commit 0e9913b7364e0c2cd54606c0492454666bf66fc3
author Mike Reed <mike@reedtribe.org> Wed Mar 30 13:22:30 2022 -0700
committer Michael Reed <mike@reedtribe.org> Wed Mar 30 13:30:20 2022 -0700
tree e8d8101e27ad2cb0fc40571b0527ee15cb0241a8
parent 7f29fd66c23229ba614c220e296bacfc7c45ff8f

optimize verts hittesting

include/rive/math/hit_test.hpp

diff --git a/include/rive/math/hit_test.hpp b/include/rive/math/hit_test.hpp
index e38e78e..424f9bb 100644
--- a/include/rive/math/hit_test.hpp
+++ b/include/rive/math/hit_test.hpp
@@ -47,5 +47,4 @@
     };
 
 } // namespace rive
-
 #endif

src/math/hit_test.cpp

diff --git a/src/math/hit_test.cpp b/src/math/hit_test.cpp
index 87ae4f7..369a3fd 100644
--- a/src/math/hit_test.cpp
+++ b/src/math/hit_test.cpp
@@ -311,6 +311,8 @@
     return nonzero != 0;
 }
 
+/////////////////////////
+
 bool HitTester::testTriangle(const IAABB& area, Vec2D a, Vec2D b, Vec2D c) {
     // Create mapping from triangle to the "unit" triangle, and look at the
     // corresponding coordinates for each point in area. If the coordinates
@@ -344,38 +346,27 @@
     return false;
 }
 
-static bool tri_overlap(const AABB& area, Vec2D a, Vec2D b, Vec2D c) {
-    const float L = std::min(a.x(), std::min(b.x(), c.x()));
-    const float R = std::max(a.x(), std::max(b.x(), c.x()));
-    const float T = std::min(a.y(), std::min(b.y(), c.y()));
-    const float B = std::max(a.y(), std::max(b.y(), c.y()));
-    return T < area.bottom() || area.top()  < B ||
-           L < area.right()  || area.left() < R;
-}
-
 bool HitTester::testMesh(const IAABB& area, Span<Vec2D> verts, Span<uint16_t> indices) {
     if (verts.size() < 3) {
         return false;
     }
 
-    // make a conservative float bounds
-    const AABB farea = AABB(area).inset(-0.5f, -0.5f);
-    // compute bounds of verts
-    const auto bounds = AABB(verts);
+    // test against the bounds of the entire mesh
+    if (true) {
+        const auto bounds = AABB(verts);
 
-    if (bounds.bottom() <= area.top || area.bottom <= bounds.top() ||
-        bounds.right() <= area.left || area.right <= bounds.left()) {
-        return false;
+        if (bounds.bottom() <= area.top || area.bottom <= bounds.top() ||
+            bounds.right() <= area.left || area.right <= bounds.left()) {
+            return false;
+        }
     }
 
     for (size_t i = 0; i < indices.size(); i += 3) {
         const auto a = verts[indices[i + 0]];
         const auto b = verts[indices[i + 1]];
         const auto c = verts[indices[i + 2]];
-        if (tri_overlap(farea, a, b, c)) {
-            if (testTriangle(area, a, b, c)) {
-                return true;
-            }
+        if (testTriangle(area, a, b, c)) {
+            return true;
         }
     }
     return false;