From 9073d56eec0d37dda201b8aaa7995652fb8afc33 Mon Sep 17 00:00:00 2001 From: antirez Date: Fri, 4 Oct 2019 18:52:07 +0200 Subject: LOLWUT: refactoring + skeleton of LOLWUT 6. --- src/lolwut.c | 121 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 120 insertions(+), 1 deletion(-) (limited to 'src/lolwut.c') diff --git a/src/lolwut.c b/src/lolwut.c index ba7e1069e..d3e8fbad5 100644 --- a/src/lolwut.c +++ b/src/lolwut.c @@ -34,8 +34,11 @@ */ #include "server.h" +#include "lolwut.h" +#include void lolwut5Command(client *c); +void lolwut6Command(client *c); /* The default target for LOLWUT if no matching version was found. * This is what unstable versions of Redis will display. */ @@ -47,11 +50,127 @@ void lolwutUnstableCommand(client *c) { sdsfree(rendered); } +/* LOLWUT [] */ void lolwutCommand(client *c) { char *v = REDIS_VERSION; - if ((v[0] == '5' && v[1] == '.') || + char verstr[64]; + + if (c->argc == 2) { + long ver; + if (getLongFromObjectOrReply(c,c->argv[1],&ver,NULL) != C_OK) return; + snprintf(verstr,sizeof(verstr),"%u.0.0",(unsigned int)ver); + v = verstr; + } + + if ((v[0] == '5' && v[1] == '.' && v[2] != '9') || (v[0] == '4' && v[1] == '.' && v[2] == '9')) lolwut5Command(c); + else if ((v[0] == '6' && v[1] == '.' && v[2] != '9') || + (v[0] == '5' && v[1] == '.' && v[2] == '9')) + lolwut6Command(c); else lolwutUnstableCommand(c); } + +/* ========================== LOLWUT Canvase =============================== + * Many LOWUT versions will likely print some computer art to the screen. + * This is the case with LOLWUT 5 and LOLWUT 6, so here there is a generic + * canvas implementation that can be reused. */ + +/* Allocate and return a new canvas of the specified size. */ +lwCanvas *lwCreateCanvas(int width, int height) { + lwCanvas *canvas = zmalloc(sizeof(*canvas)); + canvas->width = width; + canvas->height = height; + canvas->pixels = zmalloc(width*height); + memset(canvas->pixels,0,width*height); + return canvas; +} + +/* Free the canvas created by lwCreateCanvas(). */ +void lwFreeCanvas(lwCanvas *canvas) { + zfree(canvas->pixels); + zfree(canvas); +} + +/* Set a pixel to the specified color. Color is 0 or 1, where zero means no + * dot will be displyed, and 1 means dot will be displayed. + * Coordinates are arranged so that left-top corner is 0,0. You can write + * out of the size of the canvas without issues. */ +void lwDrawPixel(lwCanvas *canvas, int x, int y, int color) { + if (x < 0 || x >= canvas->width || + y < 0 || y >= canvas->height) return; + canvas->pixels[x+y*canvas->width] = color; +} + +/* Return the value of the specified pixel on the canvas. */ +int lwGetPixel(lwCanvas *canvas, int x, int y) { + if (x < 0 || x >= canvas->width || + y < 0 || y >= canvas->height) return 0; + return canvas->pixels[x+y*canvas->width]; +} + +/* Draw a line from x1,y1 to x2,y2 using the Bresenham algorithm. */ +void lwDrawLine(lwCanvas *canvas, int x1, int y1, int x2, int y2, int color) { + int dx = abs(x2-x1); + int dy = abs(y2-y1); + int sx = (x1 < x2) ? 1 : -1; + int sy = (y1 < y2) ? 1 : -1; + int err = dx-dy, e2; + + while(1) { + lwDrawPixel(canvas,x1,y1,color); + if (x1 == x2 && y1 == y2) break; + e2 = err*2; + if (e2 > -dy) { + err -= dy; + x1 += sx; + } + if (e2 < dx) { + err += dx; + y1 += sy; + } + } +} + +/* Draw a square centered at the specified x,y coordinates, with the specified + * rotation angle and size. In order to write a rotated square, we use the + * trivial fact that the parametric equation: + * + * x = sin(k) + * y = cos(k) + * + * Describes a circle for values going from 0 to 2*PI. So basically if we start + * at 45 degrees, that is k = PI/4, with the first point, and then we find + * the other three points incrementing K by PI/2 (90 degrees), we'll have the + * points of the square. In order to rotate the square, we just start with + * k = PI/4 + rotation_angle, and we are done. + * + * Of course the vanilla equations above will describe the square inside a + * circle of radius 1, so in order to draw larger squares we'll have to + * multiply the obtained coordinates, and then translate them. However this + * is much simpler than implementing the abstract concept of 2D shape and then + * performing the rotation/translation transformation, so for LOLWUT it's + * a good approach. */ +void lwDrawSquare(lwCanvas *canvas, int x, int y, float size, float angle, int color) { + int px[4], py[4]; + + /* Adjust the desired size according to the fact that the square inscribed + * into a circle of radius 1 has the side of length SQRT(2). This way + * size becomes a simple multiplication factor we can use with our + * coordinates to magnify them. */ + size /= 1.4142135623; + size = round(size); + + /* Compute the four points. */ + float k = M_PI/4 + angle; + for (int j = 0; j < 4; j++) { + px[j] = round(sin(k) * size + x); + py[j] = round(cos(k) * size + y); + k += M_PI/2; + } + + /* Draw the square. */ + for (int j = 0; j < 4; j++) + lwDrawLine(canvas,px[j],py[j],px[(j+1)%4],py[(j+1)%4],color); +} -- cgit v1.2.1