feat(matrix): add C44Matrix::Inverse

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fallenoak 2020-11-29 14:01:06 -06:00
parent 571f2369f9
commit 614f6b46e1
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3 changed files with 70 additions and 0 deletions

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@ -28,6 +28,10 @@ float C44Matrix::Determinant() {
return (this->b1 * this->c2 * this->d3 + this->c3 * this->b2 * this->d1 + this->b3 * this->c1 * this->d2 - this->c2 * this->b3 * this->d1 - this->d3 * (this->c1 * this->b2) - this->b1 * this->c3 * this->d2) * this->a0 - (this->c2 * this->b0 * this->d3 + this->c3 * this->b2 * this->d0 + this->b3 * this->c0 * this->d2 - this->b3 * this->c2 * this->d0 - this->d3 * (this->c0 * this->b2) - this->b0 * this->c3 * this->d2) * this->a1 + (this->c1 * this->b0 * this->d3 + this->c3 * this->b1 * this->d0 + this->b3 * this->c0 * this->d1 - this->b3 * this->c1 * this->d0 - this->d3 * (this->c0 * this->b1) - this->b0 * this->c3 * this->d1) * this->a2 - (this->c1 * this->b0 * this->d2 + this->c2 * this->b1 * this->d0 + this->b2 * this->c0 * this->d1 - this->b2 * this->c1 * this->d0 - this->d2 * (this->c0 * this->b1) - this->b0 * this->c2 * this->d1) * this->a3;
}
C44Matrix C44Matrix::Inverse(float det) const {
return this->Adjoint() * (1.0f / det);
}
C44Matrix operator*(const C44Matrix& l, float a) {
float a0 = l.a0 * a;
float a1 = l.a1 * a;

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@ -42,6 +42,7 @@ class C44Matrix {
, d3(d3) {};
C44Matrix Adjoint() const;
float Determinant();
C44Matrix Inverse(float det) const;
};
C44Matrix operator*(const C44Matrix& l, float a);

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@ -128,6 +128,71 @@ TEST_CASE("C44Matrix::Determinant", "[matrix]") {
}
}
TEST_CASE("C44Matrix::Inverse", "[matrix]") {
SECTION("returns inverse of identity matrix") {
C44Matrix matrix;
auto inverse = matrix.Inverse(matrix.Determinant());
CHECK(inverse.a0 == 1.0f);
CHECK(inverse.a1 == 0.0f);
CHECK(inverse.a2 == 0.0f);
CHECK(inverse.a3 == 0.0f);
CHECK(inverse.b0 == 0.0f);
CHECK(inverse.b1 == 1.0f);
CHECK(inverse.b2 == 0.0f);
CHECK(inverse.b3 == 0.0f);
CHECK(inverse.c0 == 0.0f);
CHECK(inverse.c1 == 0.0f);
CHECK(inverse.c2 == 1.0f);
CHECK(inverse.c3 == 0.0f);
CHECK(inverse.d0 == 0.0f);
CHECK(inverse.d1 == 0.0f);
CHECK(inverse.d2 == 0.0f);
CHECK(inverse.d3 == 1.0f);
}
SECTION("returns inverse of non-identity matrix") {
auto matrix = C44Matrix(1.0f, 1.0f, 1.0f, -1.0f, 1.0f, 1.0f, -1.0f, 1.0f, 1.0f, -1.0f, 1.0f, 1.0f, -1.0f, 1.0f, 1.0f, 1.0f);
auto inverse = matrix.Inverse(matrix.Determinant());
CHECK(inverse.a0 == 0.25f);
CHECK(inverse.a1 == 0.25f);
CHECK(inverse.a2 == 0.25f);
CHECK(inverse.a3 == -0.25f);
CHECK(inverse.b0 == 0.25f);
CHECK(inverse.b1 == 0.25f);
CHECK(inverse.b2 == -0.25f);
CHECK(inverse.b3 == 0.25f);
CHECK(inverse.c0 == 0.25f);
CHECK(inverse.c1 == -0.25f);
CHECK(inverse.c2 == 0.25f);
CHECK(inverse.c3 == 0.25f);
CHECK(inverse.d0 == -0.25f);
CHECK(inverse.d1 == 0.25f);
CHECK(inverse.d2 == 0.25f);
CHECK(inverse.d3 == 0.25f);
}
SECTION("does not modify self") {
auto matrix = C44Matrix(1.0f, 1.0f, 1.0f, -1.0f, 1.0f, 1.0f, -1.0f, 1.0f, 1.0f, -1.0f, 1.0f, 1.0f, -1.0f, 1.0f, 1.0f, 1.0f);
auto inverse = matrix.Inverse(matrix.Determinant());
CHECK(matrix.a0 == 1.0f);
CHECK(matrix.a1 == 1.0f);
CHECK(matrix.a2 == 1.0f);
CHECK(matrix.a3 == -1.0f);
CHECK(matrix.b0 == 1.0f);
CHECK(matrix.b1 == 1.0f);
CHECK(matrix.b2 == -1.0f);
CHECK(matrix.b3 == 1.0f);
CHECK(matrix.c0 == 1.0f);
CHECK(matrix.c1 == -1.0f);
CHECK(matrix.c2 == 1.0f);
CHECK(matrix.c3 == 1.0f);
CHECK(matrix.d0 == -1.0f);
CHECK(matrix.d1 == 1.0f);
CHECK(matrix.d2 == 1.0f);
CHECK(matrix.d3 == 1.0f);
}
}
TEST_CASE("C44Matrix global operators", "[matrix]") {
SECTION("C44Matrix * float") {
auto matrix1 = C44Matrix(1.0f, 2.0f, 3.0f, 4.0f, 5.0f, 6.0f, 7.0f, 8.0f, 9.0f, 10.0f, 11.0f, 12.0f, 13.0f, 14.0f, 15.0f, 16.0f);