affine
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affine.md
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affine.md
@ -5,39 +5,100 @@ title: Environment
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## Affine Transforms & Vector Math
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class Transformable {
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// attaributes
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PVector _position;
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float _rotation;
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float _scale;
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...
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public void display() {
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pushMatrix();
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translate(_position.x, _position.y);
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rotate(_rotation);
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scale(_scale);
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draw_shape();
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popMatrix();
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}
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...
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};
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---
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What is a geometry / shape?
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---
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What types of (2D / 3D) transformations can we apply to geometries / shapes?
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---
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<!-- ASCIImath -->
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Matrix multiplication
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What is a matrix Matrix?
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$
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[[a, b, c], [d, e, f], [g, h, i]]
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$
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Matrix [3 x 3] multiplication with a Vector [1 x 3]
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$
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[[a, b, c], [d, e, f], [g, h, i]] [[x], [y], [z]] = [[ax + by + cz], [dx + ey + fz], [gx + hy + iz]]
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$
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---
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What types of geometrical transformations (vertices transformation) can we perform using a Matrix?
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Translation
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$
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[[1, 0, tx], [0, 1, ty], [0, 0, 1]] [[x], [y], [1]] = [[dot x], [dot y], [1]]
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$
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Scaling
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$
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[[sx, 0, 0], [0, sy, 0], [0, 0, 1]] [[x], [y], [1]] = [[dot x], [dot y], [1]]
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$
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Rotation $theta$
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$
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[[cos theta, -sin theta, 0], [sin theta, cos theta, 0], [0, 0, 1]] [[x], [y], [1]] = [[dot x], [dot y], [1]]
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$
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Shearing
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$
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[[1, shx, 0], [shy, 1, 0], [0, 0, 1]] [[x], [y], [1]] = [[dot x], [dot y], [1]]
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$
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Affine Transform (Translation + Scaling + Rotation + Shearing)
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---
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What is an Affine Transform?
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Affine Transform Matrix comprises a Translation, Scaling, Rotation and Shearing
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$
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[[sx * cos theta, -sin theta * shx, tx], [sin theta * shy, sy * cos theta, ty], [0, 0, 1]] [[x], [y], [1]] = [[dot x], [dot y], [1]]
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$
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Yes, but what other types of transformations exists?
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