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Use love::Vector (8 bytes) instead of love::Vertex (20 bytes) for love.math.triangulate and love.math.isConvex.

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This commit is contained in:
Alex Szpakowski
2016-08-24 18:02:27 -03:00
parent acde58d311
commit 677a8d60b8
4 changed files with 32 additions and 35 deletions
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src/modules/math/MathModule.cpp
+16 -19
View File
@@ -29,20 +29,19 @@
#include <iostream>
using std::list;
using std::vector;
using love::Vertex;
using love::Vector;
namespace
{
// check if an angle is oriented counter clockwise
inline bool is_oriented_ccw(const Vertex &a, const Vertex &b, const Vertex &c)
inline bool is_oriented_ccw(const Vector &a, const Vector &b, const Vector &c)
{
// return det(b-a, c-a) >= 0
return ((b.x - a.x) * (c.y - a.y) - (b.y - a.y) * (c.x - a.x)) >= 0;
}
// check if a and b are on the same side of the line c->d
bool on_same_side(const Vertex &a, const Vertex &b, const Vertex &c, const Vertex &d)
bool on_same_side(const Vector &a, const Vector &b, const Vector &c, const Vector &d)
{
float px = d.x - c.x, py = d.y - c.y;
// return det(p, a-c) * det(p, b-c) >= 0
@@ -52,18 +51,16 @@ namespace
}
// checks is p is contained in the triangle abc
inline bool point_in_triangle(const Vertex &p, const Vertex &a, const Vertex &b, const Vertex &c)
inline bool point_in_triangle(const Vector &p, const Vector &a, const Vector &b, const Vector &c)
{
return on_same_side(p,a, b,c) && on_same_side(p,b, a,c) && on_same_side(p,c, a,b);
}
// checks if any vertex in `vertices' is in the triangle abc.
bool any_point_in_triangle(const list<const Vertex *> &vertices, const Vertex &a, const Vertex &b, const Vertex &c)
bool any_point_in_triangle(const list<const Vector *> &vertices, const Vector &a, const Vector &b, const Vector &c)
{
list<const Vertex *>::const_iterator it, end = vertices.end();
for (it = vertices.begin(); it != end; ++it)
for (const Vector *p : vertices)
{
const Vertex *p = *it;
if ((p != &a) && (p != &b) && (p != &c) && point_in_triangle(*p, a,b,c)) // oh god...
return true;
}
@@ -71,7 +68,7 @@ namespace
return false;
}
inline bool is_ear(const Vertex &a, const Vertex &b, const Vertex &c, const list<const Vertex *> &vertices)
inline bool is_ear(const Vector &a, const Vector &b, const Vector &c, const list<const Vector *> &vertices)
{
return is_oriented_ccw(a,b,c) && !any_point_in_triangle(vertices, a,b,c);
}
@@ -100,25 +97,25 @@ RandomGenerator *Math::newRandomGenerator()
return new RandomGenerator();
}
BezierCurve *Math::newBezierCurve(const vector<Vector> &points)
BezierCurve *Math::newBezierCurve(const std::vector<Vector> &points)
{
return new BezierCurve(points);
}
vector<Triangle> Math::triangulate(const vector<Vertex> &polygon)
std::vector<Triangle> Math::triangulate(const std::vector<love::Vector> &polygon)
{
if (polygon.size() < 3)
throw love::Exception("Not a polygon");
else if (polygon.size() == 3)
return vector<Triangle>(1, Triangle(polygon[0], polygon[1], polygon[2]));
return std::vector<Triangle>(1, Triangle(polygon[0], polygon[1], polygon[2]));
// collect list of connections and record leftmost item to check if the polygon
// has the expected winding
vector<size_t> next_idx(polygon.size()), prev_idx(polygon.size());
std::vector<size_t> next_idx(polygon.size()), prev_idx(polygon.size());
size_t idx_lm = 0;
for (size_t i = 0; i < polygon.size(); ++i)
{
const Vertex &lm = polygon[idx_lm], &p = polygon[i];
const love::Vector &lm = polygon[idx_lm], &p = polygon[i];
if (p.x < lm.x || (p.x == lm.x && p.y < lm.y))
idx_lm = i;
next_idx[i] = i+1;
@@ -132,7 +129,7 @@ vector<Triangle> Math::triangulate(const vector<Vertex> &polygon)
next_idx.swap(prev_idx);
// collect list of concave polygons
list<const Vertex *> concave_vertices;
list<const love::Vector *> concave_vertices;
for (size_t i = 0; i < polygon.size(); ++i)
{
if (!is_oriented_ccw(polygon[prev_idx[i]], polygon[i], polygon[next_idx[i]]))
@@ -140,14 +137,14 @@ vector<Triangle> Math::triangulate(const vector<Vertex> &polygon)
}
// triangulation according to kong
vector<Triangle> triangles;
std::vector<Triangle> triangles;
size_t n_vertices = polygon.size();
size_t current = 1, skipped = 0, next, prev;
while (n_vertices > 3)
{
next = next_idx[current];
prev = prev_idx[current];
const Vertex &a = polygon[prev], &b = polygon[current], &c = polygon[next];
const Vector &a = polygon[prev], &b = polygon[current], &c = polygon[next];
if (is_ear(a,b,c, concave_vertices))
{
triangles.push_back(Triangle(a,b,c));
@@ -170,7 +167,7 @@ vector<Triangle> Math::triangulate(const vector<Vertex> &polygon)
return triangles;
}
bool Math::isConvex(const std::vector<Vertex> &polygon)
bool Math::isConvex(const std::vector<love::Vector> &polygon)
{
if (polygon.size() < 3)
return false;
src/modules/math/MathModule.h
+10 -2
View File
@@ -43,6 +43,14 @@ namespace love
namespace math
{
struct Triangle
{
Triangle(const Vector &x, const Vector &y, const Vector &z)
: a(x), b(y), c(z)
{}
Vector a, b, c;
};
class BezierCurve;
class Math : public Module
@@ -87,7 +95,7 @@ public:
* @param polygon Polygon to triangulate. Must not intersect itself.
* @return List of triangles the polygon is composed of.
**/
std::vector<Triangle> triangulate(const std::vector<Vertex> &polygon);
std::vector<Triangle> triangulate(const std::vector<love::Vector> &polygon);
/**
* Checks whether a polygon is convex.
@@ -95,7 +103,7 @@ public:
* @param polygon Polygon to test.
* @return True if the polygon is convex, false otherwise.
**/
bool isConvex(const std::vector<Vertex> &polygon);
bool isConvex(const std::vector<love::Vector> &polygon);
/**
* Converts a value from the sRGB (gamma) colorspace to linear RGB.
src/modules/math/wrap_Math.cpp
+6 -6
View File
@@ -119,7 +119,7 @@ int w_newBezierCurve(lua_State *L)
int w_triangulate(lua_State *L)
{
std::vector<Vertex> vertices;
std::vector<love::Vector> vertices;
if (lua_istable(L, 1))
{
int top = (int) luax_objlen(L, 1);
@@ -129,7 +129,7 @@ int w_triangulate(lua_State *L)
lua_rawgeti(L, 1, i);
lua_rawgeti(L, 1, i+1);
Vertex v;
Vector v;
v.x = (float) luaL_checknumber(L, -2);
v.y = (float) luaL_checknumber(L, -1);
vertices.push_back(v);
@@ -143,7 +143,7 @@ int w_triangulate(lua_State *L)
vertices.reserve(top / 2);
for (int i = 1; i <= top; i += 2)
{
Vertex v;
Vector v;
v.x = (float) luaL_checknumber(L, i);
v.y = (float) luaL_checknumber(L, i+1);
vertices.push_back(v);
@@ -189,7 +189,7 @@ int w_triangulate(lua_State *L)
int w_isConvex(lua_State *L)
{
std::vector<Vertex> vertices;
std::vector<love::Vector> vertices;
if (lua_istable(L, 1))
{
int top = (int) luax_objlen(L, 1);
@@ -199,7 +199,7 @@ int w_isConvex(lua_State *L)
lua_rawgeti(L, 1, i);
lua_rawgeti(L, 1, i+1);
Vertex v;
love::Vector v;
v.x = (float) luaL_checknumber(L, -2);
v.y = (float) luaL_checknumber(L, -1);
vertices.push_back(v);
@@ -213,7 +213,7 @@ int w_isConvex(lua_State *L)
vertices.reserve(top / 2);
for (int i = 1; i <= top; i += 2)
{
Vertex v;
love::Vector v;
v.x = (float) luaL_checknumber(L, i);
v.y = (float) luaL_checknumber(L, i+1);
vertices.push_back(v);