sand effect

3 files changed, 41 insertions, 21 deletions

diff --git a/main.c b/main.c
index aa5c35c..c1b0dd0 100644
--- a/main.c
+++ b/main.c
@@ -1,29 +1,20 @@
 #include "image.h"
-#include "myrand.h"
-#include <time.h>
 #include <stdlib.h>
 
 int
 main(int argc, char **argv)
 {
-	mysrand(time(NULL));
+	if (argc < 2) {
+		fprintf(stderr, "usage: %s image.png\n", argv[0]);
+		return EXIT_FAILURE;
+	}
 
-	KldImage *cloud = kld_load("samples/cloud.jpg");
-	KldImage *sky = kld_load("samples/sky.jpg");
+	KldImage *img = kld_load(argv[1]);
+	kld_sand(img);
+	kld_grayscale(img);
+	kld_chaos3(img);
+	kld_writePAM(img, stdout);
 
-	kld_resize(cloud, sky->width, sky->height, 0);
-
-	kld_vflip(cloud);
-
-	kld_invert(sky);
-	const int m = (argc > 1) ? atoi(argv[1]) : 255;
-	kld_mod(sky, KLD_COLOR(m, m, m, 255));
-
-	kld_sub(cloud, sky);
-	kld_movechans(cloud, KLD_COLOR(3, 3, 2, -1));
-	kld_writePAM(cloud, stdout);
-
-	kld_free(sky);
-	kld_free(cloud);
-	return 0;
+	kld_free(img);
+	return EXIT_SUCCESS;
 }
diff --git a/src/image.c b/src/image.c
index 02e5ced..4103250 100644
--- a/src/image.c
+++ b/src/image.c
@@ -5,6 +5,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <sys/types.h>
 
 #define NULL_SAFETY_EX(N, X) do { \
 	if ((N) == NULL) { \
@@ -280,7 +281,7 @@ kld_copy(KldImage *dest, KldImage *src, int x, int y, int w, int h)
 			dx = x;
 		}
 		while (ix < src->width && dx < dest->width && --h != 0) {
-			kld_set(dest, dx, dy, kld_get(src, ix, iy));
+			KLD_SET(dest, dx, dy, KLD_GET(src, ix, iy));
 			dx += 1;
 			ix += 1;
 		}
@@ -429,6 +430,29 @@ kld_bit3(KldImage *img)
 }
 
 void
+kld_sand(KldImage *img)
+{
+	NULL_SAFETY();
+
+	if (img->height < 2)
+		return;
+	for (ssize_t y = img->height - 2; y >= 0; y--) {
+		for (size_t x = 0; x < img->width; x++) {
+			const KldColor px = kld_get(img, x, y);
+			ssize_t dy = y + 1;
+			if (KLD_COLOR_A(px) &&
+			    !KLD_COLOR_A(kld_get(img, x, dy)))
+			{
+				while (!KLD_COLOR_A(kld_get(img, x, dy + 1)))
+					dy += 1;
+				kld_set(img, x, y, 0);
+				kld_set(img, x, dy, px);
+			}
+		}
+	}
+}
+
+void
 kld_mod(KldImage *img, KldColor mask)
 {
 	NULL_SAFETY();
diff --git a/src/image.h b/src/image.h
index a919561..67a4bb1 100644
--- a/src/image.h
+++ b/src/image.h
@@ -3,6 +3,9 @@
 #include <stddef.h>
 #include <stdio.h>
 
+#define KLD_GET(I, X, Y) ((I)->data[X + Y * (I)->width])
+#define KLD_SET(I, X, Y, V) (I)->data[X + Y * (I)->width] = V
+
 /* return NULL on error */
 KldImage *kld_alloc(size_t w, size_t h);
 
@@ -51,6 +54,8 @@ void kld_chaos3(KldImage *img);
 
 void kld_bit3(KldImage *img);
 
+void kld_sand(KldImage *img);
+
 void kld_mod(KldImage *img, KldColor mask);
 
 /* cmd examples: