import project 3 files; added blending

[chaz/rasterize] / color.h

diff --git a/color.h b/color.h
index 2c5bf8040cc2ee0ff7cbd9ecf7665902a930fdb0..32765e0901ac2e9902041d431fc55eded1de4aee 100644 (file)
--- a/color.h
+++ b/color.h
@@ -85,7 +85,7 @@ void color_print(color_t c)
 INLINE_MAYBE
 color_t color_add(color_t c1, color_t c2)
 {
-    return color_new(c1.r + c2.r, c1.g + c2.g, c1.b + c2.b, c1.a + c2.a);
+    return color_new(c1.r + c2.r, c1.g + c2.g, c1.b + c2.b, c1.a);
 }
 
 /*
@@ -106,7 +106,6 @@ color_t color_mult(color_t c1, color_t c2)
     c1.r *= c2.r;
     c1.g *= c2.g;
     c1.b *= c2.b;
-    c1.a *= c2.a;
     return c1;
 }
 
@@ -119,7 +118,6 @@ color_t color_scale(color_t c, scal_t k)
     c.r *= k;
     c.g *= k;
     c.b *= k;
-    c.a *= k;
     return c;
 }
 
@@ -132,6 +130,15 @@ color_t color_scale2(color_t c1, color_t c2, scal_t k)
     return color_scale(color_mult(c1, c2), k);
 }
 
+INLINE_MAYBE
+color_t color_blend(color_t d, color_t s)
+{
+    d.r = (S(1.0) - s.a) * d.r + s.a * s.r;
+    d.g = (S(1.0) - s.a) * d.g + s.a * s.g;
+    d.b = (S(1.0) - s.a) * d.b + s.a * s.b;
+    return d;
+}
+
 /*
  * Clamp a color's channels to the normal range of 0.0 to 1.0.
  */
@@ -154,8 +161,7 @@ color_t color_interp(color_t c1, color_t c2, scal_t a)
 {
     return color_new(c1.r * (S(1.0) - a) + c2.r * a,
                      c1.g * (S(1.0) - a) + c2.g * a,
-                     c1.b * (S(1.0) - a) + c2.b * a,
-                     c1.a * (S(1.0) - a) + c2.a * a);
+                     c1.b * (S(1.0) - a) + c2.b * a, c1.a);
 }
 
 /*
@@ -166,8 +172,7 @@ color_t color_interp2(color_t c1, color_t c2, color_t c3, scal_t b[3])
 {
     return color_new(c1.r * b[0] + c2.r * b[1] + c3.r * b[2],
                      c1.g * b[0] + c2.g * b[1] + c3.g * b[2],
-                     c1.b * b[0] + c2.b * b[1] + c3.b * b[2],
-                     S(1.0));
+                     c1.b * b[0] + c2.b * b[1] + c3.b * b[2], c1.a);
 }