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11 votes
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How does the rendering equation incorporate shadowing

Light that is blocked will mean that $L(p*, -w_i)$ under the integral is 0 plus how much light the blocking object itself reflects. In other words the shadowing is embedded in the incoming light ...
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11 votes
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Shadow Mapping artefacts

This issue looks like standard shadow map acne artifacts. Additionally your's lighting equation is incomplete or wrong. Light shouldn't influence faces with normals facing away from it. This also ...
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8 votes
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Ray Tracing Shadows: The Shadow Line Artifact

The shadow terminator problem (as it's also known) is still something of an open problem in ray-tracing. As you say, disabling self-shadowing is not a very good workaround, because non-convex meshes ...
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7 votes
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Experimental real-time shadowing techniques?

There’s an interesting technique that’s been used in demoscene and Shadertoy projects for a while, and an analogue of which recently made it into Unreal Engine 4: using signed-distance fields and ...
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6 votes
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Shadow rays in Raytracing

Your if condition makes me suspicious. You should include the diffuse and specular shading if the intersection test didn't hit an object; that is, if ...
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  • 6,490
6 votes
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Am I missing something for ambient occlusion?

It's a bit hard to tell from your image, but it does look a bit faint. When debugging these kinds of things, it's always useful to strip down your scene as much as possible to remove any unnecessary ...
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6 votes
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Path tracer not rendering shadows

The problem appears to be unintentionally transparent surfaces Although the image is grainy, it is sufficiently clear to estimate that all of the darker regions are due to surfaces facing away from ...
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  • 5,902
6 votes
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What are some new Real-Time Graphics Rendering Techniques to get closer to real life?

PBR isn't just a feature you "add to a rendering engine" but an entire philosophy how to approach solving rendering problems. This seems to be a common prevailing misconception when people talk about ...
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  • 3,566
5 votes

What is the difference between shading and shadowing?

In simplified terms, shading controls how object's surface's brightness changes when the angle between its normal and light vector changes. Shadows are areas where the light cannot reach because it's ...
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5 votes

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

A note first From the look of your screen capture, I suspect there might still be a bug in your code. Noise is to be expected with only 16 spp, but your picture still looks surprisingly dark to me. ...
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5 votes

Path tracer not rendering shadows

is it correct having such a big light? I don't see any problem with having a big area light. That said, it also depends on the scale of your scene. If the light is large compared to it, shadows will ...
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5 votes
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Tracing shadow rays in a scene with mirrors

It depends how you define easy and what kind of constraints you have. The general case of this is rendering caustics but that's probably not what you're looking for if real time is your target. If ...
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  • 1,575
5 votes
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Better Shadow Mapping Techniques

For light sources with larger solid angle and where the shadow caster is relatively closer to the light than the receiver, you get notable soft shadowing effect. So if you render larger light sources ...
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5 votes
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How to send shadow rays to window light source with glazing

Most renderers allow you to set a flag on an object to make shadow rays ignore it (so it won't cast shadows). You could set this flag on your glazing. That said, it's not unusual to make it so that ...
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5 votes
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How did the hard, accurate shadows, work in early 3d (2000 - 2004) games?

Having not worked on these games, I can only speculate... but from your description, it sounds like a crude shadow map with orthogonal projection and no depth information. It probably has (or had) a ...
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  • 1,575
4 votes
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Sending shadow rays to the sun

Sun light can be represented as a distant light. Light sources are radial like a bulb, though in the case of the sun, it is so far away from the Earth, that a reasonable approximation is to consider ...
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3 votes
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Exponential shadow maps sampling with PCF for sampler2DShadow instead of sampler2D

PCF does N shadow tests, where each test returns 1 (in light) or 0 (in shadow), and returns the average of the results. sampler2DShadow is a special sampler where ...
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  • 3,566
3 votes

Sending shadow rays to the sun

Sunlight is typically modeled as a directional light. All rays point the same direction off into infinity.
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3 votes

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

Ah, shadows. They still are bothering after so many people spent years trying to improve them. Whether your engine is deferred or forward, the shadow pass should be quite the same, and suffer the same ...
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  • 1,689
3 votes
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In forward rendering what's the go to technique to smooth out rigid shadow due to low resolution shadowmap texture?

Percentage Closer Filtering with some amount of blur (ie. a minimum filter size in texture space) is the most basic method I know of. For example, see GPU Gems. My experience is that it is also quite ...
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  • 1,575
3 votes
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Storing shadow data

If the goal is mouse interactivity, you can do with a simple "shadow buffer", i.e. an image that holds the identity of the occluding object (if any) on every rendered pixel. You will compute this map ...
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3 votes

Am I missing something for ambient occlusion?

I'll add some guidelines to help readers understand Benedikt Bitterli's statement "Make sure to gamma correct your images". Gamma correcting images does not mean applying a power filter at the end. ...
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  • 613
3 votes

Raytracing Problem - Casting Shadows

are you sure you are not re-intersecting the same surface when checking for light occluder ? this is a classical precision issue. There are many way to tackle it: First, have a good conditioning of ...
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3 votes
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How are hard and soft shadows cast?

Hard shadows are simple that only needs a point light. How it's done is by rendering the scene from the point of view of the light and only keep only the depth information. This is the shadow map. ...
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3 votes
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OpenGL: Rendering 2D shadows

You don't need to render to texture to achieve an effect like this. Use stencil buffer. The visibility polygon can be drawn using GL_TRIANGLE_FAN, if you start ...
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  • 248
3 votes
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Path tracing with Next event estimation and area lights auto occlusion

I am no expert in offline renderers, but I'll give it a go until someone else comes with a better answer :) Shadow rays intersecting area light It is very common to assign an extent to your rays. How ...
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  • 2,468
3 votes

Silhouette below 3D model

There is a trick to shadows like this, but only this exact usecase. While you can certainly draw a true shadow using many techniques. The trick is you can just scale the object flat onto the floor ...
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  • 8,169
3 votes
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Hard Shadows with Dielectrics/Transparency

"Refracting the shadow ray" is really the wrong mental model to use to think about this. After all, shadow rays are not real things; light rays are. Shadow rays are only used to test for ...
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  • 23.7k
2 votes

searching for acceptable quality shadow mapping techniques

Well nevermind. I made some research and actually gonna: sample ESM using Poisson sampling in PCF fashion (thanks Bart Wronski for great Poisson Sample generator app) and extend this to PCSS ...
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  • 2,047
2 votes

What is the difference between shading and shadowing?

The distinction is not clear mainly because the term "shading" is an extremely broad term. One of the first uses for programmable "shaders" in real-time graphics pipeline was computing illumination on ...
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