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1500 questions
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1 answer

using importance sampling to reduce the error of outscattered radiance

http://renderman.pixar.com/view/implementing-a-skin-bssrdf In this paper on subsurface scattering, I'm trying to understand how importance sampling is used to compute single scattering. It says that the outscattered radiance for the single term,…
maogenc
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Shadow map projection issue

I am using Unity but this question might not be proper to this engine. I have projected the shadow map onto this sphere but there are grazing shadows. Is it possible to avoid it or to correct it as I am using the raw depth data of the texture. Here…
MaT
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Flat shading for non-planar polygons

I'm trying to figure out how to properly implement flat shading for meshes containing non-planar polygons (using OpenGL/GLSL). The aim is to obtain something similar to the result Blender gives (all polygons below are non-planar): To provide a bit…
Ailurus
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7
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What is the state-of-the-art on using computers to "clean-up" images?

TWO PART QUESTION - We've all seen the movies/TV shows where the police/feds/spies use computer software to take a grainy photo and do a "clean-up" to see a better picture and more details. I assume the concept is executed by some sort of uber-power…
O.M.Y.
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0 answers

Injecting Virtual point lights into 3D Grid

I am currently trying to implement light propagation volumes in DirectX 11 and I have already done the RSM part which contains position, normal, depth and flux map generation. But for Injecting Virtual point lights into light propagation volumes, we…
user3059485
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1 answer

Please help me understand what happens as an image is faded to black in order to time-step particle fading

I have a game that has simple particles (basically dots) moving around the screen leaving a trail. My ultimate goal is to be able to change the opacity of the solid black fading texture each drawing call in a way so that I can keep the length of a…
J.Doe
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1 answer

What is the basis of rendering light caustics?

I am not looking for textbooks and related how-tos, though I'm sure they can color the answer. I'd like to understand how we handle the rendering of caustic effects — and particularly time-saving models, as different from physical simulation.
New Alexandria
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7
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MSI GTX 950 2GD5T triangles per second

A friend got an MSI GTX 950 2GD5T graphics card for xmas. I said "yeah, graphics cards are super fast now, that thing probably processes 2 billion triangles per second". Then I tried to look it up to check if that was even in the right ballpark, but…
M Katz
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7
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2 answers

Best technique to draw overlapping colored line segments that follow the same route

I'm not too versed in computer graphics so my question may be vague. I'm given a sequence of GPS coordinates which I draw on an iOS map, and they define bus routes. Some of the bus routes happen to share sections of certain streets however, and when…
James Linnell
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7
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1 answer

Average intensity of an gray image

Suppose i have a 400*300 gray scale image.Now I want to scan each line horizontally and make the average of that line 128,such that the values get scaled as per their difference from mean(128) which will not cause any distortion to image.
Abdul Kahrim
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BRDF and Spherical coordinate in ray tracing

I developed a ray tracer that use standard phong/blinn phong lighting model. Now I'm modifying it to support physically based rendering, so I'm implementing various BRDF models. At the moment I'm focused on Oren-Nayar and Torrance-Sparrow model.…
Fabrizio Duroni
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1 answer

After a deformation operation on polygons, how can I check for and fix inverted polys?

I'm doing a quick and dirty automated deformation routine on a polygon body. If it was a tree, and my axis was in the center of the tree, I would like to bend the body by bending the axis. I would use a simple influencing algorithm to determine…
user3531082
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7
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1 answer

Shadow rays in Raytracing

After spending a few days making very little headway with a simple Raytracing program that implements Phong illumination (with shadows and no attenuation), I'm convinced I've made a logic error that I'm overlooking. As I understand it, the…
user1764241
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1 answer

How to calculate matching roundness of two offset rectangles?

I have two rectangles — one with a fill (blue) and one with a stroke (red). The red rectangle is being offset (depending on the stroke width) so that it appears snug and outside the edge of the blue rectangle. This set up works great except when I…
Greg Gunn
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1 answer

How to convert a thread ID into Screen Space Coord in an OpenGL Compute Shader?

I've written an implementation of the sphere tracing algorithm in OpenGL 4+. As an experiment/toy project, I'm re-implementing it using the OpenGL 4.3 compute shader, but I'm having trouble with the whole local/global invocation ID thing. The basic…
Matteo Bertello
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