src/window.c

/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 * Copyright 2023 Mike Becker. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 *   1. Redistributions of source code must retain the above copyright
 *      notice, this list of conditions and the following disclaimer.
 *
 *   2. Redistributions in binary form must reproduce the above copyright
 *      notice, this list of conditions and the following disclaimer in the
 *      documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include "ascension/window.h"
#include "ascension/context.h"
#include "ascension/error.h"
#include "ascension/utils.h"

#include <GL/glew.h>

void asc_window_settings_init_defaults(AscWindowSettings* settings) {
    settings->dimensions.width = 800;
    settings->dimensions.height = 600;
    settings->fullscreen = 0;
    settings->glsettings.depth_size = 24;
    settings->glsettings.vsync = 1;
    settings->glsettings.gl_major_version = 4;
    settings->glsettings.gl_minor_version = 0;
    settings->title = "Ascended Window";
}

void asc_window_initialize(unsigned int index, AscWindowSettings const *settings) {
    if (index >= ASC_MAX_WINDOWS) {
        asc_error("Maximum number of windows exceeded.");
        return;
    }
    AscWindow *window = &asc_context.windows[index];
    if (window->id > 0) {
        asc_error("Cannot create window - slot already occupied.");
        asc_dprintf("Tried to create window with index %u twice", index);
        return;
    }
    if (window->ui != NULL) {
        asc_dprintf("Window with index %u has a dangling UI pointer", index);
        asc_scene_node_free(window->ui);
    }

    Uint32 flags = SDL_WINDOW_OPENGL | SDL_WINDOW_SHOWN;
    flags |= settings->fullscreen ? SDL_WINDOW_FULLSCREEN_DESKTOP : SDL_WINDOW_RESIZABLE;

    window->window = SDL_CreateWindow(
            settings->title,
            SDL_WINDOWPOS_CENTERED,
            SDL_WINDOWPOS_CENTERED,
            settings->dimensions.width,
            settings->dimensions.height,
            flags
    );
    if (window->window == NULL) {
        asc_error(SDL_GetError());
        return;
    }

    window->id = SDL_GetWindowID(window->window);
    SDL_GetWindowSize(window->window,
            &window->dimensions.width,
            &window->dimensions.height
    );
    window->resized = true; // count initial sizing as resize

    if (asc_gl_context_initialize(&window->glctx, window->window, &settings->glsettings)) {
        window->ui = asc_scene_node_empty();
        asc_dprintf("Window %u initialized", window->id);
        asc_context.active_window = index;
    } else {
        asc_dprintf("Creating GL context failed for window %u", window->id);
        // cleanup on error
        SDL_DestroyWindow(window->window);
        window->window = NULL;
        window->id = 0;
    }
}

void asc_window_destroy(unsigned int index) {
    // safeguard
    if (asc_context.windows[index].id == 0) return;

    // this window cannot be active anymore
    if (asc_context.active_window == index) {
        asc_context.active_window = ASC_MAX_WINDOWS;
    }

    // pointer to the window
    AscWindow *window = &asc_context.windows[index];

    // for releasing OpenGL resources, we need to make the context current
    asc_gl_context_activate(&window->glctx);

    // destroy all scenes
    asc_scene_node_free(window->ui);
    window->ui = NULL;

    // release context related data
    asc_gl_context_destroy(&window->glctx);

    // destroy window
    if (window->window != NULL) {
        SDL_DestroyWindow(window->window);
    }

    // if another window was active, make the other context current again
    if (asc_context.active_window < ASC_MAX_WINDOWS) {
        asc_gl_context_activate(&asc_active_window->glctx);
    }

    // clean the data
    asc_dprintf("Window %u and its OpenGL context destroyed.", window->id);
    memset(window, 0, sizeof(AscWindow));
}

void asc_window_sync(unsigned int index) {
    // necessary safeguard
    if (asc_context.windows[index].id == 0) return;

    // active the window that shall be synced temporarily
    unsigned int active_index = asc_context.active_window;
    if (index != active_index) {
        asc_window_activate(index);
    }

    // Clear the color buffer for the window frame
    int window_width = asc_active_window->dimensions.width;
    int window_height = asc_active_window->dimensions.height;
    glViewport(0, 0, window_width, window_height);
    glClear(GL_COLOR_BUFFER_BIT);
    asc_recti viewport = {0, 0, window_width, window_height};

    // Draw the UI
    AscCamera ui_camera;
    asc_camera_ortho(&ui_camera, viewport);
    asc_scene_draw(asc_active_window->ui, viewport, &ui_camera);

    // Swap Buffers
    SDL_GL_SwapWindow(asc_active_window->window);

    // Clear Flags
    asc_active_window->resized = false;

    if (index != active_index) {
        asc_window_activate(active_index);
    }
}

void asc_window_activate(unsigned int index) {
    asc_context.active_window = index;
    asc_gl_context_activate(&asc_active_window->glctx);
}