// SONIC ROBO BLAST 2 //----------------------------------------------------------------------------- // Copyright (C) 2004 by Stephen McGranahan // Copyright (C) 2015-2016 by Sonic Team Junior. // // This program is free software distributed under the // terms of the GNU General Public License, version 2. // See the 'LICENSE' file for more details. //----------------------------------------------------------------------------- /// \file p_slopes.c /// \brief ZDoom + Eternity Engine Slopes, ported and enhanced by Kalaron #include "doomdef.h" #include "r_defs.h" #include "r_state.h" #include "m_bbox.h" #include "z_zone.h" #include "p_local.h" #include "p_spec.h" #include "p_slopes.h" #include "p_setup.h" #include "r_main.h" #include "p_maputl.h" #include "w_wad.h" #ifdef ESLOPE static pslope_t *slopelist = NULL; static UINT16 slopecount = 0; // Calculate line normal static void P_CalculateSlopeNormal(pslope_t *slope) { slope->normal.z = FINECOSINE(slope->zangle>>ANGLETOFINESHIFT); slope->normal.x = -FixedMul(FINESINE(slope->zangle>>ANGLETOFINESHIFT), slope->d.x); slope->normal.y = -FixedMul(FINESINE(slope->zangle>>ANGLETOFINESHIFT), slope->d.y); } // With a vertex slope that has its vertices set, configure relevant slope info static void P_ReconfigureVertexSlope(pslope_t *slope) { vector3_t vec1, vec2; // Set slope normal vec1.x = (slope->vertices[1]->x - slope->vertices[0]->x) << FRACBITS; vec1.y = (slope->vertices[1]->y - slope->vertices[0]->y) << FRACBITS; vec1.z = (slope->vertices[1]->z - slope->vertices[0]->z) << FRACBITS; vec2.x = (slope->vertices[2]->x - slope->vertices[0]->x) << FRACBITS; vec2.y = (slope->vertices[2]->y - slope->vertices[0]->y) << FRACBITS; vec2.z = (slope->vertices[2]->z - slope->vertices[0]->z) << FRACBITS; // ugggggggh fixed-point maaaaaaath slope->extent = max( max(max(abs(vec1.x), abs(vec1.y)), abs(vec1.z)), max(max(abs(vec2.x), abs(vec2.y)), abs(vec2.z)) ) >> (FRACBITS+5); vec1.x /= slope->extent; vec1.y /= slope->extent; vec1.z /= slope->extent; vec2.x /= slope->extent; vec2.y /= slope->extent; vec2.z /= slope->extent; FV3_Cross(&vec1, &vec2, &slope->normal); slope->extent = R_PointToDist2(0, 0, R_PointToDist2(0, 0, slope->normal.x, slope->normal.y), slope->normal.z); if (slope->normal.z < 0) slope->extent = -slope->extent; slope->normal.x = FixedDiv(slope->normal.x, slope->extent); slope->normal.y = FixedDiv(slope->normal.y, slope->extent); slope->normal.z = FixedDiv(slope->normal.z, slope->extent); // Set origin slope->o.x = slope->vertices[0]->x << FRACBITS; slope->o.y = slope->vertices[0]->y << FRACBITS; slope->o.z = slope->vertices[0]->z << FRACBITS; if (slope->normal.x == 0 && slope->normal.y == 0) { // Set some defaults for a non-sloped "slope" slope->zangle = slope->xydirection = 0; slope->zdelta = slope->d.x = slope->d.y = 0; } else { // Get direction vector slope->extent = R_PointToDist2(0, 0, slope->normal.x, slope->normal.y); slope->d.x = -FixedDiv(slope->normal.x, slope->extent); slope->d.y = -FixedDiv(slope->normal.y, slope->extent); // Z delta slope->zdelta = FixedDiv(slope->extent, slope->normal.z); // Get angles slope->xydirection = R_PointToAngle2(0, 0, slope->d.x, slope->d.y)+ANGLE_180; slope->zangle = InvAngle(R_PointToAngle2(0, 0, FRACUNIT, slope->zdelta)); } } // Recalculate dynamic slopes void P_RunDynamicSlopes(void) { pslope_t *slope; for (slope = slopelist; slope; slope = slope->next) { fixed_t zdelta; if (slope->flags & SL_NODYNAMIC) continue; switch(slope->refpos) { case 1: // front floor zdelta = slope->sourceline->backsector->floorheight - slope->sourceline->frontsector->floorheight; slope->o.z = slope->sourceline->frontsector->floorheight; break; case 2: // front ceiling zdelta = slope->sourceline->backsector->ceilingheight - slope->sourceline->frontsector->ceilingheight; slope->o.z = slope->sourceline->frontsector->ceilingheight; break; case 3: // back floor zdelta = slope->sourceline->frontsector->floorheight - slope->sourceline->backsector->floorheight; slope->o.z = slope->sourceline->backsector->floorheight; break; case 4: // back ceiling zdelta = slope->sourceline->frontsector->ceilingheight - slope->sourceline->backsector->ceilingheight; slope->o.z = slope->sourceline->backsector->ceilingheight; break; case 5: // vertices { mapthing_t *mt; size_t i; INT32 l; line_t *line; for (i = 0; i < 3; i++) { mt = slope->vertices[i]; l = P_FindSpecialLineFromTag(799, mt->angle, -1); if (l != -1) { line = &lines[l]; mt->z = line->frontsector->floorheight >> FRACBITS; } } P_ReconfigureVertexSlope(slope); } continue; // TODO default: I_Error("P_RunDynamicSlopes: slope has invalid type!"); } if (slope->zdelta != FixedDiv(zdelta, slope->extent)) { slope->zdelta = FixedDiv(zdelta, slope->extent); slope->zangle = R_PointToAngle2(0, 0, slope->extent, -zdelta); P_CalculateSlopeNormal(slope); } } } // // P_MakeSlope // // Alocates and fill the contents of a slope structure. // static pslope_t *P_MakeSlope(const vector3_t *o, const vector2_t *d, const fixed_t zdelta, UINT8 flags) { pslope_t *ret = Z_Malloc(sizeof(pslope_t), PU_LEVEL, NULL); memset(ret, 0, sizeof(*ret)); ret->o.x = o->x; ret->o.y = o->y; ret->o.z = o->z; ret->d.x = d->x; ret->d.y = d->y; ret->zdelta = zdelta; ret->flags = flags; // Add to the slope list ret->next = slopelist; slopelist = ret; slopecount++; ret->id = slopecount; return ret; } // // P_GetExtent // // Returns the distance to the first line within the sector that // is intersected by a line parallel to the plane normal with the point (ox, oy) // static fixed_t P_GetExtent(sector_t *sector, line_t *line) { // ZDoom code reference: v3float_t = vertex_t fixed_t fardist = -FRACUNIT; size_t i; // Find furthest vertex from the reference line. It, along with the two ends // of the line, will define the plane. for(i = 0; i < sector->linecount; i++) { line_t *li = sector->lines[i]; vertex_t tempv; fixed_t dist; // Don't compare to the slope line. if(li == line) continue; P_ClosestPointOnLine(li->v1->x, li->v1->y, line, &tempv); dist = R_PointToDist2(tempv.x, tempv.y, li->v1->x, li->v1->y); if(dist > fardist) fardist = dist; // Okay, maybe do it for v2 as well? P_ClosestPointOnLine(li->v2->x, li->v2->y, line, &tempv); dist = R_PointToDist2(tempv.x, tempv.y, li->v2->x, li->v2->y); if(dist > fardist) fardist = dist; } return fardist; } // // P_SpawnSlope_Line // // Creates one or more slopes based on the given line type and front/back // sectors. // void P_SpawnSlope_Line(int linenum) { // With dynamic slopes, it's fine to just leave this function as normal, // because checking to see if a slope had changed will waste more memory than // if the slope was just updated when called line_t *line = lines + linenum; INT16 special = line->special; pslope_t *fslope = NULL, *cslope = NULL; vector3_t origin, point; vector2_t direction; fixed_t nx, ny, dz, extent; boolean frontfloor = (special == 700 || special == 702 || special == 703); boolean backfloor = (special == 710 || special == 712 || special == 713); boolean frontceil = (special == 701 || special == 702 || special == 713); boolean backceil = (special == 711 || special == 712 || special == 703); UINT8 flags = 0; // Slope flags if (line->flags & ML_NOSONIC) flags |= SL_NOPHYSICS; if (!(line->flags & ML_NOTAILS)) flags |= SL_NODYNAMIC; if (line->flags & ML_NOKNUX) flags |= SL_ANCHORVERTEX; if(!frontfloor && !backfloor && !frontceil && !backceil) { CONS_Printf("P_SpawnSlope_Line called with non-slope line special.\n"); return; } if(!line->frontsector || !line->backsector) { CONS_Printf("P_SpawnSlope_Line used on a line without two sides.\n"); return; } { fixed_t len = R_PointToDist2(0, 0, line->dx, line->dy); nx = FixedDiv(line->dy, len); ny = -FixedDiv(line->dx, len); } origin.x = line->v1->x + (line->v2->x - line->v1->x)/2; origin.y = line->v1->y + (line->v2->y - line->v1->y)/2; // For FOF slopes, make a special function to copy to the xy origin & direction relative to the position of the FOF on the map! if(frontfloor || frontceil) { line->frontsector->hasslope = true; // Tell the software renderer that we're sloped origin.z = line->backsector->floorheight; direction.x = nx; direction.y = ny; extent = P_GetExtent(line->frontsector, line); if(extent < 0) { CONS_Printf("P_SpawnSlope_Line failed to get frontsector extent on line number %i\n", linenum); return; } // reposition the origin according to the extent point.x = origin.x + FixedMul(direction.x, extent); point.y = origin.y + FixedMul(direction.y, extent); direction.x = -direction.x; direction.y = -direction.y; // TODO: We take origin and point 's xy values and translate them to the center of an FOF! if(frontfloor) { fixed_t highest, lowest; size_t l; point.z = line->frontsector->floorheight; // Startz dz = FixedDiv(origin.z - point.z, extent); // Destinationz // In P_SpawnSlopeLine the origin is the centerpoint of the sourcelinedef fslope = line->frontsector->f_slope = P_MakeSlope(&point, &direction, dz, flags); // Set up some shit fslope->extent = extent; fslope->refpos = 1; // Now remember that f_slope IS a vector // fslope->o = origin 3D point 1 of the vector // fslope->d = destination 3D point 2 of the vector // fslope->normal is a 3D line perpendicular to the 3D vector // Sync the linedata of the line that started this slope // TODO: Anything special for control sector based slopes later? fslope->sourceline = line; // To find the real highz/lowz of a slope, you need to check all the vertexes // in the slope's sector with P_GetZAt to get the REAL lowz & highz // Although these slopes are set by floorheights the ANGLE is what a slope is, // so technically any slope can extend on forever (they are just bound by sectors) // *You can use sourceline as a reference to see if two slopes really are the same // Default points for high and low highest = point.z > origin.z ? point.z : origin.z; lowest = point.z < origin.z ? point.z : origin.z; // Now check to see what the REAL high and low points of the slope inside the sector // TODO: Is this really needed outside of FOFs? -Red for (l = 0; l < line->frontsector->linecount; l++) { fixed_t height = P_GetZAt(line->frontsector->f_slope, line->frontsector->lines[l]->v1->x, line->frontsector->lines[l]->v1->y); if (height > highest) highest = height; if (height < lowest) lowest = height; } // Sets extra clipping data for the frontsector's slope fslope->highz = highest; fslope->lowz = lowest; fslope->zangle = R_PointToAngle2(0, origin.z, extent, point.z); fslope->xydirection = R_PointToAngle2(origin.x, origin.y, point.x, point.y); P_CalculateSlopeNormal(fslope); } if(frontceil) { fixed_t highest, lowest; size_t l; origin.z = line->backsector->ceilingheight; point.z = line->frontsector->ceilingheight; dz = FixedDiv(origin.z - point.z, extent); cslope = line->frontsector->c_slope = P_MakeSlope(&point, &direction, dz, flags); // Set up some shit cslope->extent = extent; cslope->refpos = 2; // Sync the linedata of the line that started this slope // TODO: Anything special for control sector based slopes later? cslope->sourceline = line; // Remember the way the slope is formed highest = point.z > origin.z ? point.z : origin.z; lowest = point.z < origin.z ? point.z : origin.z; for (l = 0; l < line->frontsector->linecount; l++) { fixed_t height = P_GetZAt(line->frontsector->c_slope, line->frontsector->lines[l]->v1->x, line->frontsector->lines[l]->v1->y); if (height > highest) highest = height; if (height < lowest) lowest = height; } // This line special sets extra clipping data for the frontsector's slope cslope->highz = highest; cslope->lowz = lowest; cslope->zangle = R_PointToAngle2(0, origin.z, extent, point.z); cslope->xydirection = R_PointToAngle2(origin.x, origin.y, point.x, point.y); P_CalculateSlopeNormal(cslope); } } if(backfloor || backceil) { line->backsector->hasslope = true; // Tell the software renderer that we're sloped origin.z = line->frontsector->floorheight; // Backsector direction.x = -nx; direction.y = -ny; extent = P_GetExtent(line->backsector, line); if(extent < 0) { CONS_Printf("P_SpawnSlope_Line failed to get backsector extent on line number %i\n", linenum); return; } // reposition the origin according to the extent point.x = origin.x + FixedMul(direction.x, extent); point.y = origin.y + FixedMul(direction.y, extent); direction.x = -direction.x; direction.y = -direction.y; if(backfloor) { fixed_t highest, lowest; size_t l; point.z = line->backsector->floorheight; dz = FixedDiv(origin.z - point.z, extent); fslope = line->backsector->f_slope = P_MakeSlope(&point, &direction, dz, flags); // Set up some shit fslope->extent = extent; fslope->refpos = 3; // Sync the linedata of the line that started this slope // TODO: Anything special for control sector based slopes later? fslope->sourceline = line; // Remember the way the slope is formed highest = point.z > origin.z ? point.z : origin.z; lowest = point.z < origin.z ? point.z : origin.z; for (l = 0; l < line->backsector->linecount; l++) { fixed_t height = P_GetZAt(line->backsector->f_slope, line->backsector->lines[l]->v1->x, line->backsector->lines[l]->v1->y); if (height > highest) highest = height; if (height < lowest) lowest = height; } // This line special sets extra clipping data for the frontsector's slope fslope->highz = highest; fslope->lowz = lowest; fslope->zangle = R_PointToAngle2(0, origin.z, extent, point.z); fslope->xydirection = R_PointToAngle2(origin.x, origin.y, point.x, point.y); P_CalculateSlopeNormal(fslope); } if(backceil) { fixed_t highest, lowest; size_t l; origin.z = line->frontsector->ceilingheight; point.z = line->backsector->ceilingheight; dz = FixedDiv(origin.z - point.z, extent); cslope = line->backsector->c_slope = P_MakeSlope(&point, &direction, dz, flags); // Set up some shit cslope->extent = extent; cslope->refpos = 4; // Sync the linedata of the line that started this slope // TODO: Anything special for control sector based slopes later? cslope->sourceline = line; // Remember the way the slope is formed highest = point.z > origin.z ? point.z : origin.z; lowest = point.z < origin.z ? point.z : origin.z; for (l = 0; l < line->backsector->linecount; l++) { fixed_t height = P_GetZAt(line->backsector->c_slope, line->backsector->lines[l]->v1->x, line->backsector->lines[l]->v1->y); if (height > highest) highest = height; if (height < lowest) lowest = height; } // This line special sets extra clipping data for the backsector's slope cslope->highz = highest; cslope->lowz = lowest; cslope->zangle = R_PointToAngle2(0, origin.z, extent, point.z); cslope->xydirection = R_PointToAngle2(origin.x, origin.y, point.x, point.y); P_CalculateSlopeNormal(cslope); } } if(!line->tag) return; } // // P_NewVertexSlope // // Creates a new slope from three vertices with the specified IDs // static pslope_t *P_NewVertexSlope(INT16 tag1, INT16 tag2, INT16 tag3, UINT8 flags) { size_t i; mapthing_t *mt = mapthings; pslope_t *ret = Z_Malloc(sizeof(pslope_t), PU_LEVEL, NULL); memset(ret, 0, sizeof(*ret)); // Start by setting flags ret->flags = flags; // Now set up the vertex list ret->vertices = Z_Malloc(3*sizeof(mapthing_t), PU_LEVEL, NULL); memset(ret->vertices, 0, 3*sizeof(mapthing_t)); // And... look for the vertices in question. for (i = 0; i < nummapthings; i++, mt++) { if (mt->type != 750) // Haha, I'm hijacking the old Chaos Spawn thingtype for something! continue; if (!ret->vertices[0] && mt->angle == tag1) ret->vertices[0] = mt; else if (!ret->vertices[1] && mt->angle == tag2) ret->vertices[1] = mt; else if (!ret->vertices[2] && mt->angle == tag3) ret->vertices[2] = mt; } // Now set heights for each vertex, because they haven't been set yet for (i = 0; i < 3; i++) { mt = ret->vertices[i]; if (!mt) // If a vertex wasn't found, it's game over. There's nothing you can do to recover (except maybe try and kill the slope instead - TODO?) I_Error("P_NewVertexSlope: Slope vertex %s (for linedef tag %d) not found!", sizeu1(i), tag1); if (mt->extrainfo) mt->z = mt->options; else mt->z = (R_PointInSubsector(mt->x << FRACBITS, mt->y << FRACBITS)->sector->floorheight >> FRACBITS) + (mt->options >> ZSHIFT); } P_ReconfigureVertexSlope(ret); ret->refpos = 5; // Add to the slope list ret->next = slopelist; slopelist = ret; slopecount++; ret->id = slopecount; return ret; } // // P_CopySectorSlope // // Searches through tagged sectors and copies // void P_CopySectorSlope(line_t *line) { sector_t *fsec = line->frontsector; int i, special = line->special; // Check for copy linedefs for(i = -1; (i = P_FindSectorFromLineTag(line, i)) >= 0;) { sector_t *srcsec = sectors + i; if((special - 719) & 1 && !fsec->f_slope && srcsec->f_slope) fsec->f_slope = srcsec->f_slope; //P_CopySlope(srcsec->f_slope); if((special - 719) & 2 && !fsec->c_slope && srcsec->c_slope) fsec->c_slope = srcsec->c_slope; //P_CopySlope(srcsec->c_slope); } fsec->hasslope = true; line->special = 0; // Linedef was use to set slopes, it finished its job, so now make it a normal linedef } // // P_SlopeById // // Looks in the slope list for a slope with a specified ID. Mostly useful for netgame sync // pslope_t *P_SlopeById(UINT16 id) { pslope_t *ret; for (ret = slopelist; ret && ret->id != id; ret = ret->next); return ret; } // Reset the dynamic slopes pointer, and read all of the fancy schmancy slopes void P_ResetDynamicSlopes(void) { size_t i; #ifdef ESLOPE_TYPESHIM // Rewrite old specials to new ones, and give a console warning boolean warned = false; #endif slopelist = NULL; slopecount = 0; // We'll handle copy slopes later, after all the tag lists have been made. // Yes, this means copied slopes won't affect things' spawning heights. Too bad for you. for (i = 0; i < numlines; i++) { switch (lines[i].special) { #ifdef ESLOPE_TYPESHIM // Rewrite old specials to new ones, and give a console warning #define WARNME if (!warned) {warned = true; CONS_Alert(CONS_WARNING, "This level uses old slope specials.\nA conversion will be needed before 2.2's release.\n");} case 386: case 387: case 388: lines[i].special += 700-386; WARNME P_SpawnSlope_Line(i); break; case 389: case 390: case 391: case 392: lines[i].special += 710-389; WARNME P_SpawnSlope_Line(i); break; case 393: lines[i].special = 703; WARNME P_SpawnSlope_Line(i); break; case 394: case 395: case 396: lines[i].special += 720-394; WARNME break; #endif case 700: case 701: case 702: case 703: case 710: case 711: case 712: case 713: P_SpawnSlope_Line(i); break; case 704: case 705: case 714: case 715: { pslope_t **slopetoset; size_t which = lines[i].special; UINT8 flags = SL_VERTEXSLOPE; if (lines[i].flags & ML_NOSONIC) flags |= SL_NOPHYSICS; if (!(lines[i].flags & ML_NOTAILS)) flags |= SL_NODYNAMIC; if (which == 704) { slopetoset = &lines[i].frontsector->f_slope; which = 0; } else if (which == 705) { slopetoset = &lines[i].frontsector->c_slope; which = 0; } else if (which == 714) { slopetoset = &lines[i].backsector->f_slope; which = 1; } else // 715 { slopetoset = &lines[i].backsector->c_slope; which = 1; } if (lines[i].flags & ML_NOKNUX) *slopetoset = P_NewVertexSlope(lines[i].tag, sides[lines[i].sidenum[which]].textureoffset >> FRACBITS, sides[lines[i].sidenum[which]].rowoffset >> FRACBITS, flags); else *slopetoset = P_NewVertexSlope(lines[i].tag, lines[i].tag, lines[i].tag, flags); sides[lines[i].sidenum[which]].sector->hasslope = true; } break; default: break; } } } // ============================================================================ // // Various utilities related to slopes // // // P_GetZAt // // Returns the height of the sloped plane at (x, y) as a fixed_t // fixed_t P_GetZAt(pslope_t *slope, fixed_t x, fixed_t y) { fixed_t dist = FixedMul(x - slope->o.x, slope->d.x) + FixedMul(y - slope->o.y, slope->d.y); return slope->o.z + FixedMul(dist, slope->zdelta); } // // P_QuantizeMomentumToSlope // // When given a vector, rotates it and aligns it to a slope void P_QuantizeMomentumToSlope(vector3_t *momentum, pslope_t *slope) { vector3_t axis; // Fuck you, C90. if (slope->flags & SL_NOPHYSICS) return; // No physics, no quantizing. axis.x = -slope->d.y; axis.y = slope->d.x; axis.z = 0; FV3_Rotate(momentum, &axis, slope->zangle >> ANGLETOFINESHIFT); } // // P_ReverseQuantizeMomentumToSlope // // When given a vector, rotates and aligns it to a flat surface (from being relative to a given slope) void P_ReverseQuantizeMomentumToSlope(vector3_t *momentum, pslope_t *slope) { slope->zangle = InvAngle(slope->zangle); P_QuantizeMomentumToSlope(momentum, slope); slope->zangle = InvAngle(slope->zangle); } // // P_SlopeLaunch // // Handles slope ejection for objects void P_SlopeLaunch(mobj_t *mo) { if (!(mo->standingslope->flags & SL_NOPHYSICS)) // If there's physics, time for launching. { // Double the pre-rotation Z, then halve the post-rotation Z. This reduces the // vertical launch given from slopes while increasing the horizontal launch // given. Good for SRB2's gravity and horizontal speeds. vector3_t slopemom; slopemom.x = mo->momx; slopemom.y = mo->momy; slopemom.z = mo->momz*2; P_QuantizeMomentumToSlope(&slopemom, mo->standingslope); mo->momx = slopemom.x; mo->momy = slopemom.y; mo->momz = slopemom.z/2; } //CONS_Printf("Launched off of slope.\n"); mo->standingslope = NULL; } // // P_GetWallTransferMomZ // // It would be nice to have a single function that does everything necessary for slope-to-wall transfer. // However, it needs to be seperated out in P_XYMovement to take into account momentum before and after hitting the wall. // This just performs the necessary calculations for getting the base vertical momentum; the horizontal is already reasonably calculated by P_SlideMove. fixed_t P_GetWallTransferMomZ(mobj_t *mo, pslope_t *slope) { vector3_t slopemom, axis; angle_t ang; if (mo->standingslope->flags & SL_NOPHYSICS) return 0; // If there's physics, time for launching. // Doesn't kill the vertical momentum as much as P_SlopeLaunch does. ang = slope->zangle + ANG15*((slope->zangle > 0) ? 1 : -1); if (ang > ANGLE_90 && ang < ANGLE_180) ang = ((slope->zangle > 0) ? ANGLE_90 : InvAngle(ANGLE_90)); // hard cap of directly upwards slopemom.x = mo->momx; slopemom.y = mo->momy; slopemom.z = 3*(mo->momz/2); axis.x = -slope->d.y; axis.y = slope->d.x; axis.z = 0; FV3_Rotate(&slopemom, &axis, ang >> ANGLETOFINESHIFT); return 2*(slopemom.z/3); } // Function to help handle landing on slopes void P_HandleSlopeLanding(mobj_t *thing, pslope_t *slope) { vector3_t mom; // Ditto. if (slope->flags & SL_NOPHYSICS) { // No physics, no need to make anything complicated. if (P_MobjFlip(thing)*(thing->momz) < 0) { // falling, land on slope thing->momz = -P_MobjFlip(thing); thing->standingslope = slope; } return; } mom.x = thing->momx; mom.y = thing->momy; mom.z = thing->momz*2; P_ReverseQuantizeMomentumToSlope(&mom, slope); if (P_MobjFlip(thing)*mom.z < 0) { // falling, land on slope thing->momx = mom.x; thing->momy = mom.y; thing->momz = -P_MobjFlip(thing); thing->standingslope = slope; } } // https://yourlogicalfallacyis.com/slippery-slope // Handles sliding down slopes, like if they were made of butter :) void P_ButteredSlope(mobj_t *mo) { fixed_t thrust; if (!mo->standingslope) return; if (mo->standingslope->flags & SL_NOPHYSICS) return; // No physics, no butter. if (mo->flags & (MF_NOCLIPHEIGHT|MF_NOGRAVITY)) return; // don't slide down slopes if you can't touch them or you're not affected by gravity if (mo->player) { if (abs(mo->standingslope->zdelta) < FRACUNIT/4 && !(mo->player->pflags & PF_SPINNING)) return; // Don't slide on non-steep slopes unless spinning if (abs(mo->standingslope->zdelta) < FRACUNIT/2 && !(mo->player->rmomx || mo->player->rmomy)) return; // Allow the player to stand still on slopes below a certain steepness } thrust = FINESINE(mo->standingslope->zangle>>ANGLETOFINESHIFT) * 3 / 2 * (mo->eflags & MFE_VERTICALFLIP ? 1 : -1); if (mo->player && (mo->player->pflags & PF_SPINNING)) { fixed_t mult = 0; if (mo->momx || mo->momy) { angle_t angle = R_PointToAngle2(0, 0, mo->momx, mo->momy) - mo->standingslope->xydirection; if (P_MobjFlip(mo) * mo->standingslope->zdelta < 0) angle ^= ANGLE_180; mult = FINECOSINE(angle >> ANGLETOFINESHIFT); } thrust = FixedMul(thrust, FRACUNIT*2/3 + mult/8); } if (mo->momx || mo->momy) // Slightly increase thrust based on the object's speed thrust = FixedMul(thrust, FRACUNIT+P_AproxDistance(mo->momx, mo->momy)/16); // This makes it harder to zigzag up steep slopes, as well as allows greater top speed when rolling down // Let's get the gravity strength for the object... thrust = FixedMul(thrust, abs(P_GetMobjGravity(mo))); // ... and its friction against the ground for good measure (divided by original friction to keep behaviour for normal slopes the same). thrust = FixedMul(thrust, FixedDiv(mo->friction, ORIG_FRICTION)); P_Thrust(mo, mo->standingslope->xydirection, thrust); } // EOF #endif // #ifdef ESLOPE