Antialiasing Dr. Scott Schaefer.

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Presentation transcript:

Antialiasing Dr. Scott Schaefer

What is aliasing?

What is aliasing?

What is aliasing?

What is aliasing?

Why Does Aliasing Exist? Nyquist Limit: Must sample more than twice the maximum frequency

Why Does Aliasing Exist? Nyquist Limit: Must sample more than twice the maximum frequency

Why Does Aliasing Exist? Nyquist Limit: Must sample more than twice the maximum frequency

Why Does Aliasing Exist? Nyquist Limit: Must sample more than twice the maximum frequency

Why Does Aliasing Exist? Nyquist Limit: Must sample more than twice the maximum frequency

Why Does Aliasing Exist? Nyquist Limit: Must sample more than twice the maximum frequency

Why Does Aliasing Exist? Nyquist Limit: Must sample more than twice the maximum frequency

Why Does Aliasing Exist? Nyquist Limit: Must sample more than twice the maximum frequency

Aliasing in Computer Graphics Polygons Textures

Aliasing in Computer Graphics Polygons Textures

Aliasing in Computer Graphics Polygons Textures

Aliasing in Computer Graphics Polygons Textures

Aliasing in Computer Graphics Polygons Textures

Aliasing in Computer Graphics Polygons Textures

Aliasing in Computer Graphics Polygons Textures

Removing Aliasing Two options: Filter out high-frequencies after drawing Filter out high-frequencies before drawing

Multisampling Sample multiple times per pixel

Multisampling Sample multiple times per pixel 2x2 Grid

Multisampling Sample multiple times per pixel Rotated Grid

Multisampling Sample multiple times per pixel 4x4 Checker

Multisampling Sample multiple times per pixel 8 Rooks

Coverage Sampling Antialiasing Full pixel samples (shader) are too expensive Sample color and coverage separately

Texture Filtering

Texture Filtering

Removing High Frequencies

Removing High Frequencies

Removing High Frequencies Fourier

Removing High Frequencies Fourier

Removing High Frequencies Fourier

Filtering

Filtering Fourier

Filtering Fourier

Filtering Fourier

The Ideal Filter… Not So Ideal

The Ideal Filter… Not So Ideal Negative values

The Ideal Filter… Not So Ideal Infinite support

Common Filters Filter Fourier Transform Box

Common Filters Filter Fourier Transform blurring Box

Common Filters Filter Fourier Transform aliasing Box

Common Filters Filter Fourier Transform Tent

Common Filters Filter Fourier Transform Lanczos 3

Filtering Images

Filtering Images

Filtering Images

Mipmapping: Realtime Filtering

Mipmapping: Realtime Filtering

Mipmapping: Realtime Filtering

Mipmapping: Realtime Filtering

Mipmapping: Realtime Filtering

Mipmapping: Realtime Filtering

Mipmapping: Realtime Filtering

Mipmapping: Realtime Filtering

Mipmapping: Realtime Filtering

Mipmapping: Realtime Filtering

Mipmapping: Realtime Filtering

Mipmapping: Realtime Filtering

Anisotropic Filtering

Anisotropic Filtering

Anisotropic Filtering

Anisotropic Filtering

Mipmapping

Anisotropic Mipmapping

Analytic Antialiasing

Analytic Antialiasing

Simple Analytic Antialiasing

Simple Analytic Antialiasing

Simple Analytic Antialiasing

Analytic Antialiasing

Analytic Antialiasing

Morphological Antialiasing