bulk data dump

stars.c

@@ -0,0 +1,146 @@
+/********************************
+ Parallax sidescrolling starfield
+ Jason Bou-Samra [ParagonSoft]
+ 28/03/2024
+ to compile:
+ cc -o stars stars.c -lSDL2
+ ********************************/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <SDL2/SDL.h>
+#include <stdbool.h>
+
+int initSDL (void);
+int shutdownSDL (void);
+
+bool quit = false;                  		/* quit flag */
+
+SDL_Window *window = NULL;
+SDL_Renderer *sr;
+SDL_Event event;
+
+/* window paramaters */
+#define WIDTH 640				/* pixels */
+#define HEIGHT 512				/* pixels */
+#define TITLE "Starfield"			/* window title */
+
+int StarAmount = 256;
+int xres = 640;
+int yres = 512;
+
+struct StarField {				/* star structure */
+int x;
+int y;
+int speed;
+};
+
+int main(int argc, char **argv)			/* allow StarAmount as paramater */
+{
+
+	    const char* filename = argv[1];	/* parse command line arguments */
+  if (argc != 2){				/* display usage if less than 2 arguments passed */
+      printf("Usage: stars [<quantity>]\n\
+stars --help for help\n");
+      return 1;
+    }						// display usage, then exit
+
+if(!strcmp(filename, "--about")) {
+    printf("Paralax sidescrolling starfield\n\
+Jason Bou-Samra 20/03/2024.\n\n"); return 0;
+    }						/* display about, then exit */
+
+if(!strcmp (filename,  "--help")) {
+    printf("Usage: stars [<quantity>]\n\n\
+OPTIONS\n\
+--about            displays about message\n\
+--help             displays this help message\n"); return 0;
+    }
+
+    StarAmount = atoi(argv[1]);
+if (StarAmount == 0) {
+printf("invalid options\n\
+stars --help for help\n"); return 0;}
+	initSDL ();
+
+struct StarField stars[StarAmount];		/* array of StarField structs, named stars */
+
+for (int x = 1; x < StarAmount; x++)		/* setup initial values */
+{
+stars[x].x = rand() % (xres ); 
+stars[x].y = rand() % (yres );
+stars[x].speed = rand() % (5+1);
+}
+
+  while (quit == false) {			/* poll for quit event */
+
+  	      while (SDL_PollEvent (&event))
+	{
+	  if (event.type == SDL_QUIT || event.type == SDL_WINDOWEVENT_CLOSE)
+	    {
+	      quit = true;
+	    }
+	}
+      if (quit)
+	{
+	  break;				/* breakout of loop if quit is true */
+	}
+
+	SDL_SetRenderDrawColor(sr, 0x00, 0x00, 0x00, 0xFF);	/* set background colour for window */
+	SDL_RenderClear(sr);			/* clear window */
+
+	for (int x = 1; x < StarAmount; x++)
+		{
+		stars[x].x = stars[x].x + stars[x].speed;
+
+		if (stars[x].x > xres)
+			{
+			stars[x].x = 0;
+			stars[x].y = rand() % (yres );
+			}
+
+	SDL_SetRenderDrawColor(sr, 51*stars[x].speed, 51*stars[x].speed, 51*stars[x].speed, 0xFF); /* star color (R, G, B, A) */
+	SDL_RenderDrawPoint(sr, stars[x].x, stars[x].y);	/* plot star */
+}
+ 	SDL_RenderPresent (sr);
+}																			// keep going until quit event
+
+  shutdownSDL ();				/* bye */
+return 0;
+}
+
+/* initialise SDL */
+int initSDL ()
+{
+  SDL_Init (SDL_INIT_EVERYTHING);
+
+/* new window */
+  window = SDL_CreateWindow (TITLE,			/* title */
+			     SDL_WINDOWPOS_UNDEFINED,	/* x pos */
+			     SDL_WINDOWPOS_UNDEFINED,	/* w pos */
+			     WIDTH,			/* width */
+			     HEIGHT,			/* height */
+			     0);			/* Additional flag(s) */
+
+  /* deal with error */
+  if (window == NULL)
+    {
+      fprintf (stderr, "SDL window failed to initialise: %s\n",
+	       SDL_GetError ());
+      return 1;
+    }
+
+/* creater renderer */
+  sr = SDL_CreateRenderer (window, 0, SDL_RENDERER_ACCELERATED | SDL_RENDERER_PRESENTVSYNC);
+}
+
+/* shutdown routine */
+int shutdownSDL ()
+{
+  SDL_DestroyWindow (window);			/* free memory */
+  SDL_Quit ();					/* shutdown entire sdl sub-systems */
+  return 0;
+}
+
+/* message */
+char message[] = { "Yes, Jesus loves you!" };