Questions tagged [rendering]

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7
votes
2answers
807 views

Eye Parallax Refraction

I am trying to implement the Parallax Refraction effect explained by Jorge Jimenez on this presentation: http://www.iryoku.com/downloads/Next-Generation-Character-Rendering-v6.pptx and I am facing ...
4
votes
2answers
120 views

Correctness of logical steps for create the matrix of viewing transformation

In general, I understand the creation of viewing transformation matrix, but I have my doubts. For example, let's say that a world coordinate (called $A$) has a center at $(1,1,1)$, and the view ...
4
votes
2answers
454 views

Texture Mapping jagged pixel edges

I'm currently writing a software renderer. I managed to implement texture mapping and it works fine. Only issue is, that the edges between the pixels are sometimes jagged in x direction as you can see ...
8
votes
1answer
172 views

searching for acceptable quality shadow mapping techniques

Recently while searching of solving the shadow acne problem of traditional shadow mapping I implemented exponential shadow maps. It did the trick (no acne at all) but at the same time introduced other ...
7
votes
1answer
2k views

Perspective Correct Texture Mapping

So I'm trying to correctly map my textures in my software renderer using the u, v coordinates but I can't seem to get it working. I got affine texture mapping working. This is what I can produce using ...
2
votes
1answer
571 views

How to clip multiple tiled textures to polygon in Webgl / opengl

I have a bunch of planes each with their own texture in a grid. Currently I am rendering these as separate planes, each with their own texture, although I could use a single plane with multiple faces. ...
1
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2answers
468 views

Only show opaque objects behind transparent objects

I would like to make certain objects in my scene transparent, but only the parts visible to the camera when opaque. Currently, when I make objects transparent, I can see other transparent objects ...
1
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1answer
49 views

Photo-realism blind experiment [closed]

I need a lot of real time rendered images and real images where it's recorded which one is which to prove either way whether existing gaming computers have the hardware to be photo-realistic to ...
13
votes
3answers
2k views

Correct Specular Term of the Cook-Torrance / Torrance-Sparrow Model

For a while I have been doing some research on the topic of Physically Based Rendering. One reflection model that is mentioned over and over is the Cook-Torrance / Torrance-Sparrow model. It seems ...
5
votes
1answer
360 views

How do CAD programs render non-polygonal 3D objects?

How CAD programs handle displaying B-Reps and NURBS/T-Splines in their viewports? Assuming viewport uses OpenGL API - are those programs transform every object into triangles and creating/deleting ...
3
votes
1answer
475 views

ping pong between same framebuffer two color attachments

In order to optimize I'm trying to set up a setup which ping pong between same framebuffer two color attachments to apply some postprocess effects. It seems to work (effects are applied) but ...
1
vote
0answers
99 views

Can I Implement Clustered Lighting with WebGL?

Do current WebGL capabilities allow to use Clustered Lighting? If not what is it missing to allow that? Basically WebGL uses GLES 2, so is that possible with GLES 2? I want to implement this one: ...
2
votes
2answers
179 views

Can I use the same vertices to render multiple things?

I'm passing my vertex shader a bunch of vertices and color data. I would like to first render the triangles and then render a point at each vertex. The triangles render fine, but I can't think of a ...
1
vote
1answer
943 views

Dark stripes on surfaces in V-Ray when rendering to texture (baking)

I am working in 3DS Max with V-Ray 3.4. I have recently been encountering strange artifacts on baked textures. Surfaces that should be flat smooth objects render with dark stripes or other unusual ...
8
votes
2answers
159 views

Are vertices reprocessed per-poly for indexed meshes?

I've been digging a bit into what actually happens at a hardware level on the GPU, and found NVidia's Life of a triangle which explains the pipeline pretty well, at least for green boxes. One thing I ...
4
votes
1answer
352 views

How to create specular surface in Mitsuba Renderer

I am a newbie in computer graphics and I am trying to develop a special case of path tracing really slowly! But first: I came up studying the Mitsuba renderer and one of its uses in the so-called GDPT ...
4
votes
1answer
671 views

What is the definition of “motion to photon” in VR?

The rough definition of "MTP" is clear. But the exact one is not. You can refer to these links: What is Motion-To-Photon Latency? | chioka.in Motion-to-photon latency | xinreality.com/wiki. But from ...
5
votes
1answer
215 views

Efficiently rendering sprites

In order to naïvely render sprites, you can send single rectangles with their position, rotation, size, and texture. This is very easy, but given that reducing state changes, draw calls, and data ...
1
vote
1answer
372 views

Distributed parallel rendering in Gaming or VR rendering

VR rendering needs a lot of GPU power. VR SLI can help that. But, is it possible for us to use distributed parallel rendering technology to improve the performance dramatically? There is an open ...
1
vote
0answers
447 views

Billboards or impostors when objects' instances are re-scaled [closed]

Billboarding/impostors mean, roughly, representing complex 3D objects in 2D or with simple quadrilaterals, for the sake of LOD systems. Consider the case of rendering a very numerous asteroid field ...
1
vote
1answer
75 views

What does $E_L$ mean in the context of shading equations from the book “Real time rendering”?

We will use $E_L$ for irradiance perpendicular to $l$ Where $l$ is the light vector. What does this mean? How do I calculate $E_L$?
1
vote
1answer
300 views

Blinn Phong rendering

I am trying to render Blinn Phong as a BRDF model on a surface plane. I assume that every normal in every pixel is perpendicular with the plane. I know that to do a rendering we have to use 3d ...
7
votes
1answer
158 views

Proper architecture for rendering history of streamed data (points)

Overview My program receives some data points (0-400 per sec). ...
5
votes
1answer
239 views

Rendering same vertex-array in different modes

here is my vertex array I am using: ...
7
votes
2answers
1k views

Rendering equation - why unsolvable directly?

Why is the rendering equation, introduced by Kajiya in 1986, not solvable directly/analytically?
4
votes
1answer
179 views

How fast should I expect to render the silhouette of a 20k triangle model?

Using VTK 7.0 I have found that rendering a 20k triangle STL model takes approximately 17ms on my Nvidia GTX970. However, I am only interested in the silhouette of this model (like the image below) ...
13
votes
4answers
410 views

What physical properties are “lacking” to keep this 3D scene from looking like a real photograph?

So I know that I'm basically asking to identify the main problem to be solved in creating realistic 3d Graphics, but as someone without much technical experience in the field, I'm curious that if ...
7
votes
1answer
796 views

Resulting Probabilty Density in Path Tracer for paths using Next Event Estimation

I am trying to implement my own Gradient Domain Path Tracer by following the code of this guy who already implemented it: https://gist.github.com/BachiLi/4f5c6e5a4fef5773dab1 I already managed to ...
8
votes
2answers
537 views

Can (and how so) shaders paint screen pixels beyond those that occupied by the shaded mesh?

I have some experience programming geometry and compute shaders - but never adventured myself in really playing with the fragment shaders. Currently, I am trying to better understand how they work and ...
5
votes
1answer
808 views

Role of PDF of Uniform Random Sampling in a path tracer

I am trying to implement my own path tracer but before arriving to the question I want to give you a short overview: In the implementation of the rendering equation I use some particular technique in ...
8
votes
1answer
430 views

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 ...
13
votes
3answers
2k views

Importance Sampling of Environment Maps

What is the best currently known and ideally also production-verified approach for sampling environment maps (EM) in a MIS-based uni-directional path tracer and similar types of renderers? I would ...
6
votes
2answers
106 views

Global illumination leading to image variation

I have a 3D scene I use to generate some images which I then process in Matlab. I noticed that when global illumination (GI) is not enabled, rendering always generates exactly the same pixel-for-pixel ...
11
votes
2answers
2k views

What kind of technology would be involved in the rendering of human nails?

There are many references related to the physically-based rendering of several natural features of the numan body, such as skin, hair, eyes. However, I could not find specific information about the ...
3
votes
1answer
688 views

How to blend World Space Normals

I am trying to blend two world space normals inside a shader. One comes from a tangent space normal map converted into world space using a classic TBN matrix and the other one is a mesh normal map in ...
7
votes
2answers
220 views

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 ...
4
votes
1answer
989 views

How could I use bent normal map

This might be a general question but I have some difficulties about understanding baked bent normal maps and how to use it inside a shader in Unity. From what I understand, bent normals are ...
1
vote
1answer
558 views

Can Frameless rendering reduce latency? And, can FPGA do 3D rendering instead of GPU?

In virtual reality, the motion-to-photon time is very important. Oculus says it has to be less than 20ms. Maybe 10~15ms is better. Some people try to introduce Frameless rendering technology into VR. ...
1
vote
1answer
148 views

Can V-Sync avoid tearing? I think it can't. Am I wrong?

1) Update the front buffer will cause screen tearing, every one knows it. 2) But V-Sync, I think it still get the same issue. Why I get this idea? 2.1) When GPU flips to the back buffer, current ...
4
votes
1answer
64 views

In what order to apply lighting and translucency?

I'm making a game that is supposed to like like a early 90s 3D game, so i'm rendering in software on an 8-bit indexed bitmap, using lookup tables for translucency and lighting. Now I have to draw a ...
1
vote
1answer
700 views

OpenGL C++ Camera Rotation Problem

Currently for a university assignment I have been given a 3D rendering engine, capable of rendering a 3D world. One task is to create a first person camera for it (I know with OpenGL you don't have a ...
9
votes
2answers
4k views

Cause of shadow acne

I know how shadow mapping works but I am not getting the cause of shadow acne! Can anyone tell me cause of shadow acne in a simple way and how is it related to depth map resolution?
11
votes
1answer
3k views

Loop performance in a shader

I am wondering what's the best way to integrate a dynamic loop function in a shader? First, it seems that dynamic arrays are not possible. So, is it better to create a maximum size array and only ...
11
votes
1answer
555 views

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 ...
4
votes
1answer
304 views

Jitter texture generation

I am currently reading the awesome paper by Jorge Jimenez about Character rendering : Next Generation Character Rendering In the part about multi-sampled transmittance he uses some Poisson offsets ...
6
votes
1answer
2k views

What's the difference between irradiance and fluence/radiant exposure?

A paper$^1$ I'm reading says fluence measures the incoming radiance from all directions and that fluence is similar to irradiance. It's defined by $\phi(x) = \int_{4 \pi} L(x, \vec{\omega'}) d\omega' $...
3
votes
2answers
980 views

How to determine the object-to-world matrix

I want to ray trace a triangular mesh that I load from a file. The vertices' coordinates are expressed in the reference frame associated with the object (i.e the mesh) and I don't know the object-to-...
3
votes
1answer
629 views

Shadow appears to be too dark in my ray tracer

I'm currently working working on a unbiased path tracer. To test how accurate it is. I created a scene in my path tracer and LuxRender then compare the rendered image. I found that the shadow in the ...
2
votes
1answer
90 views

Slide a rectangle along a sphere

I'm using NASA WorldWind to place a rectangle on the Earth ('sphere'). When I drag the rectangle on the sphere, the rectangle changes shape and size but the dimensions should be preserved. What is ...
6
votes
1answer
95 views

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 ...