1 files changed, 50 insertions, 8 deletions

diff --git a/glslwrite.c b/glslwrite.c
index 2913ae8..6673146 100644
--- a/glslwrite.c
+++ b/glslwrite.c
@@ -27,6 +27,7 @@
 
 #include <stdbool.h>
 #include <stdio.h>
+#include <unistd.h>
 
 #include <png.h>
 
@@ -36,12 +37,17 @@
 #include <SDL2/SDL_opengl.h>
 
 
+static float step = 20;
+static unsigned frame = 0;
+static unsigned max_frame = 0;
+
+
 static void savePNG(int width, int height, const char *output_dir) {
 	uint8_t pixels[width*height*4];
 	glReadPixels(0, 0, width, height, GL_RGBA, GL_UNSIGNED_INT_8_8_8_8, pixels);
 
 	char filename[strlen(output_dir) + 20];
-	snprintf(filename, sizeof(filename), "%s/%010u.png", output_dir, (unsigned)current_time);
+	snprintf(filename, sizeof(filename), "%s/%010u.png", output_dir, frame);
 
 	FILE *f = fopen(filename, "wb");
 	if (!f) {
@@ -84,12 +90,47 @@ static void savePNG(int width, int height, const char *output_dir) {
 	fclose(f);
 }
 
+static void usage(void) {
+	fprintf(stderr, "Usage: glslwrite [-s <step>] [-f <frames>] [-0 <param0>] [-1 <param1>] [-2 <param2>] <shader>\n");
+	exit(1);
+}
+
 int main(int argc, char *argv[]) {
-	if (argc != 3) {
-		fprintf(stderr, "Usage: glslwrite <shader> <output directory>\n");
-		exit(1);
+	while (true) {
+		int c = getopt(argc, argv, "s:f:0:1:2:");
+		if (c == -1)
+			break;
+
+		switch (c) {
+		case 's':
+			step = atof(optarg);
+			break;
+
+		case 'f':
+			max_frame = atoi(optarg);
+			break;
+
+		case '0':
+			param0 = atoi(optarg);
+			break;
+
+		case '1':
+			param1 = atoi(optarg);
+			break;
+
+		case '2':
+			param2 = atoi(optarg);
+			break;
+
+		default:
+			fprintf(stderr, "Invalid option '%c'\n", optopt);
+			usage();
+		}
 	}
 
+	if (argc - optind != 2)
+		usage();
+
 	SDL_Init(SDL_INIT_VIDEO);
 
 	SDL_GL_SetAttribute(SDL_GL_RED_SIZE, 8);
@@ -100,11 +141,11 @@ int main(int argc, char *argv[]) {
 	SDL_Window *window = SDL_CreateWindow("glslwrite", 0, 0, 800, 800, SDL_WINDOW_OPENGL|SDL_WINDOW_RESIZABLE);
 	SDL_GLContext ctx = SDL_GL_CreateContext(window);
 
-	filename = argv[1];
+	filename = argv[optind];
 	init();
 	load();
 
-	while (true) {
+	while (!max_frame || frame < max_frame) {
 		SDL_Event e;
 
 		while (SDL_PollEvent(&e)) {
@@ -128,8 +169,9 @@ int main(int argc, char *argv[]) {
 		render(width, height);
 		SDL_GL_SwapWindow(window);
 
-		savePNG(width, height, argv[2]);
-		current_time += 20;
+		savePNG(width, height, argv[optind+1]);
+		current_time += step;
+		frame++;
 	}
 
  quit: