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https://git.code.sf.net/p/quake/quakeforge
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Add code to clip the motion of the box to the leaf's portals.
Unfortunately, something is broken (all box tests fail due to 0 fraction).
This commit is contained in:
Bill Currie
parent
5ee552ea5b
commit
8fc99566ab
1 changed files with 274 additions and 3 deletions
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@ -133,9 +133,232 @@ check_in_leaf (hull_t *hull, trace_t *trace, clipleaf_t *leaf, plane_t *plane,
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return 0;
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return 0;
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}
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}
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typedef struct {
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plane_t planes[3];
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winding_t points[3];
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winding_t edges[3];
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clipport_t portals[3];
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} clipbox_t;
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/** Initialize the clipbox representing the faces that might hit the portal.
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When a box is moving, at most three of its faces might hit the portal.
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Those faces all face such that the dot product of their normal and the
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box's velocity is positive (ie, n.v > 0). When the motion is in an axial
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plane, only two faces might hit. For axial motion, only one face.
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The faces are set up such that the first point of each winding is the
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leading corner of the box, and the edges are set up such that testing
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only the first three edges of each winding covers all nine edges (ie,
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the forth edge of one face is the reverse of the first edge of the next
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face).
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The windings are clockwise when looking down the face's normal (ie, when
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looking at the front of the face).
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*/
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static void
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init_box (const trace_t *trace, clipbox_t *box, const vec3_t vel)
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{
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vec3_t p;
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int u[3];
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int i, j, k;
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vec_t s[2] = {1, -1};
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//FIXME rotated box
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for (i = 0; i < 3; i++)
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u[i] = (vel[i] >= 0 ? 1 : -1);
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Vector3Scale (u, trace->extents, p);
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for (i = 0; i < 3; i++) {
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box->portals[i].planenum = i;
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box->portals[i].next[0] = 0;
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box->portals[i].next[0] = 0;
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box->portals[i].leafs[0] = 0;
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box->portals[i].leafs[0] = 0;
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box->portals[i].winding = &box->points[i];
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box->portals[i].edges = &box->edges[i];
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VectorZero (box->planes[i].normal);
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box->planes[i].normal[i] = u[i];
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box->planes[i].dist = DotProduct (p, box->planes[i].normal);
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box->planes[i].type = i;
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box->points[i].numpoints = 4;
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box->edges[i].numpoints = 4;
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VectorCopy (u, box->points[i].points[0]);
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VectorZero (box->edges[i].points[0]);
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j = (i + (u[0]*u[1]*u[2] + 3) / 2) % 3;
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box->edges[i].points[0][j] = -u[j];
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for (j = 1; j < 4; j++) {
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box->points[i].points[j][i] = box->points[i].points[j - 1][i];
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box->edges[i].points[j][i] = box->edges[i].points[j - 1][i];
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for (k = 0; k < 2; k++) {
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int a, b;
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a = (i + 1 + k) % 3;
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b = (i + 2 - k) % 3;
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box->points[i].points[j][a]
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= s[k] * u[i] * box->points[i].points[j - 1][b];
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box->edges[i].points[j][a]
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= s[k] * u[i] * box->edges[i].points[j - 1][b];
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}
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Vector3Scale (box->points[i].points[j - 1], trace->extents,
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box->points[i].points[j - 1]);
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}
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Vector3Scale (box->points[i].points[3], trace->extents,
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box->points[i].points[3]);
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}
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}
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static vec_t
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edge_portal_dist (const plane_t *plane, const clipport_t *portal,
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const vec3_t p1, const vec3_t p2, const vec3_t vel)
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{
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int i;
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winding_t *winding = portal->winding;
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winding_t *edges = portal->edges;
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// check for edge point hitting portal face
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{
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vec_t t1, t2, vn;
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vn = DotProduct (vel, plane->normal);
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t1 = PlaneDiff (p1, plane);
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t2 = PlaneDiff (p2, plane);
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// ensure p1 is the closest point to the plane
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if ((0 < t1 && t1 > t2)
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|| (0 > t1 && t1 < t2)) {
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// p2 is closer to the plane, so swap the points and times
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const vec_t *r = p2;
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vec_t t = t2;
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t2 = t1; t1 = t;
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p2 = p1; p1 = r;
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}
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if (vn * t1 > 0) {
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// the edge is travelling away from the portal's plane
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return 1;
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}
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// if t1 * t2 < 0, the points straddle the portal's plane and the
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// nearest point test can be skipped
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if (vn && t1 * t2 > 0) { //FIXME epsilon
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vec3_t x, c;
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vec3_t imp;
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if (t1 >= vn) {
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// the edge doesn't make it as far as the portal's plane
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return 1;
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}
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VectorMultSub (p1, t1 / vn, vel, imp);
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for (i = 0; i < winding->numpoints; i++) {
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VectorSubtract (imp, winding->points[i], x);
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CrossProduct (x, edges->points[i], c);
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if (DotProduct (c, plane->normal) >= 0)
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break; // miss
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}
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if (i == winding->numpoints) {
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// the closer end of the edge hit the portal, so t1/vn is the
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// fraction
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return t1 / vn;
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}
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// the closer end of the edge missed the portal, check the farther
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// end, but only with this portal edge.
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VectorMultSub (p2, t2 / vn, vel, imp);
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VectorSubtract (imp, winding->points[i], x);
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CrossProduct (x, edges->points[i], c);
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if (DotProduct (c, plane->normal) >= 0) {
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// both impacts are on the outside of this portal edge, so the
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// edge being tested misses the portal
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return 1;
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}
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// the two impact points are on both sides of a portal edge, so the
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// edge being tested might hit a portal edge rather than the portal
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// face
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}
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}
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{
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vec3_t e;
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vec_t frac = 1.0;
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vec_t ee;
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plane_t ep;
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// set up the plane through which the edge travels
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VectorSubtract (p2, p1, e);
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ee = DotProduct (e, e);
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CrossProduct (e, vel, ep.normal);
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ep.dist = DotProduct (p1, ep.normal);
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for (i = 0; i < winding->numpoints; i++) {
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vec_t t, te, vn;
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const vec_t *r = winding->points[i];
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const vec_t *v = edges->points[i];
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vec3_t x, y, z;
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vn = DotProduct (v, ep.normal);
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if (!vn) // FIXME epsilon
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continue; // portal edge is parallel to the plane
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t = PlaneDiff (r, &ep);
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if (t < 0 || t > vn)
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continue; // portal edge does not reach the plane
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// impact point of portal edge with the plane
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VectorMultSub (r, t / vn, v, x);
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// project the impact point back to the edge along the velocity
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VectorSubtract (x, p1, y);
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t = DotProduct (y, vel) / DotProduct (vel, vel);
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VectorMultSub (x, t, vel, y);
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if (t >= frac)
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continue; // this is not the nearest edge pair
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// check projected impact point's position along the edge
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VectorSubtract (y, p1, z);
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te = DotProduct (z, e);
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if (te < 0 || te > ee)
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continue; // the edge misses the portal edge
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// the edges hit, and they are the closes edge pair so far
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frac = t;
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}
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return frac;
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}
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}
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static vec_t
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box_portal_dist (const hull_t *hull, const clipport_t *portal,
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const clipbox_t *box, const vec3_t start, const vec3_t vel)
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{
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vec3_t nvel;
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plane_t *plane = hull->planes + portal->planenum;
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int i, j;
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vec_t frac, t;
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vec3_t p1, p2;
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for (i = 0; i < 3; i++) {
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// all faces on box have 4 points (and edges), but we need test only
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// three on each face
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for (j = 0; j < 3; j++) {
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VectorAdd (box->points->points[j], start, p1);
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VectorAdd (box->points->points[j + 1], start, p2);
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t = edge_portal_dist (plane, portal, p1, p2, vel);
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if (t < frac)
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frac = t;
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}
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}
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VectorNegate (vel, nvel);
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for (i = 0; i < portal->winding->numpoints; i++) {
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j = i + 1;
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if (j >= portal->winding->numpoints)
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j -= portal->winding->numpoints;
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VectorSubtract (portal->winding->points[i], start, p1);
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VectorSubtract (portal->winding->points[j], start, p2);
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for (j = 0; j < 3; j++) {
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const clipport_t *p = &box->portals[j];
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t = edge_portal_dist (box->planes + p->planenum, p, p1, p2, nvel);
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if (t < frac)
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frac = t;
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}
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}
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return frac;
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}
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static inline void
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static inline void
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calc_impact (trace_t *trace, const vec3_t start, const vec3_t end,
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calc_impact (hull_t *hull, trace_t *trace,
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plane_t *plane)
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const vec3_t start, const vec3_t end,
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clipleaf_t *leaf, plane_t *plane)
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{
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{
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vec_t t1, t2, frac, offset;
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vec_t t1, t2, frac, offset;
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vec3_t dist;
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vec3_t dist;
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@ -151,6 +374,53 @@ calc_impact (trace_t *trace, const vec3_t start, const vec3_t end,
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frac = (t1 - offset - DIST_EPSILON) / (t1 - t2);
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frac = (t1 - offset - DIST_EPSILON) / (t1 - t2);
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}
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}
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frac = bound (0, frac, 1);
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frac = bound (0, frac, 1);
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if (leaf && trace->type != tr_point) {
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int i;
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int side;
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int planenum;
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clipport_t *portal;
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vec3_t impact;
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clipbox_t box;
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planenum = plane - hull->planes;
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VectorSubtract (end, start, dist);
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VectorMultAdd (start, frac, dist, impact);
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if (DotProduct (dist, plane->normal) > 0)
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VectorMultAdd (impact, offset, plane->normal, impact);
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else
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VectorMultSub (impact, offset, plane->normal, impact);
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init_box (trace, &box, dist);
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for (portal = leaf->portals; portal; portal = portal->next[side]) {
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side = portal->leafs[1] == leaf;
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if (portal->planenum != planenum)
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continue;
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for (i = 0; i < portal->winding->numpoints; i++) {
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vec3_t r, s;
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VectorSubtract (impact, portal->winding->points[i], r);
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CrossProduct (r, portal->edges->points[i], s);
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if (DotProduct (s, plane->normal) <= 0)
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continue; // "hit"
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break; // "miss";
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}
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if (i == portal->winding->numpoints)
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goto finish_impact; // impact with the face of the polygon
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}
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for (portal = leaf->portals; portal; portal = portal->next[side]) {
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vec_t t;
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side = portal->leafs[1] == leaf;
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if (portal->planenum != planenum)
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continue;
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t = box_portal_dist (hull, portal, &box, start, dist);
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if (t < frac)
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frac = t;
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}
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}
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finish_impact:
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if (frac < trace->fraction) {
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if (frac < trace->fraction) {
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trace->fraction = frac;
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trace->fraction = frac;
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VectorSubtract (end, start, dist);
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VectorSubtract (end, start, dist);
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@ -221,7 +491,8 @@ MOD_TraceLine (hull_t *hull, int num,
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} else {
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} else {
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// crossing from an empty leaf to a solid leaf: the trace
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// crossing from an empty leaf to a solid leaf: the trace
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// has collided.
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// has collided.
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calc_impact (trace, start_point, end_point, split_plane);
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calc_impact (hull, trace, start_point, end_point, leaf,
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split_plane);
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if (trace->type == tr_point)
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if (trace->type == tr_point)
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return;
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return;
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}
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}
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