raytracer_challenge/tests/02_2_canvas.cpp

/*!
 * 02_2_canvas.cpp
 *
 * Copyright (c) 2015-2024, NADAL Jean-Baptiste. All rights reserved.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
 * MA 02110-1301 USA
 *
 * @Author:  NADAL Jean-Baptiste
 * @Date: 31/01/2024
 *
 */

/*---------------------------------------------------------------------------*/

#include <catch.hpp>

#include "canvas.h"

using namespace Raytracer;

/* ------------------------------------------------------------------------- */

SCENARIO("Creating a canvas", "[features/canvas.feature]")
{
    GIVEN("c <-canvas(10, 20)")
    {
        Canvas c(10, 20);
        THEN("c.width = 10")
        {
            REQUIRE(c.width() == 10);
        }
        AND_THEN("c.height = 20")
        {
            REQUIRE(c.height() == 20);
        }
        for (int i = 0; i < 10; ++i)
        {
            for (int j = 0; j < 20; ++j)
            {
                AND_THEN("every pixel of c is color(0,0,0)")
                {
                    REQUIRE(c.pixel_at(2, 3) == Color(0, 0, 0));
                }
            }
        }
    }
}

/* ------------------------------------------------------------------------- */

SCENARIO("Writing pixels to a canvas", "[features/canvas.feature]")
{
    GIVEN("c <-canvas(10, 20)")
    {
        Canvas c(10, 20);
        AND_GIVEN("red <-color(1, 0, 0)")
        {
            Color red(1, 0, 0);

            WHEN("write_pixel(c,2,3,red)")
            {
                c.write_pixel(2, 3, red);
                THEN("pixel_at(c,2,3) = red")
                {
                    REQUIRE(c.pixel_at(2, 3) == red);
                }
            }
        }
    }
}

/* ------------------------------------------------------------------------- */

SCENARIO("Constructing the PPM pixel data", "[features/canvas.feature]")
{
    std::string ppm, the_ref_ppm;
    GIVEN("c <-canvas(5, 3)")
    {
        Canvas c(5, 3);
        AND_GIVEN(" c1 color(1.5, 0, 0)")
        {
            Color c1(1.5, 0, 0);
            AND_GIVEN(" c2 color(0, 0.5, 0)")
            {
                Color c2(0, 0.5, 0);
                AND_GIVEN(" c3 color(-0.5, 0, 1))")
                {
                    Color c3(-0.5, 0, 1);
                    WHEN("write_pixel(c, 0, 0, c1)")
                    {
                        c.write_pixel(0, 0, c1);
                        AND_WHEN("write_pixel(c, 2, 1, c2)")
                        {
                            c.write_pixel(2, 1, c2);
                            AND_WHEN("write_pixel(c, 4, 2, c3)")
                            {
                                c.write_pixel(4, 2, c3);
                                AND_WHEN("ppm <- canvas_to_ppm(c)")
                                {
                                    ppm = c.to_ppm();

                                    the_ref_ppm = "P3\n5 3\n255\n";
                                    the_ref_ppm += "255 0 0 0 0 0 0 0 0 0 0 0 0 0 0\n";
                                    the_ref_ppm += "0 0 0 0 0 0 0 128 0 0 0 0 0 0 0\n";
                                    the_ref_ppm += "0 0 0 0 0 0 0 0 0 0 0 0 0 0 255\n";
                                    THEN("line 4-6 of ppm are 255 0 0 ....")
                                    {
                                        REQUIRE(ppm == the_ref_ppm);
                                    }
                                }
                            }
                        }
                    }
                }
            }
        }
    }
}

/* ------------------------------------------------------------------------- */

SCENARIO("Split long lines in PPM files", "[features/canvas.feature]")
{
    std::string ppm, the_ref_ppm;
    GIVEN("c <-canvas(10, 2)")
    {
        Canvas c(10, 2);
        WHEN("every pixel of c is set to color(1,0.8,0.6)")
        {
            for (int j = 0; j < 2; ++j)
            {
                for (int i = 0; i < 10; ++i)
                {
                    c.write_pixel(i, j, Color(1, 0.8, 0.6));
                }
            }

            AND_WHEN("ppm <- canvas_to_ppm(c)")
            {
                ppm = c.to_ppm();

                the_ref_ppm = "P3\n10 2\n255\n";
                the_ref_ppm += "255 204 153 255 204 153 255 204 153 255 204 153 255 204 153 255 204\n";
                the_ref_ppm += "153 255 204 153 255 204 153 255 204 153 255 204 153\n";
                the_ref_ppm += "255 204 153 255 204 153 255 204 153 255 204 153 255 204 153 255 204\n";
                the_ref_ppm += "153 255 204 153 255 204 153 255 204 153 255 204 153\n";

                THEN("line 4-7 of ppm are 255 204 153 255 204 ...")
                {
                    REQUIRE(ppm == the_ref_ppm);
                }
            }
        }
    }
}