Transparent Render Node

[rohit.gonsalves]

Hello There,

I using following code to render a specific node on my RenderTarget. I need node should be render on transparent target so I can use it for further processing.

Probably renderNode method internally flushing the render target with opaque black first?

But node is rendered on opaque black. How may I achieve the other areas as transparent? May there is way using GBuffers?

	RenderState::saveState();
	RenderState::clearStates();
	RenderState::setBlendFunc(RenderState::BLEND_SRC_ALPHA, RenderState::BLEND_ONE_MINUS_SRC_ALPHA, RenderState::BLEND_OP_ADD);
	RenderState::flushStates();

	m_objTextureRender->bindColorTexture(0, textureOutput);
	m_objTextureRender->enable();

	RenderState::setBufferMask(0, RenderState::BUFFER_ALL);
	//This red never shows up as internally target is flushed with opaque black.
	RenderState::clearBuffer(RenderState::BUFFER_ALL, vec4(1.0f,0.f,0.f,1.0f));	

	m_objTextureRender->flush();

	if (m_objIDNode != nullptr)
	{
		m_objViewport->renderNode(m_objPlayer->getCamera(), m_objIDNode);
		m_objTextureRender->flush();
	}
			
	m_objTextureRender->disable();
	m_objTextureRender->unbindColorTexture(0);

	RenderState::restoreState();

Please suggest.

Rohit

[sweetluna]

Hi,

You can use renderTexture2D to render node to the specified texture w/o needing of creating own render target.
Regarding alpha channel, you can set this flag for your viewport

m_objViewport->setNodeLightUsage(Viewport::USAGE_WORLD_LIGHT);

The only thing to consider this will render environment with 0 alpha sky.

[rohit.gonsalves]

Thanks @sweetluna,

This solved my issue. Prior to this I was trying it with Auxiliary. But Alpha blend things were not working with Auxiliary. This render node by setting skip flags gave me the correct result.

I chose to define render target as BG color is of choice for generating different masks.

Rohit