// ### BOILERPLATE ###
// Orthographic Cube Firmware
// Copyright (C) 2006 Peter Todd <pete@petertodd.org>
// 
// 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 the Free Software Foundation, Inc.,
// 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
// ### BOILERPLATE ###

// Cube rendering stuff. 

// The cube is stored as x,y,z co-ordinates. However the co-ordinates are
// either 0 or 1, corresponding to -l and +l where l is the length of the sides
// of the cube.

// A vertex is the end of a wire. Stored as x,y
typedef struct {
	uint8_t x;
	uint8_t y;
} vertex_t;

// The current orientation of the cube in terms of rotation around the x and y axis.
uint8_t xrot,yrot;

#include <proj_lookup.tbl>

// Initalizes all the wires into the shape of a cube and sets the initial orientation.
void cube_init(){
	xrot = yrot = 0;

#if 0
	
#define wasdasdf(i,ax,ay,az,bx,by,bz) {wire[i].a.x = ax; wire[i].a.y = ay; wire[i].a.z = az; wire[i].b.x = bx; wire[i].b.y = by; wire[i].b.z = bz; } 

	// Front
	w( 0, 0,0,0, 1,0,0);
	w( 1, 1,0,0, 1,1,0);
	w( 2, 1,1,0, 0,1,0);
	w( 3, 0,1,0, 0,0,0);
#undef w

#endif
}

// Encapsulates the proj_lookup #defines
#define pl_x(x,y,z) proj_lookup_x(x,y,z,xrot,yrot)
#define pl_y(x,y,z) proj_lookup_y(x,y,z,xrot,yrot)

// Takes the wireframe buffer and renders it. Each 3d wire is rotated with
// respect to the current orientation, and then projected onto a 2d line
// orthographically, IE, by throwing away z.
void render_cube(){
static	vertex_t a,b,c,d,e,f,g,h;
	
	// Since the only thing we ever do is draw a cube, everything is hardcoded.
	//
	// We also reuse results as needed to avoid recalculating co-ordinates
	
	
	// To save on typing all this is encapsulated into the #define l
	//
	// x,y,z are the co-ordinates to lookup, j is which of the temporary vertexes to put the results in
#define l(vx,vy,vz,j) do {j.x = pl_x(vx,vy,vz); j.y = pl_y(vx,vy,vz); } while (0);

	// Our second time-saver is d, which draws a line between vertex's a and b
#define d(a,b) draw_line(a.x,a.y,b.x,b.y);
	
	// front
	//
	// a,b,c,d are saved to create the sides
	l(0,0,0,a); 
	l(1,0,0,b);
	l(1,1,0,c);
	l(0,1,0,d);
	d(a,b);
	d(b,c);
	d(c,d);
	d(d,a);

	// backside, also doing sides at the same time
	l(0,0,1,e); 
	l(1,0,1,f);
	l(1,1,1,g);
	l(0,1,1,h);

	d(e,f);
	d(f,g);
	d(g,h);
	d(h,e);

	d(a,e);
	d(b,f);
	d(c,g);
	d(d,h);
}