X-Git-Url: https://git.dogcows.com/gitweb?p=chaz%2Frasterize;a=blobdiff_plain;f=vec.h;h=48635238202c5de1a437161028112bf1085352c1;hp=2c1269dccc88eb567e1962ecbcda2d8e5d082f56;hb=95850b98f73ad7033af60a30e324e9c3cda55389;hpb=c875478cdd823c7df8fdc859941bd9e5948c9315

diff --git a/vec.h b/vec.h
index 2c1269d..4863523 100644
--- a/vec.h
+++ b/vec.h
@@ -57,10 +57,11 @@ vec_t vec_new(scal_t x, scal_t y, scal_t z)
     return vec_new2(x, y, z, S(1.0));
 }
 
-#define VEC_ZERO    vec_new(S(0.0), S(0.0), S(0.0))
-#define VEC_ORTHO_X vec_new(S(1.0), S(0.0), S(0.0))
-#define VEC_ORTHO_Y vec_new(S(0.0), S(1.0), S(0.0))
-#define VEC_ORTHO_Z vec_new(S(0.0), S(0.0), S(1.0))
+#define VEC_ZERO      vec_new(S(0.0), S(0.0), S(0.0))
+#define VEC_ORTHO_X   vec_new(S(1.0), S(0.0), S(0.0))
+#define VEC_ORTHO_Y   vec_new(S(0.0), S(1.0), S(0.0))
+#define VEC_ORTHO_Z   vec_new(S(0.0), S(0.0), S(1.0))
+#define VEC_ZERO_FREE vec_new2(S(0.0), S(0.0), S(0.0), S(0.0))
 
 
 /*
@@ -106,6 +107,21 @@ bool vec_isequal(vec_t a, vec_t b)
     return (a.x == b.x && a.y == b.y && a.z == b.z && a.w == b.w);
 }
 
+/*
+ * Determine whether or not two vectors are mostly equal.
+ */
+INLINE_MAYBE
+bool vec_isequal2(vec_t a, vec_t b, scal_t epsilon)
+{
+    return scal_isequal2(a.x, b.x, epsilon) &&
+           scal_isequal2(a.y, b.y, epsilon) &&
+           scal_isequal2(a.z, b.z, epsilon) &&
+           scal_isequal2(a.w, b.w, epsilon);
+}
+
+/*
+ * Determine if one vector is "less than" another, for purposes of sorting.
+ */
 INLINE_MAYBE
 int vec_compare(vec_t a, vec_t b)
 {
@@ -140,6 +156,15 @@ vec_t vec_add(vec_t a, vec_t b)
     return a;
 }
 
+/*
+ * Add three vectors together.
+ */
+INLINE_MAYBE
+vec_t vec_add2(vec_t a, vec_t b, vec_t c)
+{
+    return vec_add(vec_add(a, b), c);
+}
+
 /*
  * Subtract a vector from another vector.
  */
@@ -224,5 +249,18 @@ vec_t vec_homodiv(vec_t v)
 }
 
 
+/*
+ * Interpolate smoothly between three vectors with barycentric coordinates.
+ */
+INLINE_MAYBE
+vec_t vec_interp(vec_t v1, vec_t v2, vec_t v3, scal_t b[3])
+{
+    return vec_new(v1.x * b[0] + v2.x * b[1] + v3.x * b[2],
+                   v1.y * b[0] + v2.y * b[1] + v3.y * b[2],
+                   v1.z * b[0] + v2.z * b[1] + v3.z * b[2]);
+}
+
+
+
 #endif // _VEC_H_