Computer Graphics Stack Exchange
Computer Graphics Stack Exchange

Questions tagged [optimisation]

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What is the cost of changing state?

Programmers are supposed to have a fairly good idea of the cost of certain operations: for example the cost of an instruction on CPU, the cost of a L1, L2, or L3 cache miss, the cost of a LHS. When it comes to graphics, I realize I have little to no…
Julien Guertault
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How can virtual texturing actually be efficient?

For reference, what I'm referring to is the "generic name" for the technique first(I believe) introduced with idTech 5's MegaTexture technology. See the video here for a quick glance on how it works. I've been skimming some papers and publications…
Llamageddon
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GL_STATIC_DRAW vs GL_DYNAMIC_DRAW vs GL_STREAM_DRAW: does it matter?

In OpenGL the buffer object functions (glBufferData, glBufferSubData, and probably a few others) have a parameter usage, described by the documentation as a hint of the intended usage, likely meant to help the implementation yield better…
Julien Guertault
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How many polygons in a scene can modern hardware reach while maintaining realtime, and how to get there?

A fairly basic, in some ways, question, but one that many people, myself included, don't really know the answer to. GPU manufacturers often cite extremely high numbers, and the spread between polygon counts that various game engines claim to support…
Llamageddon
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Is using many texture maps bad for caching?

If I have many textures (say 5+ maps) bound to the same texture unit, does it work worse for cache than if I had only 2 or 3 textures?
Felipe Lira
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How does Texture Cache work in Tile Based Rendering GPU

How does cache work with tile based rendering? Are there any tips on how to improve cache hit ratio for it? (for instance, if tiles are processed horizontally and I have vertical segments of triangles with the same texture, does it work worse for…
Felipe Lira
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The most performant way to organize vertex data on modern GPUs

Say I have a model made up of vertices, each with position, normal, tangent, and texcoord attributes, where triangles are specified by index triples. If we just focus on the vertex attributes, I'm aware of two broad strategies: the structure of…
lcmylin
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Encode two R11G11B10F buffers into one using Y'CbCr?

We are trying to optimize Lighting in fillrate. Integrated graphics chips are very slow in memory access. There are two Light Buffers: one for Diffuse and one for Specular. Both use format R11G11B10F. Is there any way to pack two buffers into one?…
Unreal_Skif
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What methods/technologies to reduce required performance for virtual reality are there?

I'm interested in virtual reality, but according to some sources, less than 1% of computers in use today have the necessary performance to run modern VR games, granted many of them are not intended for gaming, that's still a huge barrier for the…
Syzygy
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The meaning of early ray termination and front-to-back traversal in ray tracing

I'm new to computer graphics. These days I've been trying to understand how ray tracing using an acceleration data structure works. I came across the term "early ray termination" several times, I looked it over the internet several times too, but I…
S.E.K.
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How much precision do I need in my G-Buffer?

I'm in the process of working out how to pack all the information I need for a Physically Based Deferred Renderer into a G-Buffer without using an obscene amount of render targets. What I have so far is 4 3-part vectors:…
Mark A. Ropper
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Image based lighting, tangent space coordinates, and optimization

When I saw an implementation of normal mapping that computed the TBN matrix in the vertex shader and converted everything (in particular the view vector and light vector) to tangent space at that stage, it seemed like the proper way to do. This way…
Julien Guertault
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How much processing power does stenciling actually save?

For example, let's assume I'm rendering cascaded shadow mapping, but for whatever reason, instead of one of the typical approach, I do the following: Render the lowest resolution shadowmap Copy part of the shadowmap to the next shadowmap, covering…
Llamageddon
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Do stencil tests use any acceleration techniques?

Stencil bits are often used for optimizations, for instance having full screen lighting passes only affect certain pixels. Does the stencil test mechanism use any acceleration structures of any kind (like maybe dividing the screen into a coarser…
Alan Wolfe
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How Texture Prefetch works?

I know GPU prefetches textures and that's why dependent texture reads are slower, but how does it work and at what point that happens? EDIT: Split the content of this question into others as suggested by trichoplax Here's a link to other…
Felipe Lira
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