Make exponent an optional command-line param

1 files changed, 6 insertions, 1 deletions

diff --git a/attract.c b/attract.c
index 47f4a42..66fbee4 100644
--- a/attract.c
+++ b/attract.c
@@ -119,13 +119,18 @@ static void* thread_entry(void *arg_vp){
 	pthread_exit(NULL);
 }
 
-int main(void){
+int main(int argc,char **argv){
 	struct config cfg={
 		.unitsz=200,
 		.width=500, .height=500,
 		.exponent=8.5
 	};
 
+	assert(argc==1||argc==2);
+	if(argc==2){
+		cfg.exponent=strtod(argv[1],NULL);
+	}
+
 	unsigned char img[cfg.width*cfg.height*3];
 
 	int nthreads=sysconf(_SC_NPROCESSORS_ONLN);