a technique for generating an image by tracing the path of light through pixels in an image plane and simulating the effects of its encounters with virtual objects
0
votes
0answers
34 views
Camera with physical parameters
I need to create a Camera following this parameters :
[camera]
focal_length = 1.119968176
width = 4912
height = 3264
pixel_aspect = 1
principal_point = 0.5 0.5
rotation = -0.9926100969 -0.1198614389 ...
1
vote
1answer
34 views
DirectX shader - how to spread raytracer computation over multiple frames?
I'm playing around making a shadertoy style SDF raytracer in HLSL and to make it run faster on high resolutions (1080p and up) I'd like to spread the computation over multiple frames.
Right now I ...
-1
votes
1answer
46 views
FInd out if AABB is left/right/below or obove a ray
What algorithms are there to find out in which quadrant of the ray an AABB is given a roll value? My idea was to rotate the cube by the negative rotation of the ray and move it by the negative ...
0
votes
0answers
11 views
How to use Bidirectional path tracing on sky dome for rendering indoor
Is it possible to use bidirectional path tracing to render an indoor scene where
the light source is skylight(no sun) coming through a window? I think I roughly
know how this is done if the light ...
0
votes
1answer
60 views
Calculate distance from the centre to the edge of a cube in OpenGL
I'm trying to calculate the distance between a central point on a cube and anywhere on the surface of the cube, depending on the location of a second 3D point.
I have two vertices in 3D; Q and P. Q ...
3
votes
1answer
64 views
Hit detection for partially covered object?
Say you have a character standing behind cover such that some of its body parts like a shoe or a palm is still outside the cover.
An explosion takes place close to the cover . In real life this ...
0
votes
0answers
75 views
How to use Halton sequence in Quasi-Monte Carlo for Global Illuminaiton
I am trying to use Halton sequence numbers for MC estimator for rendering equation. At the moment I pass one instance of .Net Random object and get next number every time using same object thought the ...
4
votes
1answer
80 views
Ray-tracing Moveable Objects
I am fond of creating graphics and animations using the frameworks on the iOS platform; lately, I discovered that, in order to create better visual designs, those higher-level of frameworks do not ...
0
votes
0answers
44 views
Does light source color defines its radiance?
My understanding is that a light source can emits wavelength in red colour; and the same red light source (viewed from the same angle) can have more intensity if it emits much more light flux and ...
0
votes
0answers
43 views
Dark image on Stochastic path tracing
I am trying to implement stochastic path tracing, where direct and indirect illuminations are evaluated separately. Below is an example of the direct illuminance with 4 rays per pixel and 16 shadow ...
0
votes
0answers
110 views
How should i go about rendering voxels?
What i would like to do is something like this:
And iv'e considered just brute-forcing it with raytracing and octrees and such. However, is it fast enough? What would be the fastest method for ...
0
votes
1answer
28 views
How to find a point of taking into account the distortion of the projection
I can not find the material that will help me to implement the algorithm of coordinate transformation based on the distortion of the projection.
I am creating a code recognition algorithm (similar to ...
0
votes
1answer
130 views
Project camera-to-pixel ray in world coordinates
I'm trying to implement a very simple ray tracing function but I have a problem with projecting the camera ray (from camera to pixel) to the world space.
In the screen coordinates have the pixel ...
0
votes
1answer
38 views
Limit Quaternion/vector3 axe in a certain interval
I have some trouble to understand, and handle Quaternion and Vector3. I'm improving the tutorial Tank of Unity:
EDIT: Because a video explain so much better, there is a link to the 30 secondes video ...
0
votes
0answers
34 views
How to convert Non-Axis Aligned Bounding Boxes to AABB
I'm trying to write a raytracer to render boxes (cubes) that are arbitrarily rotated, i.e. not necessarily axis aligned. While I'm reasonably comfortable ray-tracing an axis-aligned cube, I don't know ...
0
votes
0answers
63 views
Spectral path tracing - image color/brightness incorrect
I implemented a spectral path tracing using physically base BRDF models such as Oren-Nayar,Specular Reflection and Transmission, Lambertian. All calculation in the path tracer uses standard illuminant ...
2
votes
0answers
47 views
Bidirectional Path Tracing questions
I'm coding a Bidirectional Path Tracing application for school in C++ and I have some questions (I haven't found useful explanations on the web)
1) Why does the EyePath have one more vertex?
2) When ...
4
votes
1answer
72 views
Ray tracing - BRDF using Cornell measured spectral data
I wrote a ray tracer that implements various BRDF models (Oren Nayar, Lamber, Torrance Sparrow and so on).
Now I'm trying to implement a BRDF from measured data.
I choose the Cornell database data ...
2
votes
2answers
213 views
Efficiency - Cubemap or Raytraced reflection?
I'm an amateur in 3D game development. The thing I want to know is shading related.
For reflection purpose, which will be the efficient way? Either "Realtime render to Cubemap" or "Ray trace based" ...
3
votes
1answer
41 views
How can I calculate the U,V texture coordinates on a disk at infinity given only a view vector and a vector pointing to the disk's center?
I'm using an approach similar to Bruneton's paper on atmospheric scattering for rendering my sky and am trying to extend it to add a textured moon.
Long story short, the paper works by essentially ...
3
votes
2answers
483 views
How do I test for intersection between a ray and a cone?
I decided that writing a ray-tracer in my game was a brilliant idea, and so now I am looking for code to use for ray to primitive intersection tests. I have based my effort on this very nimble yet ...
9
votes
3answers
374 views
BRDF and Spherical coordinate in ray tracing
I developed a ray tracer that use standard phong/blinn phong lighting model. Now I'm modifying it to support physically based rendering, so I'm implementing various BRDF models. At the moment I'm ...
0
votes
2answers
97 views
Poor CUDA performance, raytracing
I use CUDA 7.5 to learn the basics of raytracing. So far I've done nothing but constant color no-lighting spheres-only raytracing. But my delta time is already 14 - 16 ms for 800x600 resolution - 1 ...
0
votes
1answer
199 views
Getting ray using gluUnProject or inverted MVP matrix
I've read a lot of topics here, on SO, opengl.org etc.
Example how gluUnProject should work (from NeHe tutorial):
winX = (float)x;
winY = (float)viewport[3] - (float)y;
glReadPixels( x, int(winY), 1, ...
1
vote
2answers
131 views
Cursor position to a 3D ray using angles
I've been stuck for a month trying to get gluUnProject working. After my attempts to use gluUnProject failed (as well as attempts to implement gluUnProject functionality manually) I implemented method ...
1
vote
1answer
173 views
Ray tracing - glossy reflection
Here I am again with my ray tracer for ipad. Now I'm trying to add glossy reflection to an object. How do i implement it?
I read some documentation online like these:
http://www.cs.cmu.edu/afs/cs/...
0
votes
2answers
233 views
Raypicking / raytracing in OpenGL
Alright, so before you down vote saying that OpenGL doesn't support rays for rendering, please read:
So I want to detect a quad in opengl 1.1( I don't want to use opengl 3.0). I wanted to detect it ...
0
votes
1answer
51 views
Ray tracing - texture and phong lighting
Other questione releated to my ray tracer implementation for iPad.
If I have a polygon that has a texture and a material, how do I calculate the color using Phong lighting model? Is the texture used ...
2
votes
1answer
230 views
Ray tracing - draw polygon (square/bounded plane)
I'm going on with my own ray tracer as an iPad app for a school project. This is the result with soft shadow, antialiasing, pure reflective and pure transparent object:
Now i want to change the ...
1
vote
1answer
769 views
Ray tracing - soft shadow
I'm implementing my own ray tracer as an iPad app for a school project. At the moment this is the result:
I need to add the last requirement, soft shadows, but I can't find a complete reference ...
2
votes
1answer
479 views
Simple Doom style engine question
I've just started making a 'raycast' engine, a pseudo 3D FPS engine similar to Wolfenstein/Doom. I haven't done much reading so my implementation is likely very naive.
My current working prototype ...
0
votes
0answers
79 views
A simple “beam tracing” simulation
I am trying to implement a simple beam tracing simulation. Basically it models the path of a beam within a pipe:
In the picture, the beam starts emitting from p1, hitting the boundary at p2 and ...
1
vote
1answer
363 views
C++ Ray Traversing in 3D Voxel game
I'm currently working on a Voxel game in 3D and need a tad bit of help to figure out what Voxel the player is looking at. This is the data I currently have:
GRRLIB_Camera3dSettings(Player.x, Player.y,...
0
votes
1answer
3k views
How to calculate ray polygon intersection? [duplicate]
I'm in a class where we are creating a ray tracer from the ground up in C++. I'm at a point where I can't seem to wrap my head around the math that is required to calculate the point at which a ray ...
0
votes
0answers
376 views
Ray-Triangle Intersection Detection using Barycentric Coordinates
I am attempting to convert the algorithm from http://www.cbloom.com/3d/techdocs/fast_ray_tri.txt to java code, but my solution does not function correctly.
The only intentional change I made was for ...
8
votes
1answer
325 views
Specular banding with high specular power
We're having some issues with our ray tracing in DirectX, especially with some serious banding issues with specular. With high specular power (above 8) banding starts. I'm wondering if this is an HDR/...
0
votes
1answer
176 views
Degenerate AABB (axis aligned bounding box), does this always intersect?
I'm studying ray-AABB intersections and I'm asking myself: what would happen if one of the dimensions of the axis aligned bounding box was degenerated?
For instance:
AABB_min = {1,1,1}
AABB_max = {...
2
votes
1answer
2k views
Rendering lightmaps at runtime
I'm creating a procedural terrain system for Unity. And I'm looking for ways to efficiently cast self-shadows on it. If it wasn't procedural, I could simply bake a lightmap using Beast. But, I can't ...
0
votes
1answer
232 views
Overlapping sibling problem in AABB tree
I'm trying to make a real-time GPU (CUDA) ray tracer, and for now I'm tracing single rays, but I've ran into a problem: the BVH. This [PDF]paper has been my inspiration for the theoretical part, and ...
2
votes
1answer
2k views
Ray Tracing in 3D - generating a ray
A ray is shot from the camera eye to the camera screen at point (i,j) how do I get the coordinates of that point in 3D world coordinates?
The best I could find online is for point S
S = Q + au + bv
...
2
votes
2answers
782 views
Raytracer texture mapping (to triangle mesh) leaving artifacts
So I am trying to get OBJ loading working in my raytracer. Loading OBJs works fine, but I am having some trouble with getting the texture mapping working.
Here is an image of my result. It is ...
4
votes
2answers
550 views
What is the state of the art of ray tracing on the GPU?
I think ray trace rendering had to be done on the CPU for a long time. But since we have compute shaders in OpenGL 4.3 now, it might be possible to move the computations on the GPU and perform ...
3
votes
2answers
243 views
How does a point squared equal the radius squared?
I am working on a simple ray tracer but I don't understand some of the formulas.
One that is bugging me at the moment is this:
If a sphere is centred at origin, a point p lies on a sphere of ...
4
votes
1answer
185 views
Forcing early-z with raytracing
I'm working on a GLSL raytracer, and I need to be able to edit gl_FragDepth in the FS. However, doing so disables early-z culling. The scene is rendered front-to-back and the FS can only push points ...
1
vote
1answer
972 views
Ray Tracing Shadows in deferred rendering
Recently I have programmed a raytracer for fun and found it beutifully simple how shadows are created compared to a rasterizer. Now, I couldn't help but I think if it would be possible to implement ...
2
votes
1answer
285 views
Ray Tracing concers: Efficient Data Structure and Photon Mapping
I'm trying to build a simple ray tracer for specific target scenes. An example of such scene can be seen below.
I'm concerned as to what accelerating data structure would be most efficient in this ...
3
votes
4answers
1k views
Real-time ray tracing: How is it done?
I wonder what technology applications like Xara3D use to be able to perform real-time ray tracing.
How is such good quality rendering done in real-time?
3
votes
1answer
929 views
What is an easy way to work subsurface scattering into a raycaster?
I've got some neat effects with path tracing:
I want to add in an ability to do subsurface scattering, but I'm unsure of the general algorithm. With path tracing, it's:
foreach pixel:
trace( ...
7
votes
4answers
3k views
Impact of variable-length loops on GPU shaders
Its popular to render procedural content inside the GPU e.g. in the demoscene (drawing a single quad to fill the screen and letting the GPU compute the pixels).
Ray marching is popular:
This means ...
1
vote
1answer
557 views
Intersecting Ray with Extruded 2D Shapes (e.g. Extruded Text)
I'm looking for a way to find intersection between a ray and an extruded 2D shape or text (defied by a Bézier curve). Any ideas?
