X-Git-Url: https://git.dogcows.com/gitweb?p=chaz%2Frasterize;a=blobdiff_plain;f=vec.h;h=2634de621fc590366e61e3a109188eb817de3e54;hp=614e31dfec4c0e68bdbcb5b08ae0be7399ef4ef7;hb=3955aa40277c4b86a43b21e78d55d2fea7b643ce;hpb=b0a8ea303e942930350bf85c860afc969442c7a4

diff --git a/vec.h b/vec.h
index 614e31d..2634de6 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))
 
 
 /*
@@ -155,6 +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.
  */
@@ -239,5 +249,36 @@ 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]);
+}
+
+/*
+ * Interpolate smoothly between three texture coordinates with barycentric
+ * coordinates and perspective correction.
+ */
+INLINE_MAYBE
+vec_t vec_tinterp(vec_t v1, vec_t v2, vec_t v3, scal_t b[3])
+{
+    scal_t denom = (S(1.0) / v1.w) * b[0]
+                 + (S(1.0) / v2.w) * b[1]
+                 + (S(1.0) / v3.w) * b[2];
+    return vec_new(scal_clamp(((v1.x / v1.w) * b[0]
+                             + (v2.x / v2.w) * b[1]
+                             + (v3.x / v3.w) * b[2]) / denom, S(0.0), S(1.0)),
+                   scal_clamp(((v1.y / v1.w) * b[0]
+                             + (v2.y / v2.w) * b[1]
+                             + (v3.y / v3.w) * b[2]) / denom, S(0.0), S(1.0)),
+                   S(0.0));
+}
+
+
 #endif // _VEC_H_