On Thursday 22 November 2012 Nov, Andrew Hunter wrote:

> Hey Boudewijn,

>

> Sounds like the exposure function affecting the alpha channel. Alpha is

> usually normalized to 0 - 1, so it would make sense if positive exposure

> adjustments are clamped.

Yes -- that's what I figured. Unfortunately, I don't know why -- or rather, I don't know why that doesn't happen with the ocio display demo app. The code in Krita is pretty much the same, down to the same generated LUT -- and the shader calls the OCIODisplay method to calculate the color:

const char * m_fragShaderText = ""

"\n"

"uniform sampler2D tex1;\n"

"uniform sampler3D tex2;\n"

"\n"

"void main()\n"

"{\n"

" vec4 col = texture2D(tex1, gl_TexCoord[0].st);\n"

" gl_FragColor = OCIODisplay(col, tex2);\n"

"}\n"

I must be missing something else.

--

Boudewijn Rempt

http://www.valdyas.org, http://www.krita.org, http://www.boudewijnrempt.nl