Tag Archives: Shadows

Meshless Real-time Ray Tracing Demo Video

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Meshless Real-time Ray Tracer

I was recently asked to put together a video showcasing my ray tracing project for the University of Hull to show some of the new Computer Science students starting this September. As detailed in my last post, ray tracing was the subject of my third year dissertation project and I have since been extending the project into real-time using DirectX 11, endeavouring hopefully to continue it as part of my MSc by creating a rendering program that can be used to design and produce complex implicit ray marched geometry through a simple UI interface.

The video unfortunately had to be recorded at 640×480 resolution to maintain good FPS due to my aging laptop GPU (around 4 years old now!). As a result, I recommend not viewing it in full-screen to avoid scaling ‘fuzziness’.

 

 

Scene Loading:

Recently I have been working on a scene loading system for it in preparation for implementing a UI with the ability to save and load created scenes. I developed a scene scripting format that allows simple definition of the various distance functions that make up a scene, along with material types and lighting properties. The scene loader parses a scene file and then procedurally generates the HLSL distance field code that will be executed in the pixel shader to render the scene. I’ve used a similar looking format to POVRay’s scene files.

Below is an example of one of my scene files showing a simple scene with a single sphere and plane with a single light :
#Scene Test
 
light
{
     position <-1.5, 3, -4.5>
}
 
sphere
{
     radius 1
     position <-2,1,0>
}
material
{
     diffuse <1,0,0,0.25>
     specular <1,1,1,25> 
}
 
plane
{
     normal <0,1,0>
}
material
{
     diffuse <0.5,1,0.5,0.5>
     specular <1,1,1,99> 
}
More complex operations such as blending can be represented in the scene file as follows:
blend
{
    threshold 1
    sphere
    {
        radius 1
        position <-2,1,0> 
    }    
    torus
    {
        radius <1, 0.44>
        position <2,1,0> 
    }
}
 
Due to the recursive nature in which I have implemented the parsing, it also allows me to nest blending operations like the following series of blended spheres, resulting in a single complex surface:
 
blend
{
     threshold 1
     blend
     {
          threshold 1
          blend
          {
               threshold 1
               sphere
               {
                    radius 1
                    position <-2,1,0>
               }
               sphere
               {
                    radius 1
                    position <2,1,0>
               }
          }
          sphere
          {
               radius 1
               position <0,2,0>
          }
     }
     sphere
     {
          radius 1
          position <0,1,-2>
     }
}
material
{
     diffuse <1,0,1,0.25>
     specular <1,1,1,25> 
}
For more complex scene featuring blending, twisting and domain repetition, an example scene file looks like this:
#Scene Test
 
light
{
     position <-1.5, 3, -4.5>
}
 
repeatBegin
{
     frequency <8.1,0,8.1>
}
 
twistY
{
     magnitude 0.04
     box
     {
          dimensions <1,4,1>
          position <0,3,0>
     }
}
material
{
     diffuse <1,0.5,0,0.1>
     specular <1,1,1,5> 
}
 
sphere
{
     radius 2
     position <0,9,0>
}
material
{
     diffuse <0,0.5,1,0.5>
     specular <1,1,1,30> 
}
 
repeatEnd
 
plane
{
     normal <0,1,0>
}
material
{
     diffuse <0.2,0.2,0.2,0.5>
     specular <1,1,1,99> 
}
Currently my scene files support spheres, cubes, tori and also a ‘Blob’ shape which takes any number of component spheres as parameters and blends them together. It also supports custom blending of the above shapes, domain twisting and repetition operations. Materials can be specified with both diffuse and specular components, with the 4th diffuse tuple representing reflectivity, and the 4th specular tuple representing shininess.

 

As the project develops, I’ll need to implement a way of creating custom distance functions that aren’t just template primitive shapes, but defined more generally to allow users to create surfaces using anchor points This will likely be a main focus for my masters dissertation if I take this topic.