From 1a50dff7e807d2e159b26bdb9d29f34beb660034 Mon Sep 17 00:00:00 2001 From: havoc Date: Tue, 11 Oct 2005 09:58:50 +0000 Subject: [PATCH] changed the unused line/sphere collision code to use Vector macros instead of doing everything manually (possibly improving readability) git-svn-id: svn://svn.icculus.org/twilight/trunk/darkplaces@5734 d7cf8633-e32d-0410-b094-e92efae38249 --- collision.c | 49 ++++++++++++++++--------------------------------- 1 file changed, 16 insertions(+), 33 deletions(-) diff --git a/collision.c b/collision.c index 4dc31a9d..693d653d 100644 --- a/collision.c +++ b/collision.c @@ -1054,7 +1054,10 @@ void Collision_ClipTrace_BrushBox(trace_t *trace, const vec3_t cmins, const vec3 Collision_TraceBrushBrushFloat(trace, thisbrush_start, thisbrush_end, boxbrush, boxbrush); } -// LordHavoc: currently unused and not yet tested +//pseudocode for detecting line/sphere overlap without calculating an impact point +//linesphereorigin = sphereorigin - linestart;linediff = lineend - linestart;linespherefrac = DotProduct(linesphereorigin, linediff) / DotProduct(linediff, linediff);return VectorLength2(linesphereorigin - bound(0, linespherefrac, 1) * linediff) >= sphereradius*sphereradius; + +// LordHavoc: currently unused, but tested // note: this can be used for tracing a moving sphere vs a stationary sphere, // by simply adding the moving sphere's radius to the sphereradius parameter, // all the results are correct (impactpoint, impactnormal, and fraction) @@ -1063,35 +1066,26 @@ float Collision_ClipTrace_Line_Sphere(double *linestart, double *lineend, double double dir[3], scale, v[3], deviationdist, impactdist, linelength; // make sure the impactpoint and impactnormal are valid even if there is // no collision - impactpoint[0] = lineend[0]; - impactpoint[1] = lineend[1]; - impactpoint[2] = lineend[2]; - impactnormal[0] = 0; - impactnormal[1] = 0; - impactnormal[2] = 0; + VectorCopy(lineend, impactpoint); + VectorClear(impactnormal); // calculate line direction - dir[0] = lineend[0] - linestart[0]; - dir[1] = lineend[1] - linestart[1]; - dir[2] = lineend[2] - linestart[2]; + VectorSubtract(lineend, linestart, dir); // normalize direction - linelength = sqrt(dir[0] * dir[0] + dir[1] * dir[1] + dir[2] * dir[2]); + linelength = VectorLength(dir); if (linelength) { scale = 1.0 / linelength; - dir[0] *= scale; - dir[1] *= scale; - dir[2] *= scale; + VectorScale(dir, scale, dir); } // this dotproduct calculates the distance along the line at which the // sphere origin is (nearest point to the sphere origin on the line) - impactdist = dir[0] * (sphereorigin[0] - linestart[0]) + dir[1] * (sphereorigin[1] - linestart[1]) + dir[2] * (sphereorigin[2] - linestart[2]); + impactdist = DotProduct(sphereorigin, dir) - DotProduct(linestart, dir); // calculate point on line at that distance, and subtract the // sphereorigin from it, so we have a vector to measure for the distance // of the line from the sphereorigin (deviation, how off-center it is) - v[0] = linestart[0] + impactdist * dir[0] - sphereorigin[0]; - v[1] = linestart[1] + impactdist * dir[1] - sphereorigin[1]; - v[2] = linestart[2] + impactdist * dir[2] - sphereorigin[2]; - deviationdist = v[0] * v[0] + v[1] * v[1] + v[2] * v[2]; + VectorMA(linestart, impactdist, dir, v); + VectorSubtract(v, sphereorigin, v); + deviationdist = VectorLength2(v); // if outside the radius, it's a miss for sure // (we do this comparison using squared radius to avoid a sqrt) if (deviationdist > sphereradius*sphereradius) @@ -1103,22 +1097,11 @@ float Collision_ClipTrace_Line_Sphere(double *linestart, double *lineend, double if (impactdist < 0) return 1; // miss (linestart is past or inside sphere) // calculate new impactpoint - impactpoint[0] = linestart[0] + impactdist * dir[0]; - impactpoint[1] = linestart[1] + impactdist * dir[1]; - impactpoint[2] = linestart[2] + impactdist * dir[2]; + VectorMA(linestart, impactdist, dir, impactpoint); // calculate impactnormal (surface normal at point of impact) - impactnormal[0] = impactpoint[0] - sphereorigin[0]; - impactnormal[1] = impactpoint[1] - sphereorigin[1]; - impactnormal[2] = impactpoint[2] - sphereorigin[2]; + VectorSubtract(impactpoint, sphereorigin, impactnormal); // normalize impactnormal - scale = impactnormal[0] * impactnormal[0] + impactnormal[1] * impactnormal[1] + impactnormal[2] * impactnormal[2]; - if (scale) - { - scale = 1.0 / sqrt(scale); - impactnormal[0] *= scale; - impactnormal[1] *= scale; - impactnormal[2] *= scale; - } + VectorNormalize(impactnormal); // return fraction of movement distance return impactdist / linelength; } -- 2.39.2