/*
================
GL_SubdivideSurface
Breaks a polygon up along axial 64 unit
boundaries so that turbulent and sky warps
can be done reasonably.
================
*/
void GL_SubdivideSurface (msurface_t *fa)
{
vec3_t verts[64];
int numverts;
int i;
int lindex;
float *vec;
warpface = fa;
//
// convert edges back to a normal polygon
//
numverts = 0;
for (i=0 ; i<fa->numedges ; i++)
{
lindex = loadmodel->surfedges[fa->firstedge + i];
if (lindex > 0)
vec = loadmodel->vertexes[loadmodel->edges[lindex].v[0]].position;
else
vec = loadmodel->vertexes[loadmodel->edges[-lindex].v[1]].position;
VectorCopy (vec, verts[numverts]);
numverts++;
}
SubdividePolygon (numverts, verts[0]);
}
/*
================
GL_SubdivideSurface
================
*/
void GL_SubdivideSurface (msurface_t *fa)
{
vec3_t verts[64];
int i;
warpface = fa;
//the first poly in the chain is the undivided poly for newwater rendering.
//grab the verts from that.
for (i=0; i<fa->polys->numverts; i++)
VectorCopy (fa->polys->verts[i], verts[i]);
SubdividePolygon (fa->polys->numverts, verts[0]);
}
void SubdividePolygon (int numverts, float *verts)
{
int i, j, k;
vec3_t mins, maxs;
float m;
float *v;
vec3_t front[64], back[64];
int f, b;
float dist[64];
float frac;
glpoly_t *poly;
float s, t;
vec3_t total;
float total_s, total_t;
if (numverts > 60)
ri.Sys_Error (ERR_DROP, "numverts = %i", numverts);
BoundPoly (numverts, verts, mins, maxs);
for (i=0 ; i<3 ; i++)
{
m = (mins[i] + maxs[i]) * 0.5;
m = SUBDIVIDE_SIZE * floor (m/SUBDIVIDE_SIZE + 0.5);
if (maxs[i] - m < 8)
continue;
if (m - mins[i] < 8)
continue;
// cut it
v = verts + i;
for (j=0 ; j<numverts ; j++, v+= 3)
dist[j] = *v - m;
// wrap cases
dist[j] = dist[0];
v-=i;
VectorCopy (verts, v);
f = b = 0;
v = verts;
for (j=0 ; j<numverts ; j++, v+= 3)
{
if (dist[j] >= 0)
{
VectorCopy (v, front[f]);
f++;
}
if (dist[j] <= 0)
{
VectorCopy (v, back[b]);
b++;
}
if (dist[j] == 0 || dist[j+1] == 0)
continue;
if ( (dist[j] > 0) != (dist[j+1] > 0) )
{
// clip point
frac = dist[j] / (dist[j] - dist[j+1]);
for (k=0 ; k<3 ; k++)
front[f][k] = back[b][k] = v[k] + frac*(v[3+k] - v[k]);
f++;
b++;
}
}
SubdividePolygon (f, front[0]);
SubdividePolygon (b, back[0]);
return;
}
// add a point in the center to help keep warp valid
poly = Hunk_Alloc (sizeof(glpoly_t) + ((numverts-4)+2) * VERTEXSIZE*sizeof(float));
poly->next = warpface->polys;
warpface->polys = poly;
poly->numverts = numverts+2;
VectorClear (total);
total_s = 0;
total_t = 0;
for (i=0 ; i<numverts ; i++, verts+= 3)
{
VectorCopy (verts, poly->verts[i+1]);
s = DotProduct (verts, warpface->texinfo->vecs[0]);
t = DotProduct (verts, warpface->texinfo->vecs[1]);
total_s += s;
total_t += t;
VectorAdd (total, verts, total);
poly->verts[i+1][3] = s;
poly->verts[i+1][4] = t;
}
VectorScale (total, (1.0/numverts), poly->verts[0]);
poly->verts[0][3] = total_s/numverts;
poly->verts[0][4] = total_t/numverts;
// copy first vertex to last
memcpy (poly->verts[i+1], poly->verts[1], sizeof(poly->verts[0]));
}
void SubdividePolygon (int numverts, float *verts)
{
int i, j, k;
vec3_t mins, maxs;
float m;
float *v;
vec3_t front[64], back[64];
int f, b;
float dist[64];
float frac;
glpoly_t *poly;
float s, t;
if (numverts > 60)
Sys_Error ("numverts = %i", numverts);
BoundPoly (numverts, verts, mins, maxs);
for (i=0 ; i<3 ; i++)
{
m = (mins[i] + maxs[i]) * 0.5;
m = gl_subdivide_size.value * floor (m/gl_subdivide_size.value + 0.5);
if (maxs[i] - m < 8)
continue;
if (m - mins[i] < 8)
continue;
// cut it
v = verts + i;
for (j=0 ; j<numverts ; j++, v+= 3)
dist[j] = *v - m;
// wrap cases
dist[j] = dist[0];
v-=i;
VectorCopy (verts, v);
f = b = 0;
v = verts;
for (j=0 ; j<numverts ; j++, v+= 3)
{
if (dist[j] >= 0)
{
VectorCopy (v, front[f]);
f++;
}
if (dist[j] <= 0)
{
VectorCopy (v, back[b]);
b++;
}
if (dist[j] == 0 || dist[j+1] == 0)
continue;
if ( (dist[j] > 0) != (dist[j+1] > 0) )
{
// clip point
frac = dist[j] / (dist[j] - dist[j+1]);
for (k=0 ; k<3 ; k++)
front[f][k] = back[b][k] = v[k] + frac*(v[3+k] - v[k]);
f++;
b++;
}
}
SubdividePolygon (f, front[0]);
SubdividePolygon (b, back[0]);
return;
}
poly = (glpoly_t*) Hunk_Alloc (sizeof(glpoly_t) + (numverts-4) * VERTEXSIZE*sizeof(float));
poly->next = warpface->polys;
warpface->polys = poly;
poly->numverts = numverts;
for (i=0 ; i<numverts ; i++, verts+= 3)
{
VectorCopy (verts, poly->verts[i]);
s = DotProduct (verts, warpface->texinfo->vecs[0]);
t = DotProduct (verts, warpface->texinfo->vecs[1]);
poly->verts[i][3] = s;
poly->verts[i][4] = t;
}
}