Questions tagged [rendering]

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0answers
69 views

Mitsuba Bidirectional Framework

I'm confused by the Mitsuba bidirectional framework for quite a while now, especially by the different eval and connect ...
6
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1answer
189 views

3D projection that increases objects' size as they become more distant

tl;dr Is there a name for a type of (non-physical) projection that causes objects to become larger the farther they are from a camera? With a fisheye projection, an object twice as far from the ...
9
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0answers
210 views

Help with start up bias in Metropolis Light Transport

I'm trying to implement metropolis light transport based on this paper, and I have the basic thing working. I run the algorithm multiple times with different starting points, add the results for each ...
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0answers
71 views

Can one application inject triangles into the graphics pipeline of another application?

If I have two applications that I've written running on a machine, is it possible to have one application inject triangles into the scene of the other application? So effectively, the data for meshes ...
5
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2answers
217 views

What is missing in this image that stops it from looking like a photograph?

Look at this image: This is CG, Saya, a project meant to make as real CG as possible to the point of becoming indistinguishable from reality. I would say that it is pretty believable. But, it still ...
3
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1answer
89 views

Need help reasoning about video oscillation >60hz

I want to make a basic video oscillator for the web. What I want to do is basically illustrated in a tutorial for Lumen: essentially, I want to define an oscillator to turn on and off a color signal ...
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0answers
41 views

What could cause realtime lighting within a viewport to be calculated on the wrong part of the screen?

(I initially posted this in a section that is less suited for the particular issue, oops) I'm having this issue on some of my client's computers (this is for a Unity asset) that I cannot reproduce on ...
5
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3answers
1k views

Formula for the ambient light intensity of a scene?

I understand that ambient light is light that occurs a result of light from a given source refecting off an infinite number of points in a scene, thereby illuminating all objects in the scene ...
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0answers
61 views

Specular Highlight Gray When Behind Model

What would cause this grayscaled backside? When my camera is behind my model I see a grayscale specular highlight. However, in front of it is perfectly fine. Here's my shading code. (Software ...
3
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3answers
141 views

What is name for far lowcontrast blueish landspace?

What is the name of effect, that we see on far objects in outdoors ? These objects are low-contrast, foggy ? Is it only fog or some scattering ?
1
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1answer
132 views

How to generate a 2d histogram?

I'm playing around with volume rendering and looking into multi dimensional transfer functions. I keep seeing images like this for 2d transfer functions: I've read numerous papers and articles but ...
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0answers
151 views

Can I voxelize 3D set of points without reconstructing surface first?

I have huge point cloud data I want to render them at interactive frame frate. Process I know is 1.point cloud data 2.triangulate it using delnauy or other triangulation algo 3.surface ...
5
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1answer
1k views

How to know when rendering is complete in WebGL?

gl.drawArrays()/gl.drawElements() initiates a drawing and returns immediately. There is also (non-recommended) gl.finish() that (theoretically) blocks execution until rendering is complete. Is there ...
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0answers
75 views

Find RGB intensity values at center of face using Gouraud shading [duplicate]

Consider a triangular face of three vertices A(0,2,-1), B(1,0,1) and the origin O, and the normal vectors at the vertices are nA=(0,1,0), nB=(1,0,0) and nO=(0,0,1), respectively. The incident light is ...
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0answers
86 views

Advice on synthetic data generation using 3D mesh

I'm developing a deep learning algorithm to find and classify (post consumption) plastic bottles on a conveyor belt. A way to train my model is to get tons of labeled images of each bottle, which for ...
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0answers
77 views

Artifacts (numerical errors?) in rasterisation renderer

This might be not laser precision question but this issue appeared a long time ago when first trying to render some scene with 3D models in rasterisation renderer and apply some lighting, ...
3
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1answer
117 views

The constructor of hyperboloid in pbrt-v3

The book omitted the explanation of the constructor of hyperboloid. Could someone give some explanations about: Why the arguments are two points? What are the meanings of ah and ch? Why is there a ...
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1answer
567 views

Fundamental Questions: Building vs Compiling vs Rendering vs Coding vs Running?

I'm using Urho3D on Raspberry Pi, but the following questions apply to all platforms. What should I do in order to reduce the load of online real-time rendering of the game? Does building/compiling/...
3
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1answer
915 views

What is the equation for flat shading?

Is there an equation for flat shading? To my understanding, it is this: $$I = I_a \times K_a + F_{att} \times I_l \times (K_d \times (N \times L))$$ Final intensity = ambient reflection x ...
7
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2answers
604 views

How to handle a parametric equation in raytracing?

After taking a look at the Mobius strip, I noticed its equation is really simple and tried to add it into my Raytracer. I tried a "naive" way by simply generating N...
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2answers
988 views

How to calculate the RGB intensity values at center of face using flat shading?

Consider a triangular face of three vertices A(0,2,1), B(3,0,1) and the origin, and the normal vectors at the vertices are nA=(0,0,1), nB=(1,1,0) and nO=(-1,-1,1), respectively. The incident light is ...
3
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1answer
361 views

How do you calculate cos(theta) for diffuse in flat shading?

Consider a triangular face of three vertices $A=(0,2,1)$, $B=(3,0,1)$ and the origin $O$, with normal vectors $(0,0,1)$, $(1,1,0)$, and $(-1,-1,1)$, respectively. The incident light is white and ...
1
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1answer
336 views

Beginner CG Research Project [closed]

This summer I will be working with a professor on a research topic of my choice, in the field of graphics & simulation. While my professor is knowledgeable in the area he is being very hands off ...
1
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1answer
101 views

Need help with VBO/VAO

It's been a long time since I last used OpenGL and I can't figure out VAOs anymore... I want to make a simple voxel engine using geometry shaders. This is what I want to do: vbo1: array of GLfloat ...
4
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1answer
753 views

Energy conservation of BRDF

I'm reading Advanced Global Illumination. Here is the part confusing me: What do the second equation and $\delta$-function mean? Why the third equation is a sufficient condition even though a reason ...
5
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1answer
735 views

Why the BRDF of specular reflection is infinite in the reflection direction?

I know the BRDF of specular reflection is nonzero only in the reflection direction. But why it is infinite? A paragraph on page 36 of Advanced Global Illumination:
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2answers
1k views

Can you batch vertex data and still sort by depth?

In order to reduce the amount of draw calls per frame I've decided to use a vertex array object to store vertex data from several different meshes. More precisely, I use the vao to the define the ...
4
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2answers
1k views

My perspective projection is messed up?

So I've been messing with perspective projection matrices recently. I used numpy and GTK/Cairo to make a very small Python renderer. I'm very confused with the results I'm getting though. I took this ...
1
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1answer
746 views

How can I send custom bitmap to frame buffer?

I was trying to make a CPU-based ray tracer but I know after all the calculation I will end up with an array of pixels. I don't know how to paint it on the screen. What are the various ways to do that?...
8
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2answers
931 views

What is a good approach for handling uniforms in modern OpenGL?

I'm creating a renderer using modern OpenGL (3.1 and up) and now I'm trying to create an efficient but flexible way of handling uniforms. I've been reading up on uniform buffer objects and on what a '...
1
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1answer
876 views

Which technique is fast to generate real-time reflections?

I want to know about some technique with which i can generate nice reflections on the surface. I know one conventional technique where we invert an object and render it and blend it with the floor but ...
3
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1answer
3k views

Multiple VAO share a VBO

Let's say I have a have 10 different terrains. Each terrain have the same x and z coordinates, but they have different y coordinate, normals and colors. The indices used for element rendering is also ...
2
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0answers
504 views

Calculating intensities of Virtual Point Lights in Instant Radiosity from IES lights

Short introduction I created a function that interpolates the IES luminious intensities (candelas) using Hermite interpolation, so in my code all light sources have $I(\theta, \phi)$ function - but ...
5
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1answer
121 views

Trying to understand environmental cubemaps

I am trying to implement a physically based renderer, in OpenGL. I was planning to implement the Cook-Torrance BRDF. I read about radiance cubemaps (for reflections), like the one discussed here, for ...
1
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2answers
495 views

Challenges of Offline Rendering

What are some of the challenges of Offline Rendering? I know one problem that is faced is performance and rendering times, are there any more issues? Path Traced photos seem to have reached the ...
4
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1answer
135 views

Volumetric Obscurance : line integrals

I would like to compute volumetric obscurance with line integrals like described in this paper. For a 2D sample, it is possible to know the "depth in sphere". But I don't understand how they compute ...
6
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1answer
254 views

Mix shader looks wrong on my path tracer

I apologize if my methods seem way off because this is my first time trying to build a path tracer and I'm struggling quite a bit. Currently, I am trying to mimic the "mix shader" node in Blender 3D ...
3
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1answer
724 views

Do animation studios like Pixar, Dreamworks, and Disney use super-sampling?

Does any of their rendering techniques involve rendering an area at a higher resolution just to scale it down in order to mitigate artifacts? I know they use ray methods rather than rasterization ...
7
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2answers
7k views

How to achieve gimbal lock with Euler angles?

I was studying about Euler angles and I came across the problem gimbal lock which can occur by using Euler angles. In gimbal lock we lose one axis of rotation. But how? And when does it happen? On ...
5
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1answer
1k views

Do GPU performance improve when rendering at native or half resolution, compared to fixed scaling?

This might be an odd question, but I was wondering if you could improve GPU performance with games, comparatively, when using doubles/halves of the native resolution, instead of an odd ratio of that. ...
5
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1answer
428 views

Binary scene voxelization using imageStore - problem

This problem has been haunting me for some time but I was busy with other things. I can't finish my GI technique (specifically occlusion step) without solving it. I made a binary scene voxelization ...
5
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0answers
756 views

Percentage-closer Soft Shadows implementation

I am trying to implement the Percentage-closer Soft Shadows (PCSS) from NVidia inside Unity but I am facing some issue and I don't know where they come from and then, I do not know how to solve them......
11
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1answer
502 views

Ocean Wave Rendering

How could I generate the waves for a water body with whitecaps & foam and variable intensity of the waves? Is the surface a mesh with a normal map? Is there a formula for generating that? Is there ...
6
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1answer
2k views

Depth of Field in Path Tracing: What do I do with the secondary ray?

How can I implement Depth of Field in my Path Tracer? I have read this article which explains the theory behind everything & I already have a good understanding of what this effect needs to ...
7
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1answer
3k views

Area Lights in Path Tracing

I have been following the scratchapixel ray tracing tutorials online which have been great at explaining the theory behind everything & how to implement it. However, I reached the point where I ...
4
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0answers
141 views

How is glint rendering done in Ray Tracing?

How is glint rendering done with ray tracing in the photo below? Is it just a simple normal map? I found a paper online that describes the exact same method used in the photo above but I have no ...
5
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1answer
3k views

What are the benefits of downscaling on modern games?

I'm a software engineer and although I currently don't work on anything related to computer graphics, I understand how downscaling works, what I don't understand is why most modern games default to ...
5
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1answer
921 views

How is data stored into a frame buffer?

I am an electronic engineer. I am trying to design (personal project) a 3D graphics hardware renderer. It shall only render wireframes at this stage, no filling and no shading, not even backface ...
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2answers
243 views

Can I have lower color bit depth in sample buffer than target framebuffer?

I´m looking into uses of high amount of samples in multisampling. If I have an RGBA8 framebuffer and render to it using multisample with many samples, say 32, dithering on per-sample level should ...
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3answers
330 views

How are Physically Based Rendering Methods Researched?

Recently a question that came to my mind was that How are Physically Based Rendering Techniques researched and developed? Do people just use current equations by physicists or do they create their own?...