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Questions tagged [shadow]

Shadows cast by objects in front of lights, whether raytraced, shadow maps, shadow volumes, or any other technique

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0answers
60 views

Understanding bad shadows with voxel ray tracing

I have a voxel raytracer that is generating some weird shadows and I want to understand what is the source of the problem. The image is voxelized, resulting in: I then generate Hard shadows from the ...
0
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0answers
69 views

Changing coordinate system from texelFetch to textureLod is breaking the algebra

I have a scene rendered using texelFetch() and I am trying to modify the shader to use textureLod() instead. This is the image generated with texelFetch: When I try to change the shader to use ...
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0answers
61 views

Voxel cone tracing artifacts (what causes them and how to solve them)?

I am trying to generate soft shadows using voxel cone tracing. Which gives me the next images: In the first image you can see an artifact of a sequence of horizontal shadows alternating with ...
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0answers
85 views

Handling shadow acne for dynamic surfaces

My path-tracer is generally fine and gives good output for regular test scenes, but I've noticed dense fireflies and dark speckles over fractal surfaces. The noise disappears if I render without light ...
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0answers
69 views

What is voxel based global illumination in a nutshell?

As title says. What are the broad, general ideas of voxel based global illumination and what exactly makes it efficient enough to produce real time dynamic shadows with so much photorealism?
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0answers
56 views

Omnidirectional Faded Soft Shadows

I'm doing research to implement a shadow algorithm for omnidirectional soft shadows in a real-time 3D renderer. I've read about PCF but to me it doesn't look very realistic since it doesn't "fade" ...
1
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1answer
80 views

How to use shadow mapping and deferred rendering to create a large amount of lights?

Ok so I am trying to understand how to combine these 2 techniques and I am failing. The main goal is to reach the O(lights+fragments) complexity of deferred rendering, instead of O(lights*fragments) ...
5
votes
2answers
202 views

How did the hard, accurate shadows, work in early 3d (2000 - 2004) games?

I've been hunting around the internet for a while now, and I can't find anything about the specific shadow technique that I'm looking for. I can only recall one game in particular that used it, and I ...
3
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0answers
75 views

How can you efficiently get the last element occluding light when rendering shadows?

A long time ago I made an application that used volumetric rendering and I developed some shadowing equations that I felt very happy with, since they have pretty good results. For these equations to ...
4
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1answer
167 views

Experimental real-time shadowing techniques?

The three most popular shadowing techniques for real time applications are: Shadow maps Advantages: Fast "Simple" Disadvantages: Numerical limitations lead to artifacts and jaggy shadows You ...
2
votes
1answer
837 views

Path tracing with Next event estimation and area lights auto occlusion

I am working my way through my first path tracer and I am currently designing how to deal with area lights. I have two questions: Each object in my scene can have a Light attached to it, this is how ...
1
vote
1answer
389 views

OpenGL: Rendering 2D shadows

I've been working on a 2d shadow system for a school project, using this method to generate visibility polygons. However, I'm having issues figuring out how to draw those visibility polygons in a way ...
2
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1answer
85 views

DX9 Shadow map PCF issue

I am trying to do simple PCF with Unity but I am facing some issues and I don't know where they come from. If anybody has an idea... Here are two examples ...
6
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0answers
281 views

Cascaded shadow maps. Seams between cascades

I implemented cascaded shadow maps, where shadow maps for each cascade is rendered to one canvas: The light projections for each cascade are calculated from the bounding spheres of camera sub-...
6
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0answers
140 views

Dual paraboloid shadow texture edge seams

I implemented dual paraboloid shadows for point lights. The goal was to reduce the number of shadow passes. Also the target is GLES3.0 so no layered rendering is available. The shadows work, and ...
1
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0answers
40 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 ...
4
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1answer
247 views

Tracing shadow rays in a scene with mirrors

In my real time ray tracer, I shoot primary rays from the eye, and at hit points, I trace to a single light source to determine if the object is shadowed or lit. Pretty straightforward stuff so far. ...
6
votes
1answer
446 views

Ray Tracing Shadows: The Shadow Line Artifact

By using smooth shading (i.e. interpolation of normals), an object can have a smooth look despite low polygon count. A nasty artifact that can happen when casting shadow rays is the Shadow Line ...
5
votes
3answers
111 views

In forward rendering what's the go to technique to smooth out rigid shadow due to low resolution shadowmap texture?

I am building my own graphic engine. My depth texture is significantly smaller than that of the screen. The low resolution depth map results in rigid shadow like this... I am sure this is a common ...
4
votes
1answer
119 views

How to send shadow rays to window light source with glazing

For rendering an indoor scene where light source is skylight coming in through the window opening, one can consider the window polyline as the light source, with the sky distribution, in direct ...
4
votes
3answers
208 views

Sending shadow rays to the sun

How is sun modelled for ray tracing rendering? Is it part of the scene, like a sphere with a centre in some far location or it is just considered as a point? Also regarding sending shadow rays to the ...
4
votes
1answer
121 views

What is this shadow mapping error called?

I have been following a tutorial, shadow mapping works more or less as expected except sometimes the shadow projects completely weirdly on nearby walls. This isn't sampling outside the lightmap ...
6
votes
0answers
391 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......
5
votes
1answer
386 views

Exponential shadow maps sampling with PCF for sampler2DShadow instead of sampler2D

I am trying to make use of free hardware PCF sampling with sampler2DShadow and extend it to more samples. So far I am sampling shadow map (...
5
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1answer
1k views

Better Shadow Mapping Techniques

Currently I have basic shadow mapping setup in my engine. I am currently trying to implement something more realistic like PCSS (percentage closer soft shadows), to get a more physically accurate ...
1
vote
1answer
597 views

What are some new Real-Time Graphics Rendering Techniques to get closer to real life? [closed]

So recently after implementing PBR in my engine, I was wondering what are some new & old Rendering Techniques that people are implementing and researching to get Real Time Graphics closer to what ...
9
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1answer
166 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
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2answers
865 views

What is the difference between shading and shadowing?

Shading and shadowing are often mentioned in how to create realistic 3D graphics, but the distinction is not clear. Are both responsible for the generation of shadows, or do they refer to the same ...
4
votes
1answer
114 views

Components that can be used for 3d shadow analysis, sunhours of surfaces throughout the year in a 3d model?

I want to develop a component for 3d shadow analysis of 3d city model. I decided to use ray tracing for this purpose. For every time step (for sun's dynamic position during the year) rays will be sent ...
9
votes
1answer
387 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 ...
2
votes
2answers
531 views

How are hard and soft shadows cast?

I have been studying computer graphics, from the book Fundamentals of Computer Graphic (but the third edition), and I lastly read about texture mapping and shadow maps. Though, I didn't exactly ...
5
votes
1answer
346 views

How to compensate low amount of rays reaching the light in a Path Tracer

I am trying to implement for research purposes a path tracer, but so far but results are not so good and I will explain you why. The general idea before getting to the code: I am working on paths ...
3
votes
2answers
453 views

Path tracer not rendering shadows

I am trying to implement for research purposes a gradient-domain path tracer. In order to achieve this step I first need a working Path tracer. I have been creating one so far but results are wrong ...
8
votes
2answers
343 views

Raytracing Problem - Casting Shadows

So I was tasked to create a model of the Cornell Box. I've managed to do everything up until casting shadows, in which case some shadows are cast when there should not be any. Here are pictures of ...
2
votes
0answers
117 views

Shadow Mapping Errors

I recently started to create a shadow mapping system in OpenTK. I ran into a problem: The depthtexture is always completly white -> no depth. Even if the color from the shader is changed (I know it ...
5
votes
1answer
2k views

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'...
4
votes
2answers
105 views

Storing shadow data

Given a 3D space and a light source, I use ray casting to determine the shadows generated in the scene. If I'm to store the shadow data (boundary of the shadow, object which cast the shadow, etc.) ...
7
votes
1answer
625 views

Shadow Mapping artefacts

I've been playing around with shadow mapping in OpenGL using depth textures. The depth texture is fine and I can map it onto the scene but I have some strange artefacts on the back of the object: My ...
7
votes
2answers
853 views

Am I missing something for ambient occlusion?

I'm trying to implement ambient occlusion in Python 3 and I'm seeing shadows beneath my reflective spheres but they seem very faint. I'm not sure if that means I've missed something, or if I just have ...