/*
 * This file is part of the DXX-Rebirth project <http://www.dxx-rebirth.com/>.
 * It is copyright by its individual contributors, as recorded in the
 * project's Git history.  See COPYING.txt at the top level for license
 * terms and a link to the Git history.
 */
/*
 * 
 * Rod routines
 * 
 */


#include "3d.h"
#include "globvars.h"
#include "maths.h"

grs_point blob_vertices[4];

struct rod_4point
{
	g3s_point *point_list[4];
	g3s_point points[4];
};

//compute the corners of a rod.  fills in vertbuf.
static int calc_rod_corners(rod_4point &rod_point_group, g3s_point *bot_point,fix bot_width,g3s_point *top_point,fix top_width)
{
	vms_vector delta_vec,top,tempv,rod_norm;
	ubyte codes_and;
	int i;

	//compute vector from one point to other, do cross product with vector
	//from eye to get perpendiclar

	vm_vec_sub(&delta_vec,&bot_point->p3_vec,&top_point->p3_vec);

	//unscale for aspect

	delta_vec.x = fixdiv(delta_vec.x,Matrix_scale.x);
	delta_vec.y = fixdiv(delta_vec.y,Matrix_scale.y);

	//calc perp vector

	//do lots of normalizing to prevent overflowing.  When this code works,
	//it should be optimized

	vm_vec_normalize(&delta_vec);

	vm_vec_copy_normalize(&top,&top_point->p3_vec);

	vm_vec_cross(&rod_norm,&delta_vec,&top);

	vm_vec_normalize(&rod_norm);

	//scale for aspect

	rod_norm.x = fixmul(rod_norm.x,Matrix_scale.x);
	rod_norm.y = fixmul(rod_norm.y,Matrix_scale.y);

	//now we have the usable edge.  generate four points

	//top points

	vm_vec_copy_scale(&tempv,&rod_norm,top_width);
	tempv.z = 0;

	rod_point_group.point_list[0] = &rod_point_group.points[0];
	rod_point_group.point_list[1] = &rod_point_group.points[1];
	rod_point_group.point_list[2] = &rod_point_group.points[2];
	rod_point_group.point_list[3] = &rod_point_group.points[3];
	g3s_point (&rod_points)[4] = rod_point_group.points;
	vm_vec_add(&rod_points[0].p3_vec,&top_point->p3_vec,&tempv);
	vm_vec_sub(&rod_points[1].p3_vec,&top_point->p3_vec,&tempv);

	vm_vec_copy_scale(&tempv,&rod_norm,bot_width);
	tempv.z = 0;

	vm_vec_sub(&rod_points[2].p3_vec,&bot_point->p3_vec,&tempv);
	vm_vec_add(&rod_points[3].p3_vec,&bot_point->p3_vec,&tempv);


	//now code the four points

	for (i=0,codes_and=0xff;i<4;i++)
		codes_and &= g3_code_point(&rod_points[i]);

	if (codes_and)
		return 1;		//1 means off screen

	//clear flags for new points (not projected)

	for (i=0;i<4;i++)
		rod_points[i].p3_flags = 0;

	return 0;
}

//draw a bitmap object that is always facing you
//returns 1 if off screen, 0 if drew
void g3_draw_rod_tmap(grs_bitmap *bitmap,g3s_point *bot_point,fix bot_width,g3s_point *top_point,fix top_width,g3s_lrgb light)
{
	rod_4point rod;
	if (calc_rod_corners(rod,bot_point,bot_width,top_point,top_width))
		return;

	const fix average_light = static_cast<unsigned>(light.r+light.g+light.b)/3;
	const array<g3s_uvl, 4> uvl_list{{
		{ 0x0200, 0x0200, average_light },
		{ 0xfe00, 0x0200, average_light },
		{ 0xfe00, 0xfe00, average_light },
		{ 0x0200, 0xfe00, average_light }
	}};
	const array<g3s_lrgb, 4> lrgb_list{{
		light,
		light,
		light,
		light,
	}};

	g3_draw_tmap(rod.point_list,uvl_list,lrgb_list,bitmap);
}

#ifndef OGL
//draws a bitmap with the specified 3d width & height 
//returns 1 if off screen, 0 if drew
bool g3_draw_bitmap(vms_vector *pos,fix width,fix height,grs_bitmap *bm)
{
	g3s_point pnt;
	fix w,h;
	if (g3_rotate_point(&pnt,pos) & CC_BEHIND)
		return 1;
	g3_project_point(&pnt);
	if (pnt.p3_flags & PF_OVERFLOW)
		return 1;
#ifndef __powerc
	fix t;
	if (checkmuldiv(&t,width,Canv_w2,pnt.p3_z))
		w = fixmul(t,Matrix_scale.x);
	else
		return 1;

	if (checkmuldiv(&t,height,Canv_h2,pnt.p3_z))
		h = fixmul(t,Matrix_scale.y);
	else
		return 1;
#else
	if (pnt.p3_z == 0)
		return 1;
	double fz = f2fl(pnt.p3_z);
	w = fixmul(fl2f(((f2fl(width)*fCanv_w2) / fz)), Matrix_scale.x);
	h = fixmul(fl2f(((f2fl(height)*fCanv_h2) / fz)), Matrix_scale.y);
#endif
	blob_vertices[0].x = pnt.p3_sx - w;
	blob_vertices[0].y = blob_vertices[1].y = pnt.p3_sy - h;
	blob_vertices[1].x = blob_vertices[2].x = pnt.p3_sx + w;
	blob_vertices[2].y = pnt.p3_sy + h;
	scale_bitmap(bm, blob_vertices, 0);
	return 0;
}
#endif