col_add

2 files changed, 10 insertions, 0 deletions

diff --git a/render.c b/render.c
index 3e5758b..f5e7b50 100644
--- a/render.c
+++ b/render.c
@@ -165,6 +165,15 @@ Colour col_scl(Colour a, unsigned char s) {
 	return r;
 }
 
+Colour col_add(Colour a, Colour b) {
+	Colour r;
+	r.r = ((int)a.r + (int)b.r) & 0xff;
+	r.g = ((int)a.g + (int)b.g) & 0xff;
+	r.b = ((int)a.b + (int)b.b) & 0xff;
+	r.a = ((int)a.a + (int)b.a) & 0xff;
+	return r;
+}
+
 void ren_begin(Renderer* r, Colour* t, int* d, int w, int h) {
 	r->t = t;
 	r->vp[0] = w;
diff --git a/render.h b/render.h
index fcce37e..74bcd7f 100644
--- a/render.h
+++ b/render.h
@@ -42,6 +42,7 @@ Colour blend(Colour dst, Colour src);
 Colour blend_mod(Colour dst, Colour src, Colour mod);
 Colour col_mul(Colour a, Colour b);
 Colour col_scl(Colour a, unsigned char s);
+Colour col_add(Colour a, Colour b);
 
 typedef struct {
 	Colour* p;