GTK4_GG_hack/gg/GtkGLArea.c

/*
 *      Gem-graph OpenGL experiments
 *
 *      Desc: User interface functions
 *
 *  Copyright (C) 2023 Adrien Bourmault <neox@a-lec.org>
 *
 *  This file is part of Gem-graph.
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU Affero General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU Affero General Public License for more details.
 *
 *  You should have received a copy of the GNU Affero General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <unistd.h>
#include <gtk-4.0/gtk/gtk.h>
#include <glib-2.0/glib.h>

#include "../../include/base.h"
#include "../../include/ui.h"
#include "../../include/graphics.h"

struct stack_index_t {
    long stack_id;
    void *container_widget;
    void *gl_area;
};

static struct stack_index_t *stack_index = NULL;
size_t stack_index_size = 0;


/*
 *  Look for stack entry and returns stack_id
 *
 *  @params container_widget, generally the GtkBox that contains the GLArea
 *
 *  @returns stack_id
 */
long ui_get_graphic_stack(void *container_widget)
{
    // look for stack_index entry
    for (int i = 0; i < stack_index_size; i++) {
        if (stack_index[i].container_widget == (void *)container_widget) {
            return stack_index[i].stack_id;
        }
    }
    return -1;
}

/*
 *  Look for stack entry and returns stack_id
 *
 *  @params container_widget, generally the GtkBox that contains the GLArea
 *
 *  @returns stack_id
 */
long ui_is_graphic_stack_ready(void *container_widget)
{
    // look for stack_index entry
    for (int i = 0; i < stack_index_size; i++) {
        if (stack_index[i].container_widget == (void *)container_widget) {
            return stack_index[i].stack_id;
        }
    }
    return -1;
}

/*
 *  Look for stack entry and initializes OpenGL for it
 *
 *  @params container_widget, generally the GtkBox that contains the GLArea
 *
 *  @returns bool, true if success
 */
bool ui_init_graphic_stack(void *container_widget, GError *error_buffer)
{
    //g_printerr("[debug] ui_init_graphic_stack()\n");

    //g_printerr("[debug] ui_init_graphic_stack() : target is %p\n", container_widget);

    // look for stack_index entry
    for (int i = 0; i < stack_index_size; i++) {
        //g_printerr("[debug]     ui_init_graphic_stack() : i is %d\n", i);
        //g_printerr("[debug]     ui_init_graphic_stack() : target would be %p\n",
                   //stack_index[i].container_widget);
        if (stack_index[i].container_widget == (void *)container_widget) {
            stack_index[i].stack_id = graphics_init(&error_buffer);
            //g_printerr("[debug] ui_init_graphic_stack() : stack_id is %d\n",
                       //stack_index[i].stack_id);
            if (stack_index[i].stack_id >= 0)
                return true;
            else
                return false;
        }
    }
    return false;
}

/*
 *  Look for stack entry and shutdowns OpenGL for it
 *
 *  @params container_widget, generally the GtkBox that contains the GLArea
 *
 *  @returns bool, true if success
 */
bool ui_shutdown_graphic_stack(void *container_widget, GError *error_buffer)
{
    // look for stack_index entry
    for (int i = 0; i < stack_index_size; i++) {
        if (stack_index[i].container_widget == (void *)container_widget) {
            if (graphics_shutdown(stack_index[i].stack_id,
                                  &error_buffer) == false) {
                return false;
            }
            stack_index[i].stack_id = 0;
            return true;
        }
    }
    return false;
}


void ui_clean_stack_index(void)
{
    // look for stack_index entry
    for (int i = 0; i < stack_index_size; i++) {
        stack_index[i].stack_id = 0;
    }
    return;
}

/*
 *  Look for stack entry and triggers OpenGL for drawing
 *
 *  @params container_widget, generally the GtkBox that contains the GLArea
 *
 *  @returns bool, true if success
 */
bool ui_render_stack(GtkWidget *container_widget)
{
    // look for stack_index entry
    for (int i = 0; i < stack_index_size; i++) {
        if (stack_index[i].container_widget == (void *)container_widget) {
            graphics_draw(stack_index[i].stack_id);
            return true;
        }
    }
    return false;
}

/*
 *  Look for stack entry and triggers OpenGL for drawing
 *
 *  @params container_widget, generally the GtkBox that contains the GLArea
 *
 *  @returns bool, true if success
 */
bool ui_update_axis_stack(GtkWidget *container_widget, int axis, int value)
{
    // look for stack_index entry
    for (int i = 0; i < stack_index_size; i++) {
        if (stack_index[i].container_widget == (void *)container_widget) {
            graphic_stack[stack_index[i].stack_id].rotation_angles[axis] = value;
            gtk_widget_queue_draw((GtkWidget*)(stack_index[i].gl_area));
            return true;
        }
    }
    return false;
}

/*
 *  Look for every stack entry and shutdowns OpenGL for it
 *
 *  @params void
 *
 *  @returns bool, true if success
 */
void ui_shutdown_all_graphic_stacks(void)
{
    // look for stack_index entry
    for (int i = 0; i < stack_index_size; i++) {
        graphics_shutdown(stack_index[i].stack_id, NULL);
    }
    return;
}

/*
 *  Creates a slider widget
 *
 *  @params axis, meaning which axis we're building (for label)
 *
 *  @returns GtkWidget*, pointer to the new widget
 */
GtkWidget *create_axis_slider(int axis)
{
    GtkWidget *box, *label, *slider;
    GtkAdjustment *adj;
    const char *text;

    box = gtk_box_new(GTK_ORIENTATION_HORIZONTAL, 0);

    switch (axis) {
    case X_AXIS:
        text = "X";
        break;

    case Y_AXIS:
        text = "Y";
        break;

    case Z_AXIS:
        text = "Z";
        break;

    default:
        g_assert_not_reached();
    }

    label = gtk_label_new(text);
    gtk_box_append(GTK_BOX(box), label);
    gtk_widget_show(label);

    adj = gtk_adjustment_new(0.0, 0.0, 360.0, 1.0, 12.0, 0.0);
    g_signal_connect(adj, "value-changed",
                                        G_CALLBACK(on_axis_value_change),
                                        (gpointer) label);
    slider = gtk_scale_new(GTK_ORIENTATION_HORIZONTAL, adj);
    gtk_box_append(GTK_BOX(box), slider);
    gtk_widget_set_hexpand(slider, TRUE);
    gtk_widget_show(slider);

    gtk_widget_show(box);

    return box;
}

/*
 *  Creates GLArea and indexes it
 *
 *  @params target_mode, meaning which ui_stack we're on
 *          target_widget, meaning the box that will host the GLArea
 *
 *  @returns bool, true if success
 */
bool ui_setup_glarea(int target_mode, GtkWidget *target_widget)
{
    GtkWidget *gl_area;

    ////g_printerr("[debug] ui_setup_glarea()\n");

    assert(target_widget);

    ////g_printerr("[debug] ui_setup_glarea() : target is %p\n", target_widget);

    if (stack_index == NULL) {
        stack_index = g_malloc(sizeof(struct stack_index_t));
        stack_index_size = 1;
    } else {
        // look for stack_index entry
        for (int i = 0; i < stack_index_size; i++) {
            if (stack_index[i].container_widget == (void *)target_widget) {
                return false;
            }
        }
        // create entry
        stack_index =
            g_realloc(stack_index,
                      ++stack_index_size * sizeof(struct stack_index_t));
    }

    gl_area = GTK_WIDGET(gtk_gl_area_new());
    assert(gl_area);

    //gtk_widget_set_size_request(gl_area, 1000, 1000);
    gtk_gl_area_set_auto_render(GTK_GL_AREA(gl_area), true);
    gtk_widget_set_hexpand(gl_area, TRUE);
    gtk_widget_set_vexpand(gl_area, TRUE);
    //gtk_widget_set_halign(gl_area, GTK_ALIGN_CENTER);
    //gtk_widget_set_valign(gl_area, GTK_ALIGN_CENTER);

    // The main "draw" call for GtkGLArea
    g_signal_connect(GTK_GL_AREA(gl_area),
                     "render",
                     G_CALLBACK(on_glarea_render), NULL);

    g_signal_connect(gl_area,
                     "realize",
                     G_CALLBACK(on_glarea_realize), NULL);

    g_signal_connect(gl_area,
                     "unrealize",
                     G_CALLBACK(on_glarea_unrealize), NULL);

    stack_index[stack_index_size-1].container_widget =
        (void*)target_widget;

    stack_index[stack_index_size-1].gl_area = (void*)gl_area;

    ////g_printerr("[debug] ui_setup_glarea() : set target to %p\n", target_widget);

    ////g_printerr("[debug] ui_setup_glarea() : stack_index (@0x%p) had %ld elements\n",
               //stack_index,
               //stack_index_size);

    gtk_box_append(GTK_BOX(target_widget), gl_area);
    gtk_widget_show(GTK_WIDGET(gl_area));

    // Create sliders
    for(int i = 0; i < N_AXIS; i++)
        gtk_box_append(GTK_BOX(target_widget), create_axis_slider(i));

    return true;
}