From c29e4ecb7de4cb10f48b2526bc1abae847c718e2 Mon Sep 17 00:00:00 2001
From: pacien
Date: Thu, 28 Dec 2017 01:19:45 +0100
Subject: Add new geometry common types and functions

Signed-off-by: pacien <pacien.trangirard@pacien.net>
---
 src/common/geom.c         | 27 ++++++++++++++++++++++++++-
 src/morpher/trianglemap.c |  2 +-
 2 files changed, 27 insertions(+), 2 deletions(-)

(limited to 'src')

diff --git a/src/common/geom.c b/src/common/geom.c
index 219270f..eb35727 100644
--- a/src/common/geom.c
+++ b/src/common/geom.c
@@ -1,6 +1,12 @@
 #include "common/geom.h"
+#include <math.h>
+#include <common/geom.h>
 #include "morpher/matrix.h"
 
+static inline IntVector int_round(RealVector x) {
+  return (IntVector) round(x);
+}
+
 CartesianMapping m(int x, int y) {
   return (CartesianMapping) {{x, y},
                              {x, y}};
@@ -10,6 +16,10 @@ CartesianVector v(int x, int y) {
   return (CartesianVector) {x, y};
 }
 
+BarycentricVector b(double a, double b) {
+  return (BarycentricVector) {a, b};
+}
+
 bool mappings_equals(CartesianMapping m1, CartesianMapping m2) {
   return vector_equals(m1.origin, m2.origin) && vector_equals(m1.target, m2.target);
 }
@@ -18,7 +28,22 @@ bool vector_equals(CartesianVector v1, CartesianVector v2) {
   return v1.x == v2.x && v1.y == v2.y;
 }
 
-IntVector triangle_area(CartesianVector v1, CartesianVector v2, CartesianVector v3) {
+bool barycentric_vector_equals(BarycentricVector b1, BarycentricVector b2) {
+  return b1.a == b2.a && b1.b == b2.b;
+}
+
+IntVector square_area(CartesianVector v1, CartesianVector v2, CartesianVector v3) {
   return matrix_int_det2(v1.x - v3.x, v2.x - v3.x,
                          v1.y - v3.y, v2.y - v3.y);
 }
+
+BarycentricVector cartesian_to_barycentric(Triangle t, CartesianVector p) {
+  RealVector total_area = square_area(t.v[0], t.v[1], t.v[2]);
+  return (BarycentricVector) {square_area(t.v[1], t.v[2], p) / total_area,
+                              square_area(t.v[2], t.v[0], p) / total_area};
+}
+
+CartesianVector barycentric_to_cartesian(Triangle t, BarycentricVector p) {
+  return (CartesianVector) {int_round(p.a * (t.v[0].x - t.v[2].x) + p.b * (t.v[1].x - t.v[2].x) + t.v[2].x),
+                            int_round(p.a * (t.v[0].y - t.v[2].y) + p.b * (t.v[1].y - t.v[2].y) + t.v[2].y)};
+}
diff --git a/src/morpher/trianglemap.c b/src/morpher/trianglemap.c
index e2f3eb9..ad526bc 100644
--- a/src/morpher/trianglemap.c
+++ b/src/morpher/trianglemap.c
@@ -30,7 +30,7 @@ TriangleMap *trianglemap_to(TriangleMap *t, CartesianVector v) {
   int edge;
 
   for (edge = 0; edge < 3; ++edge)
-    if (triangle_area(t->vertices[edge].origin, t->vertices[(edge + 1) % 3].origin, v) > 0)
+    if (square_area(t->vertices[edge].origin, t->vertices[(edge + 1) % 3].origin, v) > 0)
       return t->neighbors[edge];
 
   return t;
-- 
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