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comment @# @;
1.1
date 2020.05.29.18.30.51; author gtoal; state Exp;
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desc
@hidden surface removal now works
@
1.1
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@Initial revision
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text
@
blockgrid.c
#include <vectrex.h>
// WARNING! This is some pretty horrendous code, and too close examination of
// it may make you go blind. I've basically enumerated the perspective view from
// each of four quadrants manually. I have no doubt that this code could be
// greatly simplified, but that is for another day and probably another programmer.
// One in a series of quick & dirty hacks.
// unfortunately I made the sizes of these areas even, i.e. with a block boundary
// running down x==0 and y==0 which requires special cases for various vectors (not
// yet implemented).
//
// If I had chosen an odd-sized playfield there would be blocks running down the
// centers and no ambiguity on viewing the vectors on either side...
// might handle that in a later revision. Also need to consider scrolling
// by smaller units than a complete block...
// TO DO: take the flicker hit only when changing the view, otherwise replay the
// previously-generated vectors...
// would also be nice to coalesce multiple vectors into a single line...
// Only algorithmic improvement needed: the ground-level vectors sometimes go underneath
// a block, and need to be clipped. Fortunately the excess length is trivial to calculate -
// it is the same ix<<SHIFT that would be used to draw the diagonal in the adjacent block!
#define set_scale(s) do { VIA_t1_cnt_lo = (unsigned int)s; } while (0)
#ifdef BIGGG
#define SIZE 4
#define SHIFT 1
#define GROUND_SCALE 0x6B
#else
#ifdef REGULAR
#define SIZE 2
#define SHIFT 2
#define GROUND_SCALE 0x6F
#else
#define SIZE 2
#define SHIFT 3
#define GROUND_SCALE 0x5D
#endif
#endif
int sq[SIZE*2][SIZE*2];
void Move(int x, int y) {
Reset0Ref();
Moveto_d(y, x);
}
void Skip(int dx, int dy) {
Moveto_d((int)(dy), (int)(dx));
}
void Line(int dx, int dy) {
Draw_Line_d((int)(dy), (int)(dx));
}
#define YH (24*4/SIZE)
#define XW (31*4/SIZE)
// I've enumerated all the cases of the four quadrants, but the special cases of the
// centerlines (x == 0 or y == 0) remain to be handled.
void roof(int move) {
int ix,x;
int iy,y;
Intensity_1F();
set_scale(move);
for (iy = -SIZE, y = -SIZE*YH; iy < SIZE; y+=YH, iy+=1) {
Reset0Ref();
Skip(-SIZE*XW, y);
for (ix = -SIZE, x = -SIZE*XW; ix < SIZE; x+=XW, ix+=1) {
if ((sq[ix+SIZE][iy+SIZE]) || ((iy > -SIZE) && sq[ix+SIZE][iy+SIZE-1])) {
if (iy >= 0) {
if (sq[ix+SIZE][iy+SIZE] != sq[ix+SIZE][iy+SIZE-1]) Line(XW, 0); else Skip(XW, 0);
} else if (iy < 0) {
if ( ((iy == -SIZE) && sq[ix+SIZE][iy+SIZE])
|| (iy > -SIZE && !sq[ix+SIZE][iy+SIZE])
|| ((iy > -SIZE) && sq[ix+SIZE][iy+SIZE] && !sq[ix+SIZE][iy+SIZE-1])) {
Line(XW, 0); // horizontal line below block
} else Skip(XW, 0);
} else Skip(XW, 0);
} else Skip(XW, 0); // horizontal below block
if ( (!sq[ix+SIZE][iy+SIZE] && (sq[ix+SIZE+1][iy+SIZE]) && (ix < SIZE-1)) // lhs of next
|| (sq[ix+SIZE][iy+SIZE] && !sq[ix+SIZE+1][iy+SIZE] && (ix < SIZE-1))
|| (ix == SIZE-1 && sq[ix+SIZE][iy+SIZE])
) { // rhs
Line(0, YH+1);
} else {
Skip(0, YH+1); // rhs verticals
}
if (iy == SIZE-1) {
if (sq[ix+SIZE][iy+SIZE]) Line(-XW, 0); else Skip(-XW, 0); // top row horizontals
Skip(XW, 0);
}
Skip(0, -YH);
}
Reset0Ref();
Skip(-SIZE*XW, y);
if (sq[/*ix+SIZE*/0][iy+SIZE]) Line(0, YH/*-1*/); // leftmost vertical
}
}
void ground(int move) {
int ix,x;
int iy,y;
Intensity_1F();
set_scale(move);
for (iy = -SIZE, y = -SIZE*YH; iy < SIZE; y+=YH, iy+=1) {
Reset0Ref();
Skip(-SIZE*XW, y);
for (ix = -SIZE, x = -SIZE*XW; ix < SIZE; x+=XW, ix+=1) {
if (iy > 0) {
if (sq[ix+SIZE][iy+SIZE] && !sq[ix+SIZE][iy+SIZE-1] ) {
Line(XW, 0);
} else Skip(XW, 0);
} else if (iy < 0) {
if ((iy > -SIZE) && sq[ix+SIZE][iy+SIZE-1] && !sq[ix+SIZE][iy+SIZE] ) {
Line(XW, 0); // horizontal line at top of block
} else Skip(XW, 0);
} else {
Skip(XW, 0);
}
if ((ix >= 0) && (ix < SIZE-1)) {
if (!sq[ix+SIZE][iy+SIZE] && sq[ix+SIZE+1][iy+SIZE]) {
Line(0, YH+1);
} else Skip(0, YH+1);
} else if (ix < 0) {
if (sq[ix+SIZE][iy+SIZE] && !sq[ix+1+SIZE][iy+SIZE]) {
Line(0, YH+1);
} else Skip(0, YH+1);
} else Skip(0, YH+1); // vertical at rhs of block
Skip(0, -YH);
}
Reset0Ref();
Skip(-SIZE*XW, y);
}
}
void support_nearest_center(int move, int draw) {
int ix,x;
int iy,y;
Intensity_a(0x18);
set_scale(move);
for (iy = -SIZE, y = -SIZE*YH; iy <= SIZE; y+=YH, iy+=1) {
for (ix = -SIZE, x = -SIZE*XW; ix <= SIZE; x+=XW, ix+=1) {
if (ix||iy) {
Reset0Ref();
Move(x, y);
set_scale(draw);
if (ix <= 0) {
if (iy <= 0) {
// diagonals at bottom left of sq[ix+SIZE][iy+SIZE]
if (!sq[ix+SIZE][iy+SIZE]) { // solid squares occlude themselves
if (ix == -SIZE) {
if (iy != -SIZE) {
if (sq[ix+SIZE][iy+SIZE-1]) {
Line(-ix<<SHIFT,-iy<<SHIFT);
}
}
} else {
if (iy == -SIZE) {
if (sq[ix+SIZE-1][iy+SIZE]) Line(-ix<<SHIFT,-iy<<SHIFT);
} else {
if (!sq[ix+SIZE-1][iy+SIZE] && !sq[ix+SIZE-1][iy+SIZE-1] && sq[ix+SIZE][iy+SIZE-1]) {
Line(-ix<<SHIFT,-iy<<SHIFT);
} if (sq[ix+SIZE-1][iy+SIZE] && !sq[ix+SIZE-1][iy+SIZE-1] && !sq[ix+SIZE][iy+SIZE-1]) {
Line(-ix<<SHIFT,-iy<<SHIFT);
} else if (sq[ix+SIZE-1][iy+SIZE] && sq[ix+SIZE][iy+SIZE-1]) {
Line(-ix<<SHIFT,-iy<<SHIFT);
} else if (sq[ix+SIZE-1][iy+SIZE-1] && !sq[ix+SIZE-1][iy+SIZE] && !sq[ix+SIZE][iy+SIZE-1]) {
Line(-ix<<SHIFT,-iy<<SHIFT);
}
}
}
}
} else if (iy > 0) {
// REMAINING QUADRANT TO BE DONE
// diagonal is at lower left corner of sq[ix][iy]
if (ix == -SIZE) {
if (iy < SIZE) {
if (sq[ix+SIZE][iy+SIZE] && !sq[ix+SIZE][iy+SIZE-1]) Line(-ix<<SHIFT,-iy<<SHIFT);
}
} else {
if (iy == SIZE) {
if (sq[ix+SIZE-1][iy+SIZE-1] && !sq[ix+SIZE][iy+SIZE-1]) Line(-ix<<SHIFT,-iy<<SHIFT);
} else {
// diagonal is at lower left corner of sq[ix][iy]
if (!sq[ix+SIZE][iy+SIZE-1]) {
if (sq[ix+SIZE-1][iy+SIZE-1] && !sq[ix+SIZE-1][iy+SIZE] && !sq[ix+SIZE][iy+SIZE-1]) {
Line(-ix<<SHIFT,-iy<<SHIFT);
} else if (sq[ix+SIZE-1][iy+SIZE] && !sq[ix+SIZE][iy+SIZE] && !sq[ix+SIZE-1][iy+SIZE-1]) {
Line(-ix<<SHIFT,-iy<<SHIFT);
} else if (sq[ix+SIZE-1][iy+SIZE-1] && sq[ix+SIZE][iy+SIZE]) {
Line(-ix<<SHIFT,-iy<<SHIFT);
} else if (!sq[ix+SIZE-1][iy+SIZE] && sq[ix+SIZE][iy+SIZE]) {
Line(-ix<<SHIFT,-iy<<SHIFT);
} else if (sq[ix+SIZE-1][iy+SIZE-1] && !sq[ix+SIZE][iy+SIZE] && !sq[ix+SIZE-1][iy+SIZE-1]) {
Line(-ix<<SHIFT,-iy<<SHIFT);
}
}
}
}
}
} else if (ix > 0) { // ALL DONE EXCEPT THE ZERO SPECIAL CASES
if (iy > 0) { // DONE
// iy == SIZE is the invisible row above the area
// diagonals are drawn at bottom left corner of sq[ix+SIZE][iy+SIZE]
if (ix == SIZE) {
if ((iy < SIZE) && sq[ix+SIZE-1][iy+SIZE] && !sq[ix+SIZE-1][iy+SIZE-1]) Line(-ix<<SHIFT,-iy<<SHIFT);
} else {
if (iy == SIZE) {
if (sq[ix+SIZE][iy+SIZE-1] && !sq[ix+SIZE-1][iy+SIZE-1]) {
Line(-ix<<SHIFT,-iy<<SHIFT);
}
} else {
if (sq[ix+SIZE][iy+SIZE] && !sq[ix+SIZE-1][iy+SIZE-1] && !sq[ix+SIZE][iy+SIZE-1]) {
if (!sq[ix+SIZE-1][iy+SIZE]) Line(-ix<<SHIFT,-iy<<SHIFT);
} else if (!sq[ix+SIZE][iy+SIZE] && !sq[ix+SIZE-1][iy+SIZE-1] &&
(sq[ix+SIZE-1][iy+SIZE] || sq[ix+SIZE][iy+SIZE-1])) {
Line(-ix<<SHIFT,-iy<<SHIFT);
} else if (!sq[ix+SIZE-1][iy+SIZE-1]) {
// diagonals are drawn at bottom left corner of sq[ix+SIZE][iy+SIZE]
// space left and below is free to draw into
if ( ((sq[ix+SIZE-1][iy+SIZE] && sq[ix+SIZE][iy+SIZE-1]))
|| (sq[ix+SIZE][iy+SIZE] && !sq[ix+SIZE-1][iy+SIZE] && !sq[ix+SIZE][iy+SIZE-1])) {
Line(-ix<<SHIFT,-iy<<SHIFT);
}
}
}
}
} else if (iy <= 0) { // DONE!
// diagonal at top-left corner of sq[ix+SIZE][iy+SIZE]
if (ix == SIZE) { // absent row to right of area
if (iy == -SIZE) { // absent row below area
} else {
if (sq[ix+SIZE-1][iy+SIZE-1] && !sq[ix+SIZE-1][iy+SIZE]) Line(-ix<<SHIFT,-iy<<SHIFT);
}
} else {
// ALWAYS draw diagonal at bottom-left corner of sq[ix+SIZE][iy+SIZE]
if (iy == -SIZE) {
if (!sq[ix+SIZE-1][iy+SIZE] && sq[ix+SIZE][iy+SIZE]) Line(-ix<<SHIFT,-iy<<SHIFT);
} else if (!sq[ix+SIZE-1][iy+SIZE]) {
// room to draw into
if (sq[ix+SIZE][iy+SIZE]) {
if (sq[ix+SIZE-1][iy+SIZE-1]) {
Line(-ix<<SHIFT,-iy<<SHIFT);
} else {
if (!sq[ix+SIZE][iy+SIZE-1]) Line(-ix<<SHIFT,-iy<<SHIFT);
}
} else if (sq[ix+SIZE-1][iy+SIZE-1]) {
if (!sq[ix+SIZE][iy+SIZE-1]) Line(-ix<<SHIFT,-iy<<SHIFT);
} else if (sq[ix+SIZE][iy+SIZE-1]) {
Line(-ix<<SHIFT,-iy<<SHIFT);
}
}
}
} else {
// iy == 0 - special case?
}
} else {
// center - ignore
}
set_scale(move);
}
}
}
}
static unsigned int _x, _a, _b, _c;
static void initRandom(unsigned int s1,unsigned int s2,unsigned int s3, unsigned int x0) {
_x = x0; _a = s1; _b = s2; _c = s3; _x++; _a = (_a^_c^_x); _b = (_b+_a); _c = ((_c+(_b>>1))^_a);
}
static int random(void) { // assert returns unsigned value that fits in an int.
_x++; _a = (_a^_c^_x); _b = (_b+_a); _c = ((_c+(_b>>1))^_a);
return (int)_c;
}
int main(void)
{
//int x, y;
unsigned int Prev_Btn_State = 0;
initRandom(12,34,56,78); (void)random();
//#define TEST1
#ifdef TEST1
sq[0][3]=1;sq[1][3]=0;sq[2][3]=0;sq[3][3]=1;
sq[0][2]=0;sq[1][2]=1;sq[2][2]=1;sq[3][2]=0;
sq[0][1]=0;sq[1][1]=1;sq[2][1]=1;sq[3][1]=0;
sq[0][0]=1;sq[1][0]=0;sq[2][0]=0;sq[3][0]=1;
#else
#ifdef TEST2
sq[0][3]=0;sq[1][3]=1;sq[2][3]=1;sq[3][3]=0;
sq[0][2]=1;sq[1][2]=0;sq[2][2]=0;sq[3][2]=1;
sq[0][1]=1;sq[1][1]=0;sq[2][1]=0;sq[3][1]=1;
sq[0][0]=0;sq[1][0]=1;sq[2][0]=1;sq[3][0]=0;
#else
#ifdef TEST3
sq[0][3]=0;sq[1][3]=1;sq[2][3]=0;sq[3][3]=1;
sq[0][2]=1;sq[1][2]=0;sq[2][2]=1;sq[3][2]=0;
sq[0][1]=0;sq[1][1]=1;sq[2][1]=0;sq[3][1]=1;
sq[0][0]=1;sq[1][0]=0;sq[2][0]=1;sq[3][0]=0;
#else
#ifdef TEST4
sq[0][3]=1;sq[1][3]=0;sq[2][3]=0;sq[3][3]=1;
sq[0][2]=1;sq[1][2]=0;sq[2][2]=0;sq[3][2]=1;
sq[0][1]=1;sq[1][1]=0;sq[2][1]=0;sq[3][1]=1;
sq[0][0]=1;sq[1][0]=0;sq[2][0]=0;sq[3][0]=1;
#else
#ifdef TEST5
sq[0][3]=1;sq[1][3]=0;sq[2][3]=1;sq[3][3]=0;
sq[0][2]=0;sq[1][2]=1;sq[2][2]=0;sq[3][2]=1;
sq[0][1]=1;sq[1][1]=0;sq[2][1]=1;sq[3][1]=0;
sq[0][0]=0;sq[1][0]=1;sq[2][0]=0;sq[3][0]=1;
#else
#ifdef TEST6
sq[0][3]=1;sq[1][3]=0;sq[2][3]=0;sq[3][3]=1;
sq[0][2]=1;sq[1][2]=0;sq[2][2]=0;sq[3][2]=1;
sq[0][1]=0;sq[1][1]=0;sq[2][1]=0;sq[3][1]=0;
sq[0][0]=0;sq[1][0]=0;sq[2][0]=0;sq[3][0]=0;
#else
#ifdef TEST7
sq[0][3]=0;sq[1][3]=0;sq[2][3]=0;sq[3][3]=0;
sq[0][2]=0;sq[1][2]=0;sq[2][2]=0;sq[3][2]=0;
sq[0][1]=1;sq[1][1]=0;sq[2][1]=0;sq[3][1]=1;
sq[0][0]=1;sq[1][0]=0;sq[2][0]=0;sq[3][0]=1;
#else
#ifdef TEST8
sq[0][3]=1;sq[1][3]=1;sq[2][3]=0;sq[3][3]=0;
sq[0][2]=0;sq[1][2]=0;sq[2][2]=0;sq[3][2]=0;
sq[0][1]=0;sq[1][1]=0;sq[2][1]=0;sq[3][1]=0;
sq[0][0]=0;sq[1][0]=0;sq[2][0]=1;sq[3][0]=1;
#else
#ifdef TEST9
sq[0][3]=1;sq[1][3]=1;sq[2][3]=1;sq[3][3]=1;
sq[0][2]=1;sq[1][2]=0;sq[2][2]=0;sq[3][2]=1;
sq[0][1]=1;sq[1][1]=0;sq[2][1]=0;sq[3][1]=1;
sq[0][0]=1;sq[1][0]=1;sq[2][0]=1;sq[3][0]=1;
#else
#ifdef TEST10
sq[0][3]=1;sq[1][3]=0;sq[2][3]=0;sq[3][3]=1;
sq[0][2]=0;sq[1][2]=0;sq[2][2]=0;sq[3][2]=0;
sq[0][1]=0;sq[1][1]=0;sq[2][1]=0;sq[3][1]=0;
sq[0][0]=1;sq[1][0]=0;sq[2][0]=0;sq[3][0]=1;
#else
int x,y;
for (y = -SIZE; y < SIZE; y++) {
for (x = -SIZE; x < SIZE; x++) {
sq[x+SIZE][y+SIZE] = random()&1;
}
}
#endif
#endif
#endif
#endif
#endif
#endif
#endif
#endif
#endif
#endif
Read_Btns();
for (;;) {
Prev_Btn_State = Vec_Btn_State;
Read_Btns();
Wait_Recal(); Intensity_7F();
roof(0x7E);
ground(GROUND_SCALE);
support_nearest_center(0x7E,(int) 0xFE);
if (((Vec_Btn_State&12) == 12) && (Vec_Btn_State != Prev_Btn_State)) {
for (y = -SIZE; y < SIZE; y++) {
for (x = -SIZE; x < SIZE; x++) {
sq[x+SIZE][y+SIZE] = random()&1;
}
}
}
}
return 0;
}
// ***************************************************************************
// end of file
// ***************************************************************************
@