Post-processing Flashcards
Lecture 9 (18 cards)
What is post-processing?
Post-processing is a set of techniques used to modify or enhance the image after the 3D scene has been rendered.
How is post-processing applied in rendering?
It is applied over the whole screen, often in a separate full-screen rendering pass using fragment shaders.
What are some examples of post-processing effects?
Examples are: blur, color grading, bloom, tone mapping, anti-aliasing and chromatic aberration.
What is Gaussian blur?
Gaussian blur is a type of blur effect that smooths an image by averaging nearby pixels using a Gaussian distribution of weights.
How is Gaussian blur implemented in shaders?
The shader samples neighbouring pixels, multiplies them by a weight and sums the results. The weights come from a Gaussian function.
Why is Gaussian blur done in two passes?
Gaussian blur is separable, so it can be done in two 1D passes (horizontal and vertical) instead of one 2D pass. This improves performance.
What is a kernel in Gaussian blur?
A kernel is a set of weights and positions used to calculate the blur from surroundining pixels.
What is HDR (High Dynamic Range) in games?
HDR allows for storing and rendering a wider range of brightness levels , keeping more detail in both dark and bright areas.
Why do we need tone mapping in HDR rendering?
Tone mapping is used to convert HDR values to a 0-1 range for display, preserving important visual detail.
How does exposure affect tone mapping?
High exposure brightens the image but may lose detail in bright areas. Low exposure darkens the image and may lose details in shadows.
How can exposure be made dynamic in games?
Dynamic exposure adjusts the brightness by averaging pixel luminance and blending with previous frames for smooth transitions.
What is aliasing in graphics?
Aliasing is the jagged appearance of edges when resolution is too low to represent a smooth line.
What is anti-aliasing?
Anti-alsiasing is any technique that reduces aliasing artifacts, especially at object edges.
What is super sampling?
Super sampling renders the scene at a higher resolution and then downsamples it, but it uses a lot of memory and performance.
What is MSAA and how does it work?
MSAA (Multi-Sample Anti-Aliasing) stores multiple depth samples per pixel and averages results, improving quality with less cost than full supersampling.
What is morphological anti-aliasing and name a few types.
Morphological Anti-Aliasing detects and smooths edges in the final image. Examples are: FXAA (Fast approximate), MLAA (Morphological)m SMAA (Subpixel Morphological).
What is temporal anti-aliasing (TAA)?
TAA (Temporal Anti-Aliasing) accumulates samples over mulitple frames by jittering sampling positions and blending results. It handles static scenes well.
What is DLSS or FSR in anti-aliasing?
DLSS (NVIDIA) and FSR (AMD) use AI based upscaling to simulate high-res rendering from lower-res images, reducing workload and aliasing. (50-series)
