add texture mapping with perspective correction

[chaz/rasterize] / tri.h

diff --git a/tri.h b/tri.h
index ce0977b5c7382d7d61867b4f463c99d641effda1..3c028be33390cffea358d340eb6e4c5ae35e621f 100644 (file)
--- a/tri.h
+++ b/tri.h
@@ -191,6 +191,19 @@ vec_t tri_normal2(tri_t t, scal_t b[3])
     return vec_normalize(vec_interp(t.a.n, t.b.n, t.c.n, b));
 }
 
+/*
+ * Calculate an interpolated texture coordinate.
+ */
+INLINE_MAYBE
+vec_t tri_tcoord(tri_t t, scal_t b[3])
+{
+#if PERSPECTIVE_FIX
+    return vec_tinterp(t.a.t, t.b.t, t.c.t, b);
+#else
+    return vec_interp(t.a.t, t.b.t, t.c.t, b);
+#endif
+}
+
 /*
  * Calculate an entirely new vertex within the triangle based on barycentric
  * coordinates.
@@ -201,6 +214,7 @@ vert_t tri_interp(tri_t t, scal_t b[3])
     vert_t v = vert_new(tri_point(t, b));
     v.c = color_interp2(t.a.c, t.b.c, t.c.c, b);
     v.n = tri_normal2(t, b);
+    v.t = tri_tcoord(t, b);
     return v;
 }