# HG changeset patch
# User John Tsiombikas <nuclear@member.fsf.org>
# Date 1511142782 -7200
# Node ID 03e8b9a5031d210f88c3884f6483dfcf90b47b13
# Parent  436f82447c44b5168919148c3aa7f23aeb6ed075
screenshot function

diff -r 436f82447c44 -r 03e8b9a5031d src/main.c
--- a/src/main.c	Sun Nov 19 00:57:39 2017 +0200
+++ b/src/main.c	Mon Nov 20 03:53:02 2017 +0200
@@ -1,6 +1,9 @@
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 #include <math.h>
+#include <errno.h>
+#include <dirent.h>
 #include <GL/glew.h>
 #include <GL/glut.h>
 #include "sdr.h"
@@ -13,6 +16,7 @@
 void keyup(unsigned char key, int x, int y);
 void mouse(int bn, int st, int x, int y);
 void motion(int x, int y);
+void screenshot(void);
 
 static int win_width = 1280, win_height = 800;
 static float win_aspect;
@@ -127,6 +131,10 @@
 		}
 		break;
 
+	case '`':
+		screenshot();
+		break;
+
 	default:
 		break;
 	}
@@ -173,3 +181,48 @@
 		glutPostRedisplay();
 	}
 }
+
+void screenshot(void)
+{
+	FILE *fp;
+	DIR *dir;
+	struct dirent *dent;
+	unsigned char *img;
+	static int shotnum = -1;
+	char fname[128];
+
+	if(shotnum == -1) {
+		shotnum = 1;
+		if((dir = opendir("."))) {
+			while((dent = readdir(dir))) {
+				int num;
+				if(sscanf(dent->d_name, "img%d.ppm", &num) == 1) {
+					if(num >= shotnum) shotnum = num + 1;
+				}
+			}
+			closedir(dir);
+		}
+	} else {
+		++shotnum;
+	}
+
+	sprintf(fname, "img%04d.ppm", shotnum > 0 ? shotnum : 0);
+	if(!(fp = fopen(fname, "wb"))) {
+		fprintf(stderr, "failed to open %s for writing: %s\n", fname, strerror(errno));
+		return;
+	}
+
+	if(!(img = malloc(win_width * win_height * 3))) {
+		fprintf(stderr, "failed to allocate screenshot buffer\n");
+		fclose(fp);
+		return;
+	}
+
+	glReadPixels(0, 0, win_width, win_height, GL_RGB, GL_UNSIGNED_BYTE, img);
+
+	fprintf(fp, "P6\n%d %d\n255\n", win_width, win_height);
+	fwrite(img, 1, win_width * win_height * 3, fp);
+	fclose(fp);
+	free(img);
+	return;
+}