision_endnudge = {0, "collision_endnudge", "0", "how much to bias collision trace end"};
 cvar_t collision_enternudge = {0, "collision_enternudge", "0", "how much to bias collision entry fraction"};
 cvar_t collision_leavenudge = {0, "collision_leavenudge", "0", "how much to bias collision exit fraction"};
-cvar_t collision_prefernudgedfraction = {0, "collision_prefernudgedfraction", "1", "whether to sort collision events by nudged fraction (1) or real fraction (0)"};
-#ifdef COLLISION_STUPID_TRACE_ENDPOS_IN_SOLID_WORKAROUND
-cvar_t collision_endposnudge = {0, "collision_endposnudge", "0", "workaround to fix trace_endpos sometimes being returned where it would be inside solid by making that collision hit (recommended: values like 1)"};
-#endif
+cvar_t collision_extendmovelength = {0, "collision_extendmovelength", "16", "internal bias on trace length to ensure detection of collisions within the collision_impactnudge/collision_enternudge/collision_leavenudge distance so that short moves do not degrade across frames (this does not alter the final trace length)"};
+cvar_t collision_extendtraceboxlength = {0, "collision_extendtraceboxlength", "1", "internal bias for tracebox() qc builtin to account for collision_impactnudge/collision_enternudge/collision_leavenudge (this does not alter the final trace length)"};
+cvar_t collision_extendtracelinelength = {0, "collision_extendtracelinelength", "1", "internal bias for traceline() qc builtin to account for collision_impactnudge/collision_enternudge/collision_leavenudge (this does not alter the final trace length)"};
 cvar_t collision_debug_tracelineasbox = {0, "collision_debug_tracelineasbox", "0", "workaround for any bugs in Collision_TraceLineBrushFloat by using Collision_TraceBrushBrushFloat"};
 cvar_t collision_cache = {0, "collision_cache", "1", "store results of collision traces for next frame to reuse if possible (optimization)"};
 //cvar_t collision_triangle_neighborsides = {0, "collision_triangle_neighborsides", "1", "override automatic side generation if triangle has neighbors with face planes that form a convex edge (perfect solution, but can not work for all edges)"};
-cvar_t collision_triangle_bevelsides = {0, "collision_triangle_bevelsides", "1", "generate sloped edge planes on triangles - if 0, see axialedgeplanes"};
+cvar_t collision_triangle_bevelsides = {0, "collision_triangle_bevelsides", "0", "generate sloped edge planes on triangles - if 0, see axialedgeplanes"};
 cvar_t collision_triangle_axialsides = {0, "collision_triangle_axialsides", "1", "generate axially-aligned edge planes on triangles - otherwise use perpendicular edge planes"};
 
 mempool_t *collision_mempool;
@@ -33,10 +32,9 @@ void Collision_Init (void)
        Cvar_RegisterVariable(&collision_endnudge);
        Cvar_RegisterVariable(&collision_enternudge);
        Cvar_RegisterVariable(&collision_leavenudge);
-       Cvar_RegisterVariable(&collision_prefernudgedfraction);
-#ifdef COLLISION_STUPID_TRACE_ENDPOS_IN_SOLID_WORKAROUND
-       Cvar_RegisterVariable(&collision_endposnudge);
-#endif
+       Cvar_RegisterVariable(&collision_extendmovelength);
+       Cvar_RegisterVariable(&collision_extendtracelinelength);
+       Cvar_RegisterVariable(&collision_extendtraceboxlength);
        Cvar_RegisterVariable(&collision_debug_tracelineasbox);
        Cvar_RegisterVariable(&collision_cache);
 //     Cvar_RegisterVariable(&collision_triangle_neighborsides);
@@ -640,21 +638,15 @@ void Collision_TraceBrushBrushFloat(trace_t *trace, const colbrushf_t *trace_sta
                        if (nplane2 & 1)
                        {
                                CrossProduct(trace_start->edgedirs[nedge1].v, other_start->edgedirs[nedge2].v, startplane);
-                               if (VectorLength2(startplane) < COLLISION_EDGECROSS_MINLENGTH2)
-                                       continue; // degenerate crossproduct
                                CrossProduct(trace_end->edgedirs[nedge1].v, other_end->edgedirs[nedge2].v, endplane);
-                               if (VectorLength2(endplane) < COLLISION_EDGECROSS_MINLENGTH2)
-                                       continue; // degenerate crossproduct
                        }
                        else
                        {
                                CrossProduct(other_start->edgedirs[nedge2].v, trace_start->edgedirs[nedge1].v, startplane);
-                               if (VectorLength2(startplane) < COLLISION_EDGECROSS_MINLENGTH2)
-                                       continue; // degenerate crossproduct
                                CrossProduct(other_end->edgedirs[nedge2].v, trace_end->edgedirs[nedge1].v, endplane);
-                               if (VectorLength2(endplane) < COLLISION_EDGECROSS_MINLENGTH2)
-                                       continue; // degenerate crossproduct
                        }
+                       if (VectorLength2(startplane) < COLLISION_EDGECROSS_MINLENGTH2 || VectorLength2(endplane) < COLLISION_EDGECROSS_MINLENGTH2)
+                               continue; // degenerate crossproducts
                        VectorNormalize(startplane);
                        VectorNormalize(endplane);
                }
@@ -665,7 +657,7 @@ void Collision_TraceBrushBrushFloat(trace_t *trace, const colbrushf_t *trace_sta
                //Con_Printf("%c%i: startdist = %f, enddist = %f, startdist / (startdist - enddist) = %f\n", nplane2 != nplane ? 'b' : 'a', nplane2, startdist, enddist, startdist / (startdist - enddist));
 
                // aside from collisions, this is also used for error correction
-               if (startdist < collision_impactnudge.value && nplane < numplanes1 && (startdepth < startdist || startdepth == 1))
+               if (startdist <= collision_impactnudge.value && nplane < numplanes1 && (startdepth < startdist || startdepth == 1))
                {
                        startdepth = startdist;
                        VectorCopy(startplane, startdepthnormal);
@@ -676,7 +668,7 @@ void Collision_TraceBrushBrushFloat(trace_t *trace, const colbrushf_t *trace_sta
                        // moving into brush
                        if (enddist >= collision_enternudge.value)
                                return;
-                       if (startdist > 0)
+                       if (startdist >= 0)
                        {
                                // enter
                                imove = 1 / (startdist - enddist);
@@ -691,14 +683,14 @@ void Collision_TraceBrushBrushFloat(trace_t *trace, const colbrushf_t *trace_sta
                                        // if the collision time range is now empty, no collision
                                        if (enterfrac > leavefrac)
                                                return;
+                                       // calculate the nudged fraction and impact normal we'll
+                                       // need if we accept this collision later
+                                       enterfrac2 = (startdist - collision_impactnudge.value) * imove;
                                        // if the collision would be further away than the trace's
                                        // existing collision data, we don't care about this
                                        // collision
-                                       if (enterfrac > trace->realfraction)
+                                       if (enterfrac2 >= trace->fraction)
                                                return;
-                                       // calculate the nudged fraction and impact normal we'll
-                                       // need if we accept this collision later
-                                       enterfrac2 = (startdist - collision_impactnudge.value) * imove;
                                        ie = 1.0f - enterfrac;
                                        newimpactplane[0] = startplane[0] * ie + endplane[0] * enterfrac;
                                        newimpactplane[1] = startplane[1] * ie + endplane[1] * enterfrac;
@@ -729,7 +721,7 @@ void Collision_TraceBrushBrushFloat(trace_t *trace, const colbrushf_t *trace_sta
                else
                {
                        // moving out of brush
-                       if (startdist > 0)
+                       if (startdist >= 0)
                                return;
                        if (enddist > 0)
                        {
@@ -763,10 +755,7 @@ void Collision_TraceBrushBrushFloat(trace_t *trace, const colbrushf_t *trace_sta
                        trace->hitsupercontents = other_start->supercontents;
                        trace->hitq3surfaceflags = hitq3surfaceflags;
                        trace->hittexture = hittexture;
-                       trace->realfraction = bound(0, enterfrac, 1);
                        trace->fraction = bound(0, enterfrac2, 1);
-                       if (collision_prefernudgedfraction.integer)
-                               trace->realfraction = trace->fraction;
                        VectorCopy(newimpactplane, trace->plane.normal);
                        trace->plane.dist = newimpactplane[3];
                }
@@ -863,14 +852,14 @@ void Collision_TraceLineBrushFloat(trace_t *trace, const vec3_t linestart, const
                                        // if the collision time range is now empty, no collision
                                        if (enterfrac > leavefrac)
                                                return;
+                                       // calculate the nudged fraction and impact normal we'll
+                                       // need if we accept this collision later
+                                       enterfrac2 = (startdist - collision_impactnudge.value) * imove;
                                        // if the collision would be further away than the trace's
                                        // existing collision data, we don't care about this
                                        // collision
-                                       if (enterfrac > trace->realfraction)
+                                       if (enterfrac2 >= trace->fraction)
                                                return;
-                                       // calculate the nudged fraction and impact normal we'll
-                                       // need if we accept this collision later
-                                       enterfrac2 = (startdist - collision_impactnudge.value) * imove;
                                        ie = 1.0f - enterfrac;
                                        newimpactplane[0] = startplane[0] * ie + endplane[0] * enterfrac;
                                        newimpactplane[1] = startplane[1] * ie + endplane[1] * enterfrac;
@@ -918,10 +907,7 @@ void Collision_TraceLineBrushFloat(trace_t *trace, const vec3_t linestart, const
                        trace->hitsupercontents = other_start->supercontents;
                        trace->hitq3surfaceflags = hitq3surfaceflags;
                        trace->hittexture = hittexture;
-                       trace->realfraction = bound(0, enterfrac, 1);
                        trace->fraction = bound(0, enterfrac2, 1);
-                       if (collision_prefernudgedfraction.integer)
-                               trace->realfraction = trace->fraction;
                        VectorCopy(newimpactplane, trace->plane.normal);
                        trace->plane.dist = newimpactplane[3];
                }
@@ -1240,9 +1226,7 @@ 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, int supercontents, int q3surfaceflags, const texture_t *texture)
 {
-#if 1
-       // more optimized
-       float d1, d2, d, f, impact[3], edgenormal[3], faceplanenormal[3], faceplanedist, faceplanenormallength2, edge01[3], edge21[3], edge02[3];
+       float d1, d2, d, f, f2, impact[3], edgenormal[3], faceplanenormal[3], faceplanedist, faceplanenormallength2, edge01[3], edge21[3], edge02[3];
 
        // this function executes:
        // 32 ops when line starts behind triangle
@@ -1299,11 +1283,12 @@ void Collision_TraceLineTriangleFloat(trace_t *trace, const vec3_t linestart, co
        // 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
+       // 4 ops
        f = (d1 - faceplanedist) * d;
+       f2  = f - collision_impactnudge.value * d;
        // skip out if this impact is further away than previous ones
        // 1 ops
-       if (f > trace->realfraction)
+       if (f2 >= trace->fraction)
                return;
        // calculate the perfect impact point for classification of insidedness
        // 9 ops
@@ -1338,14 +1323,7 @@ void Collision_TraceLineTriangleFloat(trace_t *trace, const vec3_t linestart, co
        // 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;
-
-       if (collision_prefernudgedfraction.integer)
-               trace->realfraction = trace->fraction;
+       trace->fraction = f2;
 
        // store the new trace plane (because collisions only happen from
        // the front this is always simply the triangle normal, never flipped)
@@ -1356,103 +1334,6 @@ void Collision_TraceLineTriangleFloat(trace_t *trace, const vec3_t linestart, co
        trace->hitsupercontents = supercontents;
        trace->hitq3surfaceflags = q3surfaceflags;
        trace->hittexture = texture;
-#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)
-               return;
-
-       // calculate the unnormalized end distance
-       d2 = DotProduct(faceplanenormal, lineend) - faceplanedist;
-       // if both are in front, there is no collision
-       if (d2 >= 0)
-               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)
-       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
-       f = d1 * d;
-       // skip out if this impact is further away than previous ones
-       if (f > trace->realfraction)
-               return;
-       // calculate the perfect impact point for classification of insidedness
-       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)
-
-       VectorSubtract(point2, point0, edge);
-       CrossProduct(edge, faceplanenormal, edgenormal);
-       if (DotProduct(impact, edgenormal) > DotProduct(point0, edgenormal))
-               return;
-
-       VectorSubtract(point0, point1, edge);
-       CrossProduct(edge, faceplanenormal, edgenormal);
-       if (DotProduct(impact, edgenormal) > DotProduct(point1, edgenormal))
-               return;
-
-       VectorSubtract(point1, point2, edge);
-       CrossProduct(edge, faceplanenormal, edgenormal);
-       if (DotProduct(impact, edgenormal) > DotProduct(point2, edgenormal))
-               return;
-
-       // 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) / (d1 - d2);
-       trace->fraction = bound(0, fnudged, 1);
-
-       // store the new trace endpos
-       // not needed, it's calculated later when the trace is finished
-       //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]);
-       trace->hitsupercontents = supercontents;
-       trace->hitq3surfaceflags = q3surfaceflags;
-       trace->hittexture = texture;
-#endif
 }
 
 void Collision_BoundingBoxOfBrushTraceSegment(const colbrushf_t *start, const colbrushf_t *end, vec3_t mins, vec3_t maxs, float startfrac, float endfrac)
@@ -1683,7 +1564,7 @@ static collision_cachedtrace_t *Collision_Cache_Lookup(dp_model_t *model, const
        collision_cachedtrace_parameters_t params;
        // all non-cached traces use the same index
        if (!collision_cache.integer)
-               r_refdef.stats.collisioncache_traced++;
+               r_refdef.stats[r_stat_photoncache_traced]++;
        else
        {
                // cached trace lookup
@@ -1728,12 +1609,12 @@ static collision_cachedtrace_t *Collision_Cache_Lookup(dp_model_t *model, const
                        )
                                continue;
                        // found a matching trace in the cache
-                       r_refdef.stats.collisioncache_cached++;
+                       r_refdef.stats[r_stat_photoncache_cached]++;
                        cached->valid = true;
                        collision_cachedtrace_arrayused[index] = collision_cachedtrace_sequence;
                        return cached;
                }
-               r_refdef.stats.collisioncache_traced++;
+               r_refdef.stats[r_stat_photoncache_traced]++;
                // find an unused cache entry
                for (index = collision_cachedtrace_firstfree, range = collision_cachedtrace_max;index < range;index++)
                        if (collision_cachedtrace_arrayused[index] == 0)
@@ -1782,7 +1663,7 @@ void Collision_Cache_ClipLineToGenericEntitySurfaces(trace_t *trace, dp_model_t
                return;
        }
 
-       Collision_ClipLineToGenericEntity(trace, model, NULL, NULL, vec3_origin, vec3_origin, 0, matrix, inversematrix, start, end, hitsupercontentsmask, true);
+       Collision_ClipLineToGenericEntity(trace, model, NULL, NULL, vec3_origin, vec3_origin, 0, matrix, inversematrix, start, end, hitsupercontentsmask, collision_extendmovelength.value, true);
 
        cached->result = *trace;
 }
@@ -1796,22 +1677,93 @@ void Collision_Cache_ClipLineToWorldSurfaces(trace_t *trace, dp_model_t *model,
                return;
        }
 
-       Collision_ClipLineToWorld(trace, model, start, end, hitsupercontents, true);
+       Collision_ClipLineToWorld(trace, model, start, end, hitsupercontents, collision_extendmovelength.value, true);
 
        cached->result = *trace;
 }
 
-void Collision_ClipToGenericEntity(trace_t *trace, dp_model_t *model, const frameblend_t *frameblend, const skeleton_t *skeleton, const vec3_t bodymins, const vec3_t bodymaxs, int bodysupercontents, matrix4x4_t *matrix, matrix4x4_t *inversematrix, const vec3_t start, const vec3_t mins, const vec3_t maxs, const vec3_t end, int hitsupercontentsmask)
+typedef struct extendtraceinfo_s
 {
-       float starttransformed[3], endtransformed[3];
+       trace_t *trace;
+       float realstart[3];
+       float realend[3];
+       float realdelta[3];
+       float extendstart[3];
+       float extendend[3];
+       float extenddelta[3];
+       float reallength;
+       float extendlength;
+       float scaletoextend;
+       float extend;
+}
+extendtraceinfo_t;
 
+static void Collision_ClipExtendPrepare(extendtraceinfo_t *extendtraceinfo, trace_t *trace, const vec3_t tstart, const vec3_t tend, float textend)
+{
        memset(trace, 0, sizeof(*trace));
-       trace->fraction = trace->realfraction = 1;
+       trace->fraction = 1;
+
+       extendtraceinfo->trace = trace;
+       VectorCopy(tstart, extendtraceinfo->realstart);
+       VectorCopy(tend, extendtraceinfo->realend);
+       VectorSubtract(extendtraceinfo->realend, extendtraceinfo->realstart, extendtraceinfo->realdelta);
+       VectorCopy(extendtraceinfo->realstart, extendtraceinfo->extendstart);
+       VectorCopy(extendtraceinfo->realend, extendtraceinfo->extendend);
+       VectorCopy(extendtraceinfo->realdelta, extendtraceinfo->extenddelta);
+       extendtraceinfo->reallength = VectorLength(extendtraceinfo->realdelta);
+       extendtraceinfo->extendlength = extendtraceinfo->reallength;
+       extendtraceinfo->scaletoextend = 1.0f;
+       extendtraceinfo->extend = textend;
+
+       // make the trace longer according to the extend parameter
+       if (extendtraceinfo->reallength && extendtraceinfo->extend)
+       {
+               extendtraceinfo->extendlength = extendtraceinfo->reallength + extendtraceinfo->extend;
+               extendtraceinfo->scaletoextend = extendtraceinfo->extendlength / extendtraceinfo->reallength;
+               VectorMA(extendtraceinfo->realstart, extendtraceinfo->scaletoextend, extendtraceinfo->realdelta, extendtraceinfo->extendend);
+               VectorSubtract(extendtraceinfo->extendend, extendtraceinfo->extendstart, extendtraceinfo->extenddelta);
+       }
+}
 
-       Matrix4x4_Transform(inversematrix, start, starttransformed);
-       Matrix4x4_Transform(inversematrix, end, endtransformed);
+static void Collision_ClipExtendFinish(extendtraceinfo_t *extendtraceinfo)
+{
+       trace_t *trace = extendtraceinfo->trace;
+
+       if (trace->fraction != 1.0f)
+       {
+               // undo the extended trace length
+               trace->fraction *= extendtraceinfo->scaletoextend;
+
+               // if the extended trace hit something that the unextended trace did not hit (even considering the collision_impactnudge), then we have to clear the hit information
+               if (trace->fraction > 1.0f)
+               {
+                       // note that ent may refer to either startsolid or fraction<1, we can't restore the startsolid ent unfortunately
+                       trace->ent = NULL;
+                       trace->hitq3surfaceflags = 0;
+                       trace->hitsupercontents = 0;
+                       trace->hittexture = NULL;
+                       VectorClear(trace->plane.normal);
+                       trace->plane.dist = 0.0f;
+               }
+       }
+
+       // clamp things
+       trace->fraction = bound(0, trace->fraction, 1);
+
+       // calculate the end position
+       VectorMA(extendtraceinfo->realstart, trace->fraction, extendtraceinfo->realdelta, trace->endpos);
+}
+
+void Collision_ClipToGenericEntity(trace_t *trace, dp_model_t *model, const frameblend_t *frameblend, const skeleton_t *skeleton, const vec3_t bodymins, const vec3_t bodymaxs, int bodysupercontents, matrix4x4_t *matrix, matrix4x4_t *inversematrix, const vec3_t tstart, const vec3_t mins, const vec3_t maxs, const vec3_t tend, int hitsupercontentsmask, float extend)
+{
+       vec3_t starttransformed, endtransformed;
+       extendtraceinfo_t extendtraceinfo;
+       Collision_ClipExtendPrepare(&extendtraceinfo, trace, tstart, tend, extend);
+
+       Matrix4x4_Transform(inversematrix, extendtraceinfo.extendstart, starttransformed);
+       Matrix4x4_Transform(inversematrix, extendtraceinfo.extendend, endtransformed);
 #if COLLISIONPARANOID >= 3
-       Con_Printf("trans(%f %f %f -> %f %f %f, %f %f %f -> %f %f %f)", start[0], start[1], start[2], starttransformed[0], starttransformed[1], starttransformed[2], end[0], end[1], end[2], endtransformed[0], endtransformed[1], endtransformed[2]);
+       Con_Printf("trans(%f %f %f -> %f %f %f, %f %f %f -> %f %f %f)", extendtraceinfo.extendstart[0], extendtraceinfo.extendstart[1], extendtraceinfo.extendstart[2], starttransformed[0], starttransformed[1], starttransformed[2], extendtraceinfo.extendend[0], extendtraceinfo.extendend[1], extendtraceinfo.extendend[2], endtransformed[0], endtransformed[1], endtransformed[2]);
 #endif
 
        if (model && model->TraceBox)
@@ -1824,8 +1776,8 @@ void Collision_ClipToGenericEntity(trace_t *trace, dp_model_t *model, const fram
                        colboxbrushf_t thisbrush_start, thisbrush_end;
                        Collision_BrushForBox(&thisbrush_start, mins, maxs, 0, 0, NULL);
                        Collision_BrushForBox(&thisbrush_end, mins, maxs, 0, 0, NULL);
-                       Collision_TranslateBrush(start, &thisbrush_start.brush);
-                       Collision_TranslateBrush(end, &thisbrush_end.brush);
+                       Collision_TranslateBrush(extendtraceinfo.extendstart, &thisbrush_start.brush);
+                       Collision_TranslateBrush(extendtraceinfo.extendend, &thisbrush_end.brush);
                        Collision_TransformBrush(inversematrix, &thisbrush_start.brush);
                        Collision_TransformBrush(inversematrix, &thisbrush_end.brush);
                        //Collision_TranslateBrush(starttransformed, &thisbrush_start.brush);
@@ -1837,37 +1789,34 @@ void Collision_ClipToGenericEntity(trace_t *trace, dp_model_t *model, const fram
        }
        else // and this requires that the transformation matrix doesn't have angles components, like SV_TraceBox ensures; FIXME may get called if a model is SOLID_BSP but has no TraceBox function
                Collision_ClipTrace_Box(trace, bodymins, bodymaxs, starttransformed, mins, maxs, endtransformed, hitsupercontentsmask, bodysupercontents, 0, NULL);
-       trace->fraction = bound(0, trace->fraction, 1);
-       trace->realfraction = bound(0, trace->realfraction, 1);
 
-       VectorLerp(start, trace->fraction, end, trace->endpos);
+       Collision_ClipExtendFinish(&extendtraceinfo);
+
        // transform plane
        // NOTE: this relies on plane.dist being directly after plane.normal
        Matrix4x4_TransformPositivePlane(matrix, trace->plane.normal[0], trace->plane.normal[1], trace->plane.normal[2], trace->plane.dist, trace->plane.normal);
 }
 
-void Collision_ClipToWorld(trace_t *trace, dp_model_t *model, const vec3_t start, const vec3_t mins, const vec3_t maxs, const vec3_t end, int hitsupercontents)
+void Collision_ClipToWorld(trace_t *trace, dp_model_t *model, const vec3_t tstart, const vec3_t mins, const vec3_t maxs, const vec3_t tend, int hitsupercontents, float extend)
 {
-       memset(trace, 0, sizeof(*trace));
-       trace->fraction = trace->realfraction = 1;
+       extendtraceinfo_t extendtraceinfo;
+       Collision_ClipExtendPrepare(&extendtraceinfo, trace, tstart, tend, extend);
        // ->TraceBox: TraceBrush not needed here, as worldmodel is never rotated
        if (model && model->TraceBox)
-               model->TraceBox(model, NULL, NULL, trace, start, mins, maxs, end, hitsupercontents);
-       trace->fraction = bound(0, trace->fraction, 1);
-       trace->realfraction = bound(0, trace->realfraction, 1);
-       VectorLerp(start, trace->fraction, end, trace->endpos);
+               model->TraceBox(model, NULL, NULL, trace, extendtraceinfo.extendstart, mins, maxs, extendtraceinfo.extendend, hitsupercontents);
+       Collision_ClipExtendFinish(&extendtraceinfo);
 }
 
-void Collision_ClipLineToGenericEntity(trace_t *trace, dp_model_t *model, const frameblend_t *frameblend, const skeleton_t *skeleton, const vec3_t bodymins, const vec3_t bodymaxs, int bodysupercontents, matrix4x4_t *matrix, matrix4x4_t *inversematrix, const vec3_t start, const vec3_t end, int hitsupercontentsmask, qboolean hitsurfaces)
+void Collision_ClipLineToGenericEntity(trace_t *trace, dp_model_t *model, const frameblend_t *frameblend, const skeleton_t *skeleton, const vec3_t bodymins, const vec3_t bodymaxs, int bodysupercontents, matrix4x4_t *matrix, matrix4x4_t *inversematrix, const vec3_t tstart, const vec3_t tend, int hitsupercontentsmask, float extend, qboolean hitsurfaces)
 {
-       float starttransformed[3], endtransformed[3];
-       memset(trace, 0, sizeof(*trace));
-       trace->fraction = trace->realfraction = 1;
+       vec3_t starttransformed, endtransformed;
+       extendtraceinfo_t extendtraceinfo;
+       Collision_ClipExtendPrepare(&extendtraceinfo, trace, tstart, tend, extend);
 
-       Matrix4x4_Transform(inversematrix, start, starttransformed);
-       Matrix4x4_Transform(inversematrix, end, endtransformed);
+       Matrix4x4_Transform(inversematrix, extendtraceinfo.extendstart, starttransformed);
+       Matrix4x4_Transform(inversematrix, extendtraceinfo.extendend, endtransformed);
 #if COLLISIONPARANOID >= 3
-       Con_Printf("trans(%f %f %f -> %f %f %f, %f %f %f -> %f %f %f)", start[0], start[1], start[2], starttransformed[0], starttransformed[1], starttransformed[2], end[0], end[1], end[2], endtransformed[0], endtransformed[1], endtransformed[2]);
+       Con_Printf("trans(%f %f %f -> %f %f %f, %f %f %f -> %f %f %f)", extendtraceinfo.extendstart[0], extendtraceinfo.extendstart[1], extendtraceinfo.extendstart[2], starttransformed[0], starttransformed[1], starttransformed[2], extendtraceinfo.extendend[0], extendtraceinfo.extendend[1], extendtraceinfo.extendend[2], endtransformed[0], endtransformed[1], endtransformed[2]);
 #endif
 
        if (model && model->TraceLineAgainstSurfaces && hitsurfaces)
@@ -1876,33 +1825,32 @@ void Collision_ClipLineToGenericEntity(trace_t *trace, dp_model_t *model, const
                model->TraceLine(model, frameblend, skeleton, trace, starttransformed, endtransformed, hitsupercontentsmask);
        else
                Collision_ClipTrace_Box(trace, bodymins, bodymaxs, starttransformed, vec3_origin, vec3_origin, endtransformed, hitsupercontentsmask, bodysupercontents, 0, NULL);
-       trace->fraction = bound(0, trace->fraction, 1);
-       trace->realfraction = bound(0, trace->realfraction, 1);
 
-       VectorLerp(start, trace->fraction, end, trace->endpos);
+       Collision_ClipExtendFinish(&extendtraceinfo);
+
        // transform plane
        // NOTE: this relies on plane.dist being directly after plane.normal
        Matrix4x4_TransformPositivePlane(matrix, trace->plane.normal[0], trace->plane.normal[1], trace->plane.normal[2], trace->plane.dist, trace->plane.normal);
 }
 
-void Collision_ClipLineToWorld(trace_t *trace, dp_model_t *model, const vec3_t start, const vec3_t end, int hitsupercontents, qboolean hitsurfaces)
+void Collision_ClipLineToWorld(trace_t *trace, dp_model_t *model, const vec3_t tstart, const vec3_t tend, int hitsupercontents, float extend, qboolean hitsurfaces)
 {
-       memset(trace, 0, sizeof(*trace));
-       trace->fraction = trace->realfraction = 1;
+       extendtraceinfo_t extendtraceinfo;
+       Collision_ClipExtendPrepare(&extendtraceinfo, trace, tstart, tend, extend);
+
        if (model && model->TraceLineAgainstSurfaces && hitsurfaces)
-               model->TraceLineAgainstSurfaces(model, NULL, NULL, trace, start, end, hitsupercontents);
+               model->TraceLineAgainstSurfaces(model, NULL, NULL, trace, extendtraceinfo.extendstart, extendtraceinfo.extendend, hitsupercontents);
        else if (model && model->TraceLine)
-               model->TraceLine(model, NULL, NULL, trace, start, end, hitsupercontents);
-       trace->fraction = bound(0, trace->fraction, 1);
-       trace->realfraction = bound(0, trace->realfraction, 1);
-       VectorLerp(start, trace->fraction, end, trace->endpos);
+               model->TraceLine(model, NULL, NULL, trace, extendtraceinfo.extendstart, extendtraceinfo.extendend, hitsupercontents);
+
+       Collision_ClipExtendFinish(&extendtraceinfo);
 }
 
 void Collision_ClipPointToGenericEntity(trace_t *trace, dp_model_t *model, const frameblend_t *frameblend, const skeleton_t *skeleton, const vec3_t bodymins, const vec3_t bodymaxs, int bodysupercontents, matrix4x4_t *matrix, matrix4x4_t *inversematrix, const vec3_t start, int hitsupercontentsmask)
 {
        float starttransformed[3];
        memset(trace, 0, sizeof(*trace));
-       trace->fraction = trace->realfraction = 1;
+       trace->fraction = 1;
 
        Matrix4x4_Transform(inversematrix, start, starttransformed);
 #if COLLISIONPARANOID >= 3
@@ -1923,7 +1871,7 @@ void Collision_ClipPointToGenericEntity(trace_t *trace, dp_model_t *model, const
 void Collision_ClipPointToWorld(trace_t *trace, dp_model_t *model, const vec3_t start, int hitsupercontents)
 {
        memset(trace, 0, sizeof(*trace));
-       trace->fraction = trace->realfraction = 1;
+       trace->fraction = 1;
        if (model && model->TracePoint)
                model->TracePoint(model, NULL, NULL, trace, start, hitsupercontents);
        VectorCopy(start, trace->endpos);
@@ -1939,7 +1887,7 @@ void Collision_CombineTraces(trace_t *cliptrace, const trace_t *trace, void *tou
                if (isbmodel)
                        cliptrace->bmodelstartsolid = true;
                cliptrace->startsolid = true;
-               if (cliptrace->realfraction == 1)
+               if (cliptrace->fraction == 1)
                        cliptrace->ent = touch;
                if (cliptrace->startdepth > trace->startdepth)
                {
@@ -1954,10 +1902,9 @@ void Collision_CombineTraces(trace_t *cliptrace, const trace_t *trace, void *tou
        //      cliptrace->inopen = true;
        if (trace->inwater)
                cliptrace->inwater = true;
-       if ((trace->realfraction <= cliptrace->realfraction) && (VectorLength2(trace->plane.normal) > 0))
+       if ((trace->fraction < cliptrace->fraction) && (VectorLength2(trace->plane.normal) > 0))
        {
                cliptrace->fraction = trace->fraction;
-               cliptrace->realfraction = trace->realfraction;
                VectorCopy(trace->endpos, cliptrace->endpos);
                cliptrace->plane = trace->plane;
                cliptrace->ent = touch;
@@ -1967,22 +1914,3 @@ void Collision_CombineTraces(trace_t *cliptrace, const trace_t *trace, void *tou
        }
        cliptrace->startsupercontents |= trace->startsupercontents;
 }
-
-void Collision_ShortenTrace(trace_t *trace, float shorten_factor, const vec3_t end)
-{
-       // now undo our moving end 1 qu farther...
-       trace->fraction = bound(trace->fraction, trace->fraction / shorten_factor - 1e-6, 1); // we subtract 1e-6 to guard for roundoff errors
-       trace->realfraction = bound(trace->realfraction, trace->realfraction / shorten_factor - 1e-6, 1); // we subtract 1e-6 to guard for roundoff errors
-       if(trace->fraction >= 1) // trace would NOT hit if not expanded!
-       {
-               trace->fraction = 1;
-               trace->realfraction = 1;
-               VectorCopy(end, trace->endpos);
-               memset(&trace->plane, 0, sizeof(trace->plane));
-               trace->ent = NULL;
-               trace->hitsupercontentsmask = 0;
-               trace->hitsupercontents = 0;
-               trace->hitq3surfaceflags = 0;
-               trace->hittexture = NULL;
-       }
-}