Indigo Renderer Forum

Posted: **Tue Jan 05, 2010 12:58 pm**

I'm working on a shader that blend towo textures with the "burn" equation. The problem is that I need to divide two vec3's and Indigo doesn't have that feature.¿Someone can help me?
I = Top Layer
M =Back Layer

Posted: **Tue Jan 05, 2010 1:28 pm**

Hey, I really want to help you, but I'm not sure how the division should work.

Read this: http://www.mcasco.com/qa_vdq.html

In vectors there are two ways of multiplying, the dot product and the cross product.

[...]

dot division is not defined.

[...]

cross division is also undefined.

Posted: **Tue Jan 05, 2010 1:53 pm**

I mean tex1 (r1,g1,b1)/ tex2 (r2,g2,b2) = result (r1/r2,g1/g2,b1/b2)

Posted: **Tue Jan 05, 2010 2:06 pm**

okay, here we go:

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def div(vec3 a, vec3 b) vec3: vec3(doti(a) / doti(b), dotj(a) / dotj(b), dotk(a) / dotk(b))

another question of understanding: are the components assumed to be in the range of 0-255 for this function?

Posted: **Tue Jan 05, 2010 2:28 pm**

Yes, but it can be easily converted from 0-255 to 0-1. I'm testing...

Posted: **Wed Jan 06, 2010 3:05 am**

Thanks Fused, it works!
Now I'm doing overlay, screen, etc
edit:: I think blending modes can be bundled into exporters.

Posted: **Wed Jan 06, 2010 5:15 am**

chubakueno wrote:Thanks Fused, it works!
Now I'm doing overlay, screen, etc
edit:: I think blending modes can be bundled into exporters.

Nice work chubaka,

I'm sure if you release your code you could speed up the Exporter integration

Posted: **Wed Jan 06, 2010 1:35 pm**

ZomB wrote:
chubakueno wrote:Thanks Fused, it works!
Now I'm doing overlay, screen, etc
edit:: I think blending modes can be bundled into exporters.
Nice work chubaka,

I'm sure if you release your code you could speed up the Exporter integration

Oh yes!
If you post all your shader when youre done it will make its way into the ISL blend shader in cindigo

Posted: **Thu Jan 07, 2010 3:20 pm**

Overlay:

: isl_camo_overlay.jpg (96.6 KiB) Viewed 16378 times

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						<![CDATA[
					def overlay(real it1, real jt1, real kt1, real it2, real jt2, real kt2) vec3:
						vec3(div(mul(div(it1,255.0),add(it1,mul(div(mul(2.0,it2),255.0),sub(255.0,it1)))),255.0),
							div(mul(div(jt1,255.0),add(jt1,mul(div(mul(2.0,jt2),255.0),sub(255.0,jt1)))),255.0),
							div(mul(div(kt1,255.0),add(kt1,mul(div(mul(2.0,kt2),255.0),sub(255.0,kt1)))),255.0)
							)
					def eval(vec3 pos) vec3 :
						overlay(
						doti(sample2DTextureVec3(0,getTexCoords(0)))*255.0,
						dotj(sample2DTextureVec3(0,getTexCoords(0)))*255.0,
						dotk(sample2DTextureVec3(0,getTexCoords(0)))*255.0,
						doti(sample2DTextureVec3(1,getTexCoords(0)))*255.0,
						dotj(sample2DTextureVec3(1,getTexCoords(0)))*255.0,
						dotk(sample2DTextureVec3(1,getTexCoords(0)))*255.0
						)
						]]>

Normal:

: isl_camo_normal.jpg (105.78 KiB) Viewed 16378 times

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						<![CDATA[
					def substract(real it1, real jt1, real kt1, real it2, real jt2, real kt2) vec3:
						vec3(div(add(mul(it1,0.5),mul(it2,0.5)),255.0),
							div(add(mul(jt1,0.5),mul(jt2,0.5)),255.0),
							div(add(mul(kt1,0.5),mul(kt2,0.5)),255.0)
							)
					def eval(vec3 pos) vec3 :
						substract(
						doti(sample2DTextureVec3(0,getTexCoords(0)))*255.0,
						dotj(sample2DTextureVec3(0,getTexCoords(0)))*255.0,
						dotk(sample2DTextureVec3(0,getTexCoords(0)))*255.0,
						doti(sample2DTextureVec3(1,getTexCoords(0)))*255.0,
						dotj(sample2DTextureVec3(1,getTexCoords(0)))*255.0,
						dotk(sample2DTextureVec3(1,getTexCoords(0)))*255.0
						)
						]]>

Invert:(only the camouflage)

: isl_camo_inv.jpg (74.98 KiB) Viewed 16377 times

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						<![CDATA[
					def  substract(vec3 col1, vec3 colt) vec3:
						sub(col1,colt)
					def eval(vec3 pos) vec3 :
						substract((vec3(1.0)),
						sample2DTextureVec3(0,getTexCoords(0)))
						]]>

edit:Later I'll post the other blending modes

Posted: **Thu Jan 07, 2010 3:52 pm**

wow, pretty nice, a few nitpicks if you dont mind

in the invert shader, you dont really need a subtract() finction. i fact you dont even have to use the sub() function. just use operators:

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def eval(vec3 pos) vec3 :
                  vec3(1.0) - sample2DTextureVec3(0,getTexCoords(0))

in the other two shaders:

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doti(sample2DTextureVec3(0,getTexCoords(0)))*255.0,
dotj(sample2DTextureVec3(0,getTexCoords(0)))*255.0,
dotk(sample2DTextureVec3(0,getTexCoords(0)))*255.0,

is the same thing as

Code: Select all

sample2DTextureVec3(0,getTexCoords(0)) * 255.0

and then passing that to the overlay/subtract function.

a few other optimizations/simplifications for your normal shader:

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def div(vec3 a, vec3 b) vec3: vec3(doti(a) / doti(b), dotj(a) / dotj(b), dotk(a) / dotk(b))
def substract(vec3 v1, vec3 v2) vec3:
                     div((v1 * 0.5) + (v2 * 0.5), 255.0)
                     )
               def eval(vec3 pos) vec3 :
                  substract(
                  sample2DTextureVec3(0,getTexCoords(0))*255.0,
                  sample2DTextureVec3(1,getTexCoords(0))*255.0
                  )

not tested tho

Posted: **Thu Jan 07, 2010 4:05 pm**

Yes, but you can't divide a vec3 with a real.edit:And thanks for the optimizations.

Posted: **Thu Jan 07, 2010 4:09 pm**

chubakueno wrote:Yes, but you can't divide a vec3 with a real.

easy fix

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div((v1 * 0.5) + (v2 * 0.5), vec3(255.0))

or:

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def div(vec3 a, real b) vec3: vec3(doti(a) / b, dotj(a) / b, dotk(a) / b)

Posted: **Thu Jan 07, 2010 4:48 pm**

In general, you can't divide vec3's, only real vs real

Posted: **Thu Jan 07, 2010 5:22 pm**

sorry but that is what you asked for in the beginning. then I told you its not possible and you said what you meant. Then I wrote a function that does exactly that. And now you tell me its not possible.... hello?

fused wrote:

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def div(vec3 a, real b) vec3: vec3(doti(a) / b, dotj(a) / b, dotk(a) / b)

fused wrote:

Code: Select all

def div(vec3 a, vec3 b) vec3: vec3(doti(a) / doti(b), dotj(a) / dotj(b), dotk(a) / dotk(b))

Posted: **Thu Jan 07, 2010 9:22 pm**

Neeeerd fiiiight!

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