Integrate Mapbox earcut.hpp for robust triangluation (tinyobjloader#298)

syoyo · web-flow · commit db7454cbcee9 · 2021-07-29T16:55:42.000+09:00
* Use simple triangulation rule for the quad face when triangulation. This partially solves issue no. 295.

* Embed mapbox/earcut.hpp code(for robust triangulation)

* Use mapbox/earcut.hpp for the polygon tessellation(for a polygon with 5 or more vertices).

* Use Mapbox earcut(robust triangulation) by default for python binding.

* Fix compile of Mapbox earcut code path.
diff --git a/README.md b/README.md
@@ -26,6 +26,7 @@ Old version is available as `v0.9.x` branch https://github.com/syoyo/tinyobjload
 
 ## What's new
 
+* 29 Jul, 2021 : Added Mapbox's earcut for robust triangulation. Also fixes triangulation bug.
 * 19 Feb, 2020 : The repository has been moved to https://github.com/tinyobjloader/tinyobjloader !
 * 18 May, 2019 : Python binding!(See `python` folder. Also see https://pypi.org/project/tinyobjloader/)
 * 14 Apr, 2019 : Bump version v2.0.0 rc0. New C++ API and python bindings!(1.x API still exists for backward compatibility)
@@ -139,6 +140,7 @@ TinyObjLoader is licensed under MIT license.
 ### Third party licenses.
 
 * pybind11 : BSD-style license.
+* mapbox earcut.hpp: ISC License.
 
 ## Usage
 
@@ -241,10 +243,22 @@ TinyObjLoader now use `real_t` for floating point data type.
 Default is `float(32bit)`.
 You can enable `double(64bit)` precision by using `TINYOBJLOADER_USE_DOUBLE` define.
 
+### Robust triangulation
+
+When you enable `triangulation`(default is enabled),
+TinyObjLoader triangulate polygons(faces with 4 or more vertices).
+
+Built-in trinagulation code may not work well in some polygon shape.
+
+You can define `TINYOBJLOADER_USE_MAPBOX_EARCUT` for robust triangulation using `mapbox/earcut.hpp`.
+This requires C++11 compiler though.
+
 #### Example code (Deprecated API)
 
 ```c++
 #define TINYOBJLOADER_IMPLEMENTATION // define this in only *one* .cc
+// Optional. define TINYOBJLOADER_USE_MAPBOX_EARCUT gives robust trinagulation. Requires C++11
+//#define TINYOBJLOADER_USE_MAPBOX_EARCUT
 #include "tiny_obj_loader.h"
 
 std::string inputfile = "cornell_box.obj";
@@ -315,6 +329,8 @@ for (size_t s = 0; s < shapes.size(); s++) {
 
 ```c++
 #define TINYOBJLOADER_IMPLEMENTATION // define this in only *one* .cc
+// Optional. define TINYOBJLOADER_USE_MAPBOX_EARCUT gives robust trinagulation. Requires C++11
+//#define TINYOBJLOADER_USE_MAPBOX_EARCUT
 #include "tiny_obj_loader.h"
 
 
@@ -353,7 +369,7 @@ for (size_t s = 0; s < shapes.size(); s++) {
       tinyobj::real_t vx = attrib.vertices[3*size_t(idx.vertex_index)+0];
       tinyobj::real_t vy = attrib.vertices[3*size_t(idx.vertex_index)+1];
       tinyobj::real_t vz = attrib.vertices[3*size_t(idx.vertex_index)+2];
- 
+
       // Check if `normal_index` is zero or positive. negative = no normal data
       if (idx.normal_index >= 0) {
         tinyobj::real_t nx = attrib.normals[3*size_t(idx.normal_index)+0];
diff --git a/examples/viewer/viewer.cc b/examples/viewer/viewer.cc
@@ -23,13 +23,24 @@
 #include <GLFW/glfw3.h>
 
 #define TINYOBJLOADER_IMPLEMENTATION
+// TINYOBJLOADER_USE_MAPBOX_EARCUT: Enable better triangulation. Requires C++11
+//#define TINYOBJLOADER_USE_MAPBOX_EARCUT
 #include "../../tiny_obj_loader.h"
 
 #include "trackball.h"
 
+#ifdef __clang__
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Weverything"
+#endif
+
 #define STB_IMAGE_IMPLEMENTATION
 #include "stb_image.h"
 
+#ifdef __clang__
+#pragma clang diagnostic pop
+#endif
+
 #ifdef _WIN32
 #ifdef __cplusplus
 extern "C" {
diff --git a/python/tiny_obj_loader.cc b/python/tiny_obj_loader.cc
@@ -2,5 +2,8 @@
 // Need also define this in `binding.cc`(and all compilation units)
 #define TINYOBJLOADER_USE_DOUBLE
 
+// Use robust triangulation by using Mapbox earcut.
+#define TINYOBJLOADER_USE_MAPBOX_EARCUT
+
 #define TINYOBJLOADER_IMPLEMENTATION
 #include "tiny_obj_loader.h"
diff --git a/tiny_obj_loader.h b/tiny_obj_loader.h
