/*
	gl_mod_alias.c

	Draw Alias Model

	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

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

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

#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;
	tex_coord_t *tex_coord;
	int		count;
} 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 inline void
GL_DrawAliasFrameTri (vert_order_t *vo)
{
	float			color[4];
	int				count;
	blended_vert_t *verts;
	tex_coord_t	   *tex_coord;

	verts = vo->verts;
	tex_coord = vo->tex_coord;
	color[3] = modelalpha;
	count = vo->count;
	qfglBegin (GL_TRIANGLES);
	do {
		qfglTexCoord2fv (tex_coord->st);
		VectorMultAdd (ambientcolor, verts->lightdot, shadecolor, color);
		qfglColor4fv (color);
		qfglVertex3fv (verts->vert);

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

static inline void
GL_DrawAliasFrameTri_fb (vert_order_t *vo)
{
	float			color[4] = { 1.0, 1.0, 1.0, 0.0};
	int				count;
	blended_vert_t *verts;
	tex_coord_t	   *tex_coord;

	verts = vo->verts;
	color[3] = modelalpha * 1.0;
	count = vo->count;
	tex_coord = vo->tex_coord;
	qfglBegin (GL_TRIANGLES);
	do {
		qfglTexCoord2fv (tex_coord->st);
		qfglColor4fv (color);
		qfglVertex3fv (verts->vert);

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

static inline void
GL_DrawAliasFrameTriMulti (vert_order_t *vo)
{
	float			color[4];
	int				count;
	blended_vert_t *verts;
	tex_coord_t	   *tex_coord;

	verts = vo->verts;
	tex_coord = vo->tex_coord;	
	color[3] = modelalpha;
	count = vo->count;
	qfglBegin (GL_TRIANGLES);
	do {
		// texture coordinates come from the draw list
		qglMultiTexCoord2fv (gl_mtex_enum + 0, tex_coord->st);
		qglMultiTexCoord2fv (gl_mtex_enum + 1, tex_coord->st);
		tex_coord++;

		// normals and vertexes come from the frame list
		VectorMultAdd (ambientcolor, verts->lightdot, shadecolor, color);
		qfglColor4fv (color);

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

static inline 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
			VectorMultAdd (ambientcolor, verts->lightdot, shadecolor, color);

			qfglColor4fv (color);

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

		qfglEnd ();
	}
}

static inline 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 inline 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
			VectorMultAdd (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 inline 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 (paliashdr->tex_coord) {
		vo->tex_coord = (tex_coord_t *) ((byte *) paliashdr + paliashdr->tex_coord);
	} else {
		vo->tex_coord = NULL;
	}
	vo->count = count;
	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);
				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;

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

static inline 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 (paliashdr->tex_coord) {
		vo->tex_coord = (tex_coord_t *) ((byte *) paliashdr + paliashdr->tex_coord);
	} else {
		vo->tex_coord = NULL;
	}
	vo->count = count;

	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			  texture, i;
	int			  fb_texture = 0;
	unsigned int  lnum;
	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)
					VectorMultAdd (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;

	// 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 == HEADER_MDL16) {
		VectorScale (paliashdr->mdl.scale, e->scale / 256.0, scale);
		vo = GL_GetAliasFrameVerts16 (e->frame, paliashdr, e);
	} else {
		VectorScale (paliashdr->mdl.scale, e->scale, scale);
		vo = GL_GetAliasFrameVerts (e->frame, paliashdr, e);
	}

	// setup the transform
	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 (modelalpha < 1.0)
		qfglDepthMask (GL_FALSE);

	// draw all the triangles
	if (model->fullbright) {

		qfglBindTexture (GL_TEXTURE_2D, texture);
		if (vo->tex_coord)
			GL_DrawAliasFrameTri_fb (vo);
		else 
			GL_DrawAliasFrame_fb (vo);
	} else if (!fb_texture) {
		// Model has no fullbrights, don't bother with multi
		qfglBindTexture (GL_TEXTURE_2D, texture);
		if (vo->tex_coord)
			GL_DrawAliasFrameTri (vo);
		else
			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);

			// do the heavy lifting
			if (vo->tex_coord)
				GL_DrawAliasFrameTriMulti (vo);
			else 
				GL_DrawAliasFrameMulti (vo);

			// restore the settings
			qfglDisable (GL_TEXTURE_2D);
			qglActiveTexture (gl_mtex_enum + 0);
		} else {
			if (vo->tex_coord) {
				qfglBindTexture (GL_TEXTURE_2D, texture);
				GL_DrawAliasFrameTri (vo);
				qfglBindTexture (GL_TEXTURE_2D, fb_texture);
				GL_DrawAliasFrameTri_fb (vo);
			} 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);
}