Computer Graphics Stack Exchange
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What is the difference between a point transformation and a vector transformation?

This is what my lecturer told me in the coursework: We only consider 4*4 matrices. These are used to rotate, scale or translate objects (or any combination of these operations). Matrices are also used later in the implementation of the virtual…
S.A
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Is it possible to turn a 3d rotation matrix (4x4) into its component parts (rotation, scale, etc.)?

To be more concrete, I'm working on an iOS app, and have a CATransform3D struct (basically a 4x4 transform array). Is it possible to deduce all the different "operations" this matrix implies? Things like how much rotation, scale, etc. it implies?
elsurudo
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Ray Tracing with Cones: coverage, overlapping and abutting triangles

In his classic paper Ray Tracing with Cones, John Amanatides describes a variation on classical ray tracing. By extending the concept of a ray by an aperture angle, making it a cone, aliasing effects (including those originating from too few Monte…
David Kuri
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What is ambient lighting?

Wikipedia says: An ambient light source represents a fixed-intensity and fixed-color light source that affects all objects in the scene equally. By saying "affects all objects equally" they mean all objects get the same amount of light? So if you…
Joey
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Why do adjacent triangles never overlap when rasterized?

Apologies for the following noob question, it's just I can't find a satisfactory answer anywhere... When I render a simple axis-aligned quad made up of two triangles, I don't understand why there's never any visible artefacts on the diagonal edge…
Reuben Scratton
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Why do Vertex Buffer Objects improve performance?

From my basic understanding, a Vertex Buffer Object works something like this (pseudo code): Normally, if one wanted to say, draw a square, one could issue line drawing commands. line (0, 0) -> (1, 0) line (1, 0) -> (1, 1) line (1, 1) -> (0, 1) line…
Ethan Bierlein
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When creating a JPEG, how can I minimize the occurence of artifacts?

There are 2 main factors that seem to lead to digital artifacts when creating JPEG images: Aliasing and Compression. Example: Converting a PNG with characters on it to a JPEG or placing vector images over a photograph, will result in pixelization…
Armfoot
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16bit half-float linear HDR images as (diffuse/albedo) textures?

So I been thinking about this for a while and tried to google for an answer but without any success. If all your textures are 8bit LDR images, like JPEGs, couldn't that potentially cause conflicts with exposure control/tone mapping when rendering.…
Kristoffer Helander
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What is my GPU waiting on?

I am writing an OpenCL program for use with my AMD Radeon HD 7800 series GPU. According to AMD's OpenCL programming guide, this generation of GPU has two hardware queues that can operate asynchronously. 5.5.6 Command Queue For Southern Islands and…
Mokosha
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Choosing width of data for signed distance field texture

A signed distance field texture is a technique where you store the distance from a pixel to the surface of a shape within the color information for that pixel, allowing almost vector graphics quality rendering using textures…
Alan Wolfe
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Compensation for energy loss in single-scattering microfacet BSDF models

Single-scattering microfacet-based surface models like the original Torrance-Sparrow BRDF or derived models like the BSDF for rough dielectric surfaces by Walter et al. neglect inter-reflection of light between microfacets, which results in energy…
ivokabel
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Ordering a set of unorganized points along a curve

I have a set of 3D points (which I recover from a library that performs the tessellation of a solid body) that belong to a curve (i.e., an edge of the solid). That means that the curve surely passes by each of these points. Nevertheless, the point…
andrea.al
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How updating a depth buffer works in GPU?

Right now I'm trying to implement some sort of depth buffer in software and I have a huge problem when I'm writing to it. Having one mutex is absolute overkill. So I created a number of mutexes equal to the number of threads. I'm locking a mutex…
nikitablack
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What does "muted" mean in the context of color?

I want to extract colors from images like in Adobe Kuler. When I select colorful or muted corresponding colors are shown. But what is the definition for colorful or muted colors? What do the words "colorful", "deep" and "muted" refer to?
Sandiip
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With modern fillrates and deferred rendering, is occlussion culling still relevant?

For example, while it's the current top-of-the-line GPU, the GTX 980 has a staggering 72.1 gigapixels/second fillrate, which with back-to-front rendering and/or Z buffer checks, seems almost ridiculously large, possibly even at 4k resolutions. As…
Llamageddon
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