// r_alias.c: routines for setting up to draw alias models

#include "quakedef.h"
#include "r_local.h"
#include "d_local.h"		// FIXME: shouldn't be needed (is needed for patch
						// right now, but that should move)

#define LIGHT_MIN	5	// lowest light value we'll allow, to avoid the
							//  need for inner-loop light clamping

mtriangle_t *ptriangles;
affinetridesc_t r_affinetridesc;

void *acolormap;		// FIXME: should go away

trivertx_t *r_apverts;

// TODO: these probably will go away with optimized rasterization
mdl_t *pmdl;
vec3_t r_plightvec;
int r_ambientlight;
float r_shadelight;
aliashdr_t *paliashdr;
finalvert_t *pfinalverts;
auxvert_t *pauxverts;
static float ziscale;
static model_t *pmodel;

static vec3_t alias_forward, alias_right, alias_up;

static maliasskindesc_t *pskindesc;

int r_amodels_drawn;
int a_skinwidth;
int r_anumverts;

float aliastransform[3][4];

typedef struct {
    int index0;
    int index1;
} aedge_t;

static aedge_t aedges[12] = {
    {0, 1}, {1, 2}, {2, 3}, {3, 0},
    {4, 5}, {5, 6}, {6, 7}, {7, 4},
    {0, 5}, {1, 4}, {2, 7}, {3, 6}
};

#define NUMVERTEXNORMALS	162

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

void R_AliasTransformAndProjectFinalVerts(finalvert_t * fv,
					  stvert_t * pstverts);
void R_AliasSetUpTransform(int trivial_accept);
void R_AliasTransformVector(vec3_t in, vec3_t out);
void R_AliasTransformFinalVert(finalvert_t * fv, auxvert_t * av,
			       trivertx_t * pverts, stvert_t * pstverts);
void R_AliasProjectFinalVert(finalvert_t * fv, auxvert_t * av);


/*
================
R_AliasCheckBBox
================
*/
qboolean R_AliasCheckBBox(void)
{
    int i, flags, frame, numv;
    aliashdr_t *pahdr;
    float zi, basepts[8][3], v0, v1, frac;
    finalvert_t *pv0, *pv1, viewpts[16];
    auxvert_t *pa0, *pa1, viewaux[16];
    maliasframedesc_t *pframedesc;
    qboolean zclipped, zfullyclipped;
    unsigned anyclip, allclip;
    int minz;

// expand, rotate, and translate points into worldspace

    currententity->trivial_accept = 0;
    pmodel = currententity->model;
    pahdr = Mod_Extradata(pmodel);
    pmdl = (mdl_t *) ((byte *) pahdr + pahdr->model);

    R_AliasSetUpTransform(0);

// construct the base bounding box for this frame
    frame = currententity->frame;
// TODO: don't repeat this check when drawing?
    if ((frame >= pmdl->numframes) || (frame < 0)) {
	Con_DPrintf("No such frame %d %s\n", frame, pmodel->name);
	frame = 0;
    }

    pframedesc = &pahdr->frames[frame];

// x worldspace coordinates
    basepts[0][0] = basepts[1][0] = basepts[2][0] = basepts[3][0] =
	(float) pframedesc->bboxmin.v[0];
    basepts[4][0] = basepts[5][0] = basepts[6][0] = basepts[7][0] =
	(float) pframedesc->bboxmax.v[0];

// y worldspace coordinates
    basepts[0][1] = basepts[3][1] = basepts[5][1] = basepts[6][1] =
	(float) pframedesc->bboxmin.v[1];
    basepts[1][1] = basepts[2][1] = basepts[4][1] = basepts[7][1] =
	(float) pframedesc->bboxmax.v[1];

// z worldspace coordinates
    basepts[0][2] = basepts[1][2] = basepts[4][2] = basepts[5][2] =
	(float) pframedesc->bboxmin.v[2];
    basepts[2][2] = basepts[3][2] = basepts[6][2] = basepts[7][2] =
	(float) pframedesc->bboxmax.v[2];

    zclipped = false;
    zfullyclipped = true;

    minz = 9999;
    for (i = 0; i < 8; i++) {
	R_AliasTransformVector(&basepts[i][0], &viewaux[i].fv[0]);

	if (viewaux[i].fv[2] < ALIAS_Z_CLIP_PLANE) {
	    // we must clip points that are closer than the near clip plane
	    viewpts[i].flags = ALIAS_Z_CLIP;
	    zclipped = true;
	} else {
	    if (viewaux[i].fv[2] < minz)
		minz = viewaux[i].fv[2];
	    viewpts[i].flags = 0;
	    zfullyclipped = false;
	}
    }


    if (zfullyclipped)
	return false;		// everything was near-z-clipped

    numv = 8;

    if (zclipped) {
	// organize points by edges, use edges to get new points (possible trivial
	// reject)
	for (i = 0; i < 12; i++) {
	    // edge endpoints
	    pv0 = &viewpts[aedges[i].index0];
	    pv1 = &viewpts[aedges[i].index1];
	    pa0 = &viewaux[aedges[i].index0];
	    pa1 = &viewaux[aedges[i].index1];

	    // if one end is clipped and the other isn't, make a new point
	    if (pv0->flags ^ pv1->flags) {
		frac = (ALIAS_Z_CLIP_PLANE - pa0->fv[2]) /
		    (pa1->fv[2] - pa0->fv[2]);
		viewaux[numv].fv[0] = pa0->fv[0] +
		    (pa1->fv[0] - pa0->fv[0]) * frac;
		viewaux[numv].fv[1] = pa0->fv[1] +
		    (pa1->fv[1] - pa0->fv[1]) * frac;
		viewaux[numv].fv[2] = ALIAS_Z_CLIP_PLANE;
		viewpts[numv].flags = 0;
		numv++;
	    }
	}
    }
// project the vertices that remain after clipping
    anyclip = 0;
    allclip = ALIAS_XY_CLIP_MASK;

// TODO: probably should do this loop in ASM, especially if we use floats
    for (i = 0; i < numv; i++) {
	// we don't need to bother with vertices that were z-clipped
	if (viewpts[i].flags & ALIAS_Z_CLIP)
	    continue;

	zi = 1.0 / viewaux[i].fv[2];

	// FIXME: do with chop mode in ASM, or convert to float
	v0 = (viewaux[i].fv[0] * xscale * zi) + xcenter;
	v1 = (viewaux[i].fv[1] * yscale * zi) + ycenter;

	flags = 0;

	if (v0 < r_refdef.fvrectx)
	    flags |= ALIAS_LEFT_CLIP;
	if (v1 < r_refdef.fvrecty)
	    flags |= ALIAS_TOP_CLIP;
	if (v0 > r_refdef.fvrectright)
	    flags |= ALIAS_RIGHT_CLIP;
	if (v1 > r_refdef.fvrectbottom)
	    flags |= ALIAS_BOTTOM_CLIP;

	anyclip |= flags;
	allclip &= flags;
    }

    if (allclip)
	return false;		// trivial reject off one side

    currententity->trivial_accept = !anyclip & !zclipped;

    if (currententity->trivial_accept) {
	if (minz > (r_aliastransition + (pmdl->size * r_resfudge)))
	    currententity->trivial_accept |= 2;
    }

    return true;
}


/*
================
R_AliasTransformVector
================
*/
void R_AliasTransformVector(vec3_t in, vec3_t out)
{
    out[0] = DotProduct(in, aliastransform[0]) + aliastransform[0][3];
    out[1] = DotProduct(in, aliastransform[1]) + aliastransform[1][3];
    out[2] = DotProduct(in, aliastransform[2]) + aliastransform[2][3];
}


/*
================
R_AliasPreparePoints

General clipped case
================
*/
void R_AliasPreparePoints(void)
{
    int i;
    stvert_t *pstverts;
    finalvert_t *fv;
    auxvert_t *av;
    mtriangle_t *ptri;
    finalvert_t *pfv[3];

    pstverts = (stvert_t *) ((byte *) paliashdr + paliashdr->stverts);
    r_anumverts = pmdl->numverts;
    fv = pfinalverts;
    av = pauxverts;

    for (i = 0; i < r_anumverts; i++, fv++, av++, r_apverts++, pstverts++) {
	R_AliasTransformFinalVert(fv, av, r_apverts, pstverts);
	if (av->fv[2] < ALIAS_Z_CLIP_PLANE) {
	    fv->flags |= ALIAS_Z_CLIP;
	} else {
	    R_AliasProjectFinalVert(fv, av);

	    if (fv->v[0] < r_refdef.aliasvrect.x)
		fv->flags |= ALIAS_LEFT_CLIP;
	    if (fv->v[1] < r_refdef.aliasvrect.y)
		fv->flags |= ALIAS_TOP_CLIP;
	    if (fv->v[0] > r_refdef.aliasvrectright)
		fv->flags |= ALIAS_RIGHT_CLIP;
	    if (fv->v[1] > r_refdef.aliasvrectbottom)
		fv->flags |= ALIAS_BOTTOM_CLIP;
	}
    }

//
// clip and draw all triangles
//
    r_affinetridesc.numtriangles = 1;

    ptri = (mtriangle_t *) ((byte *) paliashdr + paliashdr->triangles);
    for (i = 0; i < pmdl->numtris; i++, ptri++) {
	pfv[0] = &pfinalverts[ptri->vertindex[0]];
	pfv[1] = &pfinalverts[ptri->vertindex[1]];
	pfv[2] = &pfinalverts[ptri->vertindex[2]];

	if (pfv[0]->flags & pfv[1]->flags & pfv[2]->
	    flags & (ALIAS_XY_CLIP_MASK | ALIAS_Z_CLIP))
	    continue;		// completely clipped

	if (!((pfv[0]->flags | pfv[1]->flags | pfv[2]->flags) & (ALIAS_XY_CLIP_MASK | ALIAS_Z_CLIP))) {	// totally unclipped
	    r_affinetridesc.pfinalverts = pfinalverts;
	    r_affinetridesc.ptriangles = ptri;
	    D_PolysetDraw();
	} else {		// partially clipped
	    R_AliasClipTriangle(ptri);
	}
    }
}


/*
================
R_AliasSetUpTransform
================
*/
void R_AliasSetUpTransform(int trivial_accept)
{
    int i;
    float rotationmatrix[3][4], t2matrix[3][4];
    static float tmatrix[3][4];
    static float viewmatrix[3][4];
    vec3_t angles;

// TODO: should really be stored with the entity instead of being reconstructed
// TODO: should use a look-up table
// TODO: could cache lazily, stored in the entity

    angles[ROLL] = currententity->angles[ROLL];
    angles[PITCH] = -currententity->angles[PITCH];
    angles[YAW] = currententity->angles[YAW];
    AngleVectors(angles, alias_forward, alias_right, alias_up);

    tmatrix[0][0] = pmdl->scale[0];
    tmatrix[1][1] = pmdl->scale[1];
    tmatrix[2][2] = pmdl->scale[2];

    tmatrix[0][3] = pmdl->scale_origin[0];
    tmatrix[1][3] = pmdl->scale_origin[1];
    tmatrix[2][3] = pmdl->scale_origin[2];

// TODO: can do this with simple matrix rearrangement

    for (i = 0; i < 3; i++) {
	t2matrix[i][0] = alias_forward[i];
	t2matrix[i][1] = -alias_right[i];
	t2matrix[i][2] = alias_up[i];
    }

    t2matrix[0][3] = -modelorg[0];
    t2matrix[1][3] = -modelorg[1];
    t2matrix[2][3] = -modelorg[2];

// FIXME: can do more efficiently than full concatenation
    R_ConcatTransforms(t2matrix, tmatrix, rotationmatrix);

// TODO: should be global, set when vright, etc., set
    VectorCopy(vright, viewmatrix[0]);
    VectorCopy(vup, viewmatrix[1]);
    VectorInverse(viewmatrix[1]);
    VectorCopy(vpn, viewmatrix[2]);

//      viewmatrix[0][3] = 0;
//      viewmatrix[1][3] = 0;
//      viewmatrix[2][3] = 0;

    R_ConcatTransforms(viewmatrix, rotationmatrix, aliastransform);

// do the scaling up of x and y to screen coordinates as part of the transform
// for the unclipped case (it would mess up clipping in the clipped case).
// Also scale down z, so 1/z is scaled 31 bits for free, and scale down x and y
// correspondingly so the projected x and y come out right
// FIXME: make this work for clipped case too?
    if (trivial_accept) {
	for (i = 0; i < 4; i++) {
	    aliastransform[0][i] *= aliasxscale *
		(1.0 / ((float) 0x8000 * 0x10000));
	    aliastransform[1][i] *= aliasyscale *
		(1.0 / ((float) 0x8000 * 0x10000));
	    aliastransform[2][i] *= 1.0 / ((float) 0x8000 * 0x10000);

	}
    }
}


/*
================
R_AliasTransformFinalVert
================
*/
void R_AliasTransformFinalVert(finalvert_t * fv, auxvert_t * av,
			       trivertx_t * pverts, stvert_t * pstverts)
{
    int temp;
    float lightcos, *plightnormal;

    av->fv[0] = DotProduct(pverts->v, aliastransform[0]) +
	aliastransform[0][3];
    av->fv[1] = DotProduct(pverts->v, aliastransform[1]) +
	aliastransform[1][3];
    av->fv[2] = DotProduct(pverts->v, aliastransform[2]) +
	aliastransform[2][3];

    fv->v[2] = pstverts->s;
    fv->v[3] = pstverts->t;

    fv->flags = pstverts->onseam;

// lighting
    plightnormal = r_avertexnormals[pverts->lightnormalindex];
    lightcos = DotProduct(plightnormal, r_plightvec);
    temp = r_ambientlight;

    if (lightcos < 0) {
	temp += (int) (r_shadelight * lightcos);

	// clamp; because we limited the minimum ambient and shading light, we
	// don't have to clamp low light, just bright
	if (temp < 0)
	    temp = 0;
    }

    fv->v[4] = temp;
}


/*
================
R_AliasTransformAndProjectFinalVerts
================
*/
void R_AliasTransformAndProjectFinalVerts(finalvert_t * fv,
					  stvert_t * pstverts)
{
    int i, temp;
    float lightcos, *plightnormal, zi;
    trivertx_t *pverts;

    pverts = r_apverts;

    for (i = 0; i < r_anumverts; i++, fv++, pverts++, pstverts++) {
	// transform and project
	zi = 1.0 / (DotProduct(pverts->v, aliastransform[2]) +
		    aliastransform[2][3]);

	// x, y, and z are scaled down by 1/2**31 in the transform, so 1/z is
	// scaled up by 1/2**31, and the scaling cancels out for x and y in the
	// projection
	fv->v[5] = zi;

	fv->v[0] = ((DotProduct(pverts->v, aliastransform[0]) +
		     aliastransform[0][3]) * zi) + aliasxcenter;
	fv->v[1] = ((DotProduct(pverts->v, aliastransform[1]) +
		     aliastransform[1][3]) * zi) + aliasycenter;

	fv->v[2] = pstverts->s;
	fv->v[3] = pstverts->t;
	fv->flags = pstverts->onseam;

	// lighting
	plightnormal = r_avertexnormals[pverts->lightnormalindex];
	lightcos = DotProduct(plightnormal, r_plightvec);
	temp = r_ambientlight;

	if (lightcos < 0) {
	    temp += (int) (r_shadelight * lightcos);

	    // clamp; because we limited the minimum ambient and shading light, we
	    // don't have to clamp low light, just bright
	    if (temp < 0)
		temp = 0;
	}

	fv->v[4] = temp;
    }
}

/*
================
R_AliasProjectFinalVert
================
*/
void R_AliasProjectFinalVert(finalvert_t * fv, auxvert_t * av)
{
    float zi;

// project points
    zi = 1.0 / av->fv[2];

    fv->v[5] = zi * ziscale;

    fv->v[0] = (av->fv[0] * aliasxscale * zi) + aliasxcenter;
    fv->v[1] = (av->fv[1] * aliasyscale * zi) + aliasycenter;
}


/*
================
R_AliasPrepareUnclippedPoints
================
*/
void R_AliasPrepareUnclippedPoints(void)
{
    stvert_t *pstverts;
    finalvert_t *fv;

    pstverts = (stvert_t *) ((byte *) paliashdr + paliashdr->stverts);
    r_anumverts = pmdl->numverts;
// FIXME: just use pfinalverts directly?
    fv = pfinalverts;

    R_AliasTransformAndProjectFinalVerts(fv, pstverts);

    if (r_affinetridesc.drawtype)
	D_PolysetDrawFinalVerts(fv, r_anumverts);

    r_affinetridesc.pfinalverts = pfinalverts;
    r_affinetridesc.ptriangles = (mtriangle_t *)
	((byte *) paliashdr + paliashdr->triangles);
    r_affinetridesc.numtriangles = pmdl->numtris;

    D_PolysetDraw();
}

/*
===============
R_AliasSetupSkin
===============
*/
void R_AliasSetupSkin(void)
{
    int skinnum;
    int i, numskins;
    maliasskingroup_t *paliasskingroup;
    float *pskinintervals, fullskininterval;
    float skintargettime, skintime;

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

    pskindesc = ((maliasskindesc_t *)
		 ((byte *) paliashdr + paliashdr->skindesc)) + skinnum;
    a_skinwidth = pmdl->skinwidth;

    if (pskindesc->type == ALIAS_SKIN_GROUP) {
	paliasskingroup = (maliasskingroup_t *) ((byte *) paliashdr +
						 pskindesc->skin);
	pskinintervals = (float *)
	    ((byte *) paliashdr + paliasskingroup->intervals);
	numskins = paliasskingroup->numskins;
	fullskininterval = pskinintervals[numskins - 1];

	skintime = cl.time + currententity->syncbase;

	// when loading in Mod_LoadAliasSkinGroup, we guaranteed all interval
	// values are positive, so we don't have to worry about division by 0
	skintargettime = skintime -
	    ((int) (skintime / fullskininterval)) * fullskininterval;

	for (i = 0; i < (numskins - 1); i++) {
	    if (pskinintervals[i] > skintargettime)
		break;
	}

	pskindesc = &paliasskingroup->skindescs[i];
    }

    r_affinetridesc.pskindesc = pskindesc;
    r_affinetridesc.pskin =
	(void *) ((byte *) paliashdr + pskindesc->skin);
    r_affinetridesc.skinwidth = a_skinwidth;
    r_affinetridesc.seamfixupX16 = (a_skinwidth >> 1) << 16;
    r_affinetridesc.skinheight = pmdl->skinheight;
}

/*
================
R_AliasSetupLighting
================
*/
void R_AliasSetupLighting(alight_t * plighting)
{

// guarantee that no vertex will ever be lit below LIGHT_MIN, so we don't have
// to clamp off the bottom
    r_ambientlight = plighting->ambientlight;

    if (r_ambientlight < LIGHT_MIN)
	r_ambientlight = LIGHT_MIN;

    r_ambientlight = (255 - r_ambientlight) << VID_CBITS;

    if (r_ambientlight < LIGHT_MIN)
	r_ambientlight = LIGHT_MIN;

    r_shadelight = plighting->shadelight;

    if (r_shadelight < 0)
	r_shadelight = 0;

    r_shadelight *= VID_GRADES;

// rotate the lighting vector into the model's frame of reference
    r_plightvec[0] = DotProduct(plighting->plightvec, alias_forward);
    r_plightvec[1] = -DotProduct(plighting->plightvec, alias_right);
    r_plightvec[2] = DotProduct(plighting->plightvec, alias_up);
}

/*
=================
R_AliasSetupFrame

set r_apverts
=================
*/
void R_AliasSetupFrame(void)
{
    int frame;
    int i, numframes;
    maliasgroup_t *paliasgroup;
    float *pintervals, fullinterval, targettime, time;

    frame = currententity->frame;
    if ((frame >= pmdl->numframes) || (frame < 0)) {
	Con_DPrintf("R_AliasSetupFrame: no such frame %d\n", frame);
	frame = 0;
    }

    if (paliashdr->frames[frame].type == ALIAS_SINGLE) {
	r_apverts = (trivertx_t *)
	    ((byte *) paliashdr + paliashdr->frames[frame].frame);
	return;
    }

    paliasgroup = (maliasgroup_t *)
	((byte *) paliashdr + paliashdr->frames[frame].frame);
    pintervals = (float *) ((byte *) paliashdr + paliasgroup->intervals);
    numframes = paliasgroup->numframes;
    fullinterval = pintervals[numframes - 1];

    time = cl.time + currententity->syncbase;

//
// when loading in Mod_LoadAliasGroup, we guaranteed all interval values
// are positive, so we don't have to worry about division by 0
//
    targettime = time - ((int) (time / fullinterval)) * fullinterval;

    for (i = 0; i < (numframes - 1); i++) {
	if (pintervals[i] > targettime)
	    break;
    }

    r_apverts = (trivertx_t *)
	((byte *) paliashdr + paliasgroup->frames[i].frame);
}


/*
================
R_AliasDrawModel
================
*/
void R_AliasDrawModel(alight_t * plighting)
{
    finalvert_t finalverts[MAXALIASVERTS +
			   ((CACHE_SIZE - 1) / sizeof(finalvert_t)) + 1];
    auxvert_t auxverts[MAXALIASVERTS];

    r_amodels_drawn++;

// cache align
    pfinalverts = (finalvert_t *)
	(((long) &finalverts[0] + CACHE_SIZE - 1) & ~(CACHE_SIZE - 1));
    pauxverts = &auxverts[0];

    paliashdr = (aliashdr_t *) Mod_Extradata(currententity->model);
    pmdl = (mdl_t *) ((byte *) paliashdr + paliashdr->model);

    R_AliasSetupSkin();
    R_AliasSetUpTransform(currententity->trivial_accept);
    R_AliasSetupLighting(plighting);
    R_AliasSetupFrame();

    if (!currententity->colormap) {
	Sys_Error("R_AliasDrawModel: !currententity->colormap");
    }

    r_affinetridesc.drawtype = (currententity->trivial_accept == 3) &&
	r_recursiveaffinetriangles;

    if (r_affinetridesc.drawtype)
	D_PolysetUpdateTables();	// FIXME: precalc...

    acolormap = currententity->colormap;

    if (currententity != &cl.viewent) {
	ziscale = (float) 0x8000 *(float) 0x10000;
    } else {
	ziscale = (float) 0x8000 *(float) 0x10000 *3.0;
    }

    if (currententity->trivial_accept) {
	R_AliasPrepareUnclippedPoints();
    } else {
	R_AliasPreparePoints();
    }
}
