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math: add matrix column/row getters

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Signed-off-by: Stephen Gutekanst <stephen@hexops.com>
This commit is contained in:
Stephen Gutekanst 2023-09-08 21:24:34 -07:00
parent de90bb6c12
commit 5dda26960d
1 changed files with 68 additions and 0 deletions
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68
src/math/mat.zig
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@ -92,6 +92,16 @@ pub fn Mat(
} };
}
/// Returns the row `i` of the matrix.
pub inline fn row(m: Matrix, i: usize) RowVec {
return RowVec.init(m.v[0].v[i], m.v[1].v[i], m.v[2].v[i]);
}
/// Returns the column `i` of the matrix.
pub inline fn col(m: Matrix, i: usize) RowVec {
return RowVec.init(m.v[i].v[0], m.v[i].v[1], m.v[i].v[2]);
}
/// Constructs a 2D matrix which scales each dimension by the given vector.
// TODO: needs tests
pub inline fn scale(s: math.Vec2) Matrix {
@ -162,6 +172,16 @@ pub fn Mat(
} };
}
/// Returns the row `i` of the matrix.
pub inline fn row(m: Matrix, i: usize) RowVec {
return RowVec.init(m.v[0].v[i], m.v[1].v[i], m.v[2].v[i], m.v[3].v[i]);
}
/// Returns the column `i` of the matrix.
pub inline fn col(m: Matrix, i: usize) RowVec {
return RowVec.init(m.v[i].v[0], m.v[i].v[1], m.v[i].v[2], m.v[i].v[3]);
}
/// Constructs a 3D matrix which scales each dimension by the given vector.
// TODO: needs tests
pub inline fn scale(s: math.Vec3) Matrix {
@ -468,6 +488,54 @@ test "mat4x4_ident" {
});
}
test "Mat3x3_row" {
const m = math.Mat3x3.init(
math.vec3(0, 1, 2),
math.vec3(3, 4, 5),
math.vec3(6, 7, 8),
);
try testing.expect(math.Vec3, math.vec3(0, 1, 2)).eql(m.row(0));
try testing.expect(math.Vec3, math.vec3(3, 4, 5)).eql(m.row(1));
try testing.expect(math.Vec3, math.vec3(6, 7, 8)).eql(m.row(@TypeOf(m).rows - 1));
}
test "Mat3x3_col" {
const m = math.Mat3x3.init(
math.vec3(0, 1, 2),
math.vec3(3, 4, 5),
math.vec3(6, 7, 8),
);
try testing.expect(math.Vec3, math.vec3(0, 3, 6)).eql(m.col(0));
try testing.expect(math.Vec3, math.vec3(1, 4, 7)).eql(m.col(1));
try testing.expect(math.Vec3, math.vec3(2, 5, 8)).eql(m.col(@TypeOf(m).cols - 1));
}
test "Mat4x4_row" {
const m = math.Mat4x4.init(
math.vec4(0, 1, 2, 3),
math.vec4(4, 5, 6, 7),
math.vec4(8, 9, 10, 11),
math.vec4(12, 13, 14, 15),
);
try testing.expect(math.Vec4, math.vec4(0, 1, 2, 3)).eql(m.row(0));
try testing.expect(math.Vec4, math.vec4(4, 5, 6, 7)).eql(m.row(1));
try testing.expect(math.Vec4, math.vec4(8, 9, 10, 11)).eql(m.row(2));
try testing.expect(math.Vec4, math.vec4(12, 13, 14, 15)).eql(m.row(@TypeOf(m).rows - 1));
}
test "Mat4x4_col" {
const m = math.Mat4x4.init(
math.vec4(0, 1, 2, 3),
math.vec4(4, 5, 6, 7),
math.vec4(8, 9, 10, 11),
math.vec4(12, 13, 14, 15),
);
try testing.expect(math.Vec4, math.vec4(0, 4, 8, 12)).eql(m.col(0));
try testing.expect(math.Vec4, math.vec4(1, 5, 9, 13)).eql(m.col(1));
try testing.expect(math.Vec4, math.vec4(2, 6, 10, 14)).eql(m.col(2));
try testing.expect(math.Vec4, math.vec4(3, 7, 11, 15)).eql(m.col(@TypeOf(m).cols - 1));
}
// TODO(math): the tests below violate our styleguide (https://machengine.org/about/style/) we
// should write new tests loosely based on them: