src/camera.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/context.h"
#include "ascension/camera.h"

void asc_camera_init_(AscCamera *camera, struct asc_camera_init_args args) {
    if (args.type == ASC_CAMERA_ORTHO) {
        asc_rect rect = args.ortho.rect;
        if (rect.size.width <= 0 || rect.size.height <= 0) {
            rect.size.width = 1;
            rect.size.height = 1;
        }
        asc_camera_ortho(camera, rect);
    } else if (args.type == ASC_CAMERA_PERSPECTIVE) {
        // TODO: implement
        asc_wprintf("Camera type PERSPECTIVE is not yet implemented.");
    } else {
        // at least zero all the bytes (law of the least surprise)
        memset(camera, 0, sizeof(AscCamera));
    }
    camera->viewport_update_func = args.viewport_update_func;
    camera->projection_update_func = args.projection_update_func;
    camera->viewport_clear = args.viewport_clear;
    camera->clear_color = args.clear_color;
}

void asc_camera_ortho(AscCamera *camera, asc_rect rect) {
    asc_mat4f_unit(camera->view);
    float left = (float) rect.pos.x;
    float right = left + (float) rect.size.width;
    float top = (float) rect.pos.y;
    float bottom = top + (float) rect.size.height;
    asc_mat4f_ortho(camera->projection, left, right, bottom, top, -1, 1);
}

void asc_camera_ortho_update_size(AscCamera *camera, asc_vec2u size) {
    asc_mat4f_ortho_update_size(camera->projection, (float)size.width, (float)size.height);
}

void asc_camera_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 = camera->viewport_update_func(window_size);
    }
    if (camera->projection_update_func != NULL) {
        camera->projection_update_func(camera, window_size);
    }
}