gl_rmain.c

Quake 2 Source code for students by Theerthan You can also download from idsoftwares.com

/*
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.

*/
// r_main.c
#include "gl_local.h"

void R_Clear (void);

viddef_t	vid;

refimport_t	ri;

int GL_TEXTURE0, GL_TEXTURE1;

model_t		*r_worldmodel;

float		gldepthmin, gldepthmax;

glconfig_t gl_config;
glstate_t  gl_state;

image_t		*r_notexture;		// use for bad textures
image_t		*r_particletexture;	// little dot for particles

entity_t	*currententity;
model_t		*currentmodel;

cplane_t	frustum[4];

int			r_visframecount;	// bumped when going to a new PVS
int			r_framecount;		// used for dlight push checking

int			c_brush_polys, c_alias_polys;

float		v_blend[4];			// final blending color

void GL_Strings_f( void );

//
// view origin
//
vec3_t	vup;
vec3_t	vpn;
vec3_t	vright;
vec3_t	r_origin;

float	r_world_matrix[16];
float	r_base_world_matrix[16];

//
// screen size info
//
refdef_t	r_newrefdef;

int		r_viewcluster, r_viewcluster2, r_oldviewcluster, r_oldviewcluster2;

cvar_t	*r_norefresh;
cvar_t	*r_drawentities;
cvar_t	*r_drawworld;
cvar_t	*r_speeds;
cvar_t	*r_fullbright;
cvar_t	*r_novis;
cvar_t	*r_nocull;
cvar_t	*r_lerpmodels;
cvar_t	*r_lefthand;

cvar_t	*r_lightlevel;	// FIXME: This is a HACK to get the client's light level

cvar_t	*gl_nosubimage;
cvar_t	*gl_allow_software;

cvar_t	*gl_vertex_arrays;

cvar_t	*gl_particle_min_size;
cvar_t	*gl_particle_max_size;
cvar_t	*gl_particle_size;
cvar_t	*gl_particle_att_a;
cvar_t	*gl_particle_att_b;
cvar_t	*gl_particle_att_c;

cvar_t	*gl_ext_swapinterval;
cvar_t	*gl_ext_palettedtexture;
cvar_t	*gl_ext_multitexture;
cvar_t	*gl_ext_pointparameters;
cvar_t	*gl_ext_compiled_vertex_array;

cvar_t	*gl_log;
cvar_t	*gl_bitdepth;
cvar_t	*gl_drawbuffer;
cvar_t  *gl_driver;
cvar_t	*gl_lightmap;
cvar_t	*gl_shadows;
cvar_t	*gl_mode;
cvar_t	*gl_dynamic;
cvar_t  *gl_monolightmap;
cvar_t	*gl_modulate;
cvar_t	*gl_nobind;
cvar_t	*gl_round_down;
cvar_t	*gl_picmip;
cvar_t	*gl_skymip;
cvar_t	*gl_showtris;
cvar_t	*gl_ztrick;
cvar_t	*gl_finish;
cvar_t	*gl_clear;
cvar_t	*gl_cull;
cvar_t	*gl_polyblend;
cvar_t	*gl_flashblend;
cvar_t	*gl_playermip;
cvar_t  *gl_saturatelighting;
cvar_t	*gl_swapinterval;
cvar_t	*gl_texturemode;
cvar_t	*gl_texturealphamode;
cvar_t	*gl_texturesolidmode;
cvar_t	*gl_lockpvs;

cvar_t	*gl_3dlabs_broken;

cvar_t	*vid_fullscreen;
cvar_t	*vid_gamma;
cvar_t	*vid_ref;

/*
=================
R_CullBox

Returns true if the box is completely outside the frustom
=================
*/
qboolean R_CullBox (vec3_t mins, vec3_t maxs)
{
	int		i;

	if (r_nocull->value)
		return false;

	for (i=0 ; i<4 ; i++)
		if ( BOX_ON_PLANE_SIDE(mins, maxs, &frustum[i]) == 2)
			return true;
	return false;
}


void R_RotateForEntity (entity_t *e)
{
    qglTranslatef (e->origin[0],  e->origin[1],  e->origin[2]);

    qglRotatef (e->angles[1],  0, 0, 1);
    qglRotatef (-e->angles[0],  0, 1, 0);
    qglRotatef (-e->angles[2],  1, 0, 0);
}

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

  SPRITE MODELS

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


/*
=================
R_DrawSpriteModel

=================
*/
void R_DrawSpriteModel (entity_t *e)
{
	float alpha = 1.0F;
	vec3_t	point;
	dsprframe_t	*frame;
	float		*up, *right;
	dsprite_t		*psprite;

	// don't even bother culling, because it's just a single
	// polygon without a surface cache

	psprite = (dsprite_t *)currentmodel->extradata;

#if 0
	if (e->frame < 0 || e->frame >= psprite->numframes)
	{
		ri.Con_Printf (PRINT_ALL, "no such sprite frame %i\n", e->frame);
		e->frame = 0;
	}
#endif
	e->frame %= psprite->numframes;

	frame = &psprite->frames[e->frame];

#if 0
	if (psprite->type == SPR_ORIENTED)
	{	// bullet marks on walls
	vec3_t		v_forward, v_right, v_up;

	AngleVectors (currententity->angles, v_forward, v_right, v_up);
		up = v_up;
		right = v_right;
	}
	else
#endif
	{	// normal sprite
		up = vup;
		right = vright;
	}

	if ( e->flags & RF_TRANSLUCENT )
		alpha = e->alpha;

	if ( alpha != 1.0F )
		qglEnable( GL_BLEND );

	qglColor4f( 1, 1, 1, alpha );

    GL_Bind(currentmodel->skins[e->frame]->texnum);

	GL_TexEnv( GL_MODULATE );

	if ( alpha == 1.0 )
		qglEnable (GL_ALPHA_TEST);
	else
		qglDisable( GL_ALPHA_TEST );

	qglBegin (GL_QUADS);

	qglTexCoord2f (0, 1);
	VectorMA (e->origin, -frame->origin_y, up, point);
	VectorMA (point, -frame->origin_x, right, point);
	qglVertex3fv (point);

	qglTexCoord2f (0, 0);
	VectorMA (e->origin, frame->height - frame->origin_y, up, point);
	VectorMA (point, -frame->origin_x, right, point);
	qglVertex3fv (point);

	qglTexCoord2f (1, 0);
	VectorMA (e->origin, frame->height - frame->origin_y, up, point);
	VectorMA (point, frame->width - frame->origin_x, right, point);
	qglVertex3fv (point);

	qglTexCoord2f (1, 1);
	VectorMA (e->origin, -frame->origin_y, up, point);
	VectorMA (point, frame->width - frame->origin_x, right, point);
	qglVertex3fv (point);
	
	qglEnd ();

	qglDisable (GL_ALPHA_TEST);
	GL_TexEnv( GL_REPLACE );

	if ( alpha != 1.0F )
		qglDisable( GL_BLEND );

	qglColor4f( 1, 1, 1, 1 );
}

//==================================================================================

/*
=============
R_DrawNullModel
=============
*/
void R_DrawNullModel (void)
{
	vec3_t	shadelight;
	int		i;

	if ( currententity->flags & RF_FULLBRIGHT )
		shadelight[0] = shadelight[1] = shadelight[2] = 1.0F;
	else
		R_LightPoint (currententity->origin, shadelight);

    qglPushMatrix ();
	R_RotateForEntity (currententity);

	qglDisable (GL_TEXTURE_2D);
	qglColor3fv (shadelight);

	qglBegin (GL_TRIANGLE_FAN);
	qglVertex3f (0, 0, -16);
	for (i=0 ; i<=4 ; i++)
		qglVertex3f (16*cos(i*M_PI/2), 16*sin(i*M_PI/2), 0);
	qglEnd ();

	qglBegin (GL_TRIANGLE_FAN);
	qglVertex3f (0, 0, 16);
	for (i=4 ; i>=0 ; i--)
		qglVertex3f (16*cos(i*M_PI/2), 16*sin(i*M_PI/2), 0);
	qglEnd ();

	qglColor3f (1,1,1);
	qglPopMatrix ();
	qglEnable (GL_TEXTURE_2D);
}

/*
=============
R_DrawEntitiesOnList
=============
*/
void R_DrawEntitiesOnList (void)
{
	int		i;

	if (!r_drawentities->value)
		return;

	// draw non-transparent first
	for (i=0 ; i<r_newrefdef.num_entities ; i++)
	{
		currententity = &r_newrefdef.entities[i];
		if (currententity->flags & RF_TRANSLUCENT)
			continue;	// solid

		if ( currententity->flags & RF_BEAM )
		{
			R_DrawBeam( currententity );
		}
		else
		{
			currentmodel = currententity->model;
			if (!currentmodel)
			{
				R_DrawNullModel ();
				continue;
			}
			switch (currentmodel->type)
			{
			case mod_alias:
				R_DrawAliasModel (currententity);
				break;
			case mod_brush:
				R_DrawBrushModel (currententity);
				break;
			case mod_sprite:
				R_DrawSpriteModel (currententity);
				break;
			default:
				ri.Sys_Error (ERR_DROP, "Bad modeltype");
				break;
			}
		}
	}

	// draw transparent entities
	// we could sort these if it ever becomes a problem...
	qglDepthMask (0);		// no z writes
	for (i=0 ; i<r_newrefdef.num_entities ; i++)
	{
		currententity = &r_newrefdef.entities[i];
		if (!(currententity->flags & RF_TRANSLUCENT))
			continue;	// solid

		if ( currententity->flags & RF_BEAM )
		{
			R_DrawBeam( currententity );
		}
		else
		{
			currentmodel = currententity->model;

			if (!currentmodel)
			{
				R_DrawNullModel ();
				continue;
			}
			switch (currentmodel->type)
			{
			case mod_alias:
				R_DrawAliasModel (currententity);
				break;
			case mod_brush:
				R_DrawBrushModel (currententity);
				break;
			case mod_sprite:
				R_DrawSpriteModel (currententity);
				break;
			default:
				ri.Sys_Error (ERR_DROP, "Bad modeltype");
				break;
			}
		}
	}
	qglDepthMask (1);		// back to writing

}

/*
** GL_DrawParticles
**
*/
void GL_DrawParticles( int num_particles, const particle_t particles[], const unsigned colortable[768] )
{
	const particle_t *p;
	int				i;
	vec3_t			up, right;
	float			scale;
	byte			color[4];

    GL_Bind(r_particletexture->texnum);
	qglDepthMask( GL_FALSE );		// no z buffering
	qglEnable( GL_BLEND );
	GL_TexEnv( GL_MODULATE );
	qglBegin( GL_TRIANGLES );

	VectorScale (vup, 1.5, up);
	VectorScale (vright, 1.5, right);

	for ( p = particles, i=0 ; i < num_particles ; i++,p++)
	{
		// hack a scale up to keep particles from disapearing
		scale = ( p->origin[0] - r_origin[0] ) * vpn[0] + 
			    ( p->origin[1] - r_origin[1] ) * vpn[1] +
			    ( p->origin[2] - r_origin[2] ) * vpn[2];

		if (scale < 20)
			scale = 1;
		else
			scale = 1 + scale * 0.004;

		*(int *)color = colortable[p->color];
		color[3] = p->alpha*255;

		qglColor4ubv( color );

		qglTexCoord2f( 0.0625, 0.0625 );
		qglVertex3fv( p->origin );

		qglTexCoord2f( 1.0625, 0.0625 );
		qglVertex3f( p->origin[0] + up[0]*scale, 
			         p->origin[1] + up[1]*scale, 
					 p->origin[2] + up[2]*scale);

		qglTexCoord2f( 0.0625, 1.0625 );
		qglVertex3f( p->origin[0] + right[0]*scale, 
			         p->origin[1] + right[1]*scale, 
					 p->origin[2] + right[2]*scale);
	}

	qglEnd ();
	qglDisable( GL_BLEND );
	qglColor4f( 1,1,1,1 );
	qglDepthMask( 1 );		// back to normal Z buffering
	GL_TexEnv( GL_REPLACE );
}

/*
===============
R_DrawParticles
===============
*/
void R_DrawParticles (void)
{
	if ( gl_ext_pointparameters->value && qglPointParameterfEXT )
	{
		int i;
		unsigned char color[4];
		const particle_t *p;

		qglDepthMask( GL_FALSE );
		qglEnable( GL_BLEND );
		qglDisable( GL_TEXTURE_2D );

		qglPointSize( gl_particle_size->value );

		qglBegin( GL_POINTS );
		for ( i = 0, p = r_newrefdef.particles; i < r_newrefdef.num_particles; i++, p++ )
		{
			*(int *)color = d_8to24table[p->color];
			color[3] = p->alpha*255;

			qglColor4ubv( color );

			qglVertex3fv( p->origin );
		}
		qglEnd();

		qglDisable( GL_BLEND );
		qglColor4f( 1.0F, 1.0F, 1.0F, 1.0F );
		qglDepthMask( GL_TRUE );
		qglEnable( GL_TEXTURE_2D );

	}
	else
	{
		GL_DrawParticles( r_newrefdef.num_particles, r_newrefdef.particles, d_8to24table );
	}
}

/*
============
R_PolyBlend
============
*/
void R_PolyBlend (void)
{
	if (!gl_polyblend->value)
		return;
	if (!v_blend[3])
		return;

	qglDisable (GL_ALPHA_TEST);
	qglEnable (GL_BLEND);
	qglDisable (GL_DEPTH_TEST);
	qglDisable (GL_TEXTURE_2D);

    qglLoadIdentity ();

	// FIXME: get rid of these
    qglRotatef (-90,  1, 0, 0);	    // put Z going up
    qglRotatef (90,  0, 0, 1);	    // put Z going up

	qglColor4fv (v_blend);

	qglBegin (GL_QUADS);

	qglVertex3f (10, 100, 100);
	qglVertex3f (10, -100, 100);
	qglVertex3f (10, -100, -100);
	qglVertex3f (10, 100, -100);
	qglEnd ();

	qglDisable (GL_BLEND);
	qglEnable (GL_TEXTURE_2D);
	qglEnable (GL_ALPHA_TEST);

	qglColor4f(1,1,1,1);
}

//=======================================================================

int SignbitsForPlane (cplane_t *out)
{
	int	bits, j;

	// for fast box on planeside test

	bits = 0;
	for (j=0 ; j<3 ; j++)
	{
		if (out->normal[j] < 0)
			bits |= 1<<j;
	}
	return bits;
}


void R_SetFrustum (void)
{
	int		i;

#if 0
	/*
	** this code is wrong, since it presume a 90 degree FOV both in the
	** horizontal and vertical plane
	*/
	// front side is visible
	VectorAdd (vpn, vright, frustum[0].normal);
	VectorSubtract (vpn, vright, frustum[1].normal);
	VectorAdd (vpn, vup, frustum[2].normal);
	VectorSubtract (vpn, vup, frustum[3].normal);

	// we theoretically don't need to normalize these vectors, but I do it
	// anyway so that debugging is a little easier
	VectorNormalize( frustum[0].normal );
	VectorNormalize( frustum[1].normal );