Multiply two textures via Shader

[delle]

Hi, I'm trying to multiply the colors of two textures via Indigo Shading Language, but I'm not able to find a solution...

What I need to obtain is:

Code: Select all

result.red = Texture0.red * Texture1.red
result.green = Texture0.green * Texture1.green
result.blue= Texture0.blue* Texture1.blue

I can only obtain a mix of the two (50% Texture0+ 50% Texture1) but is not what I want...

Code: Select all

<albedo>
          <shader>
            <shader>
              <![CDATA[
                def eval(vec3 pos) vec3 : lerp(sample2DTextureVec3(0,getTexCoords(0)),sample2DTextureVec3(1,getTexCoords(0)),0.5)
              ]]>
            </shader>
          </shader>
        </albedo>

Please help

Delle

[fused]

have a look at doti() dotj() and dotk().

they give you access to the x,y,z components of a vec3.

[Kram1032]

just before you're doing that: you want things getting darker? 'cause multiplying in the range of 0->1 makes things either smaller (darker) or doesn't change them.
0*0 = 0
1*1 = 1
(the only two cases where things stay the same)
and
0.5*0.5=0.25
etc... ^^

[PureSpider]

0.5*0.5=0.5

Interesting... 1+1=3, right?

[Kram1032]

I'm sure, I hit the 2... probably hanged or so

[delle]

What I have to do is to multiply the color of two textures and/or multiply one solid color by a grayscale texture (such as RedColor * GrayTexure).

So I have to do two tasks:

• OutColor = ColorTexture * ColorTexture
  OutColor = SolidColor * GrayscaleTexture

I know... I can do it offline and then to pass the computed texture to Indigo, but since we have shaders ... why don't use them...

Any suggestion?

Delle

[fused]

What I have to do is to multiply the color of two textures and/or multiply one solid color by a grayscale texture (such as RedColor * GrayTexure).

So I have to do two tasks:

• OutColor = ColorTexture * ColorTexture
  OutColor = SolidColor * GrayscaleTexture

I know... I can do it offline and then to pass the computed texture to Indigo, but since we have shaders ... why don't use them...

Any suggestion?

Delle

try this (multipies each component of color1 with the component of color2):

Code: Select all

<albedo>
          <shader>
            <shader>
              <![CDATA[
                def multiplyColor(vec3 col1, vec3 col2) vec3:
                vec3(
                    mul(doti(col1),doti(col2)),
                    mul(dotj(col1),dotj(col2)),
                    mul(dotk(col1),dotk(col2)))
                
                def eval(vec3 pos) vec3 :
                multiplyColor(sample2DTextureVec3(0,getTexCoords(0)),sample2DTextureVec3(1,getTexCoords(0)))
              ]]>
            </shader>
          </shader>
        </albedo> 

not tested

[delle]

With this Scene (GLEditor.zip) I get this error:

Shader runtime error: No texture with index 0

But the texture "0" is present

I think that this might be an Indigo error...

Indigo: 1.1.15
Exporter: Custom exporter

Delle

[fused]

didnt have a look at your scene, but make sure that your textures are defined before the albedo element.

[fused]

works fine here

[delle]

Hi Fused, I've restricted the problem....

This Material works...

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<material> 
      <name>Material_4</name>
      <diffuse>
        <texture>
          <uv_set>default</uv_set>
          <path>.\GLEditor\ASHWOOD_IMG1_V1.bmp</path>
          <exponent>2.2</exponent>
          <b>1</b>
          <c>0</c>
        </texture>
        <albedo>
          <shader>
            <shader>
              <![CDATA[
                def multiplyColor(vec3 col1, vec3 col2) vec3: vec3(mul(doti(col1),doti(col2)),mul(dotj(col1),dotj(col2)),mul(dotk(col1),dotk(col2)))
                def eval(vec3 pos) vec3 : multiplyColor(sample2DTextureVec3(0,getTexCoords(0)),vec3(0.301961,0.149020,0.000000))
              ]]>
            </shader>
          </shader>
        </albedo>
      </diffuse>
    </material>

This does not work (same texture plus little blending between diffuse and phong sub-materials)

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<material> 
      <name>Material_4_Diffuse</name>
      <diffuse>
        <texture>
          <uv_set>default</uv_set>
          <path>.\GLEditor\ASHWOOD_IMG1_V1.bmp</path>
          <exponent>2.2</exponent>
          <b>1</b>
          <c>0</c>
        </texture>
        <albedo>
          <shader>
            <shader>
              <![CDATA[
                def multiplyColor(vec3 col1, vec3 col2) vec3: vec3(mul(doti(col1),doti(col2)),mul(dotj(col1),dotj(col2)),mul(dotk(col1),dotk(col2)))
                def eval(vec3 pos) vec3 : multiplyColor(sample2DTextureVec3(0,getTexCoords(0)),vec3(0.301961,0.149020,0.000000))
              ]]>
            </shader>
          </shader>
        </albedo>
      </diffuse>
    </material>

    <material> 
      <name>Material_4_Specular</name>
      <phong>
        <texture>
          <uv_set>default</uv_set>
          <path>.\GLEditor\ASHWOOD_IMG1_V1.bmp</path>
          <exponent>2.2</exponent>
          <b>1</b>
          <c>0</c>
        </texture>
        <diffuse_albedo>
          <shader>
            <shader>
              <![CDATA[
                def multiplyColor(vec3 col1, vec3 col2) vec3: vec3(mul(doti(col1),doti(col2)),mul(dotj(col1),dotj(col2)),mul(dotk(col1),dotk(col2)))
                def eval(vec3 pos) vec3 : multiplyColor(sample2DTextureVec3(0,getTexCoords(0)),vec3(0.301961,0.149020,0.000000))
              ]]>
            </shader>
          </shader>
        </diffuse_albedo>
        <ior>1.550000</ior>
        <exponent><constant>70.250000</constant></exponent>
        <fresnel_scale>1.0</fresnel_scale>
      </phong>
    </material>

    <material>
      <name>Material_4</name>
      <blend>
        <a_name>Material_4_Diffuse</a_name>
        <b_name>Material_4_Specular</b_name>
        <blend>
          <constant>0.650000</constant>
        </blend>
      </blend>
    </material>

Can you help me?

Thank you

Delle

[fused]

i cant test it right now, but it seems to be correct.
you are aware that those two shaders are identical and blending the materials will do pretty much nothing? is there an error message?

oh... and throw out the <fresnel_scale> element. it has no effect.

[delle]

Code: Select all

...are aware that those two shaders are identical...

Yes I know, but with the blend, the problem appears...

Delle

[fused]

then, whats the problem?

[delle]

The problem is that I must blend diffuse and phong material...