col_scl

2 files changed, 10 insertions, 0 deletions

diff --git a/render.c b/render.c
index a55e062..3e5758b 100644
--- a/render.c
+++ b/render.c
@@ -156,6 +156,15 @@ Colour col_mul(Colour a, Colour b) {
 	return r;
 }
 
+Colour col_scl(Colour a, unsigned char s) {
+	Colour r;
+	r.r = (a.r * s) >> 8;
+	r.g = (a.g * s) >> 8;
+	r.b = (a.b * s) >> 8;
+	r.a = (a.a * s) >> 8;
+	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 a30331f..fcce37e 100644
--- a/render.h
+++ b/render.h
@@ -41,6 +41,7 @@ Colour make_black(void);
 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);
 
 typedef struct {
 	Colour* p;