Implement simple hole stencil to resolve holes in GDS polygons.

.github/workflows/cmake.yml

@@ -5,8 +5,6 @@ on:
     branches: [ master ]
   pull_request:
     branches: [ master ]
-  workflow_dispatch:
-  
 
 env:
   # Customize the CMake build type here (Release, Debug, RelWithDebInfo, etc.)
@@ -21,17 +19,13 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-    - name: Checkout Repository
+    - uses: actions/checkout@v2
-      uses: actions/checkout@v2
-      with:
-        submodules: recursive
     
     - name: Install system dependencies
       if: runner.os == 'Linux'
       run: |
         sudo apt-get update
-        sudo apt-get -y install libgtk-3-dev gettext cmake python3 libpython3-dev
+        sudo apt-get -y install libgtk-3-dev gettext
-        echo "Installation successful"
 
     - name: Configure CMake
       # Configure CMake in a 'build' subdirectory. `CMAKE_BUILD_TYPE` is only required if you are using a single-configuration generator such as make.

.gitmodules

@@ -6,3 +6,6 @@
 	path = 3rdparty/libfort
 	url = https://git.shimatta.de/3rd-party/libfort
 	branch = develop
+[submodule "3rdparty/poly2tri"]
+	path = 3rdparty/poly2tri
+	url = https://git.shimatta.de/3rd-party/poly2tri.git

CMakeLists.txt

@@ -1,5 +1,8 @@
-cmake_minimum_required(VERSION 3.6...3.18)
+if (POLICY CMP0048)
-project(gds-render LANGUAGES C)
+  cmake_policy(SET CMP0048 NEW)
+endif (POLICY CMP0048)
+
+project(gds-render LANGUAGES C CXX)
 
 if(CMAKE_INSTALL_PREFIX_INITIALIZED_TO_DEFAULT)
   set(CMAKE_INSTALL_PREFIX "/usr/" CACHE PATH "..." FORCE)
@@ -25,7 +28,7 @@ if(NOT WIN32)
   set(BoldWhite   "${Esc}[1;37m")
 endif()
 
-
+cmake_minimum_required(VERSION 3.0)
 find_package(PkgConfig REQUIRED)
 pkg_search_module(GLIB REQUIRED glib-2.0)
 pkg_check_modules(GTK3 REQUIRED gtk+-3.0)
@@ -72,8 +75,6 @@ SET_SOURCE_FILES_PROPERTIES(${SOURCE_GENERATED} PROPERTIES GENERATED 1)
 
 add_subdirectory(test)
 
-add_compile_options(-Wall -Wextra -Wold-style-declaration -Wuninitialized -Wmaybe-uninitialized -Wunused-parameter)
-
 add_subdirectory(resources)
 add_subdirectory(doxygen)
 add_subdirectory(translations)
@@ -81,7 +82,14 @@ add_subdirectory(version)
 set(FORT_ENABLE_TESTING OFF CACHE INTERNAL "")
 
 add_subdirectory(3rdparty/libfort)
-install(TARGETS fort EXCLUDE_FROM_ALL)
+
+if(OPENGL_PREVIEW)
+	message("${Green}OpenGL preview activated${ColorReset}")
+	add_definitions(-DGDS_RENDER_OPGENGL_PREVIEW)
+	add_subdirectory(preview-rendering)
+endif(OPENGL_PREVIEW)
+
+add_compile_options(-Wall -Wextra -Wold-style-declaration -Wuninitialized -Wmaybe-uninitialized -Wunused-parameter)
 
 link_directories(${GLIB_LINK_DIRS} ${GTK3_LINK_DIRS} ${CAIRO_LINK_DIRS})
 add_definitions(${GLIB2_CFLAGS_OTHER})
@@ -90,6 +98,10 @@ add_executable(${PROJECT_NAME} ${SOURCE} ${SOURCE_GENERATED})
 add_dependencies(${PROJECT_NAME} glib-resources)
 add_dependencies(${PROJECT_NAME} version)
 add_dependencies(${PROJECT_NAME} translations)
+if(OPENGL_PREVIEW)
+	add_dependencies(${PROJECT_NAME} opengl-preview)
+	target_link_libraries(${PROJECT_NAME} opengl-preview)
+endif(OPENGL_PREVIEW)
 
 install (TARGETS ${PROJECT_NAME} 
 	RUNTIME	

gds-render-gui.c

@@ -44,6 +44,10 @@
 #include <gds-render/geometric/cell-geometrics.h>
 #include <gds-render/version.h>
 
+#ifdef GDS_RENDER_OPGENGL_PREVIEW
+#include <preview-rendering/preview-rendering-gui.h>
+#endif
+
 /** @brief Columns of selection tree view */
 enum cell_store_columns {
 	CELL_SEL_LIBRARY = 0,
@@ -68,6 +72,9 @@ struct _GdsRenderGui {
 
 	/* Custom fields */
 	GtkWindow *main_window;
+#ifdef GDS_RENDER_OPGENGL_PREVIEW
+	OpenGlPreviewGui *preview_gui;
+#endif
 	GtkWidget *convert_button;
 	GtkWidget *open_button;
 	GtkWidget *load_layer_button;
@@ -189,8 +196,8 @@ static gboolean cell_store_filter_visible_func(GtkTreeModel *model, GtkTreeIter
 
 	gtk_tree_model_get(model, iter, CELL_SEL_CELL, &cell, CELL_SEL_LIBRARY, &lib, -1);
 
-    /* Show always, if this is a pure lib entry */
+	/* Show always, if this is a pure lib entry */
-    if (lib && !cell) {
+	if (lib && !cell) {
 		result = TRUE;
 		goto exit_filter;
 	}
@@ -665,6 +672,9 @@ static void gds_render_gui_dispose(GObject *gobject)
 	g_clear_object(&self->save_layer_button);
 	g_clear_object(&self->open_button);
 	g_clear_object(&self->select_all_button);
+#ifdef GDS_RENDER_OPGENGL_PREVIEW
+	g_clear_object(&self->preview_gui);
+#endif
 
 	if (self->main_window) {
 		g_signal_handlers_destroy(self->main_window);
@@ -768,7 +778,15 @@ static void gds_render_gui_init(GdsRenderGui *self)
 	GtkWidget *activity_bar_box;
 	GtkWidget *auto_color_button;
 	GtkWidget *auto_naming_button;
+#ifdef GDS_RENDER_OPGENGL_PREVIEW
+	OpenGlPreviewGui *preview_gui;
 
+	preview_gui = opengl_preview_gui_new();
+	/* No need to reference the preview gui. It is already referenced upon creation */
+	self->preview_gui = preview_gui;
+
+	opengl_preview_gui_show(preview_gui);
+#endif
 	main_builder = gtk_builder_new_from_resource("/gui/main.glade");
 
 	self->cell_tree_view = GTK_TREE_VIEW(gtk_builder_get_object(main_builder, "cell-tree"));

gds-utils/gds-parser.c

@@ -364,7 +364,6 @@ static GList *append_cell(GList *curr_list, struct gds_cell **cell_ptr)
 		cell->checks.affected_by_reference_loop = GDS_CELL_CHECK_NOT_RUN;
 		cell->stats.reference_count = 0;
 		cell->stats.total_vertex_count = 0;
-		cell->stats.total_gfx_count = 0;
 		cell->stats.gfx_count = 0;
 		cell->stats.vertex_count = 0;
 	} else

main.c

@@ -96,6 +96,11 @@ static void app_about(GSimpleAction *action, GVariant *parameter, gpointer user_
 	comment_text = g_string_new(_("gds-render is a free tool for rendering GDS2 layout files into vector graphics."));
 	g_string_append_printf(comment_text, _("\n\nFull git commit: %s"), _app_git_commit);
 
+#ifdef GDS_RENDER_OPGENGL_PREVIEW
+	g_string_append_printf(comment_text, _("\nOpenGL Previev: Availabe"));
+#else
+	g_string_append_printf(comment_text, _("\nOpenGL Previev: Unavailabe"));
+#endif
 	builder = gtk_builder_new_from_resource("/gui/about.glade");
 	dialog = GTK_DIALOG(gtk_builder_get_object(builder, "about-dialog"));
 	gtk_window_set_transient_for(GTK_WINDOW(dialog), NULL);
@@ -201,7 +206,7 @@ static int start_gui(int argc, char **argv)
 	application_domain = g_string_new(NULL);
 	g_string_printf(application_domain, "de.shimatta.gds_render_%s", _app_git_commit);
 
-    gapp = gtk_application_new(application_domain->str, G_APPLICATION_DEFAULT_FLAGS);
+	gapp = gtk_application_new(application_domain->str, G_APPLICATION_FLAGS_NONE);
 	g_string_free(application_domain, TRUE);
 
 	g_application_register(G_APPLICATION(gapp), NULL, NULL);

plugins/CMakeLists.txt

@@ -1,2 +1,3 @@
 add_subdirectory(plugin-example)
 add_custom_target(plugins DEPENDS pluginexample)
+cmake_minimum_required(VERSION 3.0)

plugins/plugin-example/CMakeLists.txt

@@ -1,5 +1,5 @@
 project(pluginexample)
-cmake_minimum_required(VERSION 2.8...3.18)
+cmake_minimum_required(VERSION 3.0)
 find_package(PkgConfig REQUIRED)
 pkg_search_module(PYTHON REQUIRED python3)
 

preview-rendering/CMakeLists.txt

@@ -0,0 +1,18 @@
+project(opengl-preview)
+cmake_minimum_required(VERSION 3.0)
+
+find_package(PkgConfig REQUIRED)
+pkg_check_modules(EPOXY REQUIRED epoxy)
+pkg_search_module(GLIB REQUIRED glib-2.0)
+pkg_check_modules(GTK3 REQUIRED gtk+-3.0)
+
+aux_source_directory("src" SRCS)
+
+add_subdirectory(poly2tri-wrapper)
+
+add_library(${PROJECT_NAME} STATIC ${SRCS})
+target_include_directories(${PROJECT_NAME} PUBLIC "include")
+target_include_directories(${PROJECT_NAME} PRIVATE ${EPOXY_INCLUDE_DIRS} ${GLIB_INCLUDE_DIRS} ${GTK3_INCLUDE_DIRS})
+target_link_directories(${PROJECT_NAME} PUBLIC ${EPOXY_LINK_DIRS} ${GLIB_LINK_DIRS} ${GTK3_LINK_DIRS})
+target_link_libraries(${PROJECT_NAME} ${GLIB_LDFLAGS} ${EPOXY_LDFLAGS} ${GTK3_LDFLAGS} poly2tri-wrapper)
+

preview-rendering/include/preview-rendering/preview-rendering-gui.h

@@ -0,0 +1,14 @@
+#ifndef _PREVIEW_RENDERING_GUI_H_
+#define _PREVIEW_RENDERING_GUI_H_
+
+#include <gtk/gtk.h>
+
+G_DECLARE_FINAL_TYPE(OpenGlPreviewGui, opengl_preview_gui, GDS_RENDER, OPENGL_PREVIEW_GUI, GObject)
+
+#define TYPE_GDS_RENDER_OPENGL_PREVIEW_GUI (opengl_preview_gui_get_type())
+
+OpenGlPreviewGui *opengl_preview_gui_new(void);
+
+void opengl_preview_gui_show(OpenGlPreviewGui *self);
+
+#endif /* _PREVIEW_RENDERING_GUI_H_ */

preview-rendering/poly2tri-wrapper/CMakeLists.txt

@@ -0,0 +1,11 @@
+project(poly2tri-wrapper LANGUAGES CXX)
+cmake_minimum_required(VERSION 3.12)
+
+add_subdirectory(../../3rdparty/poly2tri poly2tri)
+set(CMAKE_CXX_STANDARD 14)
+
+aux_source_directory("src" WRAPPER_SOURCES)
+
+add_library(${PROJECT_NAME} STATIC ${WRAPPER_SOURCES})
+target_link_libraries(${PROJECT_NAME} poly2tri)
+target_include_directories(${PROJECT_NAME} PUBLIC "include")

preview-rendering/poly2tri-wrapper/include/poly2tri-wrapper/poly2tri-wrapper.h

@@ -0,0 +1,16 @@
+#ifndef _POLY2TRI_WRAPPER_H_
+#define _POLY2TRI_WRAPPER_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <gds-render/gds-utils/gds-types.h>
+
+int tesselator_triangulate_polygon(const struct gds_graphics *gfx, double scale, float **output_vertices, size_t *vertex_count);
+
+#ifdef __cplusplus
+} /* extern "C" */
+#endif
+
+#endif /* _POLY2TRI_WRAPPER_H_ */

preview-rendering/poly2tri-wrapper/src/poly2tri-wrapper.cpp

@@ -0,0 +1,132 @@
+#include <iostream>
+#include <poly2tri/poly2tri.h>
+#include <poly2tri-wrapper/poly2tri-wrapper.h>
+//#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;
+	std::vector<p2t::Point*> polyline;
+
+	if (gfx->gfx_type != GRAPHIC_POLYGON)
+		return -1;
+
+	for (vertex_iter = gfx->vertices; vertex_iter; vertex_iter = g_list_next(vertex_iter)) {
+		struct gds_point *gds_pt = (struct gds_point *)vertex_iter->data;
+		auto pt = new p2t::Point((double)gds_pt->x/scale, (double)gds_pt->y/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();
+
+
+
+	/* Free the triangles */
+	for (auto it = triangles.begin(); it != triangles.end(); it++) {
+		auto triangle = *it;
+		std::cout << "Triangle: " <<
+			     triangle->GetPoint(0)->x << "|" << triangle->GetPoint(0)->y << ","
+			  << triangle->GetPoint(1)->x << "|" << triangle->GetPoint(1)->x << ","
+			  << triangle->GetPoint(2)->x << "|" << triangle->GetPoint(2)->y
+			  << std::endl;
+	}
+
+	/* Get the amount of triangles */
+	auto count = triangles.size();
+	*output_vertices = (float *)malloc(2*sizeof(float)*3*count);
+
+	*vertex_count = count * 3;
+	/* Free the points in the vector */
+	for (unsigned int i = 0; i < count; i++) {
+		for (int j = 0; j < 3; j++) {
+			auto pt = triangles[i]->GetPoint(j);
+			unsigned int idx = i * 6 + j * 2;
+			(*output_vertices)[idx] = (float)pt->x;
+			(*output_vertices)[idx + 1] = (float)pt->y;
+		}
+	}
+
+	for (auto it = polyline.begin(); it != polyline.end(); it++)
+		delete *it;
+
+	return 0;
+}

preview-rendering/src/preview-rendering-gui.c

@@ -0,0 +1,258 @@
+#include <preview-rendering/preview-rendering-gui.h>
+#include <poly2tri-wrapper/poly2tri-wrapper.h>
+#include <epoxy/gl.h>
+
+struct _OpenGlPreviewGui {
+	GObject super;
+	GtkWindow *main_window;
+	GtkGLArea *gl_area;
+	unsigned int polygon_shader_prog;
+	unsigned int vao;
+	unsigned int vao_vertex_count;
+	unsigned int vbo;
+	float color[4];
+	gboolean line;
+};
+
+G_DEFINE_TYPE(OpenGlPreviewGui, opengl_preview_gui, G_TYPE_OBJECT)
+
+static void opengl_preview_gui_dispose(GObject *gobj)
+{
+	OpenGlPreviewGui *self;
+
+	self = GDS_RENDER_OPENGL_PREVIEW_GUI(gobj);
+
+	g_clear_object(&self->gl_area);
+
+	if (self->main_window) {
+		gtk_widget_destroy(GTK_WIDGET(self->main_window));
+		self->main_window = NULL;
+	}
+
+	G_OBJECT_CLASS(opengl_preview_gui_parent_class)->dispose(gobj);
+}
+
+static void opengl_preview_gui_class_init(OpenGlPreviewGuiClass *klass)
+{
+	GObjectClass *oclass = G_OBJECT_CLASS(klass);
+
+	oclass->dispose = opengl_preview_gui_dispose;
+}
+
+static gboolean gl_area_render(GtkGLArea *area, GdkGLContext *context, gpointer user)
+{
+	OpenGlPreviewGui *gui;
+
+	int loc;
+
+	gui = GDS_RENDER_OPENGL_PREVIEW_GUI(user);
+	gtk_gl_area_make_current(area);
+
+	glClearColor (0, 0, 0, 1.0);
+	glClear (GL_COLOR_BUFFER_BIT);
+	glPolygonMode(GL_FRONT_AND_BACK, gui->line ? GL_LINE : GL_FILL);
+	glUseProgram(gui->polygon_shader_prog);
+	glBindVertexArray(gui->vao);
+	loc = glGetUniformLocation(gui->polygon_shader_prog, "const_color");
+	glUniform4fv(loc, 1, gui->color);
+	glDrawArrays(GL_TRIANGLES, 0, gui->vao_vertex_count);
+
+	glFlush();
+
+	return TRUE;
+}
+
+static int compile_shader_from_resource(GLenum shader_type, const char *res_name, unsigned int *shader)
+{
+	int success;
+	GBytes *res_bytes;
+	const char *data;
+	gsize size;
+	int size_int;
+	int sh;
+
+	res_bytes = g_resources_lookup_data(res_name, G_RESOURCE_LOOKUP_FLAGS_NONE, NULL);
+	data = g_bytes_get_data(res_bytes, &size);
+	sh = glCreateShader(shader_type);
+	size_int = (int)size;
+	glShaderSource(sh, 1, &data, &size_int);
+	glCompileShader(sh);
+	glGetShaderiv(sh, GL_COMPILE_STATUS, &success);
+	g_bytes_unref(res_bytes);
+	if (shader)
+		*shader = sh;
+
+	return success;
+}
+
+static gboolean gl_area_realize(GtkGLArea *area, gpointer user)
+{
+	unsigned int vbo;
+	unsigned int vs;
+	unsigned int fs;
+	unsigned int prog;
+	unsigned int vao;
+	OpenGlPreviewGui *gui;
+	int success;
+	struct gds_graphics gfx;
+	struct gds_point points[20];
+	size_t vertex_count;
+
+	gui = GDS_RENDER_OPENGL_PREVIEW_GUI(user);
+
+	gui->color[0] = 0.6f;
+	gui->color[1] = 0.5f;
+	gui->color[2] = 0.12f;
+	gui->color[3] = 1.0f;
+
+	gtk_gl_area_make_current(area);
+
+	if (!compile_shader_from_resource(GL_VERTEX_SHADER, "/shaders/polygon.vs", &vs)) {
+		g_warning("Error compiling vertex shader");
+	}
+	if (!compile_shader_from_resource(GL_FRAGMENT_SHADER, "/shaders/polygon.fs", &fs)) {
+		g_warning("Error compiling fragment shader");
+	}
+
+	prog = glCreateProgram();
+	glAttachShader(prog, vs);
+	glAttachShader(prog, fs);
+	glLinkProgram(prog);
+	glGetProgramiv(prog, GL_LINK_STATUS, &success);
+	if (!success) {
+		g_warning("Error linking shader");
+	}
+	glUseProgram(prog);
+	glDeleteShader(vs);
+	glDeleteShader(fs);
+
+
+
+
+
+
+	gui->polygon_shader_prog = prog;
+
+
+	gfx.vertices = NULL;
+	points[0].x = -100;
+	points[0].y = -100;
+
+	points[1].x = -100;
+	points[1].y = +100;
+
+	points[2].x = +0;
+	points[2].y = +100;
+
+	points[3].x = +0;
+	points[3].y = 20;
+
+	points[4].x = -20;
+	points[4].y = 20;
+
+	points[5].x = -20;
+	points[5].y = -20;
+
+	points[6].x = 20;
+	points[6].y = -20;
+
+	points[7].x = 20;
+	points[7].y = 20;
+
+	points[8].x = 0;
+	points[8].y = 20;
+
+	points[9].x = 0;
+	points[9].y = 100;
+
+	points[10].x = 100;
+	points[10].y = 100;
+
+
+	points[11].x = 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 < 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);
+	glGenBuffers(1, &vbo);
+	glBindBuffer(GL_ARRAY_BUFFER, vbo);
+	glBufferData(GL_ARRAY_BUFFER, vertex_count*2*sizeof(float), vertices, GL_STATIC_DRAW);
+	glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 2*sizeof(float), (void *)0);
+	glEnableVertexAttribArray(0);
+
+	free(vertices);
+
+	gui->vao = vao;
+	gui->vbo = vbo;
+
+	g_list_free(gfx.vertices);
+
+	return TRUE;
+
+}
+
+static void on_clicked(GtkWidget *sender, gboolean *p)
+{
+	*p = !*p;
+}
+
+static void opengl_preview_gui_init(OpenGlPreviewGui *self)
+{
+	GtkBuilder *builder;
+
+	builder = gtk_builder_new_from_resource("/gui/preview-window.glade");
+	self->main_window = GTK_WINDOW(gtk_builder_get_object(builder, "main-window"));
+	self->gl_area = GTK_GL_AREA(gtk_builder_get_object(builder, "gl-area"));
+	g_signal_connect(self->gl_area, "render", G_CALLBACK(gl_area_render), self);
+	g_signal_connect(self->gl_area, "realize", G_CALLBACK(gl_area_realize), self);
+
+	g_signal_connect(gtk_builder_get_object(builder, "test-button"), "clicked", G_CALLBACK(on_clicked), &self->line);
+	self->line = FALSE;
+	g_object_ref(self->gl_area);
+}
+
+OpenGlPreviewGui *opengl_preview_gui_new(void)
+{
+	return GDS_RENDER_OPENGL_PREVIEW_GUI(g_object_new(TYPE_GDS_RENDER_OPENGL_PREVIEW_GUI, NULL));
+}
+
+void opengl_preview_gui_show(OpenGlPreviewGui *self)
+{
+	gtk_widget_show(GTK_WIDGET(self->main_window));
+}

preview-rendering/src/preview-rendering.c

@@ -0,0 +1,8 @@
+#include <epoxy/gl.h>
+
+int foobar(void)
+{
+	GLuint foo;
+	glGenBuffers(1, &foo);
+	return 42;
+}

resources/preview-window.glade

@@ -0,0 +1,43 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!-- Generated with glade 3.38.2 -->
+<interface>
+  <requires lib="gtk+" version="3.24"/>
+  <object class="GtkWindow" id="main-window">
+    <property name="can-focus">False</property>
+    <property name="default-width">1024</property>
+    <property name="default-height">500</property>
+    <child>
+      <object class="GtkBox">
+        <property name="visible">True</property>
+        <property name="can-focus">False</property>
+        <property name="baseline-position">bottom</property>
+        <child>
+          <object class="GtkButton" id="test-button">
+            <property name="label" translatable="yes">button</property>
+            <property name="visible">True</property>
+            <property name="can-focus">True</property>
+            <property name="receives-default">True</property>
+          </object>
+          <packing>
+            <property name="expand">False</property>
+            <property name="fill">True</property>
+            <property name="position">0</property>
+          </packing>
+        </child>
+        <child>
+          <object class="GtkGLArea" id="gl-area">
+            <property name="visible">True</property>
+            <property name="app-paintable">True</property>
+            <property name="can-focus">False</property>
+            <property name="has-alpha">True</property>
+          </object>
+          <packing>
+            <property name="expand">True</property>
+            <property name="fill">True</property>
+            <property name="position">1</property>
+          </packing>
+        </child>
+      </object>
+    </child>
+  </object>
+</interface>

resources/resources.xml

@@ -5,6 +5,7 @@
 		<file compressed="true">about.glade</file>
 		<file>layer-widget.glade</file>
 		<file>dialog.glade</file>
+		<file compressed="true">preview-window.glade</file>
 	</gresource>
 	<gresource prefix="/data">
 		<file compressed="true">color-palette.txt</file>
@@ -12,6 +13,10 @@
 	<gresource prefix="/images">
 		<file compressed="true" alias="logo.svg">../icon/gds-render.svg</file>
 	</gresource>
+	<gresource prefix="/shaders">
+		<file compressed="true" alias="polygon.fs">./shaders/polygon.fs.glsl</file>
+		<file compressed="true" alias="polygon.vs">./shaders/polygon.vs.glsl</file>
+	</gresource>
 </gresources>
 
 

resources/shaders/polygon.fs.glsl

@@ -0,0 +1,9 @@
+#version 330 core
+
+out vec4 FragColor;
+in  vec4 vertex_color;
+
+void main()
+{
+	FragColor = vertex_color;
+}

resources/shaders/polygon.vs.glsl

@@ -0,0 +1,12 @@
+#version 330 core
+
+//uniform mat4 mvp;
+uniform vec4 const_color;
+
+layout (location = 0) in vec2 input_vertex;
+out vec4 vertex_color;
+void main()
+{
+	gl_Position = vec4(input_vertex.x, input_vertex.y, 0.0, 1.0);
+	vertex_color = const_color;
+}

test/CMakeLists.txt

@@ -1,4 +1,5 @@
 project(gds-render-test)
+cmake_minimum_required(VERSION 3.0)
 
 add_custom_target(test "${CMAKE_CURRENT_BINARY_DIR}/${PROJECT_NAME}" "-r compact" "-s" DEPENDS ${PROJECT_NAME})
 
@@ -22,7 +23,6 @@ if(NOT WIN32)
   set(BoldWhite   "${Esc}[1;37m")
 endif()
 
-cmake_minimum_required(VERSION 2.8...3.18)
 find_package(PkgConfig REQUIRED)
 
 include_directories("${CMAKE_CURRENT_SOURCE_DIR}/catch-framework")