https://www.youtube.com/watch?v=LhQ85bPCAJ8

<aside> 💡 Objects inside the view frustum will be projected to the Near Plane (3D→2D projection). Anything outside the frustum will be clipped.

There are 6 clip planes: Near, Far, Top, Bottom, Left, Right

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• Far plane: by clipping away objects that are far away from the user, we reduce computation workload. The position of Far plane vary depending on the applications.

<aside> 💡 * Move the Near Plane forward (+ve z-axis) → Zoom In → Objects become bigger

• Move the Near Plane backward (-ve z-axis) → Zoom Out → Objects become smaller

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Compute the projection onto the Near Plane

<aside> 💡 Use similar triangles theorem to find the projected 2D points on Near Plane

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<aside> 💡 Problem: we need to divide by z to gain the correct projected points

Solution: store z value to w in gl_Position and pass it into the Rasterizer, which will handle the Perspective Division (dividing z) for us

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Other Notes:

• might need to adjust the z coordinate to be further away from the camera if you don’t see anything rendered on the screen
• rasterizer clips away vertices with z value > 1 ⇒ visible range [-1, 1]