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

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3
votes
1answer
27 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 ...
0
votes
2answers
56 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
28 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
123 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 ...
6
votes
1answer
238 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
1answer
60 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
71 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
59 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 ...
0
votes
0answers
48 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: ...
0
votes
2answers
167 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
44 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
114 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
208 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
283 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
72 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
248 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, ...
0
votes
1answer
2k 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
263 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
300 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 ...
0
votes
1answer
148 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
1k 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
216 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 ...
1
vote
1answer
1k 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
654 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
468 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
236 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
170 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 ...
0
votes
1answer
786 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
258 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 ...
1
vote
3answers
842 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
702 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
2k 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
541 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?
2
votes
3answers
337 views

Why Inverse Transform the Ray when doing Transformation?

I am adding 3D affine transformations to my ray tracer, and it seems all the literature on the web recommend inverse transforming the ray instead of transforming the 3D objects. Why is that? There ...
1
vote
1answer
532 views

How to calculate the viewing cone radius at a distance in raymarching?

I'm "raymarching distance fields" (proper lingo: sphere-tracing) in GLSL. To implement cone-marching atop of it (and also to minimize the number of raymarching steps regardless of whether ...
3
votes
1answer
423 views

Procedural mesh generation from raytracer

I'm interested in applying the following technique: Define game objects using a object definition DSL similar to what you would use for a raytracer (e.g. POVRay) Use a specialised raytracer to ...
1
vote
1answer
348 views

Realtime rendering using a ray tracing engine

I want to render an object that has a mesh with one million hexagonal elements(100 * 100 * 100). Lights, shadows and textures is not important and each element has a solid color. and finally, the ...
0
votes
1answer
232 views

3D Huge mesh rendering

I am writing a program, that as input, I have a huge (10^6 elements) 3d mesh (with hexagonal shaped elements), and I want to realtime render it, but not as real-time as a game. It just can show the ...
5
votes
1answer
2k views

Fast pixelshader 2D raytracing

I'd like to do a simple 2D shadow calculation algorithm by rendering my environment into a texture, and then use raytracing to determine what pixels of the texture are not visible to the point light ...
0
votes
2answers
312 views

Which optional features would you recommend for a raytracer? [closed]

I'm developing a basic triangle mesh raytracer on a short deadline. This means I can't implement every feature I come across, so I'm looking for some feedback about which features you think are most ...