Triangulate everything and toss the triangles into a big VA/VBO。
编辑:GLUtesselator包装:
struct TessContext
{
~TessContext()
{
for(size_t i = 0; i < combined.size(); ++i)
{
delete[] combined[i];
}
}
vector<Eigen::Vector2d> pts;
vector< GLdouble* > combined;
};
#define APIENTRY __stdcall
void APIENTRY tess_begin(GLenum type) {}
void APIENTRY tess_edgeFlag(GLboolean flag) {}
void APIENTRY tess_end() {}
void APIENTRY tess_vertex(void *data, TessContext* ctx)
{
GLdouble* coord = (GLdouble*)data;
ctx->pts.push_back(Eigen::Vector2d(coord[0], coord[1]));
}
void APIENTRY tess_combine(GLdouble coords[3], void *vertex_data[4], GLfloat weight[4], void **outData, TessContext* ctx)
{
GLdouble* newVert = new GLdouble[3];
ctx->combined.push_back(newVert);
newVert[0] = coords[0];
newVert[1] = coords[1];
newVert[2] = coords[2];
*outData = newVert;
}
template< typename Vec >
vector<Vec> Triangulate
(
const vector<Vec>& aSimplePolygon
)
{
vector<GLdouble> coords;
for(size_t i = 0; i < aSimplePolygon.size(); ++i)
{
coords.push_back(aSimplePolygon[i].x());
coords.push_back(aSimplePolygon[i].y());
coords.push_back(0);
}
GLUtesselator* tess = gluNewTess();
//gluTessProperty(tess, GLU_TESS_WINDING_RULE, GLU_TESS_WINDING_ODD);
//gluTessProperty(tess, GLU_TESS_WINDING_RULE, GLU_TESS_WINDING_NONZERO);
gluTessCallback(tess, GLU_TESS_BEGIN, (GLvoid (APIENTRY *)()) tess_begin );
gluTessCallback(tess, GLU_TESS_EDGE_FLAG, (GLvoid (APIENTRY *)()) tess_edgeFlag );
gluTessCallback(tess, GLU_TESS_VERTEX_DATA, (GLvoid (APIENTRY *)()) tess_vertex );
gluTessCallback(tess, GLU_TESS_END, (GLvoid (APIENTRY *)()) tess_end );
gluTessCallback(tess, GLU_TESS_COMBINE_DATA, (GLvoid (APIENTRY *)()) tess_combine );
gluTessNormal(tess, 0.0, 0.0, 1.0);
TessContext ctx;
gluTessBeginPolygon(tess, &ctx);
gluTessBeginContour(tess);
for(size_t i = 0; i < aSimplePolygon.size(); ++i)
{
gluTessVertex(tess, &coords[i*3], &coords[i*3]);
}
gluTessEndContour(tess);
gluTessEndPolygon(tess);
gluDeleteTess(tess);
vector<Vec> ret(ctx.pts.size());
for(size_t i = 0; i < ret.size(); ++i)
{
ret[i].x() = ctx.pts[i].x();
ret[i].y() = ctx.pts[i].y();
}
return ret;
}
用途Eigen但不是什么有趣的事。
您正在做大量的OpenGL调用。每次通话都有一些开销,这会让你的工作变慢。您必须将所有数据存储在缓冲区中,并使用几个调用来呈现所有内容。请参阅@genpfault答案。 – lvella 2012-03-22 19:39:13