/*
	glsl_main.c

	GLSL rendering

	Copyright (C) 2011 Bill Currie <bill@taniwha.org>

	Author: Bill Currie <bill@taniwha.org>
	Date: 2011/12/23

	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:

		Free Software Foundation, Inc.
		59 Temple Place - Suite 330
		Boston, MA  02111-1307, USA

*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

static __attribute__ ((used)) const char rcsid[] = "$Id$";

#ifdef HAVE_STRING_H
# include "string.h"
#endif
#ifdef HAVE_STRINGS_H
# include "strings.h"
#endif

#include "QF/cvar.h"
#include "QF/image.h"
#include "QF/render.h"
#include "QF/screen.h"
#include "QF/sys.h"

#include "QF/GLSL/defines.h"
#include "QF/GLSL/funcs.h"
#include "QF/GLSL/qf_alias.h"
#include "QF/GLSL/qf_bsp.h"
#include "QF/GLSL/qf_lightmap.h"
#include "QF/GLSL/qf_textures.h"

#include "gl_draw.h"
#include "r_cvar.h"
#include "r_dynamic.h"
#include "r_local.h"
#include "r_screen.h"

mat4_t glsl_projection;
mat4_t glsl_view;
VISIBLE vec3_t r_origin, vpn, vright, vup;
VISIBLE refdef_t r_refdef;
qboolean r_cache_thrash;
int r_init;
int r_framecount;
int d_lightstylevalue[256];
int r_visframecount;
entity_t r_worldentity;
entity_t *currententity;

void
gl_overbright_f (cvar_t *var)
{
}

VISIBLE void
R_ViewChanged (float aspect)
{
	double      xmin, xmax, ymin, ymax;
	float       fovx, fovy, neard, fard;
	vec_t      *proj = glsl_projection;

	fovx = r_refdef.fov_x;
	fovy = r_refdef.fov_y;
	neard = r_nearclip->value;
	fard = r_farclip->value;

	ymax = neard * tan (fovy * M_PI / 360);		// fov_2 / 2
	ymin = -ymax;
	xmax = neard * tan (fovx * M_PI / 360);		// fov_2 / 2
	xmin = -xmax;

	proj[0] = (2 * neard) / (xmax - xmin);
	proj[4] = 0;
	proj[8] = (xmax + xmin) / (xmax - xmin);
	proj[12] = 0;

	proj[1] = 0;
	proj[5] = (2 * neard) / (ymax - ymin);
	proj[9] = (ymax + ymin) / (ymax - ymin);
	proj[13] = 0;

	proj[2] = 0;
	proj[6] = 0;
	proj[10] = (fard + neard) / (neard - fard);
	proj[14] = (2 * fard * neard) / (neard - fard);

	proj[3] = 0;
	proj[7] = 0;
	proj[11] = -1;
	proj[15] = 0;
}

void
R_SetupFrame (void)
{
	R_AnimateLight ();
	R_ClearEnts ();
	r_framecount++;

	VectorCopy (r_refdef.vieworg, r_origin);
	AngleVectors (r_refdef.viewangles, vpn, vright, vup);

	r_viewleaf = Mod_PointInLeaf (r_origin, r_worldentity.model);
}

static void
R_SetupView (void)
{
	float       x, y, w, h;
	mat4_t      mat;
	static mat4_t z_up = {
		 0, 0, -1, 0,
		-1, 0,  0, 0,
		 0, 1,  0, 0,
		 0, 0,  0, 1,
	};

	x = r_refdef.vrect.x;
	y = (vid.height - (r_refdef.vrect.y + r_refdef.vrect.height));
	w = r_refdef.vrect.width;
	h = r_refdef.vrect.height;
	qfglViewport (x, y, w, h);

	Mat4Zero (mat);
	VectorCopy (vpn, mat + 0);
	VectorNegate (vright, mat + 4);			// we want vleft
	VectorCopy (vup, mat + 8);
	mat[15] = 1;
	Mat4Transpose (mat, mat);//AngleVectors gives the transpose of what we want
	Mat4Mult (z_up, mat, glsl_view);

	Mat4Identity (mat);
	VectorNegate (r_refdef.vieworg, mat + 12);
	Mat4Mult (glsl_view, mat, glsl_view);

	qfglEnable (GL_CULL_FACE);
	qfglEnable (GL_DEPTH_TEST);
}

static void
R_RenderEntities (void)
{
	entity_t   *ent;

	if (!r_drawentities->int_val)
		return;

	R_AliasBegin ();
	for (ent = r_ent_queue; ent; ent = ent->next) {
		if (ent->model->type != mod_alias)
			continue;
		currententity = ent;
		R_DrawAlias ();
	}
	R_AliasEnd ();

	R_SpriteBegin ();
	for (ent = r_ent_queue; ent; ent = ent->next) {
		if (ent->model->type != mod_sprite)
			continue;
		currententity = ent;
		R_DrawSprite ();
	}
	R_SpriteEnd ();
}

static void
R_DrawViewModel (void)
{
	currententity = r_view_model;
	if (r_inhibit_viewmodel
		|| !r_drawviewmodel->int_val
		|| !r_drawentities->int_val
		|| !currententity->model)
		return;

	// hack the depth range to prevent view model from poking into walls
	qfglDepthRangef (0, 0.3);
	R_AliasBegin ();
	R_DrawAlias ();
	R_AliasEnd ();
	qfglDepthRangef (0, 1);
}

VISIBLE void
R_RenderView (void)
{
	R_SetupFrame ();
	R_SetupView ();
	R_MarkLeaves ();
	R_PushDlights (vec3_origin);
	R_DrawWorld ();
	R_DrawSky ();
	R_RenderEntities ();
	R_DrawWaterSurfaces ();
	R_DrawParticles ();
	R_DrawViewModel ();
}

VISIBLE void
R_Init (void)
{
	R_InitBsp ();
	R_InitAlias ();
	R_InitSprites ();
	R_InitParticles ();
}

VISIBLE void
R_NewMap (model_t *worldmodel, struct model_s **models, int num_models)
{
	int         i;

	for (i = 0; i < 256; i++)
		d_lightstylevalue[i] = 264;		// normal light value

	memset (&r_worldentity, 0, sizeof (r_worldentity));
	r_worldentity.model = worldmodel;

	R_FreeAllEntities ();
	R_ClearParticles ();
	R_RegisterTextures (models, num_models);
	R_BuildLightmaps (models, num_models);
	R_BuildDisplayLists (models, num_models);
}

VISIBLE void
Fog_Update (float density, float red, float green, float blue, float time)
{
}

VISIBLE void
Fog_ParseWorldspawn (struct plitem_s *worldspawn)
{
}

VISIBLE void
R_LineGraph (int x, int y, int *h_vals, int count)
{
}

VISIBLE int
GL_LoadTexture (const char *identifier, int width, int height, byte *data,
				qboolean mipmap, qboolean alpha, int bytesperpixel)
{
	return 0;
}

VISIBLE void
R_ClearState (void)
{
	R_ClearEfrags ();
	R_ClearDlights ();
	R_ClearParticles ();
}

VISIBLE void
D_FlushCaches (void)
{
}