tr_surface.c

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	for ( i = 0; i < 4; i++ )
	{
		c = cos( DEG2RAD( 45 + i * 90 ) );
		s = sin( DEG2RAD( 45 + i * 90 ) );
		v[0] = ( right[0] * c + up[0] * s ) * scale * spanWidth;
		v[1] = ( right[1] * c + up[1] * s ) * scale * spanWidth;
		v[2] = ( right[2] * c + up[2] * s ) * scale * spanWidth;
		VectorAdd( start, v, pos[i] );

		if ( numSegs > 1 )
		{
			// offset by 1 segment if we're doing a long distance shot
			VectorAdd( pos[i], dir, pos[i] );
		}
	}

	for ( i = 0; i < numSegs; i++ )
	{
		int j;

		RB_CHECKOVERFLOW( 4, 6 );

		for ( j = 0; j < 4; j++ )
		{
			VectorCopy( pos[j], tess.xyz[tess.numVertexes] );
			tess.texCoords[tess.numVertexes][0][0] = ( j < 2 );
			tess.texCoords[tess.numVertexes][0][1] = ( j && j != 3 );
			tess.vertexColors[tess.numVertexes][0] = backEnd.currentEntity->e.shaderRGBA[0];
			tess.vertexColors[tess.numVertexes][1] = backEnd.currentEntity->e.shaderRGBA[1];
			tess.vertexColors[tess.numVertexes][2] = backEnd.currentEntity->e.shaderRGBA[2];
			tess.numVertexes++;

			VectorAdd( pos[j], dir, pos[j] );
		}

		tess.indexes[tess.numIndexes++] = tess.numVertexes - 4 + 0;
		tess.indexes[tess.numIndexes++] = tess.numVertexes - 4 + 1;
		tess.indexes[tess.numIndexes++] = tess.numVertexes - 4 + 3;
		tess.indexes[tess.numIndexes++] = tess.numVertexes - 4 + 3;
		tess.indexes[tess.numIndexes++] = tess.numVertexes - 4 + 1;
		tess.indexes[tess.numIndexes++] = tess.numVertexes - 4 + 2;
	}
}

/*
** RB_SurfaceRailRinges
*/
void RB_SurfaceRailRings( void ) {
	refEntity_t *e;
	int			numSegs;
	int			len;
	vec3_t		vec;
	vec3_t		right, up;
	vec3_t		start, end;

	e = &backEnd.currentEntity->e;

	VectorCopy( e->oldorigin, start );
	VectorCopy( e->origin, end );

	// compute variables
	VectorSubtract( end, start, vec );
	len = VectorNormalize( vec );
	MakeNormalVectors( vec, right, up );
	numSegs = ( len ) / r_railSegmentLength->value;
	if ( numSegs <= 0 ) {
		numSegs = 1;
	}

	VectorScale( vec, r_railSegmentLength->value, vec );

	DoRailDiscs( numSegs, start, vec, right, up );
}

/*
** RB_SurfaceRailCore
*/
void RB_SurfaceRailCore( void ) {
	refEntity_t *e;
	int			len;
	vec3_t		right;
	vec3_t		vec;
	vec3_t		start, end;
	vec3_t		v1, v2;

	e = &backEnd.currentEntity->e;

	VectorCopy( e->oldorigin, start );
	VectorCopy( e->origin, end );

	VectorSubtract( end, start, vec );
	len = VectorNormalize( vec );

	// compute side vector
	VectorSubtract( start, backEnd.viewParms.or.origin, v1 );
	VectorNormalize( v1 );
	VectorSubtract( end, backEnd.viewParms.or.origin, v2 );
	VectorNormalize( v2 );
	CrossProduct( v1, v2, right );
	VectorNormalize( right );

	DoRailCore( start, end, right, len, r_railCoreWidth->integer );
}

/*
** RB_SurfaceLightningBolt
*/
void RB_SurfaceLightningBolt( void ) {
	refEntity_t *e;
	int			len;
	vec3_t		right;
	vec3_t		vec;
	vec3_t		start, end;
	vec3_t		v1, v2;
	int			i;

	e = &backEnd.currentEntity->e;

	VectorCopy( e->oldorigin, end );
	VectorCopy( e->origin, start );

	// compute variables
	VectorSubtract( end, start, vec );
	len = VectorNormalize( vec );

	// compute side vector
	VectorSubtract( start, backEnd.viewParms.or.origin, v1 );
	VectorNormalize( v1 );
	VectorSubtract( end, backEnd.viewParms.or.origin, v2 );
	VectorNormalize( v2 );
	CrossProduct( v1, v2, right );
	VectorNormalize( right );

	for ( i = 0 ; i < 4 ; i++ ) {
		vec3_t	temp;

		DoRailCore( start, end, right, len, 8 );
		RotatePointAroundVector( temp, vec, right, 45 );
		VectorCopy( temp, right );
	}
}

/*
** VectorArrayNormalize
*
* The inputs to this routing seem to always be close to length = 1.0 (about 0.6 to 2.0)
* This means that we don't have to worry about zero length or enormously long vectors.
*/
static void VectorArrayNormalize(vec4_t *normals, unsigned int count)
{
//    assert(count);
        
#if idppc
    {
        register float half = 0.5;
        register float one  = 1.0;
        float *components = (float *)normals;
        
        // Vanilla PPC code, but since PPC has a reciprocal square root estimate instruction,
        // runs *much* faster than calling sqrt().  We'll use a single Newton-Raphson
        // refinement step to get a little more precision.  This seems to yeild results
        // that are correct to 3 decimal places and usually correct to at least 4 (sometimes 5).
        // (That is, for the given input range of about 0.6 to 2.0).
        do {
            float x, y, z;
            float B, y0, y1;
            
            x = components[0];
            y = components[1];
            z = components[2];
            components += 4;
            B = x*x + y*y + z*z;

#ifdef __GNUC__            
            asm("frsqrte %0,%1" : "=f" (y0) : "f" (B));
#else
			y0 = __frsqrte(B);
#endif
            y1 = y0 + half*y0*(one - B*y0*y0);

            x = x * y1;
            y = y * y1;
            components[-4] = x;
            z = z * y1;
            components[-3] = y;
            components[-2] = z;
        } while(count--);
    }
#else // No assembly version for this architecture, or C_ONLY defined
	// given the input, it's safe to call VectorNormalizeFast
    while (count--) {
        VectorNormalizeFast(normals[0]);
        normals++;
    }
#endif

}



/*
** LerpMeshVertexes
*/
static void LerpMeshVertexes (md3Surface_t *surf, float backlerp) 
{
	short	*oldXyz, *newXyz, *oldNormals, *newNormals;
	float	*outXyz, *outNormal;
	float	oldXyzScale, newXyzScale;
	float	oldNormalScale, newNormalScale;
	int		vertNum;
	unsigned lat, lng;
	int		numVerts;

	outXyz = tess.xyz[tess.numVertexes];
	outNormal = tess.normal[tess.numVertexes];

	newXyz = (short *)((byte *)surf + surf->ofsXyzNormals)
		+ (backEnd.currentEntity->e.frame * surf->numVerts * 4);
	newNormals = newXyz + 3;

	newXyzScale = MD3_XYZ_SCALE * (1.0 - backlerp);
	newNormalScale = 1.0 - backlerp;

	numVerts = surf->numVerts;

	if ( backlerp == 0 ) {
#if idppc_altivec
		vector signed short newNormalsVec0;
		vector signed short newNormalsVec1;
		vector signed int newNormalsIntVec;
		vector float newNormalsFloatVec;
		vector float newXyzScaleVec;
		vector unsigned char newNormalsLoadPermute;
		vector unsigned char newNormalsStorePermute;
		vector float zero;
		
		newNormalsStorePermute = vec_lvsl(0,(float *)&newXyzScaleVec);
		newXyzScaleVec = *(vector float *)&newXyzScale;
		newXyzScaleVec = vec_perm(newXyzScaleVec,newXyzScaleVec,newNormalsStorePermute);
		newXyzScaleVec = vec_splat(newXyzScaleVec,0);		
		newNormalsLoadPermute = vec_lvsl(0,newXyz);
		newNormalsStorePermute = vec_lvsr(0,outXyz);
		zero = (vector float)vec_splat_s8(0);
		//
		// just copy the vertexes
		//
		for (vertNum=0 ; vertNum < numVerts ; vertNum++,
			newXyz += 4, newNormals += 4,
			outXyz += 4, outNormal += 4) 
		{
			newNormalsLoadPermute = vec_lvsl(0,newXyz);
			newNormalsStorePermute = vec_lvsr(0,outXyz);
			newNormalsVec0 = vec_ld(0,newXyz);
			newNormalsVec1 = vec_ld(16,newXyz);
			newNormalsVec0 = vec_perm(newNormalsVec0,newNormalsVec1,newNormalsLoadPermute);
			newNormalsIntVec = vec_unpackh(newNormalsVec0);
			newNormalsFloatVec = vec_ctf(newNormalsIntVec,0);
			newNormalsFloatVec = vec_madd(newNormalsFloatVec,newXyzScaleVec,zero);
			newNormalsFloatVec = vec_perm(newNormalsFloatVec,newNormalsFloatVec,newNormalsStorePermute);
			//outXyz[0] = newXyz[0] * newXyzScale;
			//outXyz[1] = newXyz[1] * newXyzScale;
			//outXyz[2] = newXyz[2] * newXyzScale;

			lat = ( newNormals[0] >> 8 ) & 0xff;
			lng = ( newNormals[0] & 0xff );
			lat *= (FUNCTABLE_SIZE/256);
			lng *= (FUNCTABLE_SIZE/256);

			// decode X as cos( lat ) * sin( long )
			// decode Y as sin( lat ) * sin( long )
			// decode Z as cos( long )

			outNormal[0] = tr.sinTable[(lat+(FUNCTABLE_SIZE/4))&FUNCTABLE_MASK] * tr.sinTable[lng];
			outNormal[1] = tr.sinTable[lat] * tr.sinTable[lng];
			outNormal[2] = tr.sinTable[(lng+(FUNCTABLE_SIZE/4))&FUNCTABLE_MASK];

			vec_ste(newNormalsFloatVec,0,outXyz);
			vec_ste(newNormalsFloatVec,4,outXyz);
			vec_ste(newNormalsFloatVec,8,outXyz);
		}
		
#else
		//
		// just copy the vertexes
		//
		for (vertNum=0 ; vertNum < numVerts ; vertNum++,
			newXyz += 4, newNormals += 4,
			outXyz += 4, outNormal += 4) 
		{

			outXyz[0] = newXyz[0] * newXyzScale;
			outXyz[1] = newXyz[1] * newXyzScale;
			outXyz[2] = newXyz[2] * newXyzScale;

			lat = ( newNormals[0] >> 8 ) & 0xff;
			lng = ( newNormals[0] & 0xff );
			lat *= (FUNCTABLE_SIZE/256);
			lng *= (FUNCTABLE_SIZE/256);

			// decode X as cos( lat ) * sin( long )
			// decode Y as sin( lat ) * sin( long )
			// decode Z as cos( long )

			outNormal[0] = tr.sinTable[(lat+(FUNCTABLE_SIZE/4))&FUNCTABLE_MASK] * tr.sinTable[lng];
			outNormal[1] = tr.sinTable[lat] * tr.sinTable[lng];
			outNormal[2] = tr.sinTable[(lng+(FUNCTABLE_SIZE/4))&FUNCTABLE_MASK];
		}
#endif
	} else {
		//
		// interpolate and copy the vertex and normal
		//
		oldXyz = (short *)((byte *)surf + surf->ofsXyzNormals)
			+ (backEnd.currentEntity->e.oldframe * surf->numVerts * 4);
		oldNormals = oldXyz + 3;

		oldXyzScale = MD3_XYZ_SCALE * backlerp;
		oldNormalScale = backlerp;

		for (vertNum=0 ; vertNum < numVerts ; vertNum++,
			oldXyz += 4, newXyz += 4, oldNormals += 4, newNormals += 4,
			outXyz += 4, outNormal += 4) 
		{
			vec3_t uncompressedOldNormal, uncompressedNewNormal;

			// interpolate the xyz
			outXyz[0] = oldXyz[0] * oldXyzScale + newXyz[0] * newXyzScale;
			outXyz[1] = oldXyz[1] * oldXyzScale + newXyz[1] * newXyzScale;
			outXyz[2] = oldXyz[2] * oldXyzScale + newXyz[2] * newXyzScale;

			// FIXME: interpolate lat/long instead?
			lat = ( newNormals[0] >> 8 ) & 0xff;
			lng = ( newNormals[0] & 0xff );
			lat *= 4;
			lng *= 4;
			uncompressedNewNormal[0] = tr.sinTable[(lat+(FUNCTABLE_SIZE/4))&FUNCTABLE_MASK] * tr.sinTable[lng];
			uncompressedNewNormal[1] = tr.sinTable[lat] * tr.sinTable[lng];
			uncompressedNewNormal[2] = tr.sinTable[(lng+(FUNCTABLE_SIZE/4))&FUNCTABLE_MASK];

			lat = ( oldNormals[0] >> 8 ) & 0xff;
			lng = ( oldNormals[0] & 0xff );
			lat *= 4;
			lng *= 4;

			uncompressedOldNormal[0] = tr.sinTable[(lat+(FUNCTABLE_SIZE/4))&FUNCTABLE_MASK] * tr.sinTable[lng];
			uncompressedOldNormal[1] = tr.sinTable[lat] * tr.sinTable[lng];
			uncompressedOldNormal[2] = tr.sinTable[(lng+(FUNCTABLE_SIZE/4))&FUNCTABLE_MASK];

			outNormal[0] = uncompressedOldNormal[0] * oldNormalScale + uncompressedNewNormal[0] * newNormalScale;
			outNormal[1] = uncompressedOldNormal[1] * oldNormalScale + uncompressedNewNormal[1] * newNormalScale;
			outNormal[2] = uncompressedOldNormal[2] * oldNormalScale + uncompressedNewNormal[2] * newNormalScale;

//			VectorNormalize (outNormal);
		}
    	VectorArrayNormalize((vec4_t *)tess.normal[tess.numVertexes], numVerts);
   	}
}

/*
=============
RB_SurfaceMesh
=============
*/
void RB_SurfaceMesh(md3Surface_t *surface) {
	int				j;
	float			backlerp;
	int				*triangles;
	float			*texCoords;
	int				indexes;
	int				Bob, Doug;
	int				numVerts;

	if (  backEnd.currentEntity->e.oldframe == backEnd.currentEntity->e.frame ) {
		backlerp = 0;
	} else  {
		backlerp = backEnd.currentEntity->e.backlerp;
	}

	RB_CHECKOVERFLOW( surface->numVerts, surface->numTriangles*3 );

	LerpMeshVertexes (surface, backlerp);

	triangles = (int *) ((byte *)surface + surface->ofsTriangles);
	indexes = surface->numTriangles * 3;
	Bob = tess.numIndexes;
	Doug = tess.numVertexes;
	for (j = 0 ; j < indexes ; j++) {
		tess.indexes[Bob + j] = Doug + triangles[j];
	}
	tess.numIndexes += indexes;

	texCoords = (float *) ((byte *)surface + surface->ofsSt);

	numVerts = surface->numVerts;
	for ( j = 0; j < numVerts; j++ ) {
		tess.texCoords[Doug + j][0][0] = texCoords[j*2+0];
		tess.texCoords[Doug + j][0][1] = texCoords[j*2+1];
		// FIXME: fill in lightmapST for completeness?
	}

	tess.numVertexes += surface->numVerts;

}


/*