tr_shade_calc.c

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/*
===========================================================================
Copyright (C) 1999-2005 Id Software, Inc.

This file is part of Quake III Arena source code.

Quake III Arena source code 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.

Quake III Arena source code 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 Foobar; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
===========================================================================
*/
// tr_shade_calc.c

#include "tr_local.h"


#define WAVEVALUE( table, base, amplitude, phase, freq )  ((base) + table[ myftol( ( ( (phase) + tess.shaderTime * (freq) ) * FUNCTABLE_SIZE ) ) & FUNCTABLE_MASK ] * (amplitude))

static float *TableForFunc( genFunc_t func ) 
{
    switch ( func )
    {
    case GF_SIN:
        return tr.sinTable;
    case GF_TRIANGLE:
        return tr.triangleTable;
    case GF_SQUARE:
        return tr.squareTable;
    case GF_SAWTOOTH:
        return tr.sawToothTable;
    case GF_INVERSE_SAWTOOTH:
        return tr.inverseSawToothTable;
    case GF_NONE:
    default:
        break;
    }

    ri.Error( ERR_DROP, "TableForFunc called with invalid function '%d' in shader '%s'\n", func, tess.shader->name );
    return NULL;
}

/*
** EvalWaveForm
**
** Evaluates a given waveForm_t, referencing backEnd.refdef.time directly
*/
static float EvalWaveForm( const waveForm_t *wf ) 
{
    float   *table;

    table = TableForFunc( wf->func );

    return WAVEVALUE( table, wf->base, wf->amplitude, wf->phase, wf->frequency );
}

static float EvalWaveFormClamped( const waveForm_t *wf )
{
    float glow  = EvalWaveForm( wf );

    if ( glow < 0 )
    {
        return 0;
    }

    if ( glow > 1 )
    {
        return 1;
    }

    return glow;
}

/*
** RB_CalcStretchTexCoords
*/
void RB_CalcStretchTexCoords( const waveForm_t *wf, float *st )
{
    float p;
    texModInfo_t tmi;

    p = 1.0f / EvalWaveForm( wf );

    tmi.matrix[0][0] = p;
    tmi.matrix[1][0] = 0;
    tmi.translate[0] = 0.5f - 0.5f * p;

    tmi.matrix[0][1] = 0;
    tmi.matrix[1][1] = p;
    tmi.translate[1] = 0.5f - 0.5f * p;

    RB_CalcTransformTexCoords( &tmi, st );
}

/*
====================================================================

DEFORMATIONS

====================================================================
*/

/*
========================
RB_CalcDeformVertexes

========================
*/
void RB_CalcDeformVertexes( deformStage_t *ds )
{
    int i;
    vec3_t  offset;
    float   scale;
    float   *xyz = ( float * ) tess.xyz;
    float   *normal = ( float * ) tess.normal;
    float   *table;

    if ( ds->deformationWave.frequency == 0 )
    {
        scale = EvalWaveForm( &ds->deformationWave );

        for ( i = 0; i < tess.numVertexes; i++, xyz += 4, normal += 4 )
        {
            VectorScale( normal, scale, offset );
            
            xyz[0] += offset[0];
            xyz[1] += offset[1];
            xyz[2] += offset[2];
        }
    }
    else
    {
        table = TableForFunc( ds->deformationWave.func );

        for ( i = 0; i < tess.numVertexes; i++, xyz += 4, normal += 4 )
        {
            float off = ( xyz[0] + xyz[1] + xyz[2] ) * ds->deformationSpread;

            scale = WAVEVALUE( table, ds->deformationWave.base, 
                ds->deformationWave.amplitude,
                ds->deformationWave.phase + off,
                ds->deformationWave.frequency );

            VectorScale( normal, scale, offset );
            
            xyz[0] += offset[0];
            xyz[1] += offset[1];
            xyz[2] += offset[2];
        }
    }
}

/*
=========================
RB_CalcDeformNormals

Wiggle the normals for wavy environment mapping
=========================
*/
void RB_CalcDeformNormals( deformStage_t *ds ) {
    int i;
    float   scale;
    float   *xyz = ( float * ) tess.xyz;
    float   *normal = ( float * ) tess.normal;

    for ( i = 0; i < tess.numVertexes; i++, xyz += 4, normal += 4 ) {
        scale = 0.98f;
        scale = R_NoiseGet4f( xyz[0] * scale, xyz[1] * scale, xyz[2] * scale,
            tess.shaderTime * ds->deformationWave.frequency );
        normal[ 0 ] += ds->deformationWave.amplitude * scale;

        scale = 0.98f;
        scale = R_NoiseGet4f( 100 + xyz[0] * scale, xyz[1] * scale, xyz[2] * scale,
            tess.shaderTime * ds->deformationWave.frequency );
        normal[ 1 ] += ds->deformationWave.amplitude * scale;

        scale = 0.98f;
        scale = R_NoiseGet4f( 200 + xyz[0] * scale, xyz[1] * scale, xyz[2] * scale,
            tess.shaderTime * ds->deformationWave.frequency );
        normal[ 2 ] += ds->deformationWave.amplitude * scale;

        VectorNormalizeFast( normal );
    }
}

/*
========================
RB_CalcBulgeVertexes

========================
*/
void RB_CalcBulgeVertexes( deformStage_t *ds ) {
    int i;
    const float *st = ( const float * ) tess.texCoords[0];
    float       *xyz = ( float * ) tess.xyz;
    float       *normal = ( float * ) tess.normal;
    float       now;

    now = backEnd.refdef.time * ds->bulgeSpeed * 0.001f;

    for ( i = 0; i < tess.numVertexes; i++, xyz += 4, st += 4, normal += 4 ) {
        int     off;
        float scale;

        off = (float)( FUNCTABLE_SIZE / (M_PI*2) ) * ( st[0] * ds->bulgeWidth + now );

        scale = tr.sinTable[ off & FUNCTABLE_MASK ] * ds->bulgeHeight;
            
        xyz[0] += normal[0] * scale;
        xyz[1] += normal[1] * scale;
        xyz[2] += normal[2] * scale;
    }
}


/*
======================
RB_CalcMoveVertexes

A deformation that can move an entire surface along a wave path
======================
*/
void RB_CalcMoveVertexes( deformStage_t *ds ) {
    int         i;
    float       *xyz;
    float       *table;
    float       scale;
    vec3_t      offset;

    table = TableForFunc( ds->deformationWave.func );

    scale = WAVEVALUE( table, ds->deformationWave.base, 
        ds->deformationWave.amplitude,
        ds->deformationWave.phase,
        ds->deformationWave.frequency );

    VectorScale( ds->moveVector, scale, offset );

    xyz = ( float * ) tess.xyz;
    for ( i = 0; i < tess.numVertexes; i++, xyz += 4 ) {
        VectorAdd( xyz, offset, xyz );
    }
}


/*
=============
DeformText

Change a polygon into a bunch of text polygons
=============
*/
void DeformText( const char *text ) {
    int     i;
    vec3_t  origin, width, height;
    int     len;
    int     ch;
    byte    color[4];
    float   bottom, top;
    vec3_t  mid;

    height[0] = 0;
    height[1] = 0;
    height[2] = -1;
    CrossProduct( tess.normal[0], height, width );

    // find the midpoint of the box
    VectorClear( mid );
    bottom = 999999;
    top = -999999;
    for ( i = 0 ; i < 4 ; i++ ) {
        VectorAdd( tess.xyz[i], mid, mid );
        if ( tess.xyz[i][2] < bottom ) {
            bottom = tess.xyz[i][2];
        }
        if ( tess.xyz[i][2] > top ) {
            top = tess.xyz[i][2];
        }
    }
    VectorScale( mid, 0.25f, origin );

    // determine the individual character size
    height[0] = 0;
    height[1] = 0;
    height[2] = ( top - bottom ) * 0.5f;

    VectorScale( width, height[2] * -0.75f, width );

    // determine the starting position
    len = strlen( text );
    VectorMA( origin, (len-1), width, origin );

    // clear the shader indexes
    tess.numIndexes = 0;
    tess.numVertexes = 0;

    color[0] = color[1] = color[2] = color[3] = 255;

    // draw each character
    for ( i = 0 ; i < len ; i++ ) {
        ch = text[i];
        ch &= 255;

        if ( ch != ' ' ) {
            int     row, col;
            float   frow, fcol, size;

            row = ch>>4;
            col = ch&15;

            frow = row*0.0625f;
            fcol = col*0.0625f;
            size = 0.0625f;

            RB_AddQuadStampExt( origin, width, height, color, fcol, frow, fcol + size, frow + size );
        }
        VectorMA( origin, -2, width, origin );
    }
}

/*
==================
GlobalVectorToLocal
==================
*/
static void GlobalVectorToLocal( const vec3_t in, vec3_t out ) {
    out[0] = DotProduct( in, backEnd.or.axis[0] );
    out[1] = DotProduct( in, backEnd.or.axis[1] );
    out[2] = DotProduct( in, backEnd.or.axis[2] );
}

/*
=====================
AutospriteDeform

Assuming all the triangles for this shader are independant
quads, rebuild them as forward facing sprites
=====================
*/
static void AutospriteDeform( void ) {
    int     i;
    int     oldVerts;
    float   *xyz;
    vec3_t  mid, delta;
    float   radius;
    vec3_t  left, up;
    vec3_t  leftDir, upDir;

    if ( tess.numVertexes & 3 ) {
        ri.Printf( PRINT_WARNING, "Autosprite shader %s had odd vertex count", tess.shader->name );
    }
    if ( tess.numIndexes != ( tess.numVertexes >> 2 ) * 6 ) {
        ri.Printf( PRINT_WARNING, "Autosprite shader %s had odd index count", tess.shader->name );
    }

    oldVerts = tess.numVertexes;
    tess.numVertexes = 0;
    tess.numIndexes = 0;

    if ( backEnd.currentEntity != &tr.worldEntity ) {
        GlobalVectorToLocal( backEnd.viewParms.or.axis[1], leftDir );
        GlobalVectorToLocal( backEnd.viewParms.or.axis[2], upDir );
    } else {
        VectorCopy( backEnd.viewParms.or.axis[1], leftDir );
        VectorCopy( backEnd.viewParms.or.axis[2], upDir );
    }

    for ( i = 0 ; i < oldVerts ; i+=4 ) {
        // find the midpoint
        xyz = tess.xyz[i];

        mid[0] = 0.25f * (xyz[0] + xyz[4] + xyz[8] + xyz[12]);
        mid[1] = 0.25f * (xyz[1] + xyz[5] + xyz[9] + xyz[13]);
        mid[2] = 0.25f * (xyz[2] + xyz[6] + xyz[10] + xyz[14]);

        VectorSubtract( xyz, mid, delta );
        radius = VectorLength( delta ) * 0.707f;        // / sqrt(2)

        VectorScale( leftDir, radius, left );
        VectorScale( upDir, radius, up );

        if ( backEnd.viewParms.isMirror ) {
            VectorSubtract( vec3_origin, left, left );
        }

      // compensate for scale in the axes if necessary
    if ( backEnd.currentEntity->e.nonNormalizedAxes ) {
      float axisLength;
          axisLength = VectorLength( backEnd.currentEntity->e.axis[0] );
        if ( !axisLength ) {
            axisLength = 0;
        } else {
            axisLength = 1.0f / axisLength;
        }
      VectorScale(left, axisLength, left);
      VectorScale(up, axisLength, up);
    }

        RB_AddQuadStamp( mid, left, up, tess.vertexColors[i] );
    }
}


/*
=====================
Autosprite2Deform

Autosprite2 will pivot a rectangular quad along the center of its long axis
=====================
*/
int edgeVerts[6][2] = {
    { 0, 1 },
    { 0, 2 },
    { 0, 3 },
    { 1, 2 },
    { 1, 3 },
    { 2, 3 }
};

static void Autosprite2Deform( void ) {
    int     i, j, k;
    int     indexes;
    float   *xyz;
    vec3_t  forward;

    if ( tess.numVertexes & 3 ) {
        ri.Printf( PRINT_WARNING, "Autosprite2 shader %s had odd vertex count", tess.shader->name );
    }
    if ( tess.numIndexes != ( tess.numVertexes >> 2 ) * 6 ) {
        ri.Printf( PRINT_WARNING, "Autosprite2 shader %s had odd index count", tess.shader->name );
    }

    if ( backEnd.currentEntity != &tr.worldEntity ) {
        GlobalVectorToLocal( backEnd.viewParms.or.axis[0], forward );
    } else {
        VectorCopy( backEnd.viewParms.or.axis[0], forward );
    }

    // this is a lot of work for two triangles...
    // we could precalculate a lot of it is an issue, but it would mess up
    // the shader abstraction
    for ( i = 0, indexes = 0 ; i < tess.numVertexes ; i+=4, indexes+=6 ) {
        float   lengths[2];
        int     nums[2];
        vec3_t  mid[2];
        vec3_t  major, minor;
        float   *v1, *v2;

        // find the midpoint
        xyz = tess.xyz[i];

        // identify the two shortest edges
        nums[0] = nums[1] = 0;
        lengths[0] = lengths[1] = 999999;

        for ( j = 0 ; j < 6 ; j++ ) {
            float   l;
            vec3_t  temp;

            v1 = xyz + 4 * edgeVerts[j][0];
            v2 = xyz + 4 * edgeVerts[j][1];

            VectorSubtract( v1, v2, temp );
            
            l = DotProduct( temp, temp );
            if ( l < lengths[0] ) {
                nums[1] = nums[0];
                lengths[1] = lengths[0];
                nums[0] = j;
                lengths[0] = l;
            } else if ( l < lengths[1] ) {
                nums[1] = j;
                lengths[1] = l;
            }
        }

        for ( j = 0 ; j < 2 ; j++ ) {
            v1 = xyz + 4 * edgeVerts[nums[j]][0];
            v2 = xyz + 4 * edgeVerts[nums[j]][1];

            mid[j][0] = 0.5f * (v1[0] + v2[0]);
            mid[j][1] = 0.5f * (v1[1] + v2[1]);
            mid[j][2] = 0.5f * (v1[2] + v2[2]);
        }

        // find the vector of the major axis
        VectorSubtract( mid[1], mid[0], major );

        // cross this with the view direction to get minor axis
        CrossProduct( major, forward, minor );
        VectorNormalize( minor );
        
        // re-project the points
        for ( j = 0 ; j < 2 ; j++ ) {
            float   l;

            v1 = xyz + 4 * edgeVerts[nums[j]][0];
            v2 = xyz + 4 * edgeVerts[nums[j]][1];

            l = 0.5 * sqrt( lengths[j] );
            
            // we need to see which direction this edge
            // is used to determine direction of projection
            for ( k = 0 ; k < 5 ; k++ ) {
                if ( tess.indexes[ indexes + k ] == i + edgeVerts[nums[j]][0]
                    && tess.indexes[ indexes + k + 1 ] == i + edgeVerts[nums[j]][1] ) {
                    break;
                }
            }

            if ( k == 5 ) {
                VectorMA( mid[j], l, minor, v1 );
                VectorMA( mid[j], -l, minor, v2 );
            } else {
                VectorMA( mid[j], -l, minor, v1 );
                VectorMA( mid[j], l, minor, v2 );
            }
        }
    }
}


/*
=====================
RB_DeformTessGeometry

=====================
*/
void RB_DeformTessGeometry( void ) {
    int     i;
    deformStage_t   *ds;

    for ( i = 0 ; i < tess.shader->numDeforms ; i++ ) {
        ds = &tess.shader->deforms[ i ];

        switch ( ds->deformation ) {
        case DEFORM_NONE:
            break;
        case DEFORM_NORMALS:
            RB_CalcDeformNormals( ds );
            break;
        case DEFORM_WAVE:
            RB_CalcDeformVertexes( ds );
            break;
        case DEFORM_BULGE:
            RB_CalcBulgeVertexes( ds );
            break;
        case DEFORM_MOVE:
            RB_CalcMoveVertexes( ds );
            break;
        case DEFORM_PROJECTION_SHADOW:
            RB_ProjectionShadowDeform();
            break;
        case DEFORM_AUTOSPRITE:
            AutospriteDeform();
            break;
        case DEFORM_AUTOSPRITE2:
            Autosprite2Deform();
            break;
        case DEFORM_TEXT0:
        case DEFORM_TEXT1:
        case DEFORM_TEXT2:
        case DEFORM_TEXT3:
        case DEFORM_TEXT4:
        case DEFORM_TEXT5:
        case DEFORM_TEXT6:
        case DEFORM_TEXT7:
            DeformText( backEnd.refdef.text[ds->deformation - DEFORM_TEXT0] );
            break;
        }
    }
}

/*
====================================================================

COLORS

====================================================================
*/


/*
** RB_CalcColorFromEntity
*/
void RB_CalcColorFromEntity( unsigned char *dstColors )
{
    int i;
    int *pColors = ( int * ) dstColors;
    int c;

    if ( !backEnd.currentEntity )
        return;

    c = * ( int * ) backEnd.currentEntity->e.shaderRGBA;

    for ( i = 0; i < tess.numVertexes; i++, pColors++ )
    {
        *pColors = c;
    }
}

/*
** RB_CalcColorFromOneMinusEntity
*/
void RB_CalcColorFromOneMinusEntity( unsigned char *dstColors )
{
    int i;
    int *pColors = ( int * ) dstColors;
    unsigned char invModulate[3];
    int c;

    if ( !backEnd.currentEntity )
        return;

    invModulate[0] = 255 - backEnd.currentEntity->e.shaderRGBA[0];
    invModulate[1] = 255 - backEnd.currentEntity->e.shaderRGBA[1];
    invModulate[2] = 255 - backEnd.currentEntity->e.shaderRGBA[2];
    invModulate[3] = 255 - backEnd.currentEntity->e.shaderRGBA[3];  // this trashes alpha, but the AGEN block fixes it

    c = * ( int * ) invModulate;

    for ( i = 0; i < tess.numVertexes; i++, pColors++ )
    {
        *pColors = * ( int * ) invModulate;
    }
}

/*
** RB_CalcAlphaFromEntity
*/
void RB_CalcAlphaFromEntity( unsigned char *dstColors )
{
    int i;

    if ( !backEnd.currentEntity )
        return;

    dstColors += 3;

    for ( i = 0; i < tess.numVertexes; i++, dstColors += 4 )
    {
        *dstColors = backEnd.currentEntity->e.shaderRGBA[3];
    }
}

/*
** RB_CalcAlphaFromOneMinusEntity
*/
void RB_CalcAlphaFromOneMinusEntity( unsigned char *dstColors )
{
    int i;

    if ( !backEnd.currentEntity )
        return;

    dstColors += 3;

    for ( i = 0; i < tess.numVertexes; i++, dstColors += 4 )
    {
        *dstColors = 0xff - backEnd.currentEntity->e.shaderRGBA[3];
    }
}

/*
** RB_CalcWaveColor
*/
void RB_CalcWaveColor( const waveForm_t *wf, unsigned char *dstColors )
{
    int i;
    int v;
    float glow;
    int *colors = ( int * ) dstColors;
    byte    color[4];


  if ( wf->func == GF_NOISE ) {
        glow = wf->base + R_NoiseGet4f( 0, 0, 0, ( tess.shaderTime + wf->phase ) * wf->frequency ) * wf->amplitude;
    } else {
        glow = EvalWaveForm( wf ) * tr.identityLight;
    }
    
    if ( glow < 0 ) {
        glow = 0;
    }
    else if ( glow > 1 ) {
        glow = 1;
    }

    v = myftol( 255 * glow );
    color[0] = color[1] = color[2] = v;
    color[3] = 255;
    v = *(int *)color;
    
    for ( i = 0; i < tess.numVertexes; i++, colors++ ) {
        *colors = v;
    }
}

/*
** RB_CalcWaveAlpha
*/
void RB_CalcWaveAlpha( const waveForm_t *wf, unsigned char *dstColors )
{
    int i;
    int v;
    float glow;

    glow = EvalWaveFormClamped( wf );

    v = 255 * glow;

    for ( i = 0; i < tess.numVertexes; i++, dstColors += 4 )
    {
        dstColors[3] = v;
    }
}

/*
** RB_CalcModulateColorsByFog
*/
void RB_CalcModulateColorsByFog( unsigned char *colors ) {
    int     i;
    float   texCoords[SHADER_MAX_VERTEXES][2];

    // calculate texcoords so we can derive density
    // this is not wasted, because it would only have
    // been previously called if the surface was opaque
    RB_CalcFogTexCoords( texCoords[0] );

    for ( i = 0; i < tess.numVertexes; i++, colors += 4 ) {
        float f = 1.0 - R_FogFactor( texCoords[i][0], texCoords[i][1] );
        colors[0] *= f;
        colors[1] *= f;
        colors[2] *= f;
    }
}

/*
** RB_CalcModulateAlphasByFog
*/
void RB_CalcModulateAlphasByFog( unsigned char *colors ) {
    int     i;
    float   texCoords[SHADER_MAX_VERTEXES][2];

    // calculate texcoords so we can derive density
    // this is not wasted, because it would only have
    // been previously called if the surface was opaque
    RB_CalcFogTexCoords( texCoords[0] );

    for ( i = 0; i < tess.numVertexes; i++, colors += 4 ) {
        float f = 1.0 - R_FogFactor( texCoords[i][0], texCoords[i][1] );
        colors[3] *= f;
    }
}

/*
** RB_CalcModulateRGBAsByFog
*/
void RB_CalcModulateRGBAsByFog( unsigned char *colors ) {
    int     i;
    float   texCoords[SHADER_MAX_VERTEXES][2];

    // calculate texcoords so we can derive density
    // this is not wasted, because it would only have
    // been previously called if the surface was opaque
    RB_CalcFogTexCoords( texCoords[0] );

    for ( i = 0; i < tess.numVertexes; i++, colors += 4 ) {
        float f = 1.0 - R_FogFactor( texCoords[i][0], texCoords[i][1] );
        colors[0] *= f;
        colors[1] *= f;
        colors[2] *= f;
        colors[3] *= f;
    }
}


/*
====================================================================

TEX COORDS

====================================================================
*/

/*
========================
RB_CalcFogTexCoords

To do the clipped fog plane really correctly, we should use
projected textures, but I don't trust the drivers and it
doesn't fit our shader data.
========================
*/
void RB_CalcFogTexCoords( float *st ) {
    int         i;
    float       *v;
    float       s, t;
    float       eyeT;
    qboolean    eyeOutside;
    fog_t       *fog;
    vec3_t      local;
    vec4_t      fogDistanceVector, fogDepthVector;

    fog = tr.world->fogs + tess.fogNum;

    // all fogging distance is based on world Z units
    VectorSubtract( backEnd.or.origin, backEnd.viewParms.or.origin, local );
    fogDistanceVector[0] = -backEnd.or.modelMatrix[2];
    fogDistanceVector[1] = -backEnd.or.modelMatrix[6];
    fogDistanceVector[2] = -backEnd.or.modelMatrix[10];
    fogDistanceVector[3] = DotProduct( local, backEnd.viewParms.or.axis[0] );

    // scale the fog vectors based on the fog's thickness
    fogDistanceVector[0] *= fog->tcScale;
    fogDistanceVector[1] *= fog->tcScale;
    fogDistanceVector[2] *= fog->tcScale;
    fogDistanceVector[3] *= fog->tcScale;

    // rotate the gradient vector for this orientation
    if ( fog->hasSurface ) {
        fogDepthVector[0] = fog->surface[0] * backEnd.or.axis[0][0] + 
            fog->surface[1] * backEnd.or.axis[0][1] + fog->surface[2] * backEnd.or.axis[0][2];
        fogDepthVector[1] = fog->surface[0] * backEnd.or.axis[1][0] + 
            fog->surface[1] * backEnd.or.axis[1][1] + fog->surface[2] * backEnd.or.axis[1][2];
        fogDepthVector[2] = fog->surface[0] * backEnd.or.axis[2][0] + 
            fog->surface[1] * backEnd.or.axis[2][1] + fog->surface[2] * backEnd.or.axis[2][2];
        fogDepthVector[3] = -fog->surface[3] + DotProduct( backEnd.or.origin, fog->surface );

        eyeT = DotProduct( backEnd.or.viewOrigin, fogDepthVector ) + fogDepthVector[3];
    } else {
        eyeT = 1;   // non-surface fog always has eye inside
    }

    // see if the viewpoint is outside
    // this is needed for clipping distance even for constant fog

    if ( eyeT < 0 ) {
        eyeOutside = qtrue;
    } else {
        eyeOutside = qfalse;
    }

    fogDistanceVector[3] += 1.0/512;

    // calculate density for each point
    for (i = 0, v = tess.xyz[0] ; i < tess.numVertexes ; i++, v += 4) {
        // calculate the length in fog
        s = DotProduct( v, fogDistanceVector ) + fogDistanceVector[3];
        t = DotProduct( v, fogDepthVector ) + fogDepthVector[3];

        // partially clipped fogs use the T axis        
        if ( eyeOutside ) {
            if ( t < 1.0 ) {
                t = 1.0/32; // point is outside, so no fogging
            } else {
                t = 1.0/32 + 30.0/32 * t / ( t - eyeT );    // cut the distance at the fog plane
            }
        } else {
            if ( t < 0 ) {
                t = 1.0/32; // point is outside, so no fogging
            } else {
                t = 31.0/32;
            }
        }

        st[0] = s;
        st[1] = t;
        st += 2;
    }
}



/*
** RB_CalcEnvironmentTexCoords
*/
void RB_CalcEnvironmentTexCoords( float *st ) 
{
    int         i;
    float       *v, *normal;
    vec3_t      viewer, reflected;
    float       d;

    v = tess.xyz[0];
    normal = tess.normal[0];

    for (i = 0 ; i < tess.numVertexes ; i++, v += 4, normal += 4, st += 2 ) 
    {
        VectorSubtract (backEnd.or.viewOrigin, v, viewer);
        VectorNormalizeFast (viewer);

        d = DotProduct (normal, viewer);

        reflected[0] = normal[0]*2*d - viewer[0];
        reflected[1] = normal[1]*2*d - viewer[1];
        reflected[2] = normal[2]*2*d - viewer[2];

        st[0] = 0.5 + reflected[1] * 0.5;
        st[1] = 0.5 - reflected[2] * 0.5;
    }
}

/*
** RB_CalcTurbulentTexCoords
*/
void RB_CalcTurbulentTexCoords( const waveForm_t *wf, float *st )
{
    int i;
    float now;

    now = ( wf->phase + tess.shaderTime * wf->frequency );

    for ( i = 0; i < tess.numVertexes; i++, st += 2 )
    {
        float s = st[0];
        float t = st[1];

        st[0] = s + tr.sinTable[ ( ( int ) ( ( ( tess.xyz[i][0] + tess.xyz[i][2] )* 1.0/128 * 0.125 + now ) * FUNCTABLE_SIZE ) ) & ( FUNCTABLE_MASK ) ] * wf->amplitude;
        st[1] = t + tr.sinTable[ ( ( int ) ( ( tess.xyz[i][1] * 1.0/128 * 0.125 + now ) * FUNCTABLE_SIZE ) ) & ( FUNCTABLE_MASK ) ] * wf->amplitude;
    }
}

/*
** RB_CalcScaleTexCoords
*/
void RB_CalcScaleTexCoords( const float scale[2], float *st )
{
    int i;

    for ( i = 0; i < tess.numVertexes; i++, st += 2 )
    {
        st[0] *= scale[0];
        st[1] *= scale[1];
    }
}

/*
** RB_CalcScrollTexCoords
*/
void RB_CalcScrollTexCoords( const float scrollSpeed[2], float *st )
{
    int i;
    float timeScale = tess.shaderTime;
    float adjustedScrollS, adjustedScrollT;

    adjustedScrollS = scrollSpeed[0] * timeScale;
    adjustedScrollT = scrollSpeed[1] * timeScale;

    // clamp so coordinates don't continuously get larger, causing problems
    // with hardware limits
    adjustedScrollS = adjustedScrollS - floor( adjustedScrollS );
    adjustedScrollT = adjustedScrollT - floor( adjustedScrollT );

    for ( i = 0; i < tess.numVertexes; i++, st += 2 )
    {
        st[0] += adjustedScrollS;
        st[1] += adjustedScrollT;
    }
}

/*
** RB_CalcTransformTexCoords
*/
void RB_CalcTransformTexCoords( const texModInfo_t *tmi, float *st  )
{
    int i;

    for ( i = 0; i < tess.numVertexes; i++, st += 2 )
    {
        float s = st[0];
        float t = st[1];

        st[0] = s * tmi->matrix[0][0] + t * tmi->matrix[1][0] + tmi->translate[0];
        st[1] = s * tmi->matrix[0][1] + t * tmi->matrix[1][1] + tmi->translate[1];
    }
}

/*
** RB_CalcRotateTexCoords
*/
void RB_CalcRotateTexCoords( float degsPerSecond, float *st )
{
    float timeScale = tess.shaderTime;
    float degs;
    int index;
    float sinValue, cosValue;
    texModInfo_t tmi;

    degs = -degsPerSecond * timeScale;
    index = degs * ( FUNCTABLE_SIZE / 360.0f );

    sinValue = tr.sinTable[ index & FUNCTABLE_MASK ];
    cosValue = tr.sinTable[ ( index + FUNCTABLE_SIZE / 4 ) & FUNCTABLE_MASK ];

    tmi.matrix[0][0] = cosValue;
    tmi.matrix[1][0] = -sinValue;
    tmi.translate[0] = 0.5 - 0.5 * cosValue + 0.5 * sinValue;

    tmi.matrix[0][1] = sinValue;
    tmi.matrix[1][1] = cosValue;
    tmi.translate[1] = 0.5 - 0.5 * sinValue - 0.5 * cosValue;

    RB_CalcTransformTexCoords( &tmi, st );
}






#if id386 && !( (defined __linux__ || defined __FreeBSD__ ) && (defined __i386__ ) ) // rb010123

long myftol( float f ) {
    static int tmp;
    __asm fld f
    __asm fistp tmp
    __asm mov eax, tmp
}

#endif

/*
** RB_CalcSpecularAlpha
**
** Calculates specular coefficient and places it in the alpha channel
*/
vec3_t lightOrigin = { -960, 1980, 96 };        // FIXME: track dynamically

void RB_CalcSpecularAlpha( unsigned char *alphas ) {
    int         i;
    float       *v, *normal;
    vec3_t      viewer,  reflected;
    float       l, d;
    int         b;
    vec3_t      lightDir;
    int         numVertexes;

    v = tess.xyz[0];
    normal = tess.normal[0];

    alphas += 3;

    numVertexes = tess.numVertexes;
    for (i = 0 ; i < numVertexes ; i++, v += 4, normal += 4, alphas += 4) {
        float ilength;

        VectorSubtract( lightOrigin, v, lightDir );
//      ilength = Q_rsqrt( DotProduct( lightDir, lightDir ) );
        VectorNormalizeFast( lightDir );

        // calculate the specular color
        d = DotProduct (normal, lightDir);
//      d *= ilength;

        // we don't optimize for the d < 0 case since this tends to
        // cause visual artifacts such as faceted "snapping"
        reflected[0] = normal[0]*2*d - lightDir[0];
        reflected[1] = normal[1]*2*d - lightDir[1];
        reflected[2] = normal[2]*2*d - lightDir[2];

        VectorSubtract (backEnd.or.viewOrigin, v, viewer);
        ilength = Q_rsqrt( DotProduct( viewer, viewer ) );
        l = DotProduct (reflected, viewer);
        l *= ilength;

        if (l < 0) {
            b = 0;
        } else {
            l = l*l;
            l = l*l;
            b = l * 255;
            if (b > 255) {
                b = 255;
            }
        }

        *alphas = b;
    }
}

/*
** RB_CalcDiffuseColor
**
** The basic vertex lighting calc
*/
void RB_CalcDiffuseColor( unsigned char *colors )
{
    int             i, j;
    float           *v, *normal;
    float           incoming;
    trRefEntity_t   *ent;
    int             ambientLightInt;
    vec3_t          ambientLight;
    vec3_t          lightDir;
    vec3_t          directedLight;
    int             numVertexes;
#if idppc_altivec
    vector unsigned char vSel = (vector unsigned char)(0x00, 0x00, 0x00, 0xff,
                               0x00, 0x00, 0x00, 0xff,
                               0x00, 0x00, 0x00, 0xff,
                               0x00, 0x00, 0x00, 0xff);
    vector float ambientLightVec;
    vector float directedLightVec;
    vector float lightDirVec;
    vector float normalVec0, normalVec1;
    vector float incomingVec0, incomingVec1, incomingVec2;
    vector float zero, jVec;
    vector signed int jVecInt;
    vector signed short jVecShort;
    vector unsigned char jVecChar, normalPerm;
#endif
    ent = backEnd.currentEntity;
    ambientLightInt = ent->ambientLightInt;
#if idppc_altivec
    // A lot of this could be simplified if we made sure
    // entities light info was 16-byte aligned.
    jVecChar = vec_lvsl(0, ent->ambientLight);
    ambientLightVec = vec_ld(0, (vector float *)ent->ambientLight);
    jVec = vec_ld(11, (vector float *)ent->ambientLight);
    ambientLightVec = vec_perm(ambientLightVec,jVec,jVecChar);

    jVecChar = vec_lvsl(0, ent->directedLight);
    directedLightVec = vec_ld(0,(vector float *)ent->directedLight);
    jVec = vec_ld(11,(vector float *)ent->directedLight);
    directedLightVec = vec_perm(directedLightVec,jVec,jVecChar);     

    jVecChar = vec_lvsl(0, ent->lightDir);
    lightDirVec = vec_ld(0,(vector float *)ent->lightDir);
    jVec = vec_ld(11,(vector float *)ent->lightDir);
    lightDirVec = vec_perm(lightDirVec,jVec,jVecChar);   

    zero = (vector float)vec_splat_s8(0);
    VectorCopy( ent->lightDir, lightDir );
#else
    VectorCopy( ent->ambientLight, ambientLight );
    VectorCopy( ent->directedLight, directedLight );
    VectorCopy( ent->lightDir, lightDir );
#endif

    v = tess.xyz[0];
    normal = tess.normal[0];

#if idppc_altivec
    normalPerm = vec_lvsl(0,normal);
#endif
    numVertexes = tess.numVertexes;
    for (i = 0 ; i < numVertexes ; i++, v += 4, normal += 4) {
#if idppc_altivec
        normalVec0 = vec_ld(0,(vector float *)normal);
        normalVec1 = vec_ld(11,(vector float *)normal);
        normalVec0 = vec_perm(normalVec0,normalVec1,normalPerm);
        incomingVec0 = vec_madd(normalVec0, lightDirVec, zero);
        incomingVec1 = vec_sld(incomingVec0,incomingVec0,4);
        incomingVec2 = vec_add(incomingVec0,incomingVec1);
        incomingVec1 = vec_sld(incomingVec1,incomingVec1,4);
        incomingVec2 = vec_add(incomingVec2,incomingVec1);
        incomingVec0 = vec_splat(incomingVec2,0);
        incomingVec0 = vec_max(incomingVec0,zero);
        normalPerm = vec_lvsl(12,normal);
        jVec = vec_madd(incomingVec0, directedLightVec, ambientLightVec);
        jVecInt = vec_cts(jVec,0);  // RGBx
        jVecShort = vec_pack(jVecInt,jVecInt);      // RGBxRGBx
        jVecChar = vec_packsu(jVecShort,jVecShort); // RGBxRGBxRGBxRGBx
        jVecChar = vec_sel(jVecChar,vSel,vSel);     // RGBARGBARGBARGBA replace alpha with 255
        vec_ste((vector unsigned int)jVecChar,0,(unsigned int *)&colors[i*4]);  // store color
#else
        incoming = DotProduct (normal, lightDir);
        if ( incoming <= 0 ) {
            *(int *)&colors[i*4] = ambientLightInt;
            continue;
        } 
        j = myftol( ambientLight[0] + incoming * directedLight[0] );
        if ( j > 255 ) {
            j = 255;
        }
        colors[i*4+0] = j;

        j = myftol( ambientLight[1] + incoming * directedLight[1] );
        if ( j > 255 ) {
            j = 255;
        }
        colors[i*4+1] = j;

        j = myftol( ambientLight[2] + incoming * directedLight[2] );
        if ( j > 255 ) {
            j = 255;
        }
        colors[i*4+2] = j;

        colors[i*4+3] = 255;
#endif
    }
}

---