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C-JR — New simple path-tracer for Fragmentarium
#globalillumination #godrays #iq #montecarlo #renderer #shader #fragmentarium #pathtracer #volumetriclighting
Published: 2017-09-14 13:29:30 +0000 UTC; Views: 2508; Favourites: 75; Downloads: 59
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Created by Inigo Quilez - iq/2016 www.shadertoy.com/view/Xtt3WnLicense Creative Commons Attribution-NonCommercial-ShareAlike 3.0
More info here
My adaptation of this shader for Fragmentarium. This renderer is very simple, contains 2 lights - ambient and direct. So very important to have some space for light into scene.
Main feature - volumetric light as known as "God Rays"
Have fun!
upd.: added floor with rotate, materials for every object, separate colors for background and ambience, better de and shadows.
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Comments: 24
Thank you for sharing here too! 
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Do you need separation between background color and color of ambient light?
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Yes, if it can be done...... But only if it's not too much work!
Sometimes, especially with reflective surface it is much nicer to have different colours...
And I must say I am very much impressed with your work on this path tracer, Sergej! I have tried many times to combine features into something altered, but all I end up is 'a forest' of errors leading to 3 new errors once I get 1 fixed!
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I was inspired by IQ, especially his works with fractals and renderers and all works on shadertoy.com, it turns out that it is very easy - create shaders )) I searched "godrays", "voluetric light", "global illumination", "monte carlo", ... ... So there are too much examples. So than i found his youtube playlist and was surprised how easy he explain so difficuls things ) here www.youtube.com/watch?v=0ifChJ… and here too www.youtube.com/watch?v=emjuqq…
Colors... ok, maybe something else?
oh, and this, this too www.youtube.com/watch?v=aNR4n0… just watched now )
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I think I really need a "how-to" to get shadertoy code into Fragm! Somehow I am doing it very wrong! I will search FF for more info on that. IQ does great stuff. Thank you very much for the links, I have just subscribed to his youtube-channel 
Ohh, what to wish for... 3D posilight like in de-kn2cr11?
Ambilight? 
And InFocusWidth?
A rotatable Floor (with color?)
And (correct me if I am wrong) HitDistance works like Detail?
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This code was given to me by Eiffie when I answer - "is that possible to port shader from shadertiy to Frag?":
- #vertex
void main(void){gl_Position = gl_Vertex;}
#endvertex
uniform vec2 pixelSize;
uniform float time;
uniform int subframe;
#define iResolution vec3(vec2(1.0)/pixelSize,1.0)
#define iGlobalTime time
#define iFrame subframe
#define iMouse vec4(0)
void mainImage(out vec4 fragColor, in vec2 fragCoord);
void main() {
mainImage(gl_FragColor,gl_FragCoord.xy);
}
Name this ShaderToy.inc and use it like any include file...
#include "ShaderToy.inc"
//copy the text from any ShaderToy Image Tab (here is the default "new" shader)
void mainImage( out vec4 fragColor, in vec2 fragCoord )
{
vec2 uv = fragCoord.xy / iResolution.xy;
fragColor = vec4(uv,0.5+0.5*sin(iGlobalTime),1.0);
}
so if you want add scene from shadertoy, replace mainImage to yours. And there will be no camera, no fov, no moove. Need add at least Progressive2D.frag, but 3D.frag better, so this is very long work...
About 3D poslight... here I found a lot of bugs when use lighting sphere. So i'll try on this shader, maybe it will better.
Floor - done, other material for floor - in progress, for now I get 2 different colors - for fractal and for floor.
Ambilight - just from background. No background - no ambilight I can make different colors background/ambilight. Maybe can fix, no promise.
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Yes I saw that post back then about the emissive lights!
But it is not what I meant with 3D-light, luckily
I have looked at he floor colour, but it is so "woven" into the whole structure of the other raytracers, that I had no idea how to untangle it! Have the rest of the floor (3-axis plus height) working well, but better to be fitted into the path tracer itself than add every time manually
"No promise"...
Thank you also for the Shadertoy-code! I will test this weekend, see if I can get it to work too
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I don't know nothing about using ctrl-middle mouse button, I always use sliders ) Emissive light in Path = 3D light in DE
Two coordinates enough for light in the sky and place it in evey point of the inner side of the sphere. Here transformation from 2 coords to 3:
- vec3 sunDir = vec3(sin(SpotLightDir.x*PI)*cos(SpotLightDir.y*PI/2.0), sin(SpotLightDir.y*PI/2.0)*sin(SpotLightDir.x*PI), cos(SpotLightDir.x*PI));
For real 3D source of light needs a lot of changes, so finally it will be looks like emissive light in GI renderer.
About floor... It just another object on scene. In DE raytracers just see DEF function (open DE-Raytracer.frag for example, in notepad++ and choose C++ syntax - everything is immediately visible)
1) We call DE
float DE(vec3 pos) ; // Must be implemented in other file
2) get normal for this DE
vec3 normal(vec3 pos, float normalDistance)
3) Then get normal for floor
vec3 floorNormal = normalize(FloorNormal);
4) Combine DE and floor onto one
float DEF(vec3 p)
... ... ...
and then in trace function see
dist = DEF(p); - here we "call" DE and floor both
and theeeeen
So, in PathTracers by Eiffie he used more simple and convenient way. He created map with objects and special normal function with calling every id od object. So now no need to create again and again new normal finction for every new odject ) So you can add objects as many as you like. And every object will has own material (not only color).
p.s. I updated newIQPath here and on fractalforums too.
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For the floor I had used this (stolen from DE-Kn2cr11, very close to what you do)
#group Floor
uniform bool EnableFloor; checkbox[false]
uniform vec3 FloorNormal; slider[(-1,-1,-1),(0,0,1),(1,1,1)]
uniform float FloorHeight; slider[-15,0,15]
//uniform vec3 FloorColor; color[1,1,1]
bool floorHit = false;
float floorDist = 0.0;
vec3 floorNormal = normalize(FloorNormal);
float fSteps = 0.0;
.
rest of program here with old DE renamed to DE1
.
float DE(vec3 p) {
float d = DE1(p) ;
if (EnableFloor) {
floorDist = abs(dot(floorNormal,p)-FloorHeight);
if (d
return d;
} else return floorDist;
} else {
fSteps++;
return d;
}
}
Works well, but you already saw the flaw of this: much better to have a general normalisation for every shape!
With the '3D-light' like I meant
Hopefully this weekend I will have some real time to play with fragm and your goodies!
Quick update Congratulations on the floor, Sergej, it is fantastic to be able to adjust floor reflections as well!
One 'stupid' question: when saying normalisation, in very simple terms: that is controlling the behaviour of how a light-ray hits the surface of a structure at right angles?
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You can rename, but nothing will change, you need call DE in trace function and DE1 in fractal.
You can add floor2, floor3 or other object. I tried add terrain, so with great Knighty help, we have terrain in DE So it could be any another fractal.
I know what mean 3D light source
Normals need for lights/shadows, texturing... Yes, right angles Oh found picture )) so tnorm is our normal vector )
cse.csusb.edu/tongyu/courses/c…
I used calculating normal for divide textures here. The flat plane - grass, steep slope - stones.
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Oh that tnorm-image is perfect for understanding! Thank you! So easy once you know it :} But that is often so
Hm, maybe Knighty or Eiffie one day can look at the emissive light Like you say, as it is in the thread you posted it is not really very good yet...
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