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

#include <GL/glew.h>

#include <assert.h>
#include <stdio.h>

void asc_window_initialize(unsigned int index, AscGLContextSettings settings) {
    if (index >= ASC_MAX_WINDOWS) {
        asc_error("Maximum number of windows exceeded (%u/%u).", index, ASC_MAX_WINDOWS);
        return;
    }
    AscWindow *window = &asc_context.windows[index];
    if (window->id > 0) {
        asc_error("Cannot create window - slot %u already occupied.", index);
        return;
    }

    SDL_WindowFlags flags = SDL_WINDOW_OPENGL;
    flags |= settings.fullscreen ? SDL_WINDOW_FULLSCREEN : SDL_WINDOW_RESIZABLE;
    window->sdl = SDL_CreateWindow("Ascension",800, 600, flags);
    if (window->sdl == NULL) {
        asc_error("Creating Window failed: %s", SDL_GetError());
        return;
    }

    window->id = SDL_GetWindowID(window->sdl);
    {
        int x,y, w, h;
        SDL_GetWindowPosition(window->sdl, &x, &y);
        SDL_GetWindowSize(window->sdl, &w, &h);
        window->rect = ASC_RECT(x, y, w, h);
    }
    window->resized = true; // count initial sizing as resize

    // default UI scale
    window->ui_scale = 1.0f;

    if (asc_gl_context_initialize(&window->glctx, window->sdl, &settings)) {
        char ui_scene_name[16];
        snprintf(ui_scene_name, sizeof(ui_scene_name), "Window %u UI", index);
        asc_camera_init(&window->ui_camera, .type = ASC_CAMERA_ORTHO,
            .ortho.rect = ASC_RECTV(ASC_VEC2I_0, window->rect.size),
            .viewport_update_func = asc_camera_ortho_update_size);
        asc_scene_init(&window->ui, ui_scene_name, &window->ui_camera);
        asc_dprintf("Window %u initialized at index %u", window->id, index);
        asc_context.active_window = index;
    } else {
        asc_error("Creating GL context failed for window %u at index %u", window->id, index);
        // cleanup on error
        SDL_DestroyWindow(window->sdl);
        window->sdl = 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
    for (unsigned int i = 0; i < ASC_MAX_SCENES; i++) {
        asc_scene_destroy(&window->scenes[i]);
    }
    asc_scene_destroy(&window->ui);

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

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

    // 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));
}

static void asc_window_update_viewport(AscCamera *camera, asc_vec2u window_size) {
    if (camera->viewport_update_func == NULL) {
        // this assumes the viewport was initialized with zeros!
        camera->viewport.size = window_size;
    } else {
        camera->viewport_update_func(camera, window_size);
    }
}

static void asc_window_update_camera(AscCamera *camera) {
    if (camera->update_func != NULL) {
        camera->update_func(camera);
    }
}

void asc_window_sync(unsigned int index) {
    if (index > ASC_MAX_WINDOWS) {
        asc_error("Index for syncing window out of bounds (%u/%u).", index, ASC_MAX_WINDOWS);
        return;
    }
    AscWindow *window = &asc_context.windows[index];
    // necessary safeguard
    if (window->id == 0) return;

    // activate the window that shall be synced temporarily
    unsigned int active_index = asc_window_activate(index);

    // Clear the color buffer for the window frame
    glViewport(0, 0,
        (GLsizei) window->rect.size.width,
        (GLsizei) window->rect.size.height);
    glClear(GL_COLOR_BUFFER_BIT);

    // Update the viewports when the window resized
    if (window->resized) {
        for (unsigned int i = 0; i < ASC_MAX_SCENES; i++) {
            if (asc_scene_active(&window->scenes[i])) {
                asc_window_update_viewport(window->scenes[i].camera, window->rect.size);
            }
        }
        asc_window_update_viewport(window->ui.camera, window->rect.size);
    }

    // Execute camera updates
    for (unsigned int i = 0; i < ASC_MAX_SCENES; i++) {
        if (asc_scene_active(&window->scenes[i])) {
            asc_window_update_camera(window->scenes[i].camera);
        }
    }
    asc_window_update_camera(window->ui.camera);

    // Execute all behaviors
    // TODO: this can eventually be parallelized
    for (unsigned int i = 0; i < ASC_MAX_SCENES; i++) {
        asc_scene_execute_behaviors(&window->scenes[i]);
    }
    asc_scene_execute_behaviors(&window->ui);

    // Draw all scenes
    for (unsigned int i = 0; i < ASC_MAX_SCENES; i++) {
        asc_scene_draw(&window->scenes[i]);
    }
    asc_scene_draw(&window->ui);

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

    // Clear Flags
    window->resized = false;
    window->moved = false;

    asc_window_activate(active_index);
}

unsigned int asc_window_activate(unsigned int index) {
    unsigned int active_index = asc_context.active_window;
    if (active_index != index) {
        asc_context.active_window = index;
        asc_gl_context_activate(&asc_active_window->glctx);
        return active_index;
    }
    return index;
}

unsigned int asc_window_index(Uint32 id) {
    unsigned int i = 0;
    for (; i < ASC_MAX_WINDOWS ; i++) {
        if (asc_context.windows[i].id == id) break;
    }
    return i;
}

AscScene *asc_window_scene(unsigned int index) {
    return &asc_active_window->scenes[index];
}

asc_vec2u asc_window_display_resolution(void) {
    const AscWindow *window = asc_active_window;
    SDL_DisplayID display = SDL_GetDisplayForWindow(window->sdl);
    const SDL_DisplayMode *dm = SDL_GetDesktopDisplayMode(display);
    if (dm == NULL) {
        asc_error("Failed to get display mode for window %u on display %d: %s",
            window->id, display, SDL_GetError());
    }
    return ASC_VEC2U(dm->w, dm->h);
}

float asc_window_ui_scale(unsigned int index) {
    assert(asc_context.windows[index].sdl != NULL);
    return asc_context.windows[index].ui_scale;
}

// TODO: error handling for all SDL_SetStuff() functions

void asc_window_set_title(unsigned index, const char *title) {
    assert(asc_context.windows[index].sdl != NULL);
    SDL_SetWindowTitle(asc_context.windows[index].sdl, title);
}

void asc_window_set_position(unsigned index, asc_vec2i pos) {
    assert(asc_context.windows[index].sdl != NULL);
    SDL_SetWindowPosition(asc_context.windows[index].sdl, pos.x, pos.y);
}

void asc_window_center(unsigned index) {
    // TODO: add support for multiple displays
    const AscWindow *window = asc_context.windows + index;
    assert(window->sdl != NULL);
    SDL_SetWindowPosition(window->sdl, SDL_WINDOWPOS_CENTERED, SDL_WINDOWPOS_CENTERED);
}

void asc_window_hcenter(unsigned index) {
    // TODO: add support for multiple displays
    const AscWindow *window = asc_context.windows + index;
    assert(window->sdl != NULL);
    SDL_SetWindowPosition(window->sdl, SDL_WINDOWPOS_CENTERED, window->rect.pos.y);
}

void asc_window_vcenter(unsigned index) {
    // TODO: add support for multiple displays
    const AscWindow *window = asc_context.windows + index;
    assert(window->sdl != NULL);
    SDL_SetWindowPosition(window->sdl, window->rect.pos.x, SDL_WINDOWPOS_CENTERED);
}

void asc_window_set_size(unsigned index, asc_vec2u size) {
    const AscWindow *window = asc_context.windows + index;
    assert(window->sdl != NULL);
    // TODO: check what needs to be changed when SDL_WINDOW_ALLOW_HIGHDPI is supported by the engine
    SDL_SetWindowSize(window->sdl, (int)size.width, (int)size.height);
}

void asc_window_fullscreen(unsigned index, bool fullscreen) {
    const AscWindow *window = asc_context.windows + index;
    assert(window->sdl != NULL);
    SDL_SetWindowFullscreen(window->sdl, fullscreen);
}

void asc_window_vsync(unsigned index, bool vsync) {
    unsigned int active_index = asc_window_activate(index);
    SDL_GL_SetSwapInterval(vsync ? 1 : 0);
    asc_window_activate(active_index);
}