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 <cx/printf.h>

#include <GL/glew.h>

static void asc_gl_debug_callback(
        GLenum source, GLenum type, GLuint id, GLenum severity,
        GLsizei length, const GLchar* message,
        const void* userParam
) {
    cxmutstr buf = cx_asprintf(
            "source = %d, id = %u, type = %d, severity= %d, message = %.*s",
            source, id, type, severity, length, message);
    if (type == GL_DEBUG_TYPE_ERROR) {
        asc_error(buf.ptr);
    } else {
        asc_dprintf("GL debug: %.*s", (int)buf.length, buf.ptr);
    }
    cx_strfree(&buf);
}

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

static void asc_window_init_scenes(AscWindow *window) {
    asc_scene_init(&window->ui);
}

AscWindow *asc_window_initialize(unsigned int index, AscWindowSettings const *settings) {
    if (index >= ASC_MAX_WINDOWS) {
        asc_error("Maximum number of windows exceeded.");
        return NULL;
    }
    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", index);
        return NULL;
    }

    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 NULL;
    }

    window->id = SDL_GetWindowID(window->window);
    SDL_GetWindowSize(window->window,
            &window->dimensions.width,
            &window->dimensions.height
    );
    asc_mat4f_ortho(
            window->projection,
            0,
            (float) window->dimensions.width,
            (float) window->dimensions.height,
            0
    );

    SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK, SDL_GL_CONTEXT_PROFILE_CORE);
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, settings->gl_major_version);
    SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, settings->gl_minor_version);
    SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, settings->depth_size);
    SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
    window->glctx = SDL_GL_CreateContext(window->window);
    if (window->glctx == NULL) {
        asc_dprintf("Creating GL context failed for window %u", window->id);
    } else {
        glewExperimental = GL_TRUE;
        GLenum err = glewInit();
        if (err == GLEW_OK) {
            SDL_GL_SetSwapInterval(settings->vsync);
            glEnable(GL_DEPTH_TEST);
            glEnable(GL_BLEND);
            glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
            glEnable(GL_DEBUG_OUTPUT);
            glDebugMessageCallback(asc_gl_debug_callback, NULL);

            asc_dprintf("Window %u initialized", window->id);
            if (asc_primitives_init(&window->primitives)) {
                asc_window_init_scenes(window);
                asc_context.active_window = window;
                return window;
            } else {
                asc_dprintf("!!! Creating primitives for window %u failed !!!", window->id);
            }
        } else {
            asc_error(glewGetErrorString(err));
        }
    }

    // cleanup on error
    if (window->glctx != NULL) {
        SDL_GL_DeleteContext(window->glctx);
    }
    window->glctx = NULL;
    SDL_DestroyWindow(window->window);
    window->window = NULL;
    window->id = 0;
}

void asc_window_destroy(AscWindow* window) {
    // safeguard
    if (window->id == 0) return;

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

    // destroy all scenes
    asc_scene_destroy(&window->ui);

    // release context related data (we have to make the GL context current for this)
    SDL_GL_MakeCurrent(window->window, window->glctx);
    asc_primitives_destroy(&window->primitives);

    // destroy the GL context and the window
    if (window->glctx != NULL) {
        SDL_GL_DeleteContext(window->glctx);
    }
    if (window->window != NULL) {
        SDL_DestroyWindow(window->window);
    }

    // if another window was active, make the other context current again
    if (asc_context.active_window != NULL) {
        AscWindow const *aw = asc_context.active_window;
        SDL_GL_MakeCurrent(aw->window, aw->glctx);
    }

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

void asc_window_sync(AscWindow const* window) {
    AscWindow const *active_window = asc_context.active_window;
    if (window != active_window) {
        asc_window_activate(window);
    }

    // Clear viewport for new frame
    glViewport(0, 0, window->dimensions.width, window->dimensions.height);
    glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    // Draw the UI
    asc_scene_draw(&window->ui);

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

    if (window != active_window) {
        asc_window_activate(active_window);
    }
}

void asc_window_activate(AscWindow const *window) {
    SDL_GL_MakeCurrent(window->window, window->glctx);
    asc_context.active_window = (AscWindow *)window;
}