add

3 files changed, 35 insertions, 3 deletions

diff --git a/main.c b/main.c
index 53e2c30..72c12ac 100644
--- a/main.c
+++ b/main.c
@@ -13,12 +13,10 @@ main(void)
 	kldImage_resize(cloud, sky->width, sky->height, 0);
 
 	kldImage_vflip(cloud);
-	kldImage_chaos3(cloud);
 
 	kldImage_invert(sky);
-	kldImage_chaos3(sky);
 
-	kldImage_blend(cloud, sky, 0.5f);
+	kldImage_add(cloud, sky);
 	kldImage_writePAM(cloud, stdout);
 
 	kldImage_free(sky);
diff --git a/src/image.c b/src/image.c
index 46daa23..2e57a5f 100644
--- a/src/image.c
+++ b/src/image.c
@@ -471,3 +471,34 @@ kldImage_blend(KldImage *img, KldImage *other, float ratio)
 
 	return 0;
 }
+
+int
+kldImage_add(KldImage *img, KldImage *other)
+{
+	NULL_SAFETY(-1);
+	NULL_SAFETY_EX(other, -1);
+
+	if (img->width != other->width || img->height != other->height) {
+		log_error("img (%lu x %lu) and other (%lu x %lu) "
+		          "dims don't match",
+		          img->width, img->height, other->width, other->height);
+		return -1;
+	}
+
+	for (size_t i = 0; i < img->size; i++) {
+		const KldColor c0 = img->data[i];
+		const KldColor c1 = other->data[i];
+		const unsigned int r = KLD_COLOR_R(c0) + KLD_COLOR_R(c1);
+		const unsigned int g = KLD_COLOR_G(c0) + KLD_COLOR_G(c1);
+		const unsigned int b = KLD_COLOR_B(c0) + KLD_COLOR_B(c1);
+		const unsigned int a = KLD_COLOR_A(c0) + KLD_COLOR_A(c1);
+		img->data[i] = KLD_COLOR(
+		    (r > 0xff) ? 0xff : r,
+		    (g > 0xff) ? 0xff : g,
+		    (b > 0xff) ? 0xff : b,
+		    (a > 0xff) ? 0xff : a
+		);
+	}
+
+	return 0;
+}
diff --git a/src/image.h b/src/image.h
index afaaa44..fbc8442 100644
--- a/src/image.h
+++ b/src/image.h
@@ -55,3 +55,6 @@ void kldImage_mask(KldImage *img, KldColor mask);
 
 /* return -1 if sizes are not equal */
 int kldImage_blend(KldImage *img, KldImage *other, float ratio);
+
+/* return -1 if sizes are not equal */
+int kldImage_add(KldImage *img, KldImage *other);