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ericw-tools/light/trace.cc

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/* Copyright (C) 1996-1997 Id Software, Inc.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
See file, 'COPYING', for details.
*/
#include <light/light.hh>
#include <light/trace.hh>
#include <light/ltface.hh>
#include <common/bsputils.hh>
#ifdef HAVE_EMBREE
#include <light/trace_embree.hh>
#endif
#include <cassert>
#define TRACE_HIT_NONE 0
#define TRACE_HIT_SOLID (1 << 0)
#define TRACE_HIT_WATER (1 << 1)
#define TRACE_HIT_SLIME (1 << 2)
#define TRACE_HIT_LAVA (1 << 3)
#define TRACE_HIT_SKY (1 << 4)
typedef struct traceinfo_s {
vec3_t point;
const bsp2_dface_t *face;
plane_t hitplane;
/* returns true if sky was hit. */
bool hitsky;
bool hitback;
// internal
vec3_t dir;
} traceinfo_t;
/* Stopped by solid and sky */
static bool TraceFaces (traceinfo_t *ti, int node, const vec3_t start, const vec3_t end);
/*
* ---------
* TraceLine
* ---------
* Generic BSP model ray tracing function. Traces a ray from start towards
* stop. If the trace line hits one of the flagged contents along the way, the
* corresponding TRACE flag will be returned.
*
* model - The bsp model to trace against
* flags - contents which will stop the trace (must be > 0)
* start - coordinates to start trace
* stop - coordinates to end the trace
*
* TraceLine will return a negative traceflag if the point 'start' resides
* inside a leaf with one of the contents types which stop the trace.
*
* ericw -- note, this should only be used for testing occlusion.
* the hitpoint is not accurate, imagine a solid cube floating in a room,
* only one of the 6 sides will be a node with a solid leaf child.
* Yet, which side is the node with the solid leaf child determines
* what the hit point will be.
*/
static int TraceLine(const dmodel_t *model, const int traceflags,
const vec3_t start, const vec3_t end);
typedef struct tnode_s {
vec3_t normal;
vec_t dist;
int type;
int children[2];
const dplane_t *plane;
const mleaf_t *childleafs[2];
const bsp2_dnode_t *node;
} tnode_t;
typedef struct faceinfo_s {
int numedges;
plane_t *edgeplanes;
// sphere culling
vec3_t origin;
vec_t radiusSquared;
int content;
plane_t plane;
const char *texturename;
const bsp2_dface_t *face;
} faceinfo_t;
static tnode_t *tnodes;
static const mbsp_t *bsp_static;
static faceinfo_t *faceinfos;
static bool *fence_dmodels; // bsp_static->nummodels bools, true if model contains a fence texture
// from hmap2
#define PlaneDiff(point,plane) (((plane)->type < 3 ? (point)[(plane)->type] : DotProduct((point), (plane)->normal)) - (plane)->dist)
/*
==============
Light_PointInLeaf
from hmap2
==============
*/
const mleaf_t *
Light_PointInLeaf( const mbsp_t *bsp, const vec3_t point )
{
int num = 0;
while( num >= 0 )
num = bsp->dnodes[num].children[PlaneDiff(point, &bsp->dplanes[bsp->dnodes[num].planenum]) < 0];
return bsp->dleafs + (-1 - num);
}
/*
==============
Light_PointContents
from hmap2
==============
*/
int Light_PointContents( const mbsp_t *bsp, const vec3_t point )
{
return Light_PointInLeaf(bsp, point)->contents;
}
/*
* ==============
* MakeTnodes
* Converts the disk node structure into the efficient tracing structure
* ==============
*/
static void
MakeTnodes_r(int nodenum, const mbsp_t *bsp)
{
tnode_t *tnode;
int i;
bsp2_dnode_t *node;
mleaf_t *leaf;
Q_assert(nodenum >= 0);
Q_assert(nodenum < bsp->numnodes);
tnode = &tnodes[nodenum];
node = bsp->dnodes + nodenum;
tnode->plane = bsp->dplanes + node->planenum;
tnode->node = node;
tnode->type = tnode->plane->type;
VectorCopy(tnode->plane->normal, tnode->normal);
tnode->dist = tnode->plane->dist;
for (i = 0; i < 2; i++) {
int childnum = node->children[i];
if (childnum < 0) {
leaf = &bsp->dleafs[-childnum - 1];
tnode->children[i] = leaf->contents;
tnode->childleafs[i] = leaf;
} else {
tnode->children[i] = childnum;
MakeTnodes_r(childnum, bsp);
}
}
}
static inline bool SphereCullPoint(const faceinfo_t *info, const vec3_t point)
{
vec3_t delta;
vec_t deltaLengthSquared;
VectorSubtract(point, info->origin, delta);
deltaLengthSquared = DotProduct(delta, delta);
return deltaLengthSquared > info->radiusSquared;
}
static void
MakeFaceInfo(const mbsp_t *bsp, const bsp2_dface_t *face, faceinfo_t *info)
{
info->face = face;
info->numedges = face->numedges;
info->edgeplanes = Face_AllocInwardFacingEdgePlanes(bsp, face);
info->plane = Face_Plane(bsp, face);
// make sphere that bounds the face
vec3_t centroid = {0,0,0};
for (int i=0; i<face->numedges; i++)
{
const vec_t *v = GetSurfaceVertexPoint(bsp, face, i);
VectorAdd(centroid, v, centroid);
}
VectorScale(centroid, 1.0f/face->numedges, centroid);
VectorCopy(centroid, info->origin);
// calculate radius
vec_t maxRadiusSq = 0;
for (int i=0; i<face->numedges; i++)
{
vec3_t delta;
vec_t radiusSq;
const vec_t *v = GetSurfaceVertexPoint(bsp, face, i);
VectorSubtract(v, centroid, delta);
radiusSq = DotProduct(delta, delta);
if (radiusSq > maxRadiusSq)
maxRadiusSq = radiusSq;
}
info->radiusSquared = maxRadiusSq;
info->content = Face_Contents(bsp, face);
info->texturename = Face_TextureName(bsp, face);
#if 0
//test
for (int i=0; i<face->numedges; i++)
{
const vec_t *v = GetSurfaceVertexPoint(bsp, face, i);
Q_assert(!SphereCullPoint(info, v));
}
//test
{
vec_t radius = sqrt(maxRadiusSq);
radius ++;
vec3_t test;
vec3_t n = {1, 0, 0};
VectorMA(centroid, radius, n, test);
Q_assert(SphereCullPoint(info, test));
}
#endif
}
static bool
Model_HasFence(const mbsp_t *bsp, const dmodel_t *model)
{
for (int j = model->firstface; j < model->firstface + model->numfaces; j++) {
const bsp2_dface_t *face = BSP_GetFace(bsp, j);
if (Face_TextureName(bsp, face)[0] == '{') {
return true;
}
}
return false;
}
static void
MakeFenceInfo(const mbsp_t *bsp)
{
fence_dmodels = (bool *) calloc(bsp->nummodels, sizeof(bool));
for (int i = 0; i < bsp->nummodels; i++) {
fence_dmodels[i] = Model_HasFence(bsp, &bsp->dmodels[i]);
}
}
static void
BSP_MakeTnodes(const mbsp_t *bsp)
{
bsp_static = bsp;
tnodes = (tnode_t *) malloc(bsp->numnodes * sizeof(tnode_t));
for (int i = 0; i < bsp->nummodels; i++)
MakeTnodes_r(bsp->dmodels[i].headnode[0], bsp);
faceinfos = (faceinfo_t *) malloc(bsp->numfaces * sizeof(faceinfo_t));
for (int i = 0; i < bsp->numfaces; i++)
MakeFaceInfo(bsp, BSP_GetFace(bsp, i), &faceinfos[i]);
MakeFenceInfo(bsp);
}
/*
* ============================================================================
* FENCE TEXTURE TESTING
* ============================================================================
*/
/**
* Given a float texture coordinate, returns a pixel index to sample in [0, width-1].
* This assumes the texture repeats and nearest filtering
*/
uint32_t clamp_texcoord(vec_t in, uint32_t width)
{
if (in >= 0.0f)
{
return (uint32_t)in % width;
}
else
{
vec_t in_abs = ceil(fabs(in));
uint32_t in_abs_mod = (uint32_t)in_abs % width;
return (width - in_abs_mod) % width;
}
}
color_rgba //mxd. int -> color_rgba
SampleTexture(const bsp2_dface_t *face, const mbsp_t *bsp, const vec3_t point)
{
color_rgba sample{};
if (!bsp->rgbatexdatasize)
return sample;
const auto *miptex = Face_Miptex(bsp, face);
if (miptex == nullptr)
return sample;
const gtexinfo_t *tex = &bsp->texinfo[face->texinfo];
vec_t texcoord[2];
WorldToTexCoord(point, tex, texcoord);
const int x = clamp_texcoord(texcoord[0], miptex->width);
const int y = clamp_texcoord(texcoord[1], miptex->height);
assert (x >= 0);
assert (y >= 0);
color_rgba *data = (color_rgba*)((byte*)miptex + miptex->offset);
sample = data[(miptex->width * y) + x];
return sample;
}
/* assumes point is on the same plane as face */
static inline qboolean
TestHitFace(const faceinfo_t *fi, const vec3_t point)
{
return EdgePlanes_PointInside(fi->face, fi->edgeplanes, point);
}
static inline bsp2_dface_t *
SearchNodeForHitFace(const bsp2_dnode_t *bspnode, const vec3_t point)
{
// search the faces on this node
int i;
for (i=0; i<bspnode->numfaces; i++)
{
int facenum = bspnode->firstface + i;
const faceinfo_t *fi = &faceinfos[facenum];
if (SphereCullPoint(fi, point))
continue;
if (TestHitFace(fi, point)) {
return &bsp_static->dfaces[facenum];
}
}
return NULL;
}
/*
* ============================================================================
* LINE TRACING
* The major lighting operation is a point to point visibility test, performed
* by recursive subdivision of the line by the BSP tree.
* ============================================================================
*/
typedef struct {
vec3_t back;
vec3_t front;
int node;
int side;
const dplane_t *plane;
} tracestack_t;
/*
* ==============
* TraceLine
* ==============
*/
#define MAX_TSTACK 256
static int
TraceLine(const dmodel_t *model, const int traceflags,
const vec3_t start, const vec3_t stop)
{
int node, side, tracehit;
vec3_t front, back;
vec_t frontdist, backdist;
tracestack_t tracestack[MAX_TSTACK];
tracestack_t *tstack, *crossnode;
tnode_t *tnode;
// Special case for bmodels with fence textures
const int modelnum = model - &bsp_static->dmodels[0];
if (modelnum != 0 && fence_dmodels[modelnum]) {
traceinfo_t ti = {0};
bool hit = TraceFaces(&ti, model->headnode[0], start, stop);
if (hit && ti.hitsky && (traceflags & TRACE_HIT_SKY)) {
return TRACE_HIT_SKY;
} else if (hit && !ti.hitsky && (traceflags & TRACE_HIT_SOLID)) {
return TRACE_HIT_SOLID;
}
return TRACE_HIT_NONE;
}
// FIXME: check for stack overflow
// const tracestack_t *const tstack_max = tracestack + MAX_TSTACK;
if (traceflags <= 0)
Error("Internal error: %s - bad traceflags (%d)",
__func__, traceflags);
VectorCopy(start, front);
VectorCopy(stop, back);
tstack = tracestack;
node = model->headnode[0];
crossnode = NULL;
tracehit = TRACE_HIT_NONE;
while (1) {
while (node < 0) {
switch (node) {
case CONTENTS_SOLID:
if (traceflags & TRACE_HIT_SOLID)
tracehit = TRACE_HIT_SOLID;
break;
case CONTENTS_WATER:
if (traceflags & TRACE_HIT_WATER)
tracehit = TRACE_HIT_WATER;
break;
case CONTENTS_SLIME:
if (traceflags & TRACE_HIT_SLIME)
tracehit = TRACE_HIT_SLIME;
break;
case CONTENTS_LAVA:
if (traceflags & TRACE_HIT_LAVA)
tracehit = TRACE_HIT_LAVA;
break;
case CONTENTS_SKY:
if (traceflags & TRACE_HIT_SKY)
tracehit = TRACE_HIT_SKY;
break;
default:
break;
}
if (tracehit != TRACE_HIT_NONE) {
/* If we haven't crossed, start was inside flagged contents */
if (!crossnode)
return -tracehit;
return tracehit;
}
/* If the stack is empty, no obstructions were hit */
if (tstack == tracestack)
return TRACE_HIT_NONE;
/* Pop the stack and go down the back side */
crossnode = --tstack;
VectorCopy(tstack->front, front);
VectorCopy(tstack->back, back);
node = tnodes[tstack->node].children[!tstack->side];
}
tnode = &tnodes[node];
switch (tnode->type) {
case PLANE_X:
frontdist = front[0] - tnode->dist;
backdist = back[0] - tnode->dist;
break;
case PLANE_Y:
frontdist = front[1] - tnode->dist;
backdist = back[1] - tnode->dist;
break;
case PLANE_Z:
frontdist = front[2] - tnode->dist;
backdist = back[2] - tnode->dist;
break;
default:
frontdist = DotProduct(front, tnode->normal) - tnode->dist;
backdist = DotProduct(back, tnode->normal) - tnode->dist;
break;
}
if (frontdist >= -ON_EPSILON && backdist >= -ON_EPSILON) {
node = tnode->children[0];
continue;
}
if (frontdist < ON_EPSILON && backdist < ON_EPSILON) {
node = tnode->children[1];
continue;
}
/*
* If we get here, we have a clean split with front and back on
* opposite sides. The new back is the intersection point with the
* node plane. Push the other segment onto the stack and continue.
*/
side = frontdist < 0;
tstack->node = node;
tstack->side = side;
tstack->plane = tnode->plane;
VectorCopy(back, tstack->back);
VectorSubtract(back, front, back);
VectorMA(front, frontdist / (frontdist - backdist), back, back);
VectorCopy(back, tstack->front);
crossnode = tstack++;
node = tnode->children[side];
}
}
static qboolean
BSP_TestLight(const vec3_t start, const vec3_t stop, const dmodel_t *self)
{
const int traceflags = TRACE_HIT_SOLID;
int result = TRACE_HIT_NONE;
/* Check against the list of global shadow casters */
for (const modelinfo_t *model : tracelist) {
if (model->model == self)
continue;
result = TraceLine(model->model, traceflags, start, stop);
if (result != TRACE_HIT_NONE)
break;
}
/* If not yet obscured, check against the self-shadow model */
if (result == TRACE_HIT_NONE && self)
result = TraceLine(self, traceflags, start, stop);
return (result == TRACE_HIT_NONE);
}
static qboolean
BSP_TestSky(const vec3_t start, const vec3_t dirn, const dmodel_t *self)
{
//const modelinfo_t *const *model;
int traceflags = TRACE_HIT_SKY | TRACE_HIT_SOLID;
int result = TRACE_HIT_NONE;
vec3_t stop;
/* Trace towards the sunlight for a sky brush */
VectorAdd(dirn, start, stop);
result = TraceLine(tracelist[0]->model, traceflags, start, stop);
if (result != TRACE_HIT_SKY)
return false;
/* If good, check it isn't shadowed by another model */
traceflags = TRACE_HIT_SOLID;
for (const modelinfo_t *model : tracelist) {
if (model == tracelist.at(0))
continue;
if (model->model == self)
continue;
result = TraceLine(model->model, traceflags, start, stop);
if (result != TRACE_HIT_NONE)
return false;
}
/* Check for self-shadowing */
if (self) {
result = TraceLine(self, traceflags, start, stop);
if (result != TRACE_HIT_NONE)
return false;
}
return true;
}
/*
* ============
* DirtTrace
*
* returns true if the trace from start to stop hits something solid,
* or if it started in the void.
* ============
*/
static hittype_t
BSP_DirtTrace(const vec3_t start, const vec3_t dirn, const vec_t dist, const dmodel_t *self, vec_t *hitdist_out, plane_t *hitplane_out, const bsp2_dface_t **face_out)
{
vec3_t stop;
VectorMA(start, dist, dirn, stop);
traceinfo_t ti = {0};
VectorCopy(dirn, ti.dir);
if (self) {
if (TraceFaces (&ti, self->headnode[0], start, stop)) {
if (hitdist_out) {
vec3_t delta;
VectorSubtract(ti.point, start, delta);
*hitdist_out = VectorLength(delta);
}
if (hitplane_out) {
*hitplane_out = ti.hitplane;
}
if (face_out) {
*face_out = ti.face;
}
return ti.hitsky ? hittype_t::SKY : hittype_t::SOLID;
}
}
/* Check against the list of global shadow casters */
for (const modelinfo_t *model : tracelist) {
if (model->model == self)
continue;
if (TraceFaces (&ti, model->model->headnode[0], start, stop)) {
if (hitdist_out) {
vec3_t delta;
VectorSubtract(ti.point, start, delta);
*hitdist_out = VectorLength(delta);
}
if (hitplane_out) {
*hitplane_out = ti.hitplane;
}
if (face_out) {
*face_out = ti.face;
}
return ti.hitsky ? hittype_t::SKY : hittype_t::SOLID;
}
}
return hittype_t::NONE;
}
static bool
BSP_IntersectSingleModel(const vec3_t start, const vec3_t dirn, vec_t dist, const dmodel_t *self, vec_t *hitdist_out)
{
vec3_t stop;
VectorMA(start, dist, dirn, stop);
traceinfo_t ti = {0};
VectorCopy(dirn, ti.dir);
if (TraceFaces (&ti, self->headnode[0], start, stop)) {
if (hitdist_out) {
vec3_t delta;
VectorSubtract(ti.point, start, delta);
*hitdist_out = VectorLength(delta);
}
return true;
}
return false;
}
/*
=============
TraceFaces
From lordhavoc, johnfitz (RecursiveLightPoint)
=============
*/
static bool
TraceFaces (traceinfo_t *ti, int node, const vec3_t start, const vec3_t end)
{
float front, back, frac;
vec3_t mid;
tnode_t *tnode;
if (node < 0)
return false; // didn't hit anything
tnode = &tnodes[node]; //ericw
// calculate mid point
if (tnode->type < 3)
{
front = start[tnode->type] - tnode->dist;
back = end[tnode->type] - tnode->dist;
}
else
{
front = DotProduct(start, tnode->normal) - tnode->dist;
back = DotProduct(end, tnode->normal) - tnode->dist;
}
if ((back < 0) == (front < 0))
return TraceFaces (ti, tnode->children[front < 0], start, end);
frac = front / (front-back);
mid[0] = start[0] + (end[0] - start[0])*frac;
mid[1] = start[1] + (end[1] - start[1])*frac;
mid[2] = start[2] + (end[2] - start[2])*frac;
// go down front side
if (TraceFaces (ti, tnode->children[front < 0], start, mid))
return true; // hit something
else
{
// check for impact on this node
VectorCopy (mid, ti->point);
//ti->lightplane = tnode->plane;
bsp2_dface_t *face = SearchNodeForHitFace(tnode->node, mid);
if (face) {
const int facenum = face - bsp_static->dfaces;
const faceinfo_t *fi = &faceinfos[facenum];
// check fence
bool passedThroughFence = false;
if (fi->texturename[0] == '{') {
const color_rgba sample = SampleTexture(face, bsp_static, mid); //mxd. Palette index -> RGBA
if (sample.a < 255) {
passedThroughFence = true;
}
}
// only solid and sky faces stop the trace.
bool issolid, issky; //mxd
if(bsp_static->loadversion == Q2_BSPVERSION) {
issolid = !(fi->content & Q2_SURF_TRANSLUCENT);
issky = (fi->content & Q2_SURF_SKY);
} else {
issolid = (fi->content == CONTENTS_SOLID);
issky = (fi->content == CONTENTS_SKY);
}
if (!passedThroughFence && (issolid || issky)) {
ti->face = face;
ti->hitsky = issky;
VectorCopy(fi->plane.normal, ti->hitplane.normal);
ti->hitplane.dist = fi->plane.dist;
// check if we hit the back side
ti->hitback = (DotProduct(ti->dir, fi->plane.normal) >= 0);
return true;
}
}
//ericw -- no impact found on this node.
// go down back side
return TraceFaces (ti, tnode->children[front >= 0], mid, end);
}
}
//
// Embree wrappers
//
qboolean TestSky(const vec3_t start, const vec3_t dirn, const modelinfo_t *self, const bsp2_dface_t **face_out)
{
#ifdef HAVE_EMBREE
if (rtbackend == backend_embree) {
return Embree_TestSky(start, dirn, self, face_out);
}
#endif
#if 0
if (rtbackend == backend_bsp) {
return BSP_TestSky(start, dirn, self);
}
#endif
Error("no backend available");
throw; //mxd. Silences compiler warning
}
qboolean TestLight(const vec3_t start, const vec3_t stop, const modelinfo_t *self)
{
#ifdef HAVE_EMBREE
if (rtbackend == backend_embree) {
return Embree_TestLight(start, stop, self);
}
#endif
#if 0
if (rtbackend == backend_bsp) {
return BSP_TestLight(start, stop, self);
}
#endif
Error("no backend available");
throw; //mxd. Silences compiler warning
}
hittype_t DirtTrace(const vec3_t start, const vec3_t dirn, vec_t dist, const modelinfo_t *self, vec_t *hitdist_out, plane_t *hitplane_out, const bsp2_dface_t **face_out)
{
#ifdef HAVE_EMBREE
if (rtbackend == backend_embree) {
return Embree_DirtTrace(start, dirn, dist, self, hitdist_out, hitplane_out, face_out);
}
#endif
#if 0
if (rtbackend == backend_bsp) {
return BSP_DirtTrace(start, dirn, dist, self, hitdist_out, hitplane_out, face_out);
}
#endif
Error("no backend available");
throw; //mxd. Silences compiler warning
}
raystream_t *BSP_MakeRayStream(int maxrays)
{
return nullptr;
}
raystream_t *MakeRayStream(int maxrays)
{
#ifdef HAVE_EMBREE
if (rtbackend == backend_embree) {
return Embree_MakeRayStream(maxrays);
}
#endif
#if 0
if (rtbackend == backend_bsp) {
return BSP_MakeRayStream(maxrays);
}
#endif
Error("no backend available");
throw; //mxd. Silences compiler warning
}
void MakeTnodes(const mbsp_t *bsp)
{
#ifdef HAVE_EMBREE
if (rtbackend == backend_embree) {
Embree_TraceInit(bsp);
return;
}
#endif
#if 0
if (rtbackend == backend_bsp) {
BSP_MakeTnodes(bsp);
return;
}
#endif
Error("no backend available");
throw; //mxd. Silences compiler warning
}
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