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1500 questions
9
votes
1 answer

Shader uniform performance

I'd like to know if there's any performance impact based on how I struct my shader uniforms. For instance, is passing 4 floats worse than passing a single vec4?
Felipe Lira
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9
votes
2 answers

Is there a way to achieve the look of a distant flock or shoal without full simulation?

Although simulation models like Boids give good results for bird flocks or fish shoals on a small scale, simulating every single member in real time becomes unrealistic for huge numbers. Is there a way I can model a flock in the distance where only…
9
votes
1 answer

Writing to a compressed texture using a compute shader, with no extra copies

I'm trying to figure out what the best way is to generate an OpenGL texture using a compute shader. So far, I've read that pixel buffer objects are good for non-blocking CPU -> GPU transfers, and that compute shaders are capable of reading and…
Mokosha
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9
votes
1 answer

Is there an established method of approximating dust distribution on surfaces?

Intuitively, dust settles onto surfaces at a higher rate in areas where the air flow is slower. This means instead of a surface gathering an even layer of dust, there will be more in corners - corners of a room/shelf, corners formed by the placement…
9
votes
1 answer

How to get started writing a low-level GPU profiler?

I have been studying hardware corporation GPU profilers in recent days (Qualcomm, PowerVR, Intel). I've noticed that these tools seem to give more low-level details than the GPU profilers I have used in the past -- XCode's OpenGL ES frame capture…
user3412
9
votes
5 answers

Why does the 1/r² term appear with point sources?

I'm currently reading some books on radiometry. They mention that radiance is constant along a ray. It doesn't change with distance. However, I've seen some raytracer and they put the 1/r² factor when they deal with point sources. I don't get why. I…
Livetrack
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9
votes
1 answer

How does the rendering equation incorporate shadowing

This is how the rendering equation is written in the textbook $$L(p,\omega) = L_e(p,\omega) + \int f(p,\omega_i,\omega) \, L(p*,-\omega_i)\cos \theta \, d\omega_i$$ which component of this equation handles the shadowing?
user2976568
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9
votes
1 answer

Find the longest straight line between two points on surface of polygon

My shape is a slightly concave polygon, and I'd like to know the maximal diameter. I imagine a straight line between two points on the surface of the polygon, such that the line does not pass outside the polygon. Is there a general algorithm for…
jiggunjer
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9
votes
1 answer

Moving each point of a surface in direction of corresponding normal

So let assume that I have some convex smooth and unclosed surface. I'm moving each point of it in a normal direction by some constant factor (This factor is same for all points on surface). Can I replace this operation by Uniform or Non-uniform…
Ibraim Ganiev
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9
votes
3 answers

Color space of MERL BRDF database?

I know that by now it might be considered as a kind of sad recurrent joke, but by chance, does anyone here has the least information about the colorspace of RGB values in the MERL BRDF measurement database ?
Fabrice NEYRET
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9
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0 answers

3D mesh segmentation simple algorithm

I am developing the algorithm reported in this article: Least square conformal mapping. Here is presented an algorithm to flat a 3d mesh on the parametric space, but i don't understand the segmentation step. Does anyone know an alternative…
Mugna
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9
votes
2 answers

How to create a patterned object with variable pattern density in real-time?

Assume there is some value p, calculated per-frame, that varies continuously over the surface of an object. The value of p determines the density of some pattern on the surface. For example, in a case with only two possible densities if p < 0.3 it…
Ryan
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9
votes
1 answer

How should I fill a shape consisting of Bezier curves and straight lines?

I have been working on a graphics library for some time now and have gotten to the point where I have to draw Bezier and line based fonts. Up to this point I am stuck with this: The green lines are the Bezier paths, and the white part is what gets…
Creator
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9
votes
3 answers

How does a computer upscale 1024x768 resolution to 1920x1080?

Without there being black bars I mean. 1080 isn't any multiple of 768 so is there some sort of data loss?
V0ight
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9
votes
2 answers

Archimedean spiral in C++

Im trying to plot the x and y positions of an Archimedean spiral in C++. So far I've been trying something like this, but no luck: int dx = 0; int dy = 0; int x = 0; int y = 0; for (int i = 0; i < maxPoints; i++) { dx = sin(i * PI / 2); dy…
David
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