Implement simple hole stencil to resolve holes in GDS polygons.

This commit is contained in:
Mario Hüttel 2022-04-19 22:14:52 +02:00
parent a6899a3f7c
commit 01613d1977
2 changed files with 108 additions and 7 deletions

View File

@ -4,6 +4,74 @@
//#include <gds-render/gds-utils/gds-types.h>
#include <vector>
class Hole {
private:
std::vector <p2t::Point *> hole_vertices;
public:
const std::vector <p2t::Point *> &get_vertices()
{
return hole_vertices;
}
void add_vertex(const p2t::Point &point)
{
auto pt = new p2t::Point(point);
hole_vertices.push_back(pt);
}
Hole(std::vector<p2t::Point *>::iterator start, std::vector<p2t::Point *>::iterator end)
{
hole_vertices = std::vector<p2t::Point *>(start, end);
}
};
static std::vector<Hole> resolve_holes_in_polyline(std::vector<p2t::Point *> &polyline)
{
bool found = false;
std::vector<Hole> holes;
std::vector<std::pair<
std::vector<p2t::Point *>::iterator,
std::vector<p2t::Point *>::iterator>
> points_to_remove;
for (auto start_it = polyline.begin(); start_it != polyline.end(); start_it++) {
for (auto check_it = std::next(start_it); check_it != polyline.end(); check_it++) {
/* Check if points are equal */
if (**start_it == **check_it) {
if (**std::prev(check_it) == **std::next(start_it)) {
/* Found a hole. Everything between start_it and check_it can be removed */
auto hole = Hole(std::next(start_it)+1, check_it);
holes.push_back(hole);
auto tbd = std::make_pair(start_it, check_it);
points_to_remove.push_back(tbd);
found = true;
break;
}
}
}
if (found)
break;
}
/* Remove form polyline */
for (auto it_pair_it = points_to_remove.begin(); it_pair_it != points_to_remove.end(); it_pair_it++) {
auto it_pair = *it_pair_it;
delete *it_pair.first;
delete *std::next(it_pair.first);
polyline.erase(it_pair.first, it_pair.second);
}
if (found) {
auto new_holes = resolve_holes_in_polyline(polyline);
holes.insert(holes.end(), new_holes.begin(), new_holes.end());
}
return holes;
}
int tesselator_triangulate_polygon(const struct gds_graphics *gfx, double scale, float** output_vertices, size_t *vertex_count)
{
GList *vertex_iter;
@ -18,8 +86,14 @@ int tesselator_triangulate_polygon(const struct gds_graphics *gfx, double scale,
polyline.push_back(pt);
}
auto holes = resolve_holes_in_polyline(polyline);
auto my_cdt = p2t::CDT(polyline);
for (auto hole_it = holes.begin(); hole_it != holes.end(); hole_it++) {
my_cdt.AddHole((*hole_it).get_vertices());
}
my_cdt.Triangulate();
auto triangles = my_cdt.GetTriangles();

View File

@ -8,6 +8,7 @@ struct _OpenGlPreviewGui {
GtkGLArea *gl_area;
unsigned int polygon_shader_prog;
unsigned int vao;
unsigned int vao_vertex_count;
unsigned int vbo;
float color[4];
gboolean line;
@ -54,7 +55,7 @@ static gboolean gl_area_render(GtkGLArea *area, GdkGLContext *context, gpointer
glBindVertexArray(gui->vao);
loc = glGetUniformLocation(gui->polygon_shader_prog, "const_color");
glUniform4fv(loc, 1, gui->color);
glDrawArrays(GL_TRIANGLES, 0, 10*3);
glDrawArrays(GL_TRIANGLES, 0, gui->vao_vertex_count);
glFlush();
@ -94,7 +95,7 @@ static gboolean gl_area_realize(GtkGLArea *area, gpointer user)
OpenGlPreviewGui *gui;
int success;
struct gds_graphics gfx;
struct gds_point points[12];
struct gds_point points[20];
size_t vertex_count;
gui = GDS_RENDER_OPENGL_PREVIEW_GUI(user);
@ -158,28 +159,54 @@ static gboolean gl_area_realize(GtkGLArea *area, gpointer user)
points[7].x = 20;
points[7].y = 20;
points[8].x = 1;
points[8].x = 0;
points[8].y = 20;
points[9].x = 1;
points[9].x = 0;
points[9].y = 100;
points[10].x = 100;
points[10].y = 100;
points[11].x = 100;
points[11].y = -100;
points[11].y = 5;
points[12].x = 60;
points[12].y = 5;
points[13].x = 60;
points[13].y = 20;
points[14].x = 50;
points[14].y = 20;
points[15].x = 50;
points[15].y = 0;
points[16].x = 60;
points[16].y = 0;
points[17].x = 60;
points[17].y = 5;
points[18].x = 100;
points[18].y = 5;
points[19].x = 100;
points[19].y = -100;
gfx.gfx_type = GRAPHIC_POLYGON;
for (int i = 0; i < 12; i++) {
for (int i = 0; i < 20; i++) {
gfx.vertices = g_list_append(gfx.vertices, &points[i]);
}
float *vertices = NULL;
tesselator_triangulate_polygon(&gfx, 180.0, &vertices, &vertex_count);
gui->vao_vertex_count = vertex_count;
glGenVertexArrays(1, &vao);
glBindVertexArray(vao);