scummvm/graphics/primitives.cpp
2021-12-26 18:48:43 +01:00

431 lines
12 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 3 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, see <http://www.gnu.org/licenses/>.
*
*/
#include "common/algorithm.h"
#include "common/util.h"
#include "graphics/primitives.h"
namespace Graphics {
void drawLine(int x0, int y0, int x1, int y1, int color, void (*plotProc)(int, int, int, void *), void *data) {
// Bresenham's line algorithm, as described by Wikipedia
const bool steep = ABS(y1 - y0) > ABS(x1 - x0);
if (steep) {
SWAP(x0, y0);
SWAP(x1, y1);
}
const int delta_x = ABS(x1 - x0);
const int delta_y = ABS(y1 - y0);
const int delta_err = delta_y;
int x = x0;
int y = y0;
int err = 0;
const int x_step = (x0 < x1) ? 1 : -1;
const int y_step = (y0 < y1) ? 1 : -1;
if (steep)
(*plotProc)(y, x, color, data);
else
(*plotProc)(x, y, color, data);
while (x != x1) {
x += x_step;
err += delta_err;
if (2 * err > delta_x) {
y += y_step;
err -= delta_x;
}
if (steep)
(*plotProc)(y, x, color, data);
else
(*plotProc)(x, y, color, data);
}
}
void drawHLine(int x1, int x2, int y, int color, void (*plotProc)(int, int, int, void *), void *data) {
if (x1 > x2)
SWAP(x1, x2);
for (int x = x1; x <= x2; x++)
(*plotProc)(x, y, color, data);
}
void drawVLine(int x, int y1, int y2, int color, void (*plotProc)(int, int, int, void *), void *data) {
if (y1 > y2)
SWAP(y1, y2);
for (int y = y1; y <= y2; y++)
(*plotProc)(x, y, color, data);
}
void drawThickLine(int x0, int y0, int x1, int y1, int penX, int penY, int color, void (*plotProc)(int, int, int, void *), void *data) {
assert(penX > 0 && penY > 0);
// Shortcut
if (penX == 1 && penY == 1) {
drawLine(x0, y0, x1, y1, color, plotProc, data);
return;
}
// TODO: Optimize this. It currently is a very naive way of handling
// thick lines since quite often it will be drawing to the same pixel
// multiple times.
for (int x = 0; x < penX; x++)
for (int y = 0; y < penY; y++)
drawLine(x0 + x, y0 + y, x1 + x, y1 + y, color, plotProc, data);
}
/* Bresenham as presented in Foley & Van Dam */
/* Code is based on GD lib http://libgd.github.io/ */
void drawThickLine2(int x1, int y1, int x2, int y2, int thick, int color, void (*plotProc)(int, int, int, void *), void *data) {
int incr1, incr2, d, x, y, xend, yend, xdirflag, ydirflag;
int wid;
int w, wstart;
int dx = abs(x2 - x1);
int dy = abs(y2 - y1);
if (dx == 0) {
int xn = x1 - thick / 2;
Common::Rect r(xn, MIN(y1, y2), xn + thick - 1, MAX(y1, y2));
drawFilledRect(r, color, plotProc, data);
return;
} else if (dy == 0) {
int yn = y1 - thick / 2;
Common::Rect r(MIN(x1, x2), yn, MAX(x1, x2), yn + thick - 1);
drawFilledRect(r, color, plotProc, data);
return;
}
if (dy <= dx) {
/* More-or-less horizontal. use wid for vertical stroke */
/* 2.0.12: Michael Schwartz: divide rather than multiply;
TBB: but watch out for /0! */
if (dx != 0 && thick != 0) {
double ac_recip = 1.0/dx * sqrt((double)(dx * dx + dy * dy)); // 1 / cos(atan2((double)dy, (double)dx));
wid = thick * ac_recip;
} else {
wid = 1;
}
d = 2 * dy - dx;
incr1 = 2 * dy;
incr2 = 2 * (dy - dx);
if (x1 > x2) {
x = x2;
y = y2;
ydirflag = (-1);
xend = x1;
} else {
x = x1;
y = y1;
ydirflag = 1;
xend = x2;
}
/* Set up line thickness */
wstart = y - wid / 2;
for (w = wstart; w < wstart + wid; w++)
(*plotProc)(x, y, color, data);
if (((y2 - y1) * ydirflag) > 0) {
while (x < xend) {
x++;
if (d < 0) {
d += incr1;
} else {
y++;
d += incr2;
}
wstart = y - wid / 2;
for (w = wstart; w < wstart + wid; w++)
(*plotProc)(x, w, color, data);
}
} else {
while (x < xend) {
x++;
if (d < 0) {
d += incr1;
} else {
y--;
d += incr2;
}
wstart = y - wid / 2;
for (w = wstart; w < wstart + wid; w++)
(*plotProc)(x, w, color, data);
}
}
} else {
/* More-or-less vertical. use wid for horizontal stroke */
/* 2.0.12: Michael Schwartz: divide rather than multiply;
TBB: but watch out for /0! */
if (dy != 0 && thick != 0) {
double as_recip = 1.0/dy * sqrt((double)(dx * dx + dy * dy)); // 1 / sin(atan2((double)dy, (double)dx));
wid = thick * as_recip;
} else {
wid = 1;
}
d = 2 * dx - dy;
incr1 = 2 * dx;
incr2 = 2 * (dx - dy);
if (y1 > y2) {
y = y2;
x = x2;
yend = y1;
xdirflag = (-1);
} else {
y = y1;
x = x1;
yend = y2;
xdirflag = 1;
}
/* Set up line thickness */
wstart = x - wid / 2;
for (w = wstart; w < wstart + wid; w++)
(*plotProc)(w, y, color, data);
if (((x2 - x1) * xdirflag) > 0) {
while (y < yend) {
y++;
if (d < 0) {
d += incr1;
} else {
x++;
d += incr2;
}
wstart = x - wid / 2;
for (w = wstart; w < wstart + wid; w++)
(*plotProc)(w, y, color, data);
}
} else {
while (y < yend) {
y++;
if (d < 0) {
d += incr1;
} else {
x--;
d += incr2;
}
wstart = x - wid / 2;
for (w = wstart; w < wstart + wid; w++)
(*plotProc)(w, y, color, data);
}
}
}
}
void drawFilledRect(Common::Rect &rect, int color, void (*plotProc)(int, int, int, void *), void *data) {
for (int y = rect.top; y <= rect.bottom; y++)
drawHLine(rect.left, rect.right, y, color, plotProc, data);
}
void drawRect(Common::Rect &rect, int color, void (*plotProc)(int, int, int, void *), void *data) {
drawHLine(rect.left, rect.right, rect.top, color, plotProc, data);
drawHLine(rect.left, rect.right, rect.bottom, color, plotProc, data);
drawVLine(rect.left, rect.top, rect.bottom, color, plotProc, data);
drawVLine(rect.right, rect.top, rect.bottom, color, plotProc, data);
}
// http://members.chello.at/easyfilter/bresenham.html
void drawRoundRect(Common::Rect &rect, int arc, int color, bool filled, void (*plotProc)(int, int, int, void *), void *data) {
if (rect.height() < rect.width()) {
int x = -arc, y = 0, err = 2-2*arc; /* II. Quadrant */
int dy = rect.height() - arc * 2;
int r = arc;
int stop = 0;
int lastx = 0, lasty = 0;
if (dy < 0)
stop = -dy / 2;
do {
if (filled) {
drawHLine(rect.left + x + r, rect.right - x - r, rect.top - y + r - stop, color, plotProc, data);
drawHLine(rect.left + x + r, rect.right - x - r, rect.bottom + y - r + stop, color, plotProc, data);
} else {
(*plotProc)(rect.left + x + r, rect.top - y + r - stop, color, data);
(*plotProc)(rect.right - x - r, rect.top - y + r - stop, color, data);
(*plotProc)(rect.left + x + r, rect.bottom + y - r + stop, color, data);
(*plotProc)(rect.right - x - r, rect.bottom + y - r + stop, color, data);
lastx = x;
lasty = y;
}
arc = err;
if (arc <= y) err += ++y*2+1; /* e_xy+e_y < 0 */
if (arc > x || err > y) err += ++x*2+1; /* e_xy+e_x > 0 or no 2nd y-step */
if (stop && y > stop)
break;
} while (x < 0);
if (!filled) {
x = lastx;
y = lasty;
drawHLine(rect.left + x + r, rect.right - x - r, rect.top - y + r - stop, color, plotProc, data);
drawHLine(rect.left + x + r, rect.right - x - r, rect.bottom + y - r + stop, color, plotProc, data);
}
for (int i = 1; i < dy; i++) {
if (filled) {
drawHLine(rect.left, rect.right, rect.top + r + i, color, plotProc, data);
} else {
(*plotProc)(rect.left, rect.top + r + i, color, data);
(*plotProc)(rect.right, rect.top + r + i, color, data);
}
}
} else {
int y = -arc, x = 0, err = 2-2*arc; /* II. Quadrant */
int dx = rect.width() - arc * 2;
int r = arc;
int stop = 0;
int lastx = 0, lasty = 0;
if (dx < 0)
stop = -dx / 2;
do {
if (filled) {
drawVLine(rect.left - x + r - stop, rect.top + y + r, rect.bottom - y - r, color, plotProc, data);
drawVLine(rect.right + x - r + stop, rect.top + y + r, rect.bottom - y - r, color, plotProc, data);
} else {
(*plotProc)(rect.left - x + r - stop, rect.top + y + r, color, data);
(*plotProc)(rect.left - x + r - stop, rect.bottom - y - r, color, data);
(*plotProc)(rect.right + x - r + stop, rect.top + y + r, color, data);
(*plotProc)(rect.right + x - r + stop, rect.bottom - y - r, color, data);
lastx = x;
lasty = y;
}
arc = err;
if (arc <= x) err += ++x*2+1; /* e_xy+e_y < 0 */
if (arc > y || err > x) err += ++y*2+1; /* e_xy+e_x > 0 or no 2nd y-step */
if (stop && x > stop)
break;
} while (y < 0);
if (!filled) {
x = lastx;
y = lasty;
drawVLine(rect.left - x + r - stop, rect.top + y + r, rect.bottom - y - r, color, plotProc, data);
drawVLine(rect.right + x - r + stop, rect.top + y + r, rect.bottom - y - r, color, plotProc, data);
}
for (int i = 1; i < dx; i++) {
if (filled) {
drawVLine(rect.left + r + i, rect.top, rect.bottom, color, plotProc, data);
} else {
(*plotProc)(rect.left + r + i, rect.top, color, data);
(*plotProc)(rect.left + r + i, rect.bottom, color, data);
}
}
}
}
// Based on public-domain code by Darel Rex Finley, 2007
// http://alienryderflex.com/polygon_fill/
void drawPolygonScan(int *polyX, int *polyY, int npoints, Common::Rect &bbox, int color, void (*plotProc)(int, int, int, void *), void *data) {
int *nodeX = (int *)calloc(npoints, sizeof(int));
int i, j;
// Loop through the rows of the image.
for (int pixelY = bbox.top; pixelY < bbox.bottom; pixelY++) {
// Build a list of nodes.
int nodes = 0;
j = npoints - 1;
for (i = 0; i < npoints; i++) {
if ((polyY[i] < pixelY && polyY[j] >= pixelY) || (polyY[j] < pixelY && polyY[i] >= pixelY)) {
nodeX[nodes++] = (int)(polyX[i] + (double)(pixelY - polyY[i]) / (double)(polyY[j]-polyY[i]) *
(double)(polyX[j] - polyX[i]) + 0.5);
}
j = i;
}
// Sort the nodes
Common::sort(nodeX, &nodeX[nodes]);
// Fill the pixels between node pairs.
for (i = 0; i < nodes; i += 2) {
if (nodeX[i ] >= bbox.right)
break;
if (nodeX[i + 1] > bbox.left) {
nodeX[i] = MAX<int16>(nodeX[i], bbox.left);
nodeX[i + 1] = MIN<int16>(nodeX[i + 1], bbox.right);
drawHLine(nodeX[i], nodeX[i + 1], pixelY, color, plotProc, data);
}
}
}
free(nodeX);
}
// http://members.chello.at/easyfilter/bresenham.html
void drawEllipse(int x0, int y0, int x1, int y1, int color, bool filled, void (*plotProc)(int, int, int, void *), void *data) {
int a = abs(x1 - x0), b = abs(y1 - y0), b1 = b & 1; /* values of diameter */
long dx = 4 * (1 - a) * b * b, dy = 4 * (b1 + 1) * a * a; /* error increment */
long err = dx + dy + b1 * a * a, e2; /* error of 1.step */
if (x0 > x1) { x0 = x1; x1 += a; } /* if called with swapped points */
if (y0 > y1) y0 = y1; /* .. exchange them */
y0 += (b + 1) / 2; y1 = y0 - b1; /* starting pixel */
a *= 8 * a; b1 = 8 * b * b;
do {
if (filled) {
drawHLine(x0, x1, y0, color, plotProc, data);
drawHLine(x0, x1, y1, color, plotProc, data);
} else {
(*plotProc)(x1, y0, color, data); /* I. Quadrant */
(*plotProc)(x0, y0, color, data); /* II. Quadrant */
(*plotProc)(x0, y1, color, data); /* III. Quadrant */
(*plotProc)(x1, y1, color, data); /* IV. Quadrant */
}
e2 = 2*err;
if (e2 <= dy) { y0++; y1--; err += dy += a; } /* y step */
if (e2 >= dx || 2*err > dy) { x0++; x1--; err += dx += b1; } /* x step */
} while (x0 <= x1);
while (y0-y1 < b) { /* too early stop of flat ellipses a=1 */
if (filled) {
drawHLine(x0 - 1, x0 - 1, y0, color, plotProc, data); /* -> finish tip of ellipse */
drawHLine(x1 + 1, x1 + 1, y0, color, plotProc, data);
drawHLine(x0 - 1, x0 - 1, y1, color, plotProc, data);
drawHLine(x1 + 1, x1 + 1, y1, color, plotProc, data);
} else {
(*plotProc)(x0 - 1, y0, color, data); /* -> finish tip of ellipse */
(*plotProc)(x1 + 1, y0, color, data);
(*plotProc)(x0 - 1, y1, color, data);
(*plotProc)(x1 + 1, y1, color, data);
}
y0++;
y1--;
}
}
} // End of namespace Graphics