Sampling a Fusion shader

spedler

I'm writing a ShaderData plugin and what I want to do is sample a Fusion shader created programatically in the InitRender() function of my plugin.

I'm not even sure if this is feasible, but it doesn't work as expected. Here is the code to create the Fusion shader:

m_fusion = BaseShader::Alloc(Xfusion);
GeData gd;
if (m_fusion != nullptr)
{
	m_fusionBlendShader = BaseShader::Alloc(Xcolor);
	if (m_fusionBlendShader != nullptr)
	{
		m_fusionBlendShader->InitRender(irs);
		gd.SetBaseList2D(m_fusionBlendShader);
		const DescID blendID = ConstDescID(DescLevel(SLA_FUSION_BLEND_CHANNEL, DTYPE_BASELISTLINK, 0));
		m_fusion->SetParameter(blendID, gd, DESCFLAGS_SET::NONE);
	}
	m_fusionBaseShader = BaseShader::Alloc(Xcolor);
	if (m_fusionBaseShader != nullptr)
	{
		m_fusionBaseShader->InitRender(irs);
		gd.SetBaseList2D(m_fusionBaseShader);
		const DescID baseID = ConstDescID(DescLevel(SLA_FUSION_BASE_CHANNEL, DTYPE_BASELISTLINK, 0));
		m_fusion->SetParameter(baseID, gd, DESCFLAGS_SET::NONE);
	}
	m_fusion->InitRender(irs);
	m_fusionInitCount++;
}

I've just used color shaders in the Fusion blend and base channels for convenience; this should cause the Fusion to return pure white.

Everything seems to work as expected, in that it compiles and runs and the shaders are all allocated, but when I sample the Fusion shader in my shader's Output function, it always returns black. I'm not sure if this is because I haven't set the blend and base channels correctly or if this simply can't work, so any advice would be greatly appreciated.

Many thanks,
Steve

ferdinand

Hey @spedler,

Thank you for reaching out to us. At a glance, the issue seems to be that you do not insert the shaders into the fusion shader. You might want to have a look at Base Shader Manual: Access and Structure which I once added for the very case of you are currently in: Shaders which own shaders.

In case that this does not solve your issue, I would have to ask for a bit more complete code example, so that we can more easily run your code.

Cheers,
Ferdinand

spedler

Hi @ferdinand,

Thanks for this, inserting the colour shaders uner the Fusion shader and then inserting the Fusion shader under my shader works fine.

I must admit this is my fault. Because the shaders are all created in the InitRender() of my plugin, I didn't think they needed to be (or could be) inserted under my shader. I figured it would be different if the shaders were going to be added to a link field and stay in the document, but not if they're just created then destroyed when done with. So that's very useful to know.

Thanks again,
Steve