Add duck_engine example generated by Grok 3HEADmaster

1 files changed, 50 insertions, 0 deletions

diff --git a/examples/duck_engine/matrix3d.erl b/examples/duck_engine/matrix3d.erl
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+++ b/examples/duck_engine/matrix3d.erl
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+%% This is an example. Feel free to copy and reuse as you wish.
+
+-module(matrix3d).
+-export([rotate_x/1, rotate_y/1, rotate_z/1, multiply/2, apply/2]).
+
+% Rotation matrix around X-axis (angle in radians)
+rotate_x(Angle) ->
+    Cos = math:cos(Angle),
+    Sin = math:sin(Angle),
+    [[1, 0,    0   ],
+     [0, Cos, -Sin ],
+     [0, Sin,  Cos]].
+
+% Rotation matrix around Y-axis
+rotate_y(Angle) ->
+    Cos = math:cos(Angle),
+    Sin = math:sin(Angle),
+    [[ Cos,  0, Sin ],
+     [ 0,    1, 0   ],
+     [-Sin,  0, Cos]].
+
+% Rotation matrix around Z-axis
+rotate_z(Angle) ->
+    Cos = math:cos(Angle),
+    Sin = math:sin(Angle),
+    [[Cos, -Sin, 0 ],
+     [Sin,  Cos, 0 ],
+     [0,    0,   1]].
+
+% Multiply two 3x3 matrices
+multiply(A, B) ->
+    [[A11, A12, A13],
+     [A21, A22, A23],
+     [A31, A32, A33]] = A,
+    [[B11, B12, B13],
+     [B21, B22, B23],
+     [B31, B32, B33]] = B,
+    [[A11*B11 + A12*B21 + A13*B31, A11*B12 + A12*B22 + A13*B32, A11*B13 + A12*B23 + A13*B33],
+     [A21*B11 + A22*B21 + A23*B31, A21*B12 + A22*B22 + A23*B32, A21*B13 + A22*B23 + A23*B33],
+     [A31*B11 + A32*B21 + A33*B31, A31*B12 + A32*B22 + A33*B32, A31*B13 + A32*B23 + A33*B33]].
+
+% Apply a 3x3 matrix to a 3D vertex {X, Y, Z}
+apply(Matrix, {X, Y, Z}) ->
+    [[M11, M12, M13],
+     [M21, M22, M23],
+     [M31, M32, M33]] = Matrix,
+    NewX = M11 * X + M12 * Y + M13 * Z,
+    NewY = M21 * X + M22 * Y + M23 * Z,
+    NewZ = M31 * X + M32 * Y + M33 * Z,
+    {NewX, NewY, NewZ}.