/*
gl_rmain.c - renderer main loop
Copyright (C) 2010 Uncle Mike

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 3 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.
*/

#include "gl_local.h"
#include "mathlib.h"
#include "library.h"
#include "beamdef.h"
#include "particledef.h"
#include "entity_types.h"

#define IsLiquidContents( cnt )	( cnt == CONTENTS_WATER || cnt == CONTENTS_SLIME || cnt == CONTENTS_LAVA )

float		gldepthmin, gldepthmax;
ref_instance_t	RI;

static int R_RankForRenderMode( int rendermode )
{
	switch( rendermode )
	{
	case kRenderTransTexture:
		return 1;	// draw second
	case kRenderTransAdd:
		return 2;	// draw third
	case kRenderGlow:
		return 3;	// must be last!
	}
	return 0;
}

void R_AllowFog( int allowed )
{
	static int	isFogEnabled;

	if( allowed )
	{
		if( isFogEnabled )
			pglEnable( GL_FOG );
	}
	else
	{
		isFogEnabled = pglIsEnabled( GL_FOG );

		if( isFogEnabled )
			pglDisable( GL_FOG );
	}
}

/*
===============
R_OpaqueEntity

Opaque entity can be brush or studio model but sprite
===============
*/
static qboolean R_OpaqueEntity( cl_entity_t *ent )
{
	if( R_GetEntityRenderMode( ent ) == kRenderNormal )
		return true;
	return false;
}

/*
===============
R_TransEntityCompare

Sorting translucent entities by rendermode then by distance
===============
*/
static int R_TransEntityCompare( const cl_entity_t **a, const cl_entity_t **b )
{
	cl_entity_t	*ent1, *ent2;
	vec3_t		vecLen, org;
	float		dist1, dist2;
	int		rendermode1;
	int		rendermode2;

	ent1 = (cl_entity_t *)*a;
	ent2 = (cl_entity_t *)*b;
	rendermode1 = R_GetEntityRenderMode( ent1 );
	rendermode2 = R_GetEntityRenderMode( ent2 );

	// sort by distance
	if( ent1->model->type != mod_brush || rendermode1 != kRenderTransAlpha )
	{
		VectorAverage( ent1->model->mins, ent1->model->maxs, org );
		VectorAdd( ent1->origin, org, org );
		VectorSubtract( RI.vieworg, org, vecLen );
		dist1 = DotProduct( vecLen, vecLen );
	}
	else dist1 = 1000000000;

	if( ent2->model->type != mod_brush || rendermode2 != kRenderTransAlpha )
	{
		VectorAverage( ent2->model->mins, ent2->model->maxs, org );
		VectorAdd( ent2->origin, org, org );
		VectorSubtract( RI.vieworg, org, vecLen );
		dist2 = DotProduct( vecLen, vecLen );
	}
	else dist2 = 1000000000;

	if( dist1 > dist2 )
		return -1;
	if( dist1 < dist2 )
		return 1;

	// then sort by rendermode
	if( R_RankForRenderMode( rendermode1 ) > R_RankForRenderMode( rendermode2 ))
		return 1;
	if( R_RankForRenderMode( rendermode1 ) < R_RankForRenderMode( rendermode2 ))
		return -1;

	return 0;
}

/*
===============
R_WorldToScreen

Convert a given point from world into screen space
Returns true if we behind to screen
===============
*/
int R_WorldToScreen( const vec3_t point, vec3_t screen )
{
	matrix4x4	worldToScreen;
	qboolean	behind;
	float	w;

	if( !point || !screen )
		return true;

	Matrix4x4_Copy( worldToScreen, RI.worldviewProjectionMatrix );
	screen[0] = worldToScreen[0][0] * point[0] + worldToScreen[0][1] * point[1] + worldToScreen[0][2] * point[2] + worldToScreen[0][3];
	screen[1] = worldToScreen[1][0] * point[0] + worldToScreen[1][1] * point[1] + worldToScreen[1][2] * point[2] + worldToScreen[1][3];
	w = worldToScreen[3][0] * point[0] + worldToScreen[3][1] * point[1] + worldToScreen[3][2] * point[2] + worldToScreen[3][3];
	screen[2] = 0.0f; // just so we have something valid here

	if( w < 0.001f )
	{
		screen[0] *= 100000;
		screen[1] *= 100000;
		behind = true;
	}
	else
	{
		float invw = 1.0f / w;
		screen[0] *= invw;
		screen[1] *= invw;
		behind = false;
	}

	return behind;
}

/*
===============
R_ScreenToWorld

Convert a given point from screen into world space
===============
*/
void R_ScreenToWorld( const vec3_t screen, vec3_t point )
{
	matrix4x4	screenToWorld;
	float	w;

	if( !point || !screen )
		return;

	Matrix4x4_Invert_Full( screenToWorld, RI.worldviewProjectionMatrix );

	point[0] = screen[0] * screenToWorld[0][0] + screen[1] * screenToWorld[0][1] + screen[2] * screenToWorld[0][2] + screenToWorld[0][3];
	point[1] = screen[0] * screenToWorld[1][0] + screen[1] * screenToWorld[1][1] + screen[2] * screenToWorld[1][2] + screenToWorld[1][3];
	point[2] = screen[0] * screenToWorld[2][0] + screen[1] * screenToWorld[2][1] + screen[2] * screenToWorld[2][2] + screenToWorld[2][3];
	w = screen[0] * screenToWorld[3][0] + screen[1] * screenToWorld[3][1] + screen[2] * screenToWorld[3][2] + screenToWorld[3][3];
	if( w != 0.0f ) VectorScale( point, ( 1.0f / w ), point );
}

/*
===============
R_PushScene
===============
*/
void R_PushScene( void )
{
	if( ++tr.draw_stack_pos >= MAX_DRAW_STACK )
		gEngfuncs.Host_Error( "draw stack overflow\n" );

	tr.draw_list = &tr.draw_stack[tr.draw_stack_pos];
}

/*
===============
R_PopScene
===============
*/
void R_PopScene( void )
{
	if( --tr.draw_stack_pos < 0 )
		gEngfuncs.Host_Error( "draw stack underflow\n" );
	tr.draw_list = &tr.draw_stack[tr.draw_stack_pos];
}

/*
===============
R_ClearScene
===============
*/
void R_ClearScene( void )
{
	tr.draw_list->num_solid_entities = 0;
	tr.draw_list->num_trans_entities = 0;
	tr.draw_list->num_beam_entities = 0;
}

/*
===============
R_AddEntity
===============
*/
qboolean R_AddEntity( struct cl_entity_s *clent, int type )
{
	if( !r_drawentities->value )
		return false; // not allow to drawing

	if( !clent || !clent->model )
		return false; // if set to invisible, skip

	if( FBitSet( clent->curstate.effects, EF_NODRAW ))
		return false; // done

	if( !R_ModelOpaque( clent->curstate.rendermode ) && gEngfuncs.CL_FxBlend( clent ) <= 0 )
		return true; // invisible

	if( type == ET_FRAGMENTED )
		r_stats.c_client_ents++;

	if( R_OpaqueEntity( clent ))
	{
		// opaque
		if( tr.draw_list->num_solid_entities >= MAX_VISIBLE_PACKET )
			return false;

		tr.draw_list->solid_entities[tr.draw_list->num_solid_entities] = clent;
		tr.draw_list->num_solid_entities++;
	}
	else
	{
		// translucent
		if( tr.draw_list->num_trans_entities >= MAX_VISIBLE_PACKET )
			return false;

		tr.draw_list->trans_entities[tr.draw_list->num_trans_entities] = clent;
		tr.draw_list->num_trans_entities++;
	}

	return true;
}

/*
=============
R_Clear
=============
*/
static void R_Clear( int bitMask )
{
	int	bits;

	if( gEngfuncs.CL_IsDevOverviewMode( ))
		pglClearColor( 0.0f, 1.0f, 0.0f, 1.0f ); // green background (Valve rules)
	else pglClearColor( 0.5f, 0.5f, 0.5f, 1.0f );

	bits = GL_DEPTH_BUFFER_BIT;

	if( glState.stencilEnabled )
		bits |= GL_STENCIL_BUFFER_BIT;

	bits &= bitMask;

	pglClear( bits );

	// change ordering for overview
	if( RI.drawOrtho )
	{
		gldepthmin = 1.0f;
		gldepthmax = 0.0f;
	}
	else
	{
		gldepthmin = 0.0f;
		gldepthmax = 1.0f;
	}

	pglDepthFunc( GL_LEQUAL );
	pglDepthRange( gldepthmin, gldepthmax );
}

//=============================================================================
/*
===============
R_GetFarClip
===============
*/
static float R_GetFarClip( void )
{
	if( WORLDMODEL && RI.drawWorld )
		return MOVEVARS->zmax * 1.73f;
	return 2048.0f;
}

/*
===============
R_SetupFrustum
===============
*/
void R_SetupFrustum( void )
{
	ref_overview_t	*ov = gEngfuncs.GetOverviewParms();

	if( RP_NORMALPASS() && ( gEngfuncs.GetWaterLevel() >= 3 ))
	{
		RI.fov_x = atan( tan( DEG2RAD( RI.fov_x ) / 2 ) * ( 0.97 + sin( gpGlobals->time * 1.5 ) * 0.03 )) * 2 / (M_PI / 180.0);
		RI.fov_y = atan( tan( DEG2RAD( RI.fov_y ) / 2 ) * ( 1.03 - sin( gpGlobals->time * 1.5 ) * 0.03 )) * 2 / (M_PI / 180.0);
	}

	// build the transformation matrix for the given view angles
	AngleVectors( RI.viewangles, RI.vforward, RI.vright, RI.vup );

	if( !r_lockfrustum->value )
	{
		VectorCopy( RI.vieworg, RI.cullorigin );
		VectorCopy( RI.vforward, RI.cull_vforward );
		VectorCopy( RI.vright, RI.cull_vright );
		VectorCopy( RI.vup, RI.cull_vup );
	}

	if( RI.drawOrtho )
		GL_FrustumInitOrtho( &RI.frustum, ov->xLeft, ov->xRight, ov->yTop, ov->yBottom, ov->zNear, ov->zFar );
	else GL_FrustumInitProj( &RI.frustum, 0.0f, R_GetFarClip(), RI.fov_x, RI.fov_y ); // NOTE: we ignore nearplane here (mirrors only)
}

/*
=============
R_SetupProjectionMatrix
=============
*/
static void R_SetupProjectionMatrix( matrix4x4 m )
{
	GLdouble	xMin, xMax, yMin, yMax, zNear, zFar;

	if( RI.drawOrtho )
	{
		ref_overview_t *ov = gEngfuncs.GetOverviewParms();
		Matrix4x4_CreateOrtho( m, ov->xLeft, ov->xRight, ov->yTop, ov->yBottom, ov->zNear, ov->zFar );
		return;
	}

	RI.farClip = R_GetFarClip();

	zNear = 4.0f;
	zFar = max( 256.0f, RI.farClip );

	yMax = zNear * tan( RI.fov_y * M_PI / 360.0 );
	yMin = -yMax;

	xMax = zNear * tan( RI.fov_x * M_PI / 360.0 );
	xMin = -xMax;

	Matrix4x4_CreateProjection( m, xMax, xMin, yMax, yMin, zNear, zFar );
}

/*
=============
R_SetupModelviewMatrix
=============
*/
static void R_SetupModelviewMatrix( matrix4x4 m )
{
	Matrix4x4_CreateModelview( m );
	Matrix4x4_ConcatRotate( m, -RI.viewangles[2], 1, 0, 0 );
	Matrix4x4_ConcatRotate( m, -RI.viewangles[0], 0, 1, 0 );
	Matrix4x4_ConcatRotate( m, -RI.viewangles[1], 0, 0, 1 );
	Matrix4x4_ConcatTranslate( m, -RI.vieworg[0], -RI.vieworg[1], -RI.vieworg[2] );
}

/*
=============
R_LoadIdentity
=============
*/
void R_LoadIdentity( void )
{
	if( tr.modelviewIdentity ) return;

	Matrix4x4_LoadIdentity( RI.objectMatrix );
	Matrix4x4_Copy( RI.modelviewMatrix, RI.worldviewMatrix );

	pglMatrixMode( GL_MODELVIEW );
	GL_LoadMatrix( RI.modelviewMatrix );
	tr.modelviewIdentity = true;
}

/*
=============
R_RotateForEntity
=============
*/
void R_RotateForEntity( cl_entity_t *e )
{
	float	scale = 1.0f;

	if( e == gEngfuncs.GetEntityByIndex( 0 ) )
	{
		R_LoadIdentity();
		return;
	}

	if( e->model->type != mod_brush && e->curstate.scale > 0.0f )
		scale = e->curstate.scale;

	Matrix4x4_CreateFromEntity( RI.objectMatrix, e->angles, e->origin, scale );
	Matrix4x4_ConcatTransforms( RI.modelviewMatrix, RI.worldviewMatrix, RI.objectMatrix );

	pglMatrixMode( GL_MODELVIEW );
	GL_LoadMatrix( RI.modelviewMatrix );
	tr.modelviewIdentity = false;
}

/*
=============
R_TranslateForEntity
=============
*/
void R_TranslateForEntity( cl_entity_t *e )
{
	float	scale = 1.0f;

	if( e == gEngfuncs.GetEntityByIndex( 0 ) )
	{
		R_LoadIdentity();
		return;
	}

	if( e->model->type != mod_brush && e->curstate.scale > 0.0f )
		scale = e->curstate.scale;

	Matrix4x4_CreateFromEntity( RI.objectMatrix, vec3_origin, e->origin, scale );
	Matrix4x4_ConcatTransforms( RI.modelviewMatrix, RI.worldviewMatrix, RI.objectMatrix );

	pglMatrixMode( GL_MODELVIEW );
	GL_LoadMatrix( RI.modelviewMatrix );
	tr.modelviewIdentity = false;
}

/*
===============
R_FindViewLeaf
===============
*/
void R_FindViewLeaf( void )
{
	RI.oldviewleaf = RI.viewleaf;
	RI.viewleaf = gEngfuncs.Mod_PointInLeaf( RI.pvsorigin, WORLDMODEL->nodes );
}

/*
===============
R_SetupFrame
===============
*/
static void R_SetupFrame( void )
{
	// setup viewplane dist
	RI.viewplanedist = DotProduct( RI.vieworg, RI.vforward );

	if( !gl_nosort->value )
	{
		// sort translucents entities by rendermode and distance
		qsort( tr.draw_list->trans_entities, tr.draw_list->num_trans_entities, sizeof( cl_entity_t* ), R_TransEntityCompare );
	}

	// current viewleaf
	if( RI.drawWorld )
	{
		RI.isSkyVisible = false; // unknown at this moment
		R_FindViewLeaf();
	}
}

/*
=============
R_SetupGL
=============
*/
void R_SetupGL( qboolean set_gl_state )
{
	R_SetupModelviewMatrix( RI.worldviewMatrix );
	R_SetupProjectionMatrix( RI.projectionMatrix );

	Matrix4x4_Concat( RI.worldviewProjectionMatrix, RI.projectionMatrix, RI.worldviewMatrix );

	if( !set_gl_state ) return;

	if( RP_NORMALPASS( ))
	{
		int	x, x2, y, y2;

		// set up viewport (main, playersetup)
		x = floor( RI.viewport[0] * gpGlobals->width / gpGlobals->width );
		x2 = ceil(( RI.viewport[0] + RI.viewport[2] ) * gpGlobals->width / gpGlobals->width );
		y = floor( gpGlobals->height - RI.viewport[1] * gpGlobals->height / gpGlobals->height );
		y2 = ceil( gpGlobals->height - ( RI.viewport[1] + RI.viewport[3] ) * gpGlobals->height / gpGlobals->height );

		pglViewport( x, y2, x2 - x, y - y2 );
	}
	else
	{
		// envpass, mirrorpass
		pglViewport( RI.viewport[0], RI.viewport[1], RI.viewport[2], RI.viewport[3] );
	}

	pglMatrixMode( GL_PROJECTION );
	GL_LoadMatrix( RI.projectionMatrix );

	pglMatrixMode( GL_MODELVIEW );
	GL_LoadMatrix( RI.worldviewMatrix );

	if( FBitSet( RI.params, RP_CLIPPLANE ))
	{
		GLdouble	clip[4];
		mplane_t	*p = &RI.clipPlane;

		clip[0] = p->normal[0];
		clip[1] = p->normal[1];
		clip[2] = p->normal[2];
		clip[3] = -p->dist;

		pglClipPlane( GL_CLIP_PLANE0, clip );
		pglEnable( GL_CLIP_PLANE0 );
	}

	GL_Cull( GL_FRONT );

	pglDisable( GL_BLEND );
	pglDisable( GL_ALPHA_TEST );
	pglColor4f( 1.0f, 1.0f, 1.0f, 1.0f );
}

/*
=============
R_EndGL
=============
*/
static void R_EndGL( void )
{
	if( RI.params & RP_CLIPPLANE )
		pglDisable( GL_CLIP_PLANE0 );
}

/*
=============
R_RecursiveFindWaterTexture

using to find source waterleaf with
watertexture to grab fog values from it
=============
*/
static gl_texture_t *R_RecursiveFindWaterTexture( const mnode_t *node, const mnode_t *ignore, qboolean down )
{
	gl_texture_t *tex = NULL;

	// assure the initial node is not null
	// we could check it here, but we would rather check it 
	// outside the call to get rid of one additional recursion level
	Assert( node != NULL );

	// ignore solid nodes
	if( node->contents == CONTENTS_SOLID )
		return NULL;

	if( node->contents < 0 )
	{
		mleaf_t		*pleaf;
		msurface_t	**mark;
		int		i, c;

		// ignore non-liquid leaves
		if( node->contents != CONTENTS_WATER && node->contents != CONTENTS_LAVA && node->contents != CONTENTS_SLIME )
			 return NULL;

		// find texture
		pleaf = (mleaf_t *)node;
		mark = pleaf->firstmarksurface;
		c = pleaf->nummarksurfaces;	

		for( i = 0; i < c; i++, mark++ )
		{
			if( (*mark)->flags & SURF_DRAWTURB && (*mark)->texinfo && (*mark)->texinfo->texture )
				return R_GetTexture( (*mark)->texinfo->texture->gl_texturenum );
		}

		// texture not found
		return NULL;
	}

	// this is a regular node
	// traverse children
	if( node->children[0] && ( node->children[0] != ignore ))
	{
		tex = R_RecursiveFindWaterTexture( node->children[0], node, true );
		if( tex ) return tex;
	}

	if( node->children[1] && ( node->children[1] != ignore ))
	{
		tex = R_RecursiveFindWaterTexture( node->children[1], node, true );
		if( tex )	return tex;
	}

	// for down recursion, return immediately
	if( down ) return NULL;

	// texture not found, step up if any
	if( node->parent )
		return R_RecursiveFindWaterTexture( node->parent, node, false );

	// top-level node, bail out
	return NULL;
}

/*
=============
R_CheckFog

check for underwater fog
Using backward recursion to find waterline leaf
from underwater leaf (idea: XaeroX)
=============
*/
static void R_CheckFog( void )
{
	cl_entity_t	*ent;
	gl_texture_t	*tex;
	int		i, cnt, count;

	// quake global fog
	if( gEngfuncs.Host_IsQuakeCompatible( ))
	{
		if( !MOVEVARS->fog_settings )
		{
			if( pglIsEnabled( GL_FOG ))
				pglDisable( GL_FOG );
			RI.fogEnabled = false;
			return;
		}

		// quake-style global fog
		RI.fogColor[0] = ((MOVEVARS->fog_settings & 0xFF000000) >> 24) / 255.0f;
		RI.fogColor[1] = ((MOVEVARS->fog_settings & 0xFF0000) >> 16) / 255.0f;
		RI.fogColor[2] = ((MOVEVARS->fog_settings & 0xFF00) >> 8) / 255.0f;
		RI.fogDensity = ((MOVEVARS->fog_settings & 0xFF) / 255.0f) * 0.01f;
		RI.fogStart = RI.fogEnd = 0.0f;
		RI.fogColor[3] = 1.0f;
		RI.fogCustom = false;
		RI.fogEnabled = true;
		RI.fogSkybox = true;
		return;
	}

	RI.fogEnabled = false;

	if( RI.onlyClientDraw || gEngfuncs.GetWaterLevel() < 3 || !RI.drawWorld || !RI.viewleaf )
	{
		if( RI.cached_waterlevel == 3 )
                    {
			// in some cases waterlevel jumps from 3 to 1. Catch it
			RI.cached_waterlevel = gEngfuncs.GetWaterLevel();
			RI.cached_contents = CONTENTS_EMPTY;
			if( !RI.fogCustom ) pglDisable( GL_FOG );
		}
		return;
	}

	ent = gEngfuncs.CL_GetWaterEntity( RI.vieworg );
	if( ent && ent->model && ent->model->type == mod_brush && ent->curstate.skin < 0 )
		cnt = ent->curstate.skin;
	else cnt = RI.viewleaf->contents;

	RI.cached_waterlevel = gEngfuncs.GetWaterLevel();

	if( !IsLiquidContents( RI.cached_contents ) && IsLiquidContents( cnt ))
	{
		tex = NULL;

		// check for water texture
		if( ent && ent->model && ent->model->type == mod_brush )
		{
			msurface_t	*surf;
	
			count = ent->model->nummodelsurfaces;

			for( i = 0, surf = &ent->model->surfaces[ent->model->firstmodelsurface]; i < count; i++, surf++ )
			{
				if( surf->flags & SURF_DRAWTURB && surf->texinfo && surf->texinfo->texture )
				{
					tex = R_GetTexture( surf->texinfo->texture->gl_texturenum );
					RI.cached_contents = ent->curstate.skin;
					break;
				}
			}
		}
		else
		{
			tex = R_RecursiveFindWaterTexture( RI.viewleaf->parent, NULL, false );
			if( tex ) RI.cached_contents = RI.viewleaf->contents;
		}

		if( !tex ) return;	// no valid fogs

		// copy fog params
		RI.fogColor[0] = tex->fogParams[0] / 255.0f;
		RI.fogColor[1] = tex->fogParams[1] / 255.0f;
		RI.fogColor[2] = tex->fogParams[2] / 255.0f;
		RI.fogDensity = tex->fogParams[3] * 0.000025f;
		RI.fogStart = RI.fogEnd = 0.0f;
		RI.fogColor[3] = 1.0f;
		RI.fogCustom = false;
		RI.fogEnabled = true;
		RI.fogSkybox = true;
	}
	else
	{
		RI.fogCustom = false;
		RI.fogEnabled = true;
		RI.fogSkybox = true;
	}
}

/*
=============
R_CheckGLFog

special condition for Spirit 1.9
that used direct calls of glFog-functions
=============
*/
static void R_CheckGLFog( void )
{
#ifdef HACKS_RELATED_HLMODS
	if(( !RI.fogEnabled && !RI.fogCustom ) && pglIsEnabled( GL_FOG ) && VectorIsNull( RI.fogColor ))
	{
		// fill the fog color from GL-state machine
		pglGetFloatv( GL_FOG_COLOR, RI.fogColor );
		RI.fogSkybox = true;
	}
#endif
}

/*
=============
R_DrawFog

=============
*/
void R_DrawFog( void )
{
	if( !RI.fogEnabled ) return;

	pglEnable( GL_FOG );
	if( gEngfuncs.Host_IsQuakeCompatible( ))
		pglFogi( GL_FOG_MODE, GL_EXP2 );
	else pglFogi( GL_FOG_MODE, GL_EXP );
	pglFogf( GL_FOG_DENSITY, RI.fogDensity );
	pglFogfv( GL_FOG_COLOR, RI.fogColor );
	pglHint( GL_FOG_HINT, GL_NICEST );
}

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

	tr.blend = 1.0f;
	GL_CheckForErrors();

	// first draw solid entities
	for( i = 0; i < tr.draw_list->num_solid_entities && !RI.onlyClientDraw; i++ )
	{
		RI.currententity = tr.draw_list->solid_entities[i];
		RI.currentmodel = RI.currententity->model;

		Assert( RI.currententity != NULL );
		Assert( RI.currentmodel != NULL );

		switch( RI.currentmodel->type )
		{
		case mod_brush:
			R_DrawBrushModel( RI.currententity );
			break;
		case mod_alias:
			R_DrawAliasModel( RI.currententity );
			break;
		case mod_studio:
			R_DrawStudioModel( RI.currententity );
			break;
		default:
			break;
		}
	}

	GL_CheckForErrors();

	// quake-specific feature
	R_DrawAlphaTextureChains();

	GL_CheckForErrors();

	// draw sprites seperately, because of alpha blending
	for( i = 0; i < tr.draw_list->num_solid_entities && !RI.onlyClientDraw; i++ )
	{
		RI.currententity = tr.draw_list->solid_entities[i];
		RI.currentmodel = RI.currententity->model;

		Assert( RI.currententity != NULL );
		Assert( RI.currentmodel != NULL );

		switch( RI.currentmodel->type )
		{
		case mod_sprite:
			R_DrawSpriteModel( RI.currententity );
			break;
		}
	}

	GL_CheckForErrors();

	if( !RI.onlyClientDraw )
	{
		CL_DrawEFX( tr.frametime, false );
	}

	GL_CheckForErrors();

	if( RI.drawWorld )
		gEngfuncs.pfnDrawNormalTriangles();

	GL_CheckForErrors();

	// then draw translucent entities
	for( i = 0; i < tr.draw_list->num_trans_entities && !RI.onlyClientDraw; i++ )
	{
		RI.currententity = tr.draw_list->trans_entities[i];
		RI.currentmodel = RI.currententity->model;

		// handle studiomodels with custom rendermodes on texture
		if( RI.currententity->curstate.rendermode != kRenderNormal )
			tr.blend = gEngfuncs.CL_FxBlend( RI.currententity ) / 255.0f;
		else tr.blend = 1.0f; // draw as solid but sorted by distance

		if( tr.blend <= 0.0f ) continue;
	
		Assert( RI.currententity != NULL );
		Assert( RI.currentmodel != NULL );

		switch( RI.currentmodel->type )
		{
		case mod_brush:
			R_DrawBrushModel( RI.currententity );
			break;
		case mod_alias:
			R_DrawAliasModel( RI.currententity );
			break;
		case mod_studio:
			R_DrawStudioModel( RI.currententity );
			break;
		case mod_sprite:
			R_DrawSpriteModel( RI.currententity );
			break;
		default:
			break;
		}
	}

	GL_CheckForErrors();

	if( RI.drawWorld )
	{
		pglTexEnvi( GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE );
		gEngfuncs.pfnDrawTransparentTriangles ();
	}

	GL_CheckForErrors();

	if( !RI.onlyClientDraw )
	{
		R_AllowFog( false );
		CL_DrawEFX( tr.frametime, true );
		R_AllowFog( true );
	}

	GL_CheckForErrors();

	pglDisable( GL_BLEND );	// Trinity Render issues

	if( !RI.onlyClientDraw )
		R_DrawViewModel();
	CL_ExtraUpdate();

	GL_CheckForErrors();
}

/*
================
R_RenderScene

R_SetupRefParams must be called right before
================
*/
void R_RenderScene( void )
{
	if( !WORLDMODEL && RI.drawWorld )
		gEngfuncs.Host_Error( "R_RenderView: NULL worldmodel\n" );

	// frametime is valid only for normal pass
	if( RP_NORMALPASS( ))
		tr.frametime = gpGlobals->time -   gpGlobals->oldtime;
	else tr.frametime = 0.0;

	// begin a new frame
	tr.framecount++;

	R_PushDlights();

	R_SetupFrustum();
	R_SetupFrame();
	R_SetupGL( true );
	R_Clear( ~0 );

	R_MarkLeaves();
	R_DrawFog ();

	R_CheckGLFog();	
	R_DrawWorld();
	R_CheckFog();

	CL_ExtraUpdate ();	// don't let sound get messed up if going slow

	R_DrawEntitiesOnList();

	R_DrawWaterSurfaces();

	R_EndGL();
}

/*
===============
R_DoResetGamma

gamma will be reset for
some type of screenshots
===============
*/
qboolean R_DoResetGamma( void )
{
	// FIXME: this looks ugly. apply the backward gamma changes to the output image
	return false;
#if 0
	switch( cls.scrshot_action )
	{
	case scrshot_normal:
		if( CL_IsDevOverviewMode( ))
			return true;
		return false;
	case scrshot_snapshot:
		if( CL_IsDevOverviewMode( ))
			return true;
		return false;
	case scrshot_plaque:
	case scrshot_savegame:
	case scrshot_envshot:
	case scrshot_skyshot:
	case scrshot_mapshot:
		return true;
	default:
		return false;
	}
#endif
}

/*
===============
R_BeginFrame
===============
*/
void R_BeginFrame( qboolean clearScene )
{
	glConfig.softwareGammaUpdate = false;	// in case of possible fails

	if(( gl_clear->value || gEngfuncs.CL_IsDevOverviewMode( )) && clearScene && gEngfuncs.CL_GetConnState() != ref_ca_cinematic )
	{
		pglClear( GL_COLOR_BUFFER_BIT );
	}

	if( R_DoResetGamma( ))
	{
		gEngfuncs.BuildGammaTable( 1.8f, 0.0f );
		glConfig.softwareGammaUpdate = true;
		GL_RebuildLightmaps();
		glConfig.softwareGammaUpdate = false;

		// next frame will be restored gamma
		SetBits( vid_brightness->flags, FCVAR_CHANGED );
		SetBits( vid_gamma->flags, FCVAR_CHANGED );
	}
	else if( FBitSet( vid_gamma->flags, FCVAR_CHANGED ) || FBitSet( vid_brightness->flags, FCVAR_CHANGED ))
	{
		gEngfuncs.BuildGammaTable( vid_gamma->value, vid_brightness->value );
		glConfig.softwareGammaUpdate = true;
		GL_RebuildLightmaps();
		glConfig.softwareGammaUpdate = false;
	}

	R_Set2DMode( true );

	// draw buffer stuff
	pglDrawBuffer( GL_BACK );

	// update texture parameters
	if( FBitSet( gl_texture_nearest->flags|gl_lightmap_nearest->flags|gl_texture_anisotropy->flags|gl_texture_lodbias->flags, FCVAR_CHANGED ))
		R_SetTextureParameters();

	// swapinterval stuff
	GL_UpdateSwapInterval();

	CL_ExtraUpdate ();
}

/*
===============
R_SetupRefParams

set initial params for renderer
===============
*/
void R_SetupRefParams( const ref_viewpass_t *rvp )
{
	RI.params = RP_NONE;
	RI.drawWorld = FBitSet( rvp->flags, RF_DRAW_WORLD );
	RI.onlyClientDraw = FBitSet( rvp->flags, RF_ONLY_CLIENTDRAW );
	RI.farClip = 0;

	if( !FBitSet( rvp->flags, RF_DRAW_CUBEMAP ))
		RI.drawOrtho = FBitSet( rvp->flags, RF_DRAW_OVERVIEW );
	else RI.drawOrtho = false;

	// setup viewport
	RI.viewport[0] = rvp->viewport[0];
	RI.viewport[1] = rvp->viewport[1];
	RI.viewport[2] = rvp->viewport[2];
	RI.viewport[3] = rvp->viewport[3];

	// calc FOV
	RI.fov_x = rvp->fov_x;
	RI.fov_y = rvp->fov_y;

	VectorCopy( rvp->vieworigin, RI.vieworg );
	VectorCopy( rvp->viewangles, RI.viewangles );
	VectorCopy( rvp->vieworigin, RI.pvsorigin );
}

/*
===============
R_RenderFrame
===============
*/
void R_RenderFrame( const ref_viewpass_t *rvp )
{
	if( r_norefresh->value )
		return;

	// setup the initial render params
	R_SetupRefParams( rvp );

	if( gl_finish->value && RI.drawWorld )
		pglFinish();

	if( glConfig.max_multisamples > 1 && FBitSet( gl_msaa->flags, FCVAR_CHANGED ))
	{
		if( CVAR_TO_BOOL( gl_msaa ))
			pglEnable( GL_MULTISAMPLE_ARB );
		else pglDisable( GL_MULTISAMPLE_ARB );
		ClearBits( gl_msaa->flags, FCVAR_CHANGED );
	}

	// completely override rendering
	if( gRenderIface.GL_RenderFrame != NULL )
	{
		tr.fCustomRendering = true;

		if( gRenderIface.GL_RenderFrame( rvp ))
		{
			R_GatherPlayerLight();
			tr.realframecount++;
			tr.fResetVis = true;
			return;
		}
	}

	tr.fCustomRendering = false;
	if( !RI.onlyClientDraw )
		R_RunViewmodelEvents();

	tr.realframecount++; // right called after viewmodel events
	R_RenderScene();
}

/*
===============
R_EndFrame
===============
*/
void R_EndFrame( void )
{
	// flush any remaining 2D bits
	R_Set2DMode( false );

#ifdef XASH_SDL
	SDL_GL_SwapWindow( host.hWnd );
#elif defined __ANDROID__ // For direct android backend
	Android_SwapBuffers();
#endif
}

/*
===============
R_DrawCubemapView
===============
*/
void R_DrawCubemapView( const vec3_t origin, const vec3_t angles, int size )
{
	ref_viewpass_t rvp;

	// basic params
	rvp.flags = rvp.viewentity = 0;
	SetBits( rvp.flags, RF_DRAW_WORLD );
	SetBits( rvp.flags, RF_DRAW_CUBEMAP );

	rvp.viewport[0] = rvp.viewport[1] = 0;
	rvp.viewport[2] = rvp.viewport[3] = size;
	rvp.fov_x = rvp.fov_y = 90.0f; // this is a final fov value

	// setup origin & angles
	VectorCopy( origin, rvp.vieworigin );
	VectorCopy( angles, rvp.viewangles );

	R_RenderFrame( &rvp );

	RI.viewleaf = NULL;		// force markleafs next frame
}

static int GL_RenderGetParm( int parm, int arg )
{
	gl_texture_t *glt;

	switch( parm )
	{
	case PARM_TEX_WIDTH:
		glt = R_GetTexture( arg );
		return glt->width;
	case PARM_TEX_HEIGHT:
		glt = R_GetTexture( arg );
		return glt->height;
	case PARM_TEX_SRC_WIDTH:
		glt = R_GetTexture( arg );
		return glt->srcWidth;
	case PARM_TEX_SRC_HEIGHT:
		glt = R_GetTexture( arg );
		return glt->srcHeight;
	case PARM_TEX_GLFORMAT:
		glt = R_GetTexture( arg );
		return glt->format;
	case PARM_TEX_ENCODE:
		glt = R_GetTexture( arg );
		return glt->encode;
	case PARM_TEX_MIPCOUNT:
		glt = R_GetTexture( arg );
		return glt->numMips;
	case PARM_TEX_DEPTH:
		glt = R_GetTexture( arg );
		return glt->depth;
	case PARM_TEX_SKYBOX:
		Assert( arg >= 0 && arg < 6 );
		return tr.skyboxTextures[arg];
	case PARM_TEX_SKYTEXNUM:
		return tr.skytexturenum;
	case PARM_TEX_LIGHTMAP:
		arg = bound( 0, arg, MAX_LIGHTMAPS - 1 );
		return tr.lightmapTextures[arg];
	case PARM_WIDESCREEN:
		return gpGlobals->wideScreen;
	case PARM_FULLSCREEN:
		return gpGlobals->fullScreen;
	case PARM_SCREEN_WIDTH:
		return gpGlobals->width;
	case PARM_SCREEN_HEIGHT:
		return gpGlobals->height;
	case PARM_TEX_TARGET:
		glt = R_GetTexture( arg );
		return glt->target;
	case PARM_TEX_TEXNUM:
		glt = R_GetTexture( arg );
		return glt->texnum;
	case PARM_TEX_FLAGS:
		glt = R_GetTexture( arg );
		return glt->flags;
	case PARM_ACTIVE_TMU:
		return glState.activeTMU;
	case PARM_LIGHTSTYLEVALUE:
		arg = bound( 0, arg, MAX_LIGHTSTYLES - 1 );
		return tr.lightstylevalue[arg];
	case PARM_MAX_IMAGE_UNITS:
		return GL_MaxTextureUnits();
	case PARM_REBUILD_GAMMA:
		return glConfig.softwareGammaUpdate;
	case PARM_SURF_SAMPLESIZE:
		if( arg >= 0 && arg < WORLDMODEL->numsurfaces )
			return gEngfuncs.Mod_SampleSizeForFace( &WORLDMODEL->surfaces[arg] );
		return LM_SAMPLE_SIZE;
	case PARM_GL_CONTEXT_TYPE:
		return glConfig.context;
	case PARM_GLES_WRAPPER:
		return glConfig.wrapper;
	case PARM_STENCIL_ACTIVE:
		return glState.stencilEnabled;
	case PARM_SKY_SPHERE:
		return gEngfuncs.CL_GetRenderParm( parm, arg ) && !tr.fCustomSkybox;
	default:
		return gEngfuncs.CL_GetRenderParm( parm, arg );
	}
	return 0;
}

static void R_GetDetailScaleForTexture( int texture, float *xScale, float *yScale )
{
	gl_texture_t *glt = R_GetTexture( texture );

	if( xScale ) *xScale = glt->xscale;
	if( yScale ) *yScale = glt->yscale;
}

static void R_GetExtraParmsForTexture( int texture, byte *red, byte *green, byte *blue, byte *density )
{
	gl_texture_t *glt = R_GetTexture( texture );

	if( red ) *red = glt->fogParams[0];
	if( green ) *green = glt->fogParams[1];
	if( blue ) *blue = glt->fogParams[2];
	if( density ) *density = glt->fogParams[3];
}


static void R_SetCurrentEntity( cl_entity_t *ent )
{
	RI.currententity = ent;

	// set model also
	if( RI.currententity != NULL )
	{
		RI.currentmodel = RI.currententity->model;
	}
}

static void R_SetCurrentModel( model_t *mod )
{
	RI.currentmodel = mod;
}