gl_warp.c

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/*
Copyright (C) 1997-2001 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.
 
*/
// gl_warp.c -- sky and water polygons
 
#include "gl_local.h"
 
extern  model_t *loadmodel;
 
char    skyname[MAX_QPATH];
float   skyrotate;
vec3_t  skyaxis;
image_t *sky_images[6];
 
msurface_t  *warpface;
 
#define SUBDIVIDE_SIZE  64
//#define   SUBDIVIDE_SIZE  1024
 
void BoundPoly (int numverts, float *verts, vec3_t mins, vec3_t maxs)
{
    int     i, j;
    float   *v;
 
    mins[0] = mins[1] = mins[2] = 9999;
    maxs[0] = maxs[1] = maxs[2] = -9999;
    v = verts;
    for (i=0 ; i<numverts ; i++)
        for (j=0 ; j<3 ; j++, v++)
        {
            if (*v < mins[j])
                mins[j] = *v;
            if (*v > maxs[j])
                maxs[j] = *v;
        }
}
 
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]));
}
 
/*
================
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]);
}
 
//=========================================================
 
 
 
// speed up sin calculations - Ed
float   r_turbsin[] =
{
    #include "warpsin.h"
};
#define TURBSCALE (256.0 / (2 * M_PI))
 
/*
=============
EmitWaterPolys
 
Does a water warp on the pre-fragmented glpoly_t chain
=============
*/
void EmitWaterPolys (msurface_t *fa)
{
    glpoly_t    *p, *bp;
    float       *v;
    int         i;
    float       s, t, os, ot;
    float       scroll;
    float       rdt = r_newrefdef.time;
 
    if (fa->texinfo->flags & SURF_FLOWING)
        scroll = -64 * ( (r_newrefdef.time*0.5) - (int)(r_newrefdef.time*0.5) );
    else
        scroll = 0;
    for (bp=fa->polys ; bp ; bp=bp->next)
    {
        p = bp;
 
        qglBegin (GL_TRIANGLE_FAN);
        for (i=0,v=p->verts[0] ; i<p->numverts ; i++, v+=VERTEXSIZE)
        {
            os = v[3];
            ot = v[4];
 
#if !id386
            s = os + r_turbsin[(int)((ot*0.125+r_newrefdef.time) * TURBSCALE) & 255];
#else
            s = os + r_turbsin[Q_ftol( ((ot*0.125+rdt) * TURBSCALE) ) & 255];
#endif
            s += scroll;
            s *= (1.0/64);
 
#if !id386
            t = ot + r_turbsin[(int)((os*0.125+rdt) * TURBSCALE) & 255];
#else
            t = ot + r_turbsin[Q_ftol( ((os*0.125+rdt) * TURBSCALE) ) & 255];
#endif
            t *= (1.0/64);
 
            qglTexCoord2f (s, t);
            qglVertex3fv (v);
        }
        qglEnd ();
    }
}
 
 
//===================================================================
 
 
vec3_t  skyclip[6] = {
    {1,1,0},
    {1,-1,0},
    {0,-1,1},
    {0,1,1},
    {1,0,1},
    {-1,0,1} 
};
int c_sky;
 
// 1 = s, 2 = t, 3 = 2048
int st_to_vec[6][3] =
{
    {3,-1,2},
    {-3,1,2},
 
    {1,3,2},
    {-1,-3,2},
 
    {-2,-1,3},      // 0 degrees yaw, look straight up
    {2,-1,-3}       // look straight down
 
//  {-1,2,3},
//  {1,2,-3}
};
 
// s = [0]/[2], t = [1]/[2]
int vec_to_st[6][3] =
{
    {-2,3,1},
    {2,3,-1},
 
    {1,3,2},
    {-1,3,-2},
 
    {-2,-1,3},
    {-2,1,-3}
 
//  {-1,2,3},
//  {1,2,-3}
};
 
float   skymins[2][6], skymaxs[2][6];
float   sky_min, sky_max;
 
void DrawSkyPolygon (int nump, vec3_t vecs)
{
    int     i,j;
    vec3_t  v, av;
    float   s, t, dv;
    int     axis;
    float   *vp;
 
    c_sky++;
#if 0
glBegin (GL_POLYGON);
for (i=0 ; i<nump ; i++, vecs+=3)
{
    VectorAdd(vecs, r_origin, v);
    qglVertex3fv (v);
}
glEnd();
return;
#endif
    // decide which face it maps to
    VectorCopy (vec3_origin, v);
    for (i=0, vp=vecs ; i<nump ; i++, vp+=3)
    {
        VectorAdd (vp, v, v);
    }
    av[0] = fabs(v[0]);
    av[1] = fabs(v[1]);
    av[2] = fabs(v[2]);
    if (av[0] > av[1] && av[0] > av[2])
    {
        if (v[0] < 0)
            axis = 1;
        else
            axis = 0;
    }
    else if (av[1] > av[2] && av[1] > av[0])
    {
        if (v[1] < 0)
            axis = 3;
        else
            axis = 2;
    }
    else
    {
        if (v[2] < 0)
            axis = 5;
        else
            axis = 4;
    }
 
    // project new texture coords
    for (i=0 ; i<nump ; i++, vecs+=3)
    {
        j = vec_to_st[axis][2];
        if (j > 0)
            dv = vecs[j - 1];
        else
            dv = -vecs[-j - 1];
        if (dv < 0.001)
            continue;   // don't divide by zero
        j = vec_to_st[axis][0];
        if (j < 0)
            s = -vecs[-j -1] / dv;
        else
            s = vecs[j-1] / dv;
        j = vec_to_st[axis][1];
        if (j < 0)
            t = -vecs[-j -1] / dv;
        else
            t = vecs[j-1] / dv;
 
        if (s < skymins[0][axis])
            skymins[0][axis] = s;
        if (t < skymins[1][axis])
            skymins[1][axis] = t;
        if (s > skymaxs[0][axis])
            skymaxs[0][axis] = s;
        if (t > skymaxs[1][axis])
            skymaxs[1][axis] = t;
    }
}
 
#define ON_EPSILON      0.1         // point on plane side epsilon
#define MAX_CLIP_VERTS  64
void ClipSkyPolygon (int nump, vec3_t vecs, int stage)
{
    float   *norm;
    float   *v;
    qboolean    front, back;
    float   d, e;
    float   dists[MAX_CLIP_VERTS];
    int     sides[MAX_CLIP_VERTS];
    vec3_t  newv[2][MAX_CLIP_VERTS];
    int     newc[2];
    int     i, j;
 
    if (nump > MAX_CLIP_VERTS-2)
        ri.Sys_Error (ERR_DROP, "ClipSkyPolygon: MAX_CLIP_VERTS");
    if (stage == 6)
    {   // fully clipped, so draw it
        DrawSkyPolygon (nump, vecs);
        return;
    }
 
    front = back = false;
    norm = skyclip[stage];
    for (i=0, v = vecs ; i<nump ; i++, v+=3)
    {
        d = DotProduct (v, norm);
        if (d > ON_EPSILON)
        {
            front = true;
            sides[i] = SIDE_FRONT;
        }
        else if (d < -ON_EPSILON)
        {
            back = true;
            sides[i] = SIDE_BACK;
        }
        else
            sides[i] = SIDE_ON;
        dists[i] = d;
    }
 
    if (!front || !back)
    {   // not clipped
        ClipSkyPolygon (nump, vecs, stage+1);
        return;
    }
 
    // clip it
    sides[i] = sides[0];
    dists[i] = dists[0];
    VectorCopy (vecs, (vecs+(i*3)) );
    newc[0] = newc[1] = 0;
 
    for (i=0, v = vecs ; i<nump ; i++, v+=3)
    {
        switch (sides[i])
        {
        case SIDE_FRONT:
            VectorCopy (v, newv[0][newc[0]]);
            newc[0]++;
            break;
        case SIDE_BACK:
            VectorCopy (v, newv[1][newc[1]]);
            newc[1]++;
            break;
        case SIDE_ON:
            VectorCopy (v, newv[0][newc[0]]);
            newc[0]++;
            VectorCopy (v, newv[1][newc[1]]);
            newc[1]++;
            break;
        }
 
        if (sides[i] == SIDE_ON || sides[i+1] == SIDE_ON || sides[i+1] == sides[i])
            continue;
 
        d = dists[i] / (dists[i] - dists[i+1]);
        for (j=0 ; j<3 ; j++)
        {
            e = v[j] + d*(v[j+3] - v[j]);
            newv[0][newc[0]][j] = e;
            newv[1][newc[1]][j] = e;
        }
        newc[0]++;
        newc[1]++;
    }
 
    // continue
    ClipSkyPolygon (newc[0], newv[0][0], stage+1);
    ClipSkyPolygon (newc[1], newv[1][0], stage+1);
}
 
/*
=================
R_AddSkySurface
=================
*/
void R_AddSkySurface (msurface_t *fa)
{
    int         i;
    vec3_t      verts[MAX_CLIP_VERTS];
    glpoly_t    *p;
 
    // calculate vertex values for sky box
    for (p=fa->polys ; p ; p=p->next)
    {
        for (i=0 ; i<p->numverts ; i++)
        {
            VectorSubtract (p->verts[i], r_origin, verts[i]);
        }
        ClipSkyPolygon (p->numverts, verts[0], 0);
    }
}
 
 
/*
==============
R_ClearSkyBox
==============
*/
void R_ClearSkyBox (void)
{
    int     i;
 
    for (i=0 ; i<6 ; i++)
    {
        skymins[0][i] = skymins[1][i] = 9999;
        skymaxs[0][i] = skymaxs[1][i] = -9999;
    }
}
 
 
void MakeSkyVec (float s, float t, int axis)
{
    vec3_t      v, b;
    int         j, k;
 
    b[0] = s*2300;
    b[1] = t*2300;
    b[2] = 2300;
 
    for (j=0 ; j<3 ; j++)
    {
        k = st_to_vec[axis][j];
        if (k < 0)
            v[j] = -b[-k - 1];
        else
            v[j] = b[k - 1];
    }
 
    // avoid bilerp seam
    s = (s+1)*0.5;
    t = (t+1)*0.5;
 
    if (s < sky_min)
        s = sky_min;
    else if (s > sky_max)
        s = sky_max;
    if (t < sky_min)
        t = sky_min;
    else if (t > sky_max)
        t = sky_max;
 
    t = 1.0 - t;
    qglTexCoord2f (s, t);
    qglVertex3fv (v);
}
 
/*
==============
R_DrawSkyBox
==============
*/
int skytexorder[6] = {0,2,1,3,4,5};
void R_DrawSkyBox (void)
{
    int     i;
 
#if 0
qglEnable (GL_BLEND);
GL_TexEnv( GL_MODULATE );
qglColor4f (1,1,1,0.5);
qglDisable (GL_DEPTH_TEST);
#endif
    if (skyrotate)
    {   // check for no sky at all
        for (i=0 ; i<6 ; i++)
            if (skymins[0][i] < skymaxs[0][i]
            && skymins[1][i] < skymaxs[1][i])
                break;
        if (i == 6)
            return;     // nothing visible
    }
 
qglPushMatrix ();
qglTranslatef (r_origin[0], r_origin[1], r_origin[2]);
qglRotatef (r_newrefdef.time * skyrotate, skyaxis[0], skyaxis[1], skyaxis[2]);
 
    for (i=0 ; i<6 ; i++)
    {
        if (skyrotate)
        {   // hack, forces full sky to draw when rotating
            skymins[0][i] = -1;
            skymins[1][i] = -1;
            skymaxs[0][i] = 1;
            skymaxs[1][i] = 1;
        }
 
        if (skymins[0][i] >= skymaxs[0][i]
        || skymins[1][i] >= skymaxs[1][i])
            continue;
 
        GL_Bind (sky_images[skytexorder[i]]->texnum);
 
        qglBegin (GL_QUADS);
        MakeSkyVec (skymins[0][i], skymins[1][i], i);
        MakeSkyVec (skymins[0][i], skymaxs[1][i], i);
        MakeSkyVec (skymaxs[0][i], skymaxs[1][i], i);
        MakeSkyVec (skymaxs[0][i], skymins[1][i], i);
        qglEnd ();
    }
qglPopMatrix ();
#if 0
glDisable (GL_BLEND);
glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
glColor4f (1,1,1,0.5);
glEnable (GL_DEPTH_TEST);
#endif
}
 
 
/*
============
R_SetSky
============
*/
// 3dstudio environment map names
char    *suf[6] = {"rt", "bk", "lf", "ft", "up", "dn"};
void R_SetSky (char *name, float rotate, vec3_t axis)
{
    int     i;
    char    pathname[MAX_QPATH];
 
    strncpy (skyname, name, sizeof(skyname)-1);
    skyrotate = rotate;
    VectorCopy (axis, skyaxis);
 
    for (i=0 ; i<6 ; i++)
    {
        // chop down rotating skies for less memory
        if (gl_skymip->value || skyrotate)
            gl_picmip->value++;
 
        if ( qglColorTableEXT && gl_ext_palettedtexture->value )
            Com_sprintf (pathname, sizeof(pathname), "env/%s%s.pcx", skyname, suf[i]);
        else
            Com_sprintf (pathname, sizeof(pathname), "env/%s%s.tga", skyname, suf[i]);
 
        sky_images[i] = GL_FindImage (pathname, it_sky);
        if (!sky_images[i])
            sky_images[i] = r_notexture;
 
        if (gl_skymip->value || skyrotate)
        {   // take less memory
            gl_picmip->value--;
            sky_min = 1.0/256;
            sky_max = 255.0/256;
        }
        else    
        {
            sky_min = 1.0/512;
            sky_max = 511.0/512;
        }
    }
}