Start preview feature. Add dummy triangle to test OpenGL.

preview-rendering/CMakeLists.txt

@@ -1,7 +1,15 @@
 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_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})

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/src/preview-rendering-gui.c

@@ -0,0 +1,167 @@
+#include <preview-rendering/preview-rendering-gui.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 vbo;
+	float color[4];
+};
+
+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, 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, 3);
+
+	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;
+
+	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);
+
+
+	float vertices[] = {
+		-0.5f, -0.5f,
+		0.5f, -0.5f,
+		0.0f, 0.5f,
+	};
+
+	glGenVertexArrays(1, &vao);
+	glBindVertexArray(vao);
+	glGenBuffers(1, &vbo);
+	glBindBuffer(GL_ARRAY_BUFFER, vbo);
+	glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
+	glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 2*sizeof(float), (void *)0);
+	glEnableVertexAttribArray(0);
+
+
+
+	gui->polygon_shader_prog = prog;
+	gui->vao = vao;
+	gui->vbo = vbo;
+
+	return TRUE;
+
+}
+
+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_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

@@ -1,4 +1,8 @@
+#include <epoxy/gl.h>
+
 int foobar(void)
 {
+	GLuint foo;
+	glGenBuffers(1, &foo);
 	return 42;
 }