scummvm/engines/cruise/polys.cpp

281 lines
5.4 KiB
C++

/* ScummVM - Graphic Adventure Engine
*
* ScummVM is the legal property of its developers, whose names
* are too numerous to list here. Please refer to the COPYRIGHT
* file distributed with this source distribution.
*
* 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.
*
* $URL$
* $Id$
*
*/
#include "cruise/cruise_main.h"
#include "common/util.h"
namespace Cruise {
typedef char ColorP;
#define SCREENHEIGHT 200
#define MAXPTS 10
#define putdot(x,y) {if ((y >= 0) && (y < SCREENHEIGHT)) dots[y][counters[y]++] = x;}
void hline(int x1, int x2, int y, char c) {
for (; x1 <= x2; x1++) {
pixel(x1, y, c);
}
}
void vline(int x, int y1, int y2, char c) {
for (; y1 <= y2; y1++) {
pixel(x, y1, c);
}
}
void bsubline_1(int x1, int y1, int x2, int y2, char c) {
int x, y, ddx, ddy, e;
ddx = ABS(x2 - x1);
ddy = ABS(y2 - y1) << 1;
e = ddx - ddy;
ddx <<= 1;
if (x1 > x2) {
SWAP(x1, x2);
SWAP(y1, y2);
}
for (x = x1, y = y1; x <= x2; x++) {
pixel(x, y, c);
if (e < 0) {
y++;
e += ddx - ddy;
} else {
e -= ddy;
}
}
}
void bsubline_2(int x1, int y1, int x2, int y2, char c) {
int x, y, ddx, ddy, e;
ddx = ABS(x2 - x1) << 1;
ddy = ABS(y2 - y1);
e = ddy - ddx;
ddy <<= 1;
if (y1 > y2) {
SWAP(x1, x2);
SWAP(y1, y2);
}
for (y = y1, x = x1; y <= y2; y++) {
pixel(x, y, c);
if (e < 0) {
x++;
e += ddy - ddx;
} else {
e -= ddx;
}
}
}
void bsubline_3(int x1, int y1, int x2, int y2, char c) {
int x, y, ddx, ddy, e;
ddx = ABS(x1 - x2) << 1;
ddy = ABS(y2 - y1);
e = ddy - ddx;
ddy <<= 1;
if (y1 > y2) {
SWAP(x1, x2);
SWAP(y1, y2);
}
for (y = y1, x = x1; y <= y2; y++) {
pixel(x, y, c);
if (e < 0) {
x--;
e += ddy - ddx;
} else {
e -= ddx;
}
}
}
void bsubline_4(int x1, int y1, int x2, int y2, char c) {
int x, y, ddx, ddy, e;
ddy = ABS(y2 - y1) << 1;
ddx = ABS(x1 - x2);
e = ddx - ddy;
ddx <<= 1;
if (x1 > x2) {
SWAP(x1, x2);
SWAP(y1, y2);
}
for (x = x1, y = y1; x <= x2; x++) {
pixel(x, y, c);
if (e < 0) {
y--;
e += ddx - ddy;
} else {
e -= ddy;
}
}
}
void line(int x1, int y1, int x2, int y2, char c) {
float k;
if ((x1 == x2) && (y1 == y2)) {
pixel(x1, y1, c);
return;
}
if (x1 == x2) {
vline(x1, MIN(y1, y2), MAX(y1, y2), c);
return;
}
if (y1 == y2) {
hline(MIN(x1, x2), MAX(x1, x2), y1, c);
return;
}
k = (float)(y2 - y1) / (float)(x2 - x1);
if ((k >= 0) && (k <= 1)) {
bsubline_1(x1, y1, x2, y2, c);
} else if (k > 1) {
bsubline_2(x1, y1, x2, y2, c);
} else if ((k < 0) && (k >= -1)) {
bsubline_4(x1, y1, x2, y2, c);
} else {
bsubline_3(x1, y1, x2, y2, c);
}
}
// Filled polygons. This probably isn't pixel-perfect compared to the original,
// but it seems to work a bit better than the previous version.
static void add_intersect(int *intersect, int x, byte &num) {
if (num < MAXPTS) {
int i;
for (i = num; i > 0 && intersect[i - 1] > x; i--) {
intersect[i] = intersect[i - 1];
}
intersect[i] = x;
num++;
}
}
void fillpoly(int16 *point_data, int lineCount, ColorP color) {
static int intersect[SCREENHEIGHT][MAXPTS];
static byte num_intersect[SCREENHEIGHT];
switch (lineCount) {
case 0: // do nothing
return;
case 1: // draw pixel
pixel(point_data[0], point_data[1], color);
return;
case 2: // draw line
line(point_data[0], point_data[1], point_data[2], point_data[3], color);
return;
default: // go on and draw polygon
break;
}
// Reinit array counters
int x1, y1, x2, y2;
int y, i;
for (i = 0; i < SCREENHEIGHT; i++) {
num_intersect[i] = 0;
}
// Find the top/bottom of the polygon.
int top = point_data[1];
int bottom = point_data[1];
for (i = 1; i < lineCount; i++) {
if (point_data[2 * i + 1] < top)
top = point_data[2 * i + 1];
else if (point_data[2 * i + 1] > bottom)
bottom = point_data[2 * i + 1];
}
if (top < 0)
top = 0;
if (bottom >= SCREENHEIGHT)
bottom = SCREENHEIGHT - 1;
// Calculate intersections for each scan line
for (y = top; y <= bottom; y++) {
x2 = point_data[2 * lineCount - 2];
y2 = point_data[2 * lineCount - 1];
for (i = 0; i < lineCount; i++) {
x1 = x2;
y1 = y2;
x2 = point_data[2 * i];
y2 = point_data[2 * i + 1];
// Test if the line intersects the scan line
if ((y < y1) != (y < y2)) {
if (y1 == y2) {
add_intersect(intersect[y], x1, num_intersect[y]);
add_intersect(intersect[y], x2, num_intersect[y]);
} else if (x1 == x2) {
add_intersect(intersect[y], x1, num_intersect[y]);
} else {
add_intersect(intersect[y], x1 + ((y - y1) * (x2 - x1)) / (y2 - y1), num_intersect[y]);
}
}
}
}
// Drawing.
for (y = top; y <= bottom; y++) {
for (i = 0; i < num_intersect[y]; i += 2) {
hline(intersect[y][i], intersect[y][i + 1], y, color);
}
}
}
} // End of namespace Cruise