Computer Graphics Stack Exchange
Computer Graphics Stack Exchange

Questions tagged [shadow-mapping]

33 questions
14
votes
2 answers

Handling Projective Aliasing In Shadow Mapping

I'm fiddling with simple procedural 3D modeling to make teeny buildings for 3D printing. An Example: To make the models more readable onscreen, I've implemented basic shadow mapping for a single directional light. Since my scene isn't changing, I…
user2500
10
votes
1 answer

WebGL Omnidirectional Shadow Mapping Issue

First of all, I want to say that I've read a lot of post about shadow mapping using depth maps and cubemaps and I understand how they work and also, I have working experience with them using OpenGL, but, I have an issue implementing Omnidirectional…
czapata91
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9
votes
1 answer

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 question is what is causing this and how can I…
Blarglenarf
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7
votes
1 answer

Shadow map projection issue

I am using Unity but this question might not be proper to this engine. I have projected the shadow map onto this sphere but there are grazing shadows. Is it possible to avoid it or to correct it as I am using the raw depth data of the texture. Here…
MaT
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6
votes
1 answer

How should I generate the view position for a light at infinity when creating depth maps?

I'm working on implementing Bruneton's cloud rendering paper, which requires one to render a pair of depth maps, similar to how shadow mapping works. In this case, my light source is the sun (or possibly the moon), which I represent in my rendering…
stix
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6
votes
1 answer

How to render an object that recieves shadows but does not cast them in a variance shadow mapping system?

I'm currently preparing to implement variance shadow mapping based on this article. However, one point it makes concerns me: Rendering only casters (and not receivers) into the variance shadow map is incorrect! For the interpolation to work…
orost
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5
votes
0 answers

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-frustums: The code for calculation visibility value: for…
Zheden
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5
votes
3 answers

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 issue. I would like to learn "go to" technique to…
Blue Bug
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5
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0 answers

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... Here is my current setup. I am using an…
MaT
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4
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1 answer

Why is OpenGL recompiling my depth map vertex shader based on the GL state?

I've written a shader that writes depth to each face of a cube map, as part of rendering cube map shadows for a realtime 3D engine I'm writing with OpenGL and C++. The shader transforms each vertex into world space in the vertex shader, then…
b1skit
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4
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2 answers

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.) what is an efficient way to go about it? Edit: Its…
ichigo1191
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0 answers

Projective Texture / Shadow Mapping -- Why is the perspective division performed in the fragment shader?

I've just worked my way through this OpenGL shadow mapping tutorial. While I understand the basic algorithm, one thing puzzles me: During the 2nd render pass all vertices are transformed into the clip space of the light source. This is done by…
rapunzel
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1 answer

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 because I use CLAMP_TO_EDGE and if(min(ShadowCoord.x,…
Kachinsky
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3
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2 answers

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 understand how they function. I know there is also…
phong
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1 answer

How can I use multiple texturing with shadow mapping?

So, recently I followed this tutorial about shadow mapping, but in the tutorial it doesn't texture the object.. When I try to add a texture, it's distorted by the TexGen. Also I've tried to use glActiveTexture() with no success(dunno exactly how…
Bla...
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