* Copied ioq3 src to trunk

1 files changed, 845 insertions, 0 deletions

diff --git a/src/renderer/tr_sky.c b/src/renderer/tr_sky.c
new file mode 100644
index 00000000..02624f3d
--- /dev/null
+++ b/src/renderer/tr_sky.c
@@ -0,0 +1,845 @@
+/*
+===========================================================================
+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 Quake III Arena source code; if not, write to the Free Software
+Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+===========================================================================
+*/
+// tr_sky.c
+#include "tr_local.h"
+
+#define SKY_SUBDIVISIONS		8
+#define HALF_SKY_SUBDIVISIONS	(SKY_SUBDIVISIONS/2)
+
+static float s_cloudTexCoords[6][SKY_SUBDIVISIONS+1][SKY_SUBDIVISIONS+1][2];
+static float s_cloudTexP[6][SKY_SUBDIVISIONS+1][SKY_SUBDIVISIONS+1];
+
+/*
+===================================================================================
+
+POLYGON TO BOX SIDE PROJECTION
+
+===================================================================================
+*/
+
+static vec3_t sky_clip[6] = 
+{
+	{1,1,0},
+	{1,-1,0},
+	{0,-1,1},
+	{0,1,1},
+	{1,0,1},
+	{-1,0,1} 
+};
+
+static float	sky_mins[2][6], sky_maxs[2][6];
+static float	sky_min, sky_max;
+
+/*
+================
+AddSkyPolygon
+================
+*/
+static void AddSkyPolygon (int nump, vec3_t vecs) 
+{
+	int		i,j;
+	vec3_t	v, av;
+	float	s, t, dv;
+	int		axis;
+	float	*vp;
+	// s = [0]/[2], t = [1]/[2]
+	static 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}
+	};
+
+	// 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 < sky_mins[0][axis])
+			sky_mins[0][axis] = s;
+		if (t < sky_mins[1][axis])
+			sky_mins[1][axis] = t;
+		if (s > sky_maxs[0][axis])
+			sky_maxs[0][axis] = s;
+		if (t > sky_maxs[1][axis])
+			sky_maxs[1][axis] = t;
+	}
+}
+
+#define	ON_EPSILON		0.1f			// point on plane side epsilon
+#define	MAX_CLIP_VERTS	64
+/*
+================
+ClipSkyPolygon
+================
+*/
+static 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.Error (ERR_DROP, "ClipSkyPolygon: MAX_CLIP_VERTS");
+	if (stage == 6)
+	{	// fully clipped, so draw it
+		AddSkyPolygon (nump, vecs);
+		return;
+	}
+
+	front = back = qfalse;
+	norm = sky_clip[stage];
+	for (i=0, v = vecs ; i<nump ; i++, v+=3)
+	{
+		d = DotProduct (v, norm);
+		if (d > ON_EPSILON)
+		{
+			front = qtrue;
+			sides[i] = SIDE_FRONT;
+		}
+		else if (d < -ON_EPSILON)
+		{
+			back = qtrue;
+			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);
+}
+
+/*
+==============
+ClearSkyBox
+==============
+*/
+static void ClearSkyBox (void) {
+	int		i;
+
+	for (i=0 ; i<6 ; i++) {
+		sky_mins[0][i] = sky_mins[1][i] = 9999;
+		sky_maxs[0][i] = sky_maxs[1][i] = -9999;
+	}
+}
+
+/*
+================
+RB_ClipSkyPolygons
+================
+*/
+void RB_ClipSkyPolygons( shaderCommands_t *input )
+{
+	vec3_t		p[5];	// need one extra point for clipping
+	int			i, j;
+
+	ClearSkyBox();
+
+	for ( i = 0; i < input->numIndexes; i += 3 )
+	{
+		for (j = 0 ; j < 3 ; j++) 
+		{
+			VectorSubtract( input->xyz[input->indexes[i+j]],
+							backEnd.viewParms.or.origin, 
+							p[j] );
+		}
+		ClipSkyPolygon( 3, p[0], 0 );
+	}
+}
+
+/*
+===================================================================================
+
+CLOUD VERTEX GENERATION
+
+===================================================================================
+*/
+
+/*
+** MakeSkyVec
+**
+** Parms: s, t range from -1 to 1
+*/
+static void MakeSkyVec( float s, float t, int axis, float outSt[2], vec3_t outXYZ )
+{
+	// 1 = s, 2 = t, 3 = 2048
+	static 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
+	};
+
+	vec3_t		b;
+	int			j, k;
+	float	boxSize;
+
+	boxSize = backEnd.viewParms.zFar / 1.75;		// div sqrt(3)
+	b[0] = s*boxSize;
+	b[1] = t*boxSize;
+	b[2] = boxSize;
+
+	for (j=0 ; j<3 ; j++)
+	{
+		k = st_to_vec[axis][j];
+		if (k < 0)
+		{
+			outXYZ[j] = -b[-k - 1];
+		}
+		else
+		{
+			outXYZ[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;
+
+
+	if ( outSt )
+	{
+		outSt[0] = s;
+		outSt[1] = t;
+	}
+}
+
+static int	sky_texorder[6] = {0,2,1,3,4,5};
+static vec3_t	s_skyPoints[SKY_SUBDIVISIONS+1][SKY_SUBDIVISIONS+1];
+static float	s_skyTexCoords[SKY_SUBDIVISIONS+1][SKY_SUBDIVISIONS+1][2];
+
+static void DrawSkySide( struct image_s *image, const int mins[2], const int maxs[2] )
+{
+	int s, t;
+
+	GL_Bind( image );
+
+	for ( t = mins[1]+HALF_SKY_SUBDIVISIONS; t < maxs[1]+HALF_SKY_SUBDIVISIONS; t++ )
+	{
+		qglBegin( GL_TRIANGLE_STRIP );
+
+		for ( s = mins[0]+HALF_SKY_SUBDIVISIONS; s <= maxs[0]+HALF_SKY_SUBDIVISIONS; s++ )
+		{
+			qglTexCoord2fv( s_skyTexCoords[t][s] );
+			qglVertex3fv( s_skyPoints[t][s] );
+
+			qglTexCoord2fv( s_skyTexCoords[t+1][s] );
+			qglVertex3fv( s_skyPoints[t+1][s] );
+		}
+
+		qglEnd();
+	}
+}
+
+static void DrawSkyBox( shader_t *shader )
+{
+	int		i;
+
+	sky_min = 0;
+	sky_max = 1;
+
+	Com_Memset( s_skyTexCoords, 0, sizeof( s_skyTexCoords ) );
+
+	for (i=0 ; i<6 ; i++)
+	{
+		int sky_mins_subd[2], sky_maxs_subd[2];
+		int s, t;
+
+		sky_mins[0][i] = floor( sky_mins[0][i] * HALF_SKY_SUBDIVISIONS ) / HALF_SKY_SUBDIVISIONS;
+		sky_mins[1][i] = floor( sky_mins[1][i] * HALF_SKY_SUBDIVISIONS ) / HALF_SKY_SUBDIVISIONS;
+		sky_maxs[0][i] = ceil( sky_maxs[0][i] * HALF_SKY_SUBDIVISIONS ) / HALF_SKY_SUBDIVISIONS;
+		sky_maxs[1][i] = ceil( sky_maxs[1][i] * HALF_SKY_SUBDIVISIONS ) / HALF_SKY_SUBDIVISIONS;
+
+		if ( ( sky_mins[0][i] >= sky_maxs[0][i] ) ||
+			 ( sky_mins[1][i] >= sky_maxs[1][i] ) )
+		{
+			continue;
+		}
+
+		sky_mins_subd[0] = sky_mins[0][i] * HALF_SKY_SUBDIVISIONS;
+		sky_mins_subd[1] = sky_mins[1][i] * HALF_SKY_SUBDIVISIONS;
+		sky_maxs_subd[0] = sky_maxs[0][i] * HALF_SKY_SUBDIVISIONS;
+		sky_maxs_subd[1] = sky_maxs[1][i] * HALF_SKY_SUBDIVISIONS;
+
+		if ( sky_mins_subd[0] < -HALF_SKY_SUBDIVISIONS ) 
+			sky_mins_subd[0] = -HALF_SKY_SUBDIVISIONS;
+		else if ( sky_mins_subd[0] > HALF_SKY_SUBDIVISIONS ) 
+			sky_mins_subd[0] = HALF_SKY_SUBDIVISIONS;
+		if ( sky_mins_subd[1] < -HALF_SKY_SUBDIVISIONS )
+			sky_mins_subd[1] = -HALF_SKY_SUBDIVISIONS;
+		else if ( sky_mins_subd[1] > HALF_SKY_SUBDIVISIONS ) 
+			sky_mins_subd[1] = HALF_SKY_SUBDIVISIONS;
+
+		if ( sky_maxs_subd[0] < -HALF_SKY_SUBDIVISIONS ) 
+			sky_maxs_subd[0] = -HALF_SKY_SUBDIVISIONS;
+		else if ( sky_maxs_subd[0] > HALF_SKY_SUBDIVISIONS ) 
+			sky_maxs_subd[0] = HALF_SKY_SUBDIVISIONS;
+		if ( sky_maxs_subd[1] < -HALF_SKY_SUBDIVISIONS ) 
+			sky_maxs_subd[1] = -HALF_SKY_SUBDIVISIONS;
+		else if ( sky_maxs_subd[1] > HALF_SKY_SUBDIVISIONS ) 
+			sky_maxs_subd[1] = HALF_SKY_SUBDIVISIONS;
+
+		//
+		// iterate through the subdivisions
+		//
+		for ( t = sky_mins_subd[1]+HALF_SKY_SUBDIVISIONS; t <= sky_maxs_subd[1]+HALF_SKY_SUBDIVISIONS; t++ )
+		{
+			for ( s = sky_mins_subd[0]+HALF_SKY_SUBDIVISIONS; s <= sky_maxs_subd[0]+HALF_SKY_SUBDIVISIONS; s++ )
+			{
+				MakeSkyVec( ( s - HALF_SKY_SUBDIVISIONS ) / ( float ) HALF_SKY_SUBDIVISIONS, 
+							( t - HALF_SKY_SUBDIVISIONS ) / ( float ) HALF_SKY_SUBDIVISIONS, 
+							i, 
+							s_skyTexCoords[t][s], 
+							s_skyPoints[t][s] );
+			}
+		}
+
+		DrawSkySide( shader->sky.outerbox[sky_texorder[i]],
+			         sky_mins_subd,
+					 sky_maxs_subd );
+	}
+
+}
+
+static void FillCloudySkySide( const int mins[2], const int maxs[2], qboolean addIndexes )
+{
+	int s, t;
+	int vertexStart = tess.numVertexes;
+	int tHeight, sWidth;
+
+	tHeight = maxs[1] - mins[1] + 1;
+	sWidth = maxs[0] - mins[0] + 1;
+
+	for ( t = mins[1]+HALF_SKY_SUBDIVISIONS; t <= maxs[1]+HALF_SKY_SUBDIVISIONS; t++ )
+	{
+		for ( s = mins[0]+HALF_SKY_SUBDIVISIONS; s <= maxs[0]+HALF_SKY_SUBDIVISIONS; s++ )
+		{
+			VectorAdd( s_skyPoints[t][s], backEnd.viewParms.or.origin, tess.xyz[tess.numVertexes] );
+			tess.texCoords[tess.numVertexes][0][0] = s_skyTexCoords[t][s][0];
+			tess.texCoords[tess.numVertexes][0][1] = s_skyTexCoords[t][s][1];
+
+			tess.numVertexes++;
+
+			if ( tess.numVertexes >= SHADER_MAX_VERTEXES )
+			{
+				ri.Error( ERR_DROP, "SHADER_MAX_VERTEXES hit in FillCloudySkySide()\n" );
+			}
+		}
+	}
+
+	// only add indexes for one pass, otherwise it would draw multiple times for each pass
+	if ( addIndexes ) {
+		for ( t = 0; t < tHeight-1; t++ )
+		{	
+			for ( s = 0; s < sWidth-1; s++ )
+			{
+				tess.indexes[tess.numIndexes] = vertexStart + s + t * ( sWidth );
+				tess.numIndexes++;
+				tess.indexes[tess.numIndexes] = vertexStart + s + ( t + 1 ) * ( sWidth );
+				tess.numIndexes++;
+				tess.indexes[tess.numIndexes] = vertexStart + s + 1 + t * ( sWidth );
+				tess.numIndexes++;
+
+				tess.indexes[tess.numIndexes] = vertexStart + s + ( t + 1 ) * ( sWidth );
+				tess.numIndexes++;
+				tess.indexes[tess.numIndexes] = vertexStart + s + 1 + ( t + 1 ) * ( sWidth );
+				tess.numIndexes++;
+				tess.indexes[tess.numIndexes] = vertexStart + s + 1 + t * ( sWidth );
+				tess.numIndexes++;
+			}
+		}
+	}
+}
+
+static void FillCloudBox( const shader_t *shader, int stage )
+{
+	int i;
+
+	for ( i =0; i < 6; i++ )
+	{
+		int sky_mins_subd[2], sky_maxs_subd[2];
+		int s, t;
+		float MIN_T;
+
+		if ( 1 ) // FIXME? shader->sky.fullClouds )
+		{
+			MIN_T = -HALF_SKY_SUBDIVISIONS;
+
+			// still don't want to draw the bottom, even if fullClouds
+			if ( i == 5 )
+				continue;
+		}
+		else
+		{
+			switch( i )
+			{
+			case 0:
+			case 1:
+			case 2:
+			case 3:
+				MIN_T = -1;
+				break;
+			case 5:
+				// don't draw clouds beneath you
+				continue;
+			case 4:		// top
+			default:
+				MIN_T = -HALF_SKY_SUBDIVISIONS;
+				break;
+			}
+		}
+
+		sky_mins[0][i] = floor( sky_mins[0][i] * HALF_SKY_SUBDIVISIONS ) / HALF_SKY_SUBDIVISIONS;
+		sky_mins[1][i] = floor( sky_mins[1][i] * HALF_SKY_SUBDIVISIONS ) / HALF_SKY_SUBDIVISIONS;
+		sky_maxs[0][i] = ceil( sky_maxs[0][i] * HALF_SKY_SUBDIVISIONS ) / HALF_SKY_SUBDIVISIONS;
+		sky_maxs[1][i] = ceil( sky_maxs[1][i] * HALF_SKY_SUBDIVISIONS ) / HALF_SKY_SUBDIVISIONS;
+
+		if ( ( sky_mins[0][i] >= sky_maxs[0][i] ) ||
+			 ( sky_mins[1][i] >= sky_maxs[1][i] ) )
+		{
+			continue;
+		}
+
+		sky_mins_subd[0] = myftol( sky_mins[0][i] * HALF_SKY_SUBDIVISIONS );
+		sky_mins_subd[1] = myftol( sky_mins[1][i] * HALF_SKY_SUBDIVISIONS );
+		sky_maxs_subd[0] = myftol( sky_maxs[0][i] * HALF_SKY_SUBDIVISIONS );
+		sky_maxs_subd[1] = myftol( sky_maxs[1][i] * HALF_SKY_SUBDIVISIONS );
+
+		if ( sky_mins_subd[0] < -HALF_SKY_SUBDIVISIONS ) 
+			sky_mins_subd[0] = -HALF_SKY_SUBDIVISIONS;
+		else if ( sky_mins_subd[0] > HALF_SKY_SUBDIVISIONS ) 
+			sky_mins_subd[0] = HALF_SKY_SUBDIVISIONS;
+		if ( sky_mins_subd[1] < MIN_T )
+			sky_mins_subd[1] = MIN_T;
+		else if ( sky_mins_subd[1] > HALF_SKY_SUBDIVISIONS ) 
+			sky_mins_subd[1] = HALF_SKY_SUBDIVISIONS;
+
+		if ( sky_maxs_subd[0] < -HALF_SKY_SUBDIVISIONS ) 
+			sky_maxs_subd[0] = -HALF_SKY_SUBDIVISIONS;
+		else if ( sky_maxs_subd[0] > HALF_SKY_SUBDIVISIONS ) 
+			sky_maxs_subd[0] = HALF_SKY_SUBDIVISIONS;
+		if ( sky_maxs_subd[1] < MIN_T )
+			sky_maxs_subd[1] = MIN_T;
+		else if ( sky_maxs_subd[1] > HALF_SKY_SUBDIVISIONS ) 
+			sky_maxs_subd[1] = HALF_SKY_SUBDIVISIONS;
+
+		//
+		// iterate through the subdivisions
+		//
+		for ( t = sky_mins_subd[1]+HALF_SKY_SUBDIVISIONS; t <= sky_maxs_subd[1]+HALF_SKY_SUBDIVISIONS; t++ )
+		{
+			for ( s = sky_mins_subd[0]+HALF_SKY_SUBDIVISIONS; s <= sky_maxs_subd[0]+HALF_SKY_SUBDIVISIONS; s++ )
+			{
+				MakeSkyVec( ( s - HALF_SKY_SUBDIVISIONS ) / ( float ) HALF_SKY_SUBDIVISIONS, 
+							( t - HALF_SKY_SUBDIVISIONS ) / ( float ) HALF_SKY_SUBDIVISIONS, 
+							i, 
+							NULL,
+							s_skyPoints[t][s] );
+
+				s_skyTexCoords[t][s][0] = s_cloudTexCoords[i][t][s][0];
+				s_skyTexCoords[t][s][1] = s_cloudTexCoords[i][t][s][1];
+			}
+		}
+
+		// only add indexes for first stage
+		FillCloudySkySide( sky_mins_subd, sky_maxs_subd, ( stage == 0 ) );
+	}
+}
+
+/*
+** R_BuildCloudData
+*/
+void R_BuildCloudData( shaderCommands_t *input )
+{
+	int			i;
+	shader_t	*shader;
+
+	shader = input->shader;
+
+	assert( shader->isSky );
+
+	sky_min = 1.0 / 256.0f;		// FIXME: not correct?
+	sky_max = 255.0 / 256.0f;
+
+	// set up for drawing
+	tess.numIndexes = 0;
+	tess.numVertexes = 0;
+
+	if ( input->shader->sky.cloudHeight )
+	{
+		for ( i = 0; i < MAX_SHADER_STAGES; i++ )
+		{
+			if ( !tess.xstages[i] ) {
+				break;
+			}
+			FillCloudBox( input->shader, i );
+		}
+	}
+}
+
+/*
+** R_InitSkyTexCoords
+** Called when a sky shader is parsed
+*/
+#define SQR( a ) ((a)*(a))
+void R_InitSkyTexCoords( float heightCloud )
+{
+	int i, s, t;
+	float radiusWorld = 4096;
+	float p;
+	float sRad, tRad;
+	vec3_t skyVec;
+	vec3_t v;
+
+	// init zfar so MakeSkyVec works even though
+	// a world hasn't been bounded
+	backEnd.viewParms.zFar = 1024;
+
+	for ( i = 0; i < 6; i++ )
+	{
+		for ( t = 0; t <= SKY_SUBDIVISIONS; t++ )
+		{
+			for ( s = 0; s <= SKY_SUBDIVISIONS; s++ )
+			{
+				// compute vector from view origin to sky side integral point
+				MakeSkyVec( ( s - HALF_SKY_SUBDIVISIONS ) / ( float ) HALF_SKY_SUBDIVISIONS, 
+							( t - HALF_SKY_SUBDIVISIONS ) / ( float ) HALF_SKY_SUBDIVISIONS, 
+							i, 
+							NULL,
+							skyVec );
+
+				// compute parametric value 'p' that intersects with cloud layer
+				p = ( 1.0f / ( 2 * DotProduct( skyVec, skyVec ) ) ) *
+					( -2 * skyVec[2] * radiusWorld + 
+					   2 * sqrt( SQR( skyVec[2] ) * SQR( radiusWorld ) + 
+					             2 * SQR( skyVec[0] ) * radiusWorld * heightCloud +
+								 SQR( skyVec[0] ) * SQR( heightCloud ) + 
+								 2 * SQR( skyVec[1] ) * radiusWorld * heightCloud +
+								 SQR( skyVec[1] ) * SQR( heightCloud ) + 
+								 2 * SQR( skyVec[2] ) * radiusWorld * heightCloud +
+								 SQR( skyVec[2] ) * SQR( heightCloud ) ) );
+
+				s_cloudTexP[i][t][s] = p;
+
+				// compute intersection point based on p
+				VectorScale( skyVec, p, v );
+				v[2] += radiusWorld;
+
+				// compute vector from world origin to intersection point 'v'
+				VectorNormalize( v );
+
+				sRad = Q_acos( v[0] );
+				tRad = Q_acos( v[1] );
+
+				s_cloudTexCoords[i][t][s][0] = sRad;
+				s_cloudTexCoords[i][t][s][1] = tRad;
+			}
+		}
+	}
+}
+
+//======================================================================================
+
+/*
+** RB_DrawSun
+*/
+void RB_DrawSun( void ) {
+	float		size;
+	float		dist;
+	vec3_t		origin, vec1, vec2;
+	vec3_t		temp;
+
+	if ( !backEnd.skyRenderedThisView ) {
+		return;
+	}
+	if ( !r_drawSun->integer ) {
+		return;
+	}
+	qglLoadMatrixf( backEnd.viewParms.world.modelMatrix );
+	qglTranslatef (backEnd.viewParms.or.origin[0], backEnd.viewParms.or.origin[1], backEnd.viewParms.or.origin[2]);
+
+	dist = 	backEnd.viewParms.zFar / 1.75;		// div sqrt(3)
+	size = dist * 0.4;
+
+	VectorScale( tr.sunDirection, dist, origin );
+	PerpendicularVector( vec1, tr.sunDirection );
+	CrossProduct( tr.sunDirection, vec1, vec2 );
+
+	VectorScale( vec1, size, vec1 );
+	VectorScale( vec2, size, vec2 );
+
+	// farthest depth range
+	qglDepthRange( 1.0, 1.0 );
+
+	// FIXME: use quad stamp
+	RB_BeginSurface( tr.sunShader, tess.fogNum );
+		VectorCopy( origin, temp );
+		VectorSubtract( temp, vec1, temp );
+		VectorSubtract( temp, vec2, temp );
+		VectorCopy( temp, tess.xyz[tess.numVertexes] );
+		tess.texCoords[tess.numVertexes][0][0] = 0;
+		tess.texCoords[tess.numVertexes][0][1] = 0;
+		tess.vertexColors[tess.numVertexes][0] = 255;
+		tess.vertexColors[tess.numVertexes][1] = 255;
+		tess.vertexColors[tess.numVertexes][2] = 255;
+		tess.numVertexes++;
+
+		VectorCopy( origin, temp );
+		VectorAdd( temp, vec1, temp );
+		VectorSubtract( temp, vec2, temp );
+		VectorCopy( temp, tess.xyz[tess.numVertexes] );
+		tess.texCoords[tess.numVertexes][0][0] = 0;
+		tess.texCoords[tess.numVertexes][0][1] = 1;
+		tess.vertexColors[tess.numVertexes][0] = 255;
+		tess.vertexColors[tess.numVertexes][1] = 255;
+		tess.vertexColors[tess.numVertexes][2] = 255;
+		tess.numVertexes++;
+
+		VectorCopy( origin, temp );
+		VectorAdd( temp, vec1, temp );
+		VectorAdd( temp, vec2, temp );
+		VectorCopy( temp, tess.xyz[tess.numVertexes] );
+		tess.texCoords[tess.numVertexes][0][0] = 1;
+		tess.texCoords[tess.numVertexes][0][1] = 1;
+		tess.vertexColors[tess.numVertexes][0] = 255;
+		tess.vertexColors[tess.numVertexes][1] = 255;
+		tess.vertexColors[tess.numVertexes][2] = 255;
+		tess.numVertexes++;
+
+		VectorCopy( origin, temp );
+		VectorSubtract( temp, vec1, temp );
+		VectorAdd( temp, vec2, temp );
+		VectorCopy( temp, tess.xyz[tess.numVertexes] );
+		tess.texCoords[tess.numVertexes][0][0] = 1;
+		tess.texCoords[tess.numVertexes][0][1] = 0;
+		tess.vertexColors[tess.numVertexes][0] = 255;
+		tess.vertexColors[tess.numVertexes][1] = 255;
+		tess.vertexColors[tess.numVertexes][2] = 255;
+		tess.numVertexes++;
+
+		tess.indexes[tess.numIndexes++] = 0;
+		tess.indexes[tess.numIndexes++] = 1;
+		tess.indexes[tess.numIndexes++] = 2;
+		tess.indexes[tess.numIndexes++] = 0;
+		tess.indexes[tess.numIndexes++] = 2;
+		tess.indexes[tess.numIndexes++] = 3;
+
+	RB_EndSurface();
+
+	// back to normal depth range
+	qglDepthRange( 0.0, 1.0 );
+}
+
+
+
+
+/*
+================
+RB_StageIteratorSky
+
+All of the visible sky triangles are in tess
+
+Other things could be stuck in here, like birds in the sky, etc
+================
+*/
+void RB_StageIteratorSky( void ) {
+	if ( r_fastsky->integer ) {
+		return;
+	}
+
+	// go through all the polygons and project them onto
+	// the sky box to see which blocks on each side need
+	// to be drawn
+	RB_ClipSkyPolygons( &tess );
+
+	// r_showsky will let all the sky blocks be drawn in
+	// front of everything to allow developers to see how
+	// much sky is getting sucked in
+	if ( r_showsky->integer ) {
+		qglDepthRange( 0.0, 0.0 );
+	} else {
+		qglDepthRange( 1.0, 1.0 );
+	}
+
+	// draw the outer skybox
+	if ( tess.shader->sky.outerbox[0] && tess.shader->sky.outerbox[0] != tr.defaultImage ) {
+		qglColor3f( tr.identityLight, tr.identityLight, tr.identityLight );
+		
+		qglPushMatrix ();
+		GL_State( 0 );
+		qglTranslatef (backEnd.viewParms.or.origin[0], backEnd.viewParms.or.origin[1], backEnd.viewParms.or.origin[2]);
+
+		DrawSkyBox( tess.shader );
+
+		qglPopMatrix();
+	}
+
+	// generate the vertexes for all the clouds, which will be drawn
+	// by the generic shader routine
+	R_BuildCloudData( &tess );
+
+	RB_StageIteratorGeneric();
+
+	// draw the inner skybox
+
+
+	// back to normal depth range
+	qglDepthRange( 0.0, 1.0 );
+
+	// note that sky was drawn so we will draw a sun later
+	backEnd.skyRenderedThisView = qtrue;
+}
+