/*
	gl_mod_alias.c

	(description)

	Copyright (C) 1996-1997  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:

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

*/
static const char rcsid[] = 
	"$Id$";

#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#ifdef HAVE_STRING_H
# include <string.h>
#endif
#ifdef HAVE_STRINGS_H
# include <strings.h>
#endif

#include <math.h>
#include <stdio.h>
#include <stdlib.h>

#include "QF/console.h"
#include "QF/cvar.h"
#include "QF/locs.h"
#include "QF/mathlib.h"
#include "QF/qargs.h"
#include "QF/render.h"
#include "QF/skin.h"
#include "QF/sound.h"
#include "QF/sys.h"
#include "QF/vid.h"
#include "QF/GL/defines.h"
#include "QF/GL/funcs.h"
#include "QF/GL/qf_rlight.h"
#include "QF/GL/qf_rmain.h"
#include "QF/GL/qf_rsurf.h"
#include "QF/GL/qf_screen.h"
#include "QF/GL/qf_vid.h"

#include "compat.h"
#include "r_cvar.h"
#include "r_dynamic.h"
#include "r_local.h"
#include "view.h"

typedef struct {
	vec3_t      vert;
	float       lightdot;
} blended_vert_t;

typedef struct {
	blended_vert_t *verts;
	int        *order;
} vert_order_t;

float		r_avertexnormals[NUMVERTEXNORMALS][3] = {
#include "anorms.h"
};

// precalculated dot products for quantized angles
#define SHADEDOT_QUANT 16
float   r_avertexnormal_dots[SHADEDOT_QUANT][256] =
	#include "anorm_dots.h"
		;

vec3_t		shadevector;

static void
GL_DrawAliasFrame (vert_order_t *vo)
{
	float			color[4];
	int				count;
	int			   *order;
	blended_vert_t *verts;

	verts = vo->verts;
	order = vo->order;

	color[3] = modelalpha;

	while ((count = *order++)) {
		// get the vertex count and primitive type
		if (count < 0) {
			count = -count;
			qfglBegin (GL_TRIANGLE_FAN);
		} else {
			qfglBegin (GL_TRIANGLE_STRIP);
		}

		do {
			// texture coordinates come from the draw list
			qfglTexCoord2fv ((float *) order);
			order += 2;

			// normals and vertexes come from the frame list
			VectorMA (ambientcolor, verts->lightdot, shadecolor, color);

			qfglColor4fv (color);

			qfglVertex3fv (verts->vert);
			verts++;
		} while (--count);

		qfglEnd ();
	}
}

static void
GL_DrawAliasFrame_fb (vert_order_t *vo)
{
	int				count;
	int			   *order;
	blended_vert_t *verts;

	verts = vo->verts;
	order = vo->order;

	color_white[3] = modelalpha * 255;
	qfglColor4ubv (color_white);

	while ((count = *order++)) {
		// get the vertex count and primitive type
		if (count < 0) {
			count = -count;
			qfglBegin (GL_TRIANGLE_FAN);
		} else {
			qfglBegin (GL_TRIANGLE_STRIP);
		}

		do {
			// texture coordinates come from the draw list
			qfglTexCoord2fv ((float *) order);
			order += 2;

			qfglVertex3fv (verts->vert);
			verts++;
		} while (--count);

		qfglEnd ();
	}
}

static void
GL_DrawAliasFrameMulti (vert_order_t *vo)
{
	float			color[4];
	int				count;
	int			   *order;
	blended_vert_t *verts;

	verts = vo->verts;
	order = vo->order;

	color[3] = modelalpha;
	
	while ((count = *order++)) {
		// get the vertex count and primitive type
		if (count < 0) {
			count = -count;
			qfglBegin (GL_TRIANGLE_FAN);
		} else {
			qfglBegin (GL_TRIANGLE_STRIP);
		}

		do {
			// texture coordinates come from the draw list
			qglMultiTexCoord2fv (gl_mtex_enum + 0, (float *) order);
			qglMultiTexCoord2fv (gl_mtex_enum + 1, (float *) order);
			order += 2;

			// normals and vertexes come from the frame list
			VectorMA (ambientcolor, verts->lightdot, shadecolor, color);

			qfglColor4fv (color);

			qfglVertex3fv (verts->vert);
			verts++;
		} while (--count);

		qfglEnd ();
	}
}

/*
	GL_DrawAliasShadow

	Standard shadow drawing
*/
static void
GL_DrawAliasShadow (aliashdr_t *paliashdr, vert_order_t *vo)
{
	float		height, lheight;
	int			count;
	int		   *order;
	vec3_t		point;
	blended_vert_t *verts;

	verts = vo->verts;
	order = vo->order;

	lheight = currententity->origin[2] - lightspot[2];
	height = -lheight + 1.0;

	while ((count = *order++)) {
		// get the vertex count and primitive type

		if (count < 0) {
			count = -count;
			qfglBegin (GL_TRIANGLE_FAN);
		} else
			qfglBegin (GL_TRIANGLE_STRIP);

		do {
			order += 2;		// skip texture coords

			// normals and vertexes come from the frame list
			point[0] =
				verts->vert[0] * paliashdr->mdl.scale[0] +
				paliashdr->mdl.scale_origin[0];
			point[1] =
				verts->vert[1] * paliashdr->mdl.scale[1] +
				paliashdr->mdl.scale_origin[1];
			point[2] =
				verts->vert[2] * paliashdr->mdl.scale[2] +
				paliashdr->mdl.scale_origin[2] + lheight;

			point[0] -= shadevector[0] * point[2];
			point[1] -= shadevector[1] * point[2];
			point[2] = height;
			qfglVertex3fv (point);

			verts++;
		} while (--count);

		qfglEnd ();
	}
}

static vert_order_t *
GL_GetAliasFrameVerts16 (int frame, aliashdr_t *paliashdr, entity_t *e)
{
	float		interval;
	int			count, numposes, pose, i;
	trivertx16_t *verts;
	vert_order_t *vo;
	blended_vert_t *vo_v;

	if ((frame >= paliashdr->mdl.numframes) || (frame < 0)) {
		if (developer->int_val)
			Con_Printf ("R_AliasSetupFrame: no such frame %d %s\n", frame,
						currententity->model->name);
		frame = 0;
	}

	pose = paliashdr->frames[frame].firstpose;
	numposes = paliashdr->frames[frame].numposes;

	verts = (trivertx16_t *) ((byte *) paliashdr + paliashdr->posedata);

	count = paliashdr->poseverts;
	vo = Hunk_TempAlloc (sizeof (*vo) + count * sizeof (blended_vert_t));
	vo->order = (int *) ((byte *) paliashdr + paliashdr->commands);
	vo->verts = (blended_vert_t *) &vo[1];

	if (numposes > 1) {
		interval = paliashdr->frames[frame].interval;
		pose += (int) (r_realtime / interval) % numposes;
	} else {
		/*
			One tenth of a second is good for most Quake animations. If
			the nextthink is longer then the animation is usually meant
			to pause (e.g. check out the shambler magic animation in
			shambler.qc).  If its shorter then things will still be
			smoothed partly, and the jumps will be less noticable
			because of the shorter time.  So, this is probably a good
			assumption.
		*/
		interval = 0.1;
	}

	if (gl_lerp_anim->int_val) {
		trivertx16_t *verts1, *verts2;
		float       blend;
		vec3_t      v1, v2;

		e->frame_interval = interval;

		if (e->pose2 != pose) {
			e->frame_start_time = r_realtime;
			if (e->pose2 == -1) {
				e->pose1 = pose;
			} else {
				e->pose1 = e->pose2;
			}
			e->pose2 = pose;
			blend = 0.0;
		} else {
			blend = (r_realtime - e->frame_start_time) / e->frame_interval;
		}

		// wierd things start happening if blend passes 1
		if (r_paused || blend > 1.0)
			blend = 1.0;

		if (blend == 0.0) {
			verts = verts + e->pose1 * count;
		} else if (blend == 1.0) {
			verts = verts + e->pose2 * count;
		} else {
			verts1 = verts + e->pose1 * count;
			verts2 = verts + e->pose2 * count;

			for (i = 0, vo_v = vo->verts; i < count;
				 i++, vo_v++, verts1++, verts2++) {
				float      *n1, *n2;
				float       d1, d2;

				VectorBlend (v1, v2, blend, vo_v->vert);
				VectorScale (vo_v->vert, 1.0 / 256.0, vo_v->vert);
				n1 = r_avertexnormals[verts1->lightnormalindex];
				n2 = r_avertexnormals[verts2->lightnormalindex];
				d1 = DotProduct (shadevector, n1);
				d2 = DotProduct (shadevector, n2);
				vo_v->lightdot = max (0, d1 * (1.0 - blend) + d2 * blend);
			}
			return vo;
		}
	} else {
		verts += pose * count;
	}
	for (i = 0, vo_v = vo->verts; i < count; i++, vo_v++, verts++) {
		float      *n;
		float       d;

		VectorScale (verts->v, 1.0 / 256.0, vo_v->vert);
		n = r_avertexnormals[verts->lightnormalindex];
		d = DotProduct (shadevector, n);
		vo_v->lightdot = max (0.0, d);
	}
	return vo;
}

static vert_order_t *
GL_GetAliasFrameVerts (int frame, aliashdr_t *paliashdr, entity_t *e)
{
	float		  interval;
	int			  count, numposes, pose, i;
	trivertx_t	 *verts;
	vert_order_t *vo;
	blended_vert_t *vo_v;

	if ((frame >= paliashdr->mdl.numframes) || (frame < 0)) {
		if (developer->int_val)
			Con_Printf ("R_AliasSetupFrame: no such frame %d %s\n", frame,
						currententity->model->name);
		frame = 0;
	}

	pose = paliashdr->frames[frame].firstpose;
	numposes = paliashdr->frames[frame].numposes;

	verts = (trivertx_t *) ((byte *) paliashdr + paliashdr->posedata);

	count = paliashdr->poseverts;
	vo = Hunk_TempAlloc (sizeof (*vo) + count * sizeof (blended_vert_t));
	vo->order = (int *) ((byte *) paliashdr + paliashdr->commands);
	vo->verts = (blended_vert_t *) &vo[1];

	if (numposes > 1) {
		interval = paliashdr->frames[frame].interval;
		pose += (int) (r_realtime / interval) % numposes;
	} else {
		/*
			One tenth of a second is good for most Quake animations. If
			the nextthink is longer then the animation is usually meant
			to pause (e.g. check out the shambler magic animation in
			shambler.qc).  If its shorter then things will still be
			smoothed partly, and the jumps will be less noticable
			because of the shorter time.  So, this is probably a good
			assumption.
		*/
		interval = 0.1;
	}

	if (gl_lerp_anim->int_val) {
		trivertx_t *verts1, *verts2;
		float       blend;

		e->frame_interval = interval;

		if (e->pose2 != pose) {
			e->frame_start_time = r_realtime;
			if (e->pose2 == -1) {
				e->pose1 = pose;
			} else {
				e->pose1 = e->pose2;
			}
			e->pose2 = pose;
			blend = 0;
		} else {
			blend = (r_realtime - e->frame_start_time) / e->frame_interval;
		}

		// wierd things start happening if blend passes 1
		if (r_paused || blend > 1.0)
			blend = 1.0;

		if (blend == 0.0) {
			verts = verts + e->pose1 * count;
		} else if (blend == 1.0) {
			verts = verts + e->pose2 * count;
		} else {
			verts1 = verts + e->pose1 * count;
			verts2 = verts + e->pose2 * count;

			for (i = 0, vo_v = vo->verts; i < count;
				 i++, vo_v++, verts1++, verts2++) {
				float      *n1, *n2;
				float       d1, d2;

				VectorBlend (verts1->v, verts2->v, blend, vo_v->vert);
				n1 = r_avertexnormals[verts1->lightnormalindex];
				n2 = r_avertexnormals[verts2->lightnormalindex];
				d1 = DotProduct (shadevector, n1);
				d2 = DotProduct (shadevector, n2);
				vo_v->lightdot = max (0, d1 * (1.0 - blend) + d2 * blend);
			}
			return vo;
		}
	} else {
		verts += pose * count;
	}
	for (i = 0, vo_v = vo->verts; i < count; i++, vo_v++, verts++) {
		float      *n;
		float       d;

		VectorCopy (verts->v, vo_v->vert);
		n = r_avertexnormals[verts->lightnormalindex];
		d = DotProduct (shadevector, n);
		vo_v->lightdot = max (0.0, d);
	}
	return vo;
}

static maliasskindesc_t *
R_AliasGetSkindesc (int skinnum, aliashdr_t *ahdr)
{
	maliasskindesc_t *pskindesc;
	maliasskingroup_t *paliasskingroup;

	if ((skinnum >= ahdr->mdl.numskins) || (skinnum < 0)) {
		Con_DPrintf ("R_AliasSetupSkin: no such skin # %d\n", skinnum);
		skinnum = 0;
	}

	pskindesc = ((maliasskindesc_t *)
				 ((byte *) ahdr + ahdr->skindesc)) + skinnum;

	if (pskindesc->type == ALIAS_SKIN_GROUP) {
		float       fullskininterval;
		int         i;
		int         numskins;
		float       skintargettime, skintime;
		float      *pskinintervals;

		paliasskingroup = (maliasskingroup_t *) ((byte *) ahdr +
												 pskindesc->skin);
		pskinintervals = (float *)
			((byte *) ahdr + paliasskingroup->intervals);
		numskins = paliasskingroup->numskins;
		fullskininterval = pskinintervals[numskins - 1];

		skintime = r_realtime + currententity->syncbase;

		skintargettime = skintime -
			((int) (skintime / fullskininterval)) * fullskininterval;
		for (i = 0; i < (numskins - 1); i++) {
			if (pskinintervals[i] > skintargettime)
				break;
		}
		pskindesc = &paliasskingroup->skindescs[i];
	}

	return pskindesc;
}

void
R_DrawAliasModel (entity_t *e)
{
	float		  add, an, minshade, radius, shade;
	int			  lnum, texture, i;
	int			  fb_texture = 0;
	aliashdr_t	 *paliashdr;
	model_t		 *model;
	vec3_t		  dist, scale;
	vert_order_t *vo;

	model = e->model;

	radius = model->radius;
	if (e->scale != 1.0)
		radius *= e->scale;
	if (R_CullSphere (e->origin, radius))
		return;

	VectorSubtract (r_origin, e->origin, modelorg);

	if (!model->fullbright) {
		// get lighting information
		R_LightPoint (e->origin);
		ambientcolor[0] *= e->colormod[0];
		ambientcolor[1] *= e->colormod[1];
		ambientcolor[2] *= e->colormod[2];
		VectorScale (ambientcolor, 0.005, ambientcolor);
		VectorCopy (ambientcolor, shadecolor);

		for (lnum = 0; lnum < r_maxdlights; lnum++) {
			if (r_dlights[lnum].die >= r_realtime) {
				float		d;

				VectorSubtract (e->origin, r_dlights[lnum].origin, dist);
				d = DotProduct (dist, dist);
				d = max (d, 64.0) * 200.0;
				add = r_dlights[lnum].radius * r_dlights[lnum].radius * 8.0 /
					d;

				if (add > 0.0)
					VectorMA (ambientcolor, add, r_dlights[lnum].color,
							  ambientcolor);
			}
		}

		// clamp lighting so it doesn't overbright as much
		for (i = 0; i < 3; i++) {
			ambientcolor[i] = min (ambientcolor[i], 128.0 / 200.0);
			if (ambientcolor[i] + shadecolor[i] > 1)
				shadecolor[i] = 1 - ambientcolor[i];
		}
		// always give the gun some light
		shade = max (ambientcolor[0], max (ambientcolor[1], ambientcolor[2]));
		minshade = model->min_light;
		if (shade < minshade) {
			ambientcolor[0] += minshade - shade;
			ambientcolor[1] += minshade - shade;
			ambientcolor[2] += minshade - shade;
		}

		an = e->angles[1] * (M_PI / 180.0);
		shadevector[0] = cos (-an);
		shadevector[1] = sin (-an);
		shadevector[2] = 1.0;
		VectorNormalize (shadevector);
	}

	modelalpha = e->colormod[3];

	// locate the proper data
	paliashdr = Cache_Get (&e->model->cache);
	c_alias_polys += paliashdr->mdl.numtris;
	VectorScale (paliashdr->mdl.scale, e->scale, scale);

	// draw all the triangles
	qfglPushMatrix ();
	R_RotateForEntity (e);

	qfglTranslatef (paliashdr->mdl.scale_origin[0],
					paliashdr->mdl.scale_origin[1],
					paliashdr->mdl.scale_origin[2]);
	qfglScalef (scale[0], scale[1], scale[2]);

	// if the model has a colorised/external skin, use it, otherwise use
	// the skin embedded in the model data
	if (e->skin && !gl_nocolors->int_val) {
		skin_t *skin = e->skin;

		texture = skin->texture;
		if (gl_fb_models->int_val) {
			fb_texture = skin->fb_texture;
		}
	} else {
		maliasskindesc_t *skindesc;

		skindesc = R_AliasGetSkindesc (e->skinnum, paliashdr);
		texture = skindesc->texnum;
		if (gl_fb_models->int_val && !model->fullbright)
			fb_texture = skindesc->fb_texnum;
	}

	if (paliashdr->mdl.ident == POLYHEADER16)
		vo = GL_GetAliasFrameVerts16 (e->frame, paliashdr, e);
	else
		vo = GL_GetAliasFrameVerts (e->frame, paliashdr, e);

	if (modelalpha < 1.0)
		qfglDepthMask (GL_FALSE);

	if (model->fullbright) {
		qfglBindTexture (GL_TEXTURE_2D, texture);
		GL_DrawAliasFrame_fb (vo);
	} else if (!fb_texture) {
		// Model has no fullbrights, don't bother with multi
		qfglBindTexture (GL_TEXTURE_2D, texture);
		GL_DrawAliasFrame (vo);
	} else {	// try multitexture
		if (gl_mtex_active) {	// set up the textures
			qglActiveTexture (gl_mtex_enum + 0);
			qfglBindTexture (GL_TEXTURE_2D, texture);

			qglActiveTexture (gl_mtex_enum + 1);
			qfglBindTexture (GL_TEXTURE_2D, fb_texture);
			qfglTexEnvf (GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL);
			qfglEnable (GL_TEXTURE_2D);

			GL_DrawAliasFrameMulti (vo);	// do the heavy lifting

			// restore the settings
			qfglDisable (GL_TEXTURE_2D);
			qglActiveTexture (gl_mtex_enum + 0);
		} else {
			qfglBindTexture (GL_TEXTURE_2D, texture);
			GL_DrawAliasFrame (vo);

			qfglBindTexture (GL_TEXTURE_2D, fb_texture);
			GL_DrawAliasFrame_fb (vo);
		}
	}

	qfglPopMatrix ();

	// FIXME: Translucent objects should cast colored shadows
	// torches, grenades, and lightning bolts do not have shadows
	if (r_shadows->int_val && model->shadow_alpha) {
		qfglPushMatrix ();
		R_RotateForEntity (e);

		qfglDisable (GL_TEXTURE_2D);
		qfglDepthMask (GL_FALSE);
		color_black[3] = modelalpha * model->shadow_alpha;
		qfglColor4ubv (color_black);

		GL_DrawAliasShadow (paliashdr, vo);

		qfglDepthMask (GL_TRUE);
		qfglEnable (GL_TEXTURE_2D);
		qfglPopMatrix ();
	} else if (modelalpha < 1.0)
		qfglDepthMask (GL_TRUE);

	Cache_Release (&e->model->cache);
}