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1500 questions
3
votes
1 answer
Please, help me to understand why my raytracing camera rotates in wrong directions?
I'm trying to build a raytracer and I use this article on how to build camera system. The problem is that when, after calculating ray direction in camera space, I multiply it by camera-to-world transformation matrix and my camera seems to rotate in…
Roadmap
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3
votes
1 answer
Phong BRDF in Mitsuba, Tungsten and AGI
In the book AGI (Advanced Global Illumination), the Phong BRDF is
$f_r(x,\Psi\leftrightarrow\Theta)=k_s\cfrac{(R\cdot\Theta)^n}{N\cdot\Psi}+k_d$
$k_d=\cfrac{albedo}\pi$
In Mitsuba and Tungsten, the Phong BRDF is…
chaosink
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3
votes
2 answers
How does UnrealEngine handle depth?
Today I found something really interesting (I've never seen something like that). While debugging the buffers used in lightning, I see that the depth information is stored in what looks like cascades of depth.
What's going on there? Is that a…
Nacho
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3
votes
1 answer
can half of a picture be processed and viewed?
Lets say i have a picture. I send it to a server. While sending it to the server half way the upload gets canceled. Now the server has half or some of the picture. Now is there a way in which this can be processed and viewed. Are there any formats…
user7115
3
votes
3 answers
Point of view and rotation
Two questions which cross over maths/3D imaging/computer science. I'm trying to describe a point of view of an item in a 3d space and subsequently its rotation in a paper I'm writing. Versions I've had read have confused readers.
The scene is as…
Garrett Lynch
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3
votes
1 answer
human visual: relation of Distance and DPI
I was told that human's visual sharpness is 60 pixels per degree. As such, pixel per inch is approximately given by:
PPI = 1/ (Distance * tg((1/60*pi/180) )
Is this formula fully correct? (I saw similar, but slightly different versions). How is…
angel_30
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3
votes
1 answer
Most efficient way to render many OO meshes in OpenGL
I am writing a large 3D game in Java with OpenGL.
Question #1
As of now, I am rendering my 3D objects using a Model class that I defined. This class contains vertex, color, model matrix, code (a custom attribute I defined), and index arrays. I…
clabe45
- 163
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3
votes
1 answer
Correct way to set normal strength
I am working on a normal mapping. I need to have the ability to scale normal vectors to adjust the normal strength of the surface. Currently the way I am doing it basically shows plausible results. But I am still not sure that it's 100% correct and…
Michael IV
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3
votes
0 answers
Beer's law in dielectric material
I am trying to implement Beer's law according to this page in dielectric material but I am not sure have done it correctly as the image does not suggest so.
The formula is: I(s) = I(0) * pow(e, ln(A)*s)
'A' is said to be transmission coefficient…
ali
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3
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1 answer
Do I have to have a buffer bound before making a draw call?
I have a very simple OpenGL program where the positions are embedded in the GLSL code. The vertex shader looks like this:
#version 440 core
uniform float offsetX;
uniform float offsetY;
out VS_OUT
{
vec2 tc;
} vs_out;
void main()
{
const…
Startec
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3
votes
1 answer
How to correct point cloud distortion
I am using Unreal Engine to export custom render passes for the scene depth in world units. Every pixel in the render pass has a value which is the distance from the camera to that pixel in standard UE4 units. For example, a pixel with a value of…
kinkersnick
- 143
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3
votes
2 answers
Why do we multiply vertex from left side in vertex shader with matrices?
I have been learning OpenGL 3.3 and I saw this expression:
gl_Position = projection * view * model * vertex
I am confused because I read in some book that if the vector (vertex) is placed on the right side of the matrix then it would be a column…
videogamechef
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3
votes
0 answers
Slope Based Texturing
On the main page for Allegorithmic's Bitmap2Material, it mentions that the software uses a Slope Based approach over a Luminance Based approach. What exactly does this mean?
Daniel Kareh
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3
votes
1 answer
Relationship between spatial frequency of an image and Aliasing
I was looking into measuring the amount of aliasing in an image. After reading through many papers and sites, I came to the conclusion that the best method to measure the amount of aliasing in an image is by utilizing the frequency domain.
Is there…
Varun Vijaykumar
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3
votes
1 answer
How can I remove aliasing in an image without introducing blur?
I am trying to reduce aliasing in an image using some filters. I tried the Gaussian variant of filters to remove the said high frequency patterns in the image, but I feel it's a bit too much of a blur.
I need a filter that can help me do some kind…
Varun Vijaykumar
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