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Diffstat (limited to 'src/lolwut6.c')
| -rw-r--r-- | src/lolwut6.c | 201 |
1 files changed, 201 insertions, 0 deletions
diff --git a/src/lolwut6.c b/src/lolwut6.c new file mode 100644 index 0000000..1ba111c --- /dev/null +++ b/src/lolwut6.c @@ -0,0 +1,201 @@ +/* + * Copyright (c) 2019, Salvatore Sanfilippo <antirez at gmail dot com> + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are met: + * + * * Redistributions of source code must retain the above copyright notice, + * this list of conditions and the following disclaimer. + * * Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * * Neither the name of Redis nor the names of its contributors may be used + * to endorse or promote products derived from this software without + * specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + * + * ---------------------------------------------------------------------------- + * + * This file implements the LOLWUT command. The command should do something + * fun and interesting, and should be replaced by a new implementation at + * each new version of Redis. + * + * Thanks to Michele Hiki Falcone for the original image that inspired + * the image, part of his game, Plaguemon. + * + * Thanks to the Shhh computer art collective for the help in tuning the + * output to have a better artistic effect. + */ + +#include "server.h" +#include "lolwut.h" + +/* Render the canvas using the four gray levels of the standard color + * terminal: they match very well to the grayscale display of the gameboy. */ +static sds renderCanvas(lwCanvas *canvas) { + sds text = sdsempty(); + for (int y = 0; y < canvas->height; y++) { + for (int x = 0; x < canvas->width; x++) { + int color = lwGetPixel(canvas,x,y); + char *ce; /* Color escape sequence. */ + + /* Note that we set both the foreground and background color. + * This way we are able to get a more consistent result among + * different terminals implementations. */ + switch(color) { + case 0: ce = "0;30;40m"; break; /* Black */ + case 1: ce = "0;90;100m"; break; /* Gray 1 */ + case 2: ce = "0;37;47m"; break; /* Gray 2 */ + case 3: ce = "0;97;107m"; break; /* White */ + default: ce = "0;30;40m"; break; /* Just for safety. */ + } + text = sdscatprintf(text,"\033[%s \033[0m",ce); + } + if (y != canvas->height-1) text = sdscatlen(text,"\n",1); + } + return text; +} + +/* Draw a skyscraper on the canvas, according to the parameters in the + * 'skyscraper' structure. Window colors are random and are always one + * of the two grays. */ +struct skyscraper { + int xoff; /* X offset. */ + int width; /* Pixels width. */ + int height; /* Pixels height. */ + int windows; /* Draw windows if true. */ + int color; /* Color of the skyscraper. */ +}; + +void generateSkyscraper(lwCanvas *canvas, struct skyscraper *si) { + int starty = canvas->height-1; + int endy = starty - si->height + 1; + for (int y = starty; y >= endy; y--) { + for (int x = si->xoff; x < si->xoff+si->width; x++) { + /* The roof is four pixels less wide. */ + if (y == endy && (x <= si->xoff+1 || x >= si->xoff+si->width-2)) + continue; + int color = si->color; + /* Alter the color if this is a place where we want to + * draw a window. We check that we are in the inner part of the + * skyscraper, so that windows are far from the borders. */ + if (si->windows && + x > si->xoff+1 && + x < si->xoff+si->width-2 && + y > endy+1 && + y < starty-1) + { + /* Calculate the x,y position relative to the start of + * the window area. */ + int relx = x - (si->xoff+1); + int rely = y - (endy+1); + + /* Note that we want the windows to be two pixels wide + * but just one pixel tall, because terminal "pixels" + * (characters) are not square. */ + if (relx/2 % 2 && rely % 2) { + do { + color = 1 + rand() % 2; + } while (color == si->color); + /* Except we want adjacent pixels creating the same + * window to be the same color. */ + if (relx % 2) color = lwGetPixel(canvas,x-1,y); + } + } + lwDrawPixel(canvas,x,y,color); + } + } +} + +/* Generate a skyline inspired by the parallax backgrounds of 8 bit games. */ +void generateSkyline(lwCanvas *canvas) { + struct skyscraper si; + + /* First draw the background skyscraper without windows, using the + * two different grays. We use two passes to make sure that the lighter + * ones are always in the background. */ + for (int color = 2; color >= 1; color--) { + si.color = color; + for (int offset = -10; offset < canvas->width;) { + offset += rand() % 8; + si.xoff = offset; + si.width = 10 + rand()%9; + if (color == 2) + si.height = canvas->height/2 + rand()%canvas->height/2; + else + si.height = canvas->height/2 + rand()%canvas->height/3; + si.windows = 0; + generateSkyscraper(canvas, &si); + if (color == 2) + offset += si.width/2; + else + offset += si.width+1; + } + } + + /* Now draw the foreground skyscraper with the windows. */ + si.color = 0; + for (int offset = -10; offset < canvas->width;) { + offset += rand() % 8; + si.xoff = offset; + si.width = 5 + rand()%14; + if (si.width % 4) si.width += (si.width % 3); + si.height = canvas->height/3 + rand()%canvas->height/2; + si.windows = 1; + generateSkyscraper(canvas, &si); + offset += si.width+5; + } +} + +/* The LOLWUT 6 command: + * + * LOLWUT [columns] [rows] + * + * By default the command uses 80 columns, 40 squares per row + * per column. + */ +void lolwut6Command(client *c) { + long cols = 80; + long rows = 20; + + /* Parse the optional arguments if any. */ + if (c->argc > 1 && + getLongFromObjectOrReply(c,c->argv[1],&cols,NULL) != C_OK) + return; + + if (c->argc > 2 && + getLongFromObjectOrReply(c,c->argv[2],&rows,NULL) != C_OK) + return; + + /* Limits. We want LOLWUT to be always reasonably fast and cheap to execute + * so we have maximum number of columns, rows, and output resolution. */ + if (cols < 1) cols = 1; + if (cols > 1000) cols = 1000; + if (rows < 1) rows = 1; + if (rows > 1000) rows = 1000; + + /* Generate the city skyline and reply. */ + lwCanvas *canvas = lwCreateCanvas(cols,rows,3); + generateSkyline(canvas); + sds rendered = renderCanvas(canvas); + rendered = sdscat(rendered, + "\nDedicated to the 8 bit game developers of past and present.\n" + "Original 8 bit image from Plaguemon by hikikomori. Redis ver. "); + rendered = sdscat(rendered,REDIS_VERSION); + rendered = sdscatlen(rendered,"\n",1); + addReplyVerbatim(c,rendered,sdslen(rendered),"txt"); + sdsfree(rendered); + lwFreeCanvas(canvas); +} |