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math: add Matrix translation constructors

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Signed-off-by: Stephen Gutekanst <stephen@hexops.com>
This commit is contained in:
Stephen Gutekanst 2023-09-08 17:50:05 -07:00
parent 5095002b1e
commit eba9390616
1 changed files with 56 additions and 85 deletions
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141
src/math/mat.zig
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@ -60,14 +60,56 @@ pub fn Mat(
} }; } };
} }
/// Constructs a 2D matrix which scales each dimension by the given vector.
// TODO: needs tests
pub inline fn scale(v: math.Vec2) Matrix {
return init(
RowVec.init(v.x(), 0, 0, 1),
RowVec.init(0, v.y(), 0, 1),
RowVec.init(0, 0, 1, 1),
);
}
/// Constructs a 2D matrix which scales each dimension by the given scalar.
// TODO: needs tests
pub inline fn scaleScalar(scalar: Vec.T) Matrix {
return scale(Vec.splat(scalar));
}
/// Constructs a 2D matrix which translates coordinates by the given vector.
// TODO: needs tests
pub inline fn translate(v: math.Vec2) Matrix {
return init(
RowVec.init(1, 0, 0),
RowVec.init(0, 1, 0),
RowVec.init(v.x(), v.y(), 1),
);
}
/// Constructs a 2D matrix which translates coordinates by the given scalar.
// TODO: needs tests
pub inline fn translateScalar(scalar: Vec.T) Matrix {
return translate(Vec.splat(scalar));
}
},
inline math.Mat4x4, math.Mat4x4h, math.Mat4x4d => struct {
pub inline fn init(col0: Vec, col1: Vec, col2: Vec, col3: Vec) Matrix {
return .{ .v = [_]RowVec{
col0,
col1,
col2,
col3,
} };
}
/// Constructs a 3D matrix which scales each dimension by the given vector. /// Constructs a 3D matrix which scales each dimension by the given vector.
// TODO: needs tests // TODO: needs tests
pub inline fn scale(v: Vec) Matrix { pub inline fn scale(v: math.Vec3) Matrix {
return init( return init(
Vec.init(v.x(), 0, 0, 0), RowVec.init(v.x(), 0, 0, 0),
Vec.init(0, v.y(), 0, 0), RowVec.init(0, v.y(), 0, 0),
Vec.init(0, 0, v.z(), 0), RowVec.init(0, 0, v.z(), 0),
Vec.init(0, 0, 0, 1), RowVec.init(0, 0, 0, 1),
); );
} }
@ -76,31 +118,22 @@ pub fn Mat(
pub inline fn scaleScalar(scalar: Vec.T) Matrix { pub inline fn scaleScalar(scalar: Vec.T) Matrix {
return scale(Vec.splat(scalar)); return scale(Vec.splat(scalar));
} }
},
inline math.Mat4x4, math.Mat4x4h, math.Mat4x4d => struct {
pub inline fn init(col0: Vec, col1: Vec, col2: Vec, col3: Vec) Matrix {
return .{ .v = [_]Vec{
col0,
col1,
col2,
col3,
} };
}
/// Constructs a 2D matrix which scales each dimension by the given vector. /// Constructs a 3D matrix which translates coordinates by the given vector.
// TODO: needs tests // TODO: needs tests
pub inline fn scale(v: Vec) Matrix { pub inline fn translate(v: math.Vec3) Matrix {
return init( return init(
Vec.init(v.x(), 0, 0, 1), RowVec.init(1, 0, 0, 0),
Vec.init(0, v.y(), 0, 1), RowVec.init(0, 1, 0, 0),
Vec.init(0, 0, 1, 1), RowVec.init(0, 0, 1, 0),
RowVec.init(v.x(), v.y(), v.z(), 1),
); );
} }
/// Constructs a 2D matrix which scales each dimension by the given scalar. /// Constructs a 3D matrix which translates coordinates by the given scalar.
// TODO: needs tests // TODO: needs tests
pub inline fn scaleScalar(scalar: Vec.T) Matrix { pub inline fn translateScalar(scalar: Vec.T) Matrix {
return scale(Vec.splat(scalar)); return translate(Vec.splat(scalar));
} }
}, },
else => @compileError("Expected Mat3x3, Mat4x4 found '" ++ @typeName(Matrix) ++ "'"), else => @compileError("Expected Mat3x3, Mat4x4 found '" ++ @typeName(Matrix) ++ "'"),
@ -141,25 +174,6 @@ pub fn Mat(
// }); // });
// } // }
// /// Constructs a 2D matrix which translates coordinates by v.
// pub inline fn translate2d(v: Vec2) Mat3x3 {
// return init(Mat3x3, .{
// 1, 0, 0, 0,
// 0, 1, 0, 0,
// v[0], v[1], 1, 0,
// });
// }
// /// Constructs a 3D matrix which translates coordinates by v.
// pub inline fn translate3d(v: Vec3) Mat4x4 {
// return init(Mat4x4, .{
// 1, 0, 0, 0,
// 0, 1, 0, 0,
// 0, 0, 1, 0,
// v[0], v[1], v[2], 1,
// });
// }
// /// Returns the translation component of the 2D matrix. // /// Returns the translation component of the 2D matrix.
// pub inline fn translation2d(v: Mat3x3) Vec2 { // pub inline fn translation2d(v: Mat3x3) Vec2 {
// return .{ mat.index(v, 8), mat.index(v, 9) }; // return .{ mat.index(v, 8), mat.index(v, 9) };
@ -422,49 +436,6 @@ test "mat4x4_ident" {
// try expectEqual(ortho_mat[3][3], 1); // try expectEqual(ortho_mat[3][3], 1);
// } // }
// test "mat.translate2d" {
// const v = Vec2{ 1.0, -2.5 };
// const translation_mat = mat.translate2d(v);
// // Computed Values
// try expectEqual(translation_mat[2][0], v[0]);
// try expectEqual(translation_mat[2][1], v[1]);
// // Constant values, which should not change but we still check for completeness
// const zero_value_indexes = [_]u8{
// 1, 2, 3,
// 4, 4 + 2, 4 + 3,
// 4 * 2 + 3,
// };
// for (zero_value_indexes) |index| {
// try expectEqual(mat.index(translation_mat, index), 0);
// }
// try expectEqual(translation_mat[0][0], 1);
// try expectEqual(translation_mat[1][1], 1);
// try expectEqual(translation_mat[2][2], 1);
// }
// test "mat.translate3d" {
// const v = Vec3{ 1.0, -2.5, 0.001 };
// const translation_mat = mat.translate3d(v);
// // Computed Values
// try expectEqual(translation_mat[3][0], v[0]);
// try expectEqual(translation_mat[3][1], v[1]);
// try expectEqual(translation_mat[3][2], v[2]);
// // Constant values, which should not change but we still check for completeness
// const zero_value_indexes = [_]u8{
// 1, 2, 3,
// 4, 4 + 2, 4 + 3,
// 4 * 2, 4 * 2 + 1, 4 * 2 + 3,
// };
// for (zero_value_indexes) |index| {
// try expectEqual(mat.index(translation_mat, index), 0);
// }
// try expectEqual(translation_mat[3][3], 1);
// }
// test "mat.translation" { // test "mat.translation" {
// { // {
// const v = Vec2{ 1.0, -2.5 }; // const v = Vec2{ 1.0, -2.5 };