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raytracer_challenge/tests/03_matrix.cpp
2024-03-13 13:23:36 +01:00

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C++

/*!
* 03_matrix.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: 01/02/2024
*
*/
/*---------------------------------------------------------------------------*/
#include <external/catch.hpp>
#include "raytracing.h"
using namespace Raytracer;
/* ------------------------------------------------------------------------- */
SCENARIO("Constructing and inspecting a 4x4 matrix", "[features/matrices.feature]")
{
GIVEN("rgz following 4x4 matrix M")
{
Matrix M = {
{ 1, 2, 3, 4},
{ 5.5, 6.5, 7.5, 8.5},
{ 9, 10, 11, 12},
{13.5, 14.5, 15.5, 16.5}
};
THEN("M.rows = 4")
{
REQUIRE(M.rows() == 4);
}
AND_THEN("M.cols = 4")
{
REQUIRE(M.cols() == 4);
}
AND_THEN("M[0][0] = 1")
{
REQUIRE(M[0][0] == 1);
}
AND_THEN("M[0][3] = 4")
{
REQUIRE(M[0][3] == 4);
}
AND_THEN("M[1][0] = 5.5")
{
REQUIRE(M[1][0] == 5.5);
}
AND_THEN("M[1][2] = 7.5")
{
REQUIRE(M[1][2] == 7.5);
}
AND_THEN("M[2][2] = 11")
{
REQUIRE(M[2][2] == 11);
}
AND_THEN("M[3][0] = 13.5")
{
REQUIRE(M[3][0] == 13.5);
}
AND_THEN("M[3][2] = 15.5")
{
REQUIRE(M[3][2] == 15.5);
}
}
}
/* ------------------------------------------------------------------------- */
SCENARIO("A 2x2 matrix ought to be representable", "[features/matrices.feature]")
{
GIVEN("the following 2x2 matrix M")
{
Matrix M = {
{-3, 5},
{ 1, -2}
};
THEN("M.rows = 2")
{
REQUIRE(M.rows() == 2);
}
AND_THEN("M.cols = 2")
{
REQUIRE(M.cols() == 2);
}
AND_THEN("M[0][0] = -3")
{
REQUIRE(M[0][0] == -3);
}
AND_THEN("M[0][1] = 5")
{
REQUIRE(M[0][1] == 5);
}
AND_THEN("M[1][0] = 1")
{
REQUIRE(M[1][0] == 1);
}
AND_THEN("M[1][1] = -2")
{
REQUIRE(M[1][1] == -2);
}
}
}
/* ------------------------------------------------------------------------- */
SCENARIO("A 3x3 matrix ought to be representable", "[features/matrices.feature]")
{
GIVEN("the following 3x3 matrix M")
{
Matrix M = {
{-3, 5, 0},
{ 1, -2, -7},
{ 0, 1, 1}
};
THEN("M.rows = 3")
{
REQUIRE(M.rows() == 3);
}
AND_THEN("M.cols == 3")
{
REQUIRE(M.cols() == 3);
}
AND_THEN("M[0][0] = -3")
{
REQUIRE(M[0][0] == -3);
}
AND_THEN("M[1][1] = -2")
{
REQUIRE(M[1][1] == -2);
}
AND_THEN("M[2][2] = 1")
{
REQUIRE(M[2][2] == 1);
}
}
}
/* ------------------------------------------------------------------------- */
SCENARIO("Matrix equality with identical matrices", "[features/matrices.feature]")
{
GIVEN("the following matrix A")
{
Matrix A = {
{1, 2, 3, 4},
{5, 6, 7, 8},
{9, 8, 7, 6},
{5, 4, 3, 2}
};
AND_GIVEN("the following matrix B")
{
Matrix B = {
{1, 2, 3, 4},
{5, 6, 7, 8},
{9, 8, 7, 6},
{5, 4, 3, 2}
};
THEN("A = B")
{
REQUIRE(A == B);
}
}
}
}
/* ------------------------------------------------------------------------- */
SCENARIO("Matrix equality with different matrices", "[features/matrices.feature]")
{
GIVEN("the following matrix A")
{
Matrix A = {
{1, 2, 3, 4},
{5, 6, 7, 8},
{9, 8, 7, 6},
{5, 4, 3, 2}
};
AND_GIVEN("the following matrix B")
{
Matrix B = {
{2, 3, 4, 5},
{6, 7, 8, 9},
{8, 7, 6, 5},
{4, 3, 2, 1}
};
THEN("A != B")
{
REQUIRE(A != B);
}
}
}
}
/* ------------------------------------------------------------------------- */
SCENARIO("Multiplying two matrices", "[features/matrices.feature]")
{
GIVEN("the following matrix A")
{
Matrix A = {
{1, 2, 3, 4},
{5, 6, 7, 8},
{9, 8, 7, 6},
{5, 4, 3, 2}
};
AND_GIVEN("the following matrix B")
{
Matrix B = {
{-2, 1, 2, 3},
{ 3, 2, 1, -1},
{ 4, 3, 6, 5},
{ 1, 2, 7, 8}
};
AND_GIVEN("the following matrix C")
{
Matrix C = {
{20, 22, 50, 48},
{44, 54, 114, 108},
{40, 58, 110, 102},
{16, 26, 46, 42}
};
THEN("A * B = C")
REQUIRE((A * B) == C);
}
}
}
}
/* ------------------------------------------------------------------------- */
SCENARIO("A matrix multiplied by a tuple", "[features/matrices.feature]")
{
GIVEN("the following matrix A")
{
Matrix A = {
{1, 2, 3, 4},
{2, 4, 4, 2},
{8, 6, 4, 1},
{0, 0, 0, 1}
};
AND_GIVEN("b <- tuple(1, 2, 3, 1)")
{
Tuple b(1, 2, 3, 1);
THEN("A * b = tuple(18, 24, 33, 1)")
{
REQUIRE((A * b) == Tuple(18, 24, 33, 1));
}
}
}
}
/* ------------------------------------------------------------------------- */
SCENARIO("Multiplying a matrix by the identity matrix", "[features/matrices.feature]")
{
GIVEN("the following matrix A")
{
Matrix A = {
{0, 1, 2, 4},
{1, 2, 4, 8},
{2, 4, 8, 16},
{4, 8, 16, 32}
};
THEN("A * identity_matrix = A")
{
REQUIRE((A * Matrix::identity()) == A);
}
}
}
/* ------------------------------------------------------------------------- */
SCENARIO("Multiplying the identity matrix by a tuple", "[features/matrices.feature]")
{
GIVEN("a <- tuple(1, 2, 3, 4)")
{
Tuple a(1, 2, 3, 4);
THEN("identity_matrix * a = a")
{
REQUIRE((Matrix::identity() * a) == a);
}
}
}
/* ------------------------------------------------------------------------- */
SCENARIO("Transposing a matrix", "[features/matrices.feature]")
{
GIVEN("the following matrix A")
{
Matrix A = {
{0, 9, 3, 0},
{9, 8, 0, 8},
{1, 8, 5, 3},
{0, 0, 5, 8}
};
THEN("transpose(A) is the following matrix")
{
Matrix transposed = {
{0, 9, 1, 0},
{9, 8, 8, 0},
{3, 0, 5, 5},
{0, 8, 3, 8}
};
REQUIRE(A.transpose() == transposed);
}
}
}
/* ------------------------------------------------------------------------- */
SCENARIO("Transposing the identity matrix", "[features/matrices.feature]")
{
GIVEN("A <- transpose(identity_matrix)")
{
Matrix A = Matrix::identity().transpose();
THEN("A = identity_matrix")
{
REQUIRE(A == Matrix::identity());
}
}
}
/* ------------------------------------------------------------------------- */
SCENARIO("Calculating the determinant of a 2x2 matrix", "[features/matrices.feature]")
{
GIVEN("the following 2x2 matrix A")
{
Matrix A = {
{ 1, 5},
{-3, 2}
};
THEN("determinant(A) = 17")
{
REQUIRE(A.determinant() == 17);
}
}
}
/* ------------------------------------------------------------------------- */
SCENARIO("A submatrix of a 3x3 matrix is a 2x2 matrix", "[features/matrices.feature]")
{
GIVEN("the following 3x3 matrix A")
{
Matrix A = {
{ 1, 5, 0},
{-3, 2, 7},
{ 0, 6, -3}
};
Matrix B = {
{-3, 2},
{ 0, 6}
};
THEN("submatrix(A,0,2) is the following 2x2 matrix")
{
REQUIRE(A.sub_matrix(0, 2) == B);
}
}
}
/* ------------------------------------------------------------------------- */
SCENARIO("A submatrix of a 4x4 matrix is a 3x3 matrix", "[features/matrices.feature]")
{
GIVEN("the following 4x4 matrix A")
{
Matrix A = {
{-6, 1, 1, 6},
{-8, 5, 8, 6},
{-1, 0, 8, 2},
{-7, 1, -1, 1}
};
Matrix B = {
{-6, 1, 6},
{-8, 8, 6},
{-7, -1, 1}
};
THEN("submatrix(B,2,1) is the following 3x3 matrix")
{
REQUIRE(A.sub_matrix(2, 1) == B);
}
}
}
/* ------------------------------------------------------------------------- */
SCENARIO("Calculating a minor of a 3x3 matrix", "[features/matrices.feature]")
{
GIVEN("the following 3x3 matrix A")
{
Matrix A = {
{3, 5, 0},
{2, -1, -7},
{6, -1, 5}
};
AND_GIVEN("B <- submatrix(A,1,0)")
{
Matrix B = A.sub_matrix(1, 0);
THEN("determinant(B) = 25")
{
REQUIRE(B.determinant() == 25);
}
AND_THEN("minor(A,1,0)=25")
{
REQUIRE(A.minor(1, 0) == 25);
}
}
}
}
/* ------------------------------------------------------------------------- */
SCENARIO("Calculating a cofactor of a 3x3 matrix", "[features/matrices.feature]")
{
GIVEN("the following 3x3 matrix A")
{
Matrix A = {
{3, 5, 0},
{2, -1, -7},
{6, -1, 5}
};
THEN("minor(A, 0, 0) = -12")
{
REQUIRE(A.minor(0, 0) == -12);
}
AND_THEN("cofactor(A, 0, 0) = -12")
{
REQUIRE(A.cofactor(0, 0) == -12);
}
AND_THEN("minor(A, 1, 0) = 25")
{
REQUIRE(A.minor(1, 0) == 25);
}
AND_THEN("cofactor(A, 1, 0) = -25")
{
REQUIRE(A.cofactor(1, 0) == -25);
}
}
}
/* ------------------------------------------------------------------------- */
SCENARIO("Calculating the determinant of a 3x3 matrix", "[features/matrices.feature]")
{
GIVEN("the following 3x3 matrix A")
{
Matrix A = {
{ 1, 2, 6},
{-5, 8, -4},
{ 2, 6, 4}
};
THEN("cofactor(A, 0, 0) = 56")
{
REQUIRE(A.cofactor(0, 0) == 56);
}
AND_THEN("cofactor(A, 0, 1) = 12")
{
REQUIRE(A.cofactor(0, 1) == 12);
}
AND_THEN("cofactor(A, 0, 2) = -46")
{
REQUIRE(A.cofactor(0, 2) == -46);
}
AND_THEN("determinant(A) = -196")
{
REQUIRE(A.determinant() == -196);
}
}
}
/* ------------------------------------------------------------------------- */
SCENARIO("Calculating the determinant of a 4x4 matrix", "[features/matrices.feature]")
{
GIVEN("the following 4x4 matrix A")
{
Matrix A = {
{-2, -8, 3, 5},
{-3, 1, 7, 3},
{ 1, 2, -9, 6},
{-6, 7, 7, -9}
};
THEN("cofactor(A, 0, 0) = 690")
{
REQUIRE(A.cofactor(0, 0) == 690);
}
AND_THEN("cofactor(A, 0, 1) = 447")
{
REQUIRE(A.cofactor(0, 1) == 447);
}
AND_THEN("cofactor(A, 0, 2) = 210")
{
REQUIRE(A.cofactor(0, 2) == 210);
}
AND_THEN("cofactor(A, 0, 3) = 51")
{
REQUIRE(A.cofactor(0, 3) == 51);
}
AND_THEN("determinant(A) = -4071")
{
REQUIRE(A.determinant() == -4071);
}
}
}
/* ------------------------------------------------------------------------- */
SCENARIO("Testing an invertible matrix for invertibility", "[features/matrices.feature]")
{
GIVEN("the following 4x4 matrix A")
{
Matrix A = {
{6, 4, 4, 4},
{5, 5, 7, 6},
{4, -9, 3, -7},
{9, 1, 7, -6}
};
THEN("determinant(A) = -2120")
{
REQUIRE(A.determinant() == -2120);
}
AND_THEN("A is invertible")
{
REQUIRE(A.invertible() == true);
}
}
}
/* ------------------------------------------------------------------------- */
SCENARIO("Testing an noninvertible matrix for invertibility", "[features/matrices.feature]")
{
GIVEN("the following 4x4 matrix A")
{
Matrix A = {
{-4, 2, -2, -3},
{ 9, 6, 2, 6},
{ 0, -5, 1, -5},
{ 0, 0, 0, 0}
};
THEN("determinant(A) = 0")
{
REQUIRE(A.determinant() == 0);
}
AND_THEN("A is not invertible")
{
REQUIRE(A.invertible() == false);
}
}
}
/* ------------------------------------------------------------------------- */
SCENARIO("Calculating the inverse of a matrix", "[features/matrices.feature]")
{
GIVEN("the following 4x4 matrix A")
{
Matrix A = {
{-5, 2, 6, -8},
{ 1, -5, 1, 8},
{ 7, 7, -6, -7},
{ 1, -3, 7, 4}
};
Matrix a_inverted = {
{ 0.21805, 0.45113, 0.24060, -0.04511},
{-0.80827, -1.45677, -0.44361, 0.52068},
{-0.07895, -0.22368, -0.05263, 0.19737},
{-0.52256, -0.81391, -0.30075, 0.30639}
};
AND_GIVEN("B <- inverse(A)")
{
Matrix B = A.inverse();
THEN("determinant(A) = 532")
{
REQUIRE(A.determinant() == 532);
}
AND_THEN("cofactor(A, 2, 3) = -160")
{
REQUIRE(A.cofactor(2, 3) == -160);
}
AND_THEN("B[3][2] = -160.0 / 532.0")
{
REQUIRE(B[3][2] == -160.0 / 532.0);
}
AND_THEN("cofactor(A, 3, 2) = 105")
{
REQUIRE(A.cofactor(3, 2) == 105);
}
AND_THEN("B[2][3] = 105.0 / 532.0")
{
REQUIRE(B[2][3] == 105.0 / 532.0);
}
AND_THEN("B is the following 4x4 matrix")
{
REQUIRE(B == a_inverted);
}
}
}
}
/* ------------------------------------------------------------------------- */
SCENARIO("Calculating the inverse of another matrix", "[features/matrices.feature]")
{
GIVEN("the following 4x4 matrix A")
{
Matrix A = {
{ 8, -5, 9, 2},
{ 7, 5, 6, 1},
{-6, 0, 9, 6},
{-3, 0, -9, -4}
};
Matrix a_inverted = {
{-0.15385, -0.15385, -0.28205, -0.53846},
{-0.07692, 0.12308, 0.02564, 0.03077},
{ 0.35897, 0.35897, 0.43590, 0.92308},
{-0.69231, -0.69231, -0.76923, -1.92308}
};
THEN("inverse(A) is the following matrix")
{
REQUIRE(A.inverse() == a_inverted);
}
}
}
/* ------------------------------------------------------------------------- */
SCENARIO("Calculating the inverse of third matrix", "[features/matrices.feature]")
{
GIVEN("the following 4x4 matrix A")
{
Matrix A = {
{ 9, 3, 0, 9},
{-5, -2, -6, -3},
{-4, 9, 6, 4},
{-7, 6, 6, 2}
};
Matrix a_inverted = {
{-0.04074, -0.07778, 0.14444, -0.22222},
{-0.07778, 0.03333, 0.36667, -0.33333},
{-0.02901, -0.14630, -0.10926, 0.12963},
{ 0.17778, 0.06667, -0.26667, 0.33333}
};
THEN("inverse(A) is the following matrix")
{
REQUIRE(A.inverse() == a_inverted);
}
}
}
/* ------------------------------------------------------------------------- */
SCENARIO("Multiplying a product by its inverse", "[features/matrices.feature]")
{
GIVEN("the following 4x4 matrix A")
{
Matrix A = {
{ 3, -9, 7, 3},
{ 3, -8, 2, -9},
{-4, 4, 4, 1},
{-6, 5, -1, 1}
};
AND_GIVEN("the following 4x4 matrix B")
{
Matrix B = {
{8, 2, 2, 2},
{3, -1, 7, 0},
{7, 0, 5, 4},
{6, -2, 0, 5}
};
AND_GIVEN("C <- A * B")
{
Matrix C = A * B;
THEN("C * inverse(B) = A")
{
REQUIRE(C * B.inverse() == A);
}
}
}
}
}