DX11: Pixel Shader not outputting to Render Target anything when domain shader is used?

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6 comments, last by Jason Z 9 years, 10 months ago

Hey all, I've been studying up on DX11 and various graphical things using the rastertek tutorials:

http://www.rastertek.com/tutdx11.html

They've been great in helping me understand the carious parts of DX11, and I wanted to try and combine the Tesselation tutorial with the Deferred Rendering tutorial by just having the output of the Pixel Shader output to SV_Target0, SV_Target1, etc.

However, whenever I modify the code to output the the render target, I get absolutely NOTHING being sent to the target..not even the clear buffer fill color. However, if I change the Pixel Shader output from the custom PixelOutputType { float4 color : SV_Target0; } to just a float4, and render the scene straight to the default buffer (screen), everything shows up just fine.

Also, if i just comment out the HSSetShader() and DSSetShader() code, at the VERY LEAST get the fill color outputting. Is there something that I'm missing that tells the hull and domain shaders to output to the pixel shader??

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slight update, if i enable the shaders and then push NO data through, i do get the buffers filled with at least the clear fill color. So, the MOMENT i try and render data the entire buffer seems to get "wiped out..."

More to the point: What relationship does the Hull / Domain shader have with the pixel shader? Why would setting a render target from the pixel shader suddenly cause the data not to be outputted? Not even the clear color??

are you able to debug shaders? perhaps you have an unlit object that is blocking the camera's view entirely? this would show up as a black screen. are you using the debug runtime?

One thing to watch out for when using tessellation is that your vertex shader should no longer output to SV_Position. If you do this, bad things will happen. Try changing the vertex shader to output to a custom semantic, and then have your domain shader output to SV_Position.

@Burnt_Fyr

Sadly, I have to use VS2010, but the latest "windows 8 Directx SDK"...the one with DirectXMath and forces you to use DirectXTex and stuff. I don't know of any convenient debuggers for this in my situation, but if you have a suggestion i'm happy to try.

As for an unlit object blocking the camera, Here's what I've tried:

I called the function that renders the really simple scene (2 objects) WITHOUT setting the OMSetRenderTargets to the deferred buffers. So, I basically called the function straight to back buffer as if it were not deferred (by setting the OMSetRenderTargets to the pre-generated back-buffer target view). The back-buffer set is wrapped in a StartScene() call, and the swapChain Present call at the end is wrapped in EndScene();

So, if the function rendering the models to the buffer and calling the "deferred shader" is DrawScene(), then the actual ordering for straight to back buffer rendering is:

StartScene();

DrawScene();

EndScene();

This works just fine without me having to edit my shader at all. The SV_Target0 just get set to the back buffer, and for debug purposes I've deleted the other render targets from the Pixel shader output (commented out).

However, following the SAME principle for setting my deferred targets, causes NOTHING to show up...not even the fill color is sent thru.

in this case, my StartScene() is replaced by a SetRenderTargets() type function which sets the texture buffers using OMSetRenderTargets. At the end, we swtich back to the back-buffer with a SetBackBufferRenderTarget() call. thus:

SetRenderTargets();

DrawScene();

SetBackBufferRenderTarget();

somehwere later int the render call, I do the StartScene() call, but this time I am just drawing the first render target as a texture to an orthographic projected quad that takes up the screen:

StartScene();

DrawFirstTexture();

EndScene();

again, this DrawFirstTexture() is just for debugging...I want to make sure data is being outputted to the textures.

When i do THIS, nothing gets rendered to the texture. However, if i do the same method but comment out the model-rendering lines, at the very least the fill color (set to white) gets filled into the 1st texture, and shows up on screen.

@MJP

I double checked that, and even went as far as to change all non-pixel shader input semantics with POSITION in them to a custom one, like LOCATION. This still didn't work.

Here's my shader code with the larger function's body's removed:


//deferred.hlsl
//renders to multiple targets
cbuffer MatrixBuffer
{
	matrix worldMatrix;
	matrix viewMatrix;
	matrix projectionMatrix;
};

cbuffer TessellationBuffer
{
	float tessellationAmount;
	float3 padding;
};

//typedefs

struct VertexInputType
{
	float3 position : LOCATION;
	float4 color : COLOR;
	float2 tex : TEXCOORD0;
	float3 normal : NORMAL;
};

struct HullInputType
{
	float3 position : LOCATION;
	float4 color : COLOR;
	float2 tex : TEXCOORD0;
	float3 normal : NORMAL;
};

struct ConstantOutputType
{
	float edges[3] : SV_TessFactor;
	float inside : SV_InsideTessFactor;
};

struct HullOutputType
{
	float3 position : LOCATION;
	float4 color : COLOR;
	float2 tex : TEXCOORD0;
	float3 normal : NORMAL;
	
};

struct PixelInputType
{
	float4 position : SV_POSITION;
	float4 color: COLOR;
	float2 tex : TEXCOORD0;
	float3 normal : NORMAL;
};

struct PixelOutputType
{
	float4 color : SV_Target0;
	
};

Texture2D tex : register(t0);
Texture2D displacementMap : register(t1);


SamplerState SamplerType : register(s0);
SamplerState DisplacementSampler : register(s1);

//VertexShader

HullInputType DeferredVertexShader(VertexInputType input)
{
	HullInputType output;
	
	output.position = input.position;
	output.color = input.color;
	output.tex = input.tex;
	output.normal = input.normal;
	return output;
}


ConstantOutputType DeferredPatchConstantFunction(InputPatch<HullInputType, 3> inputPatch, uint patchId : SV_PrimitiveID)
{
	ConstantOutputType output;
	//...does some constant hull (patch) shader stuff
	return output;
}

//Hull Shader
[domain("tri")]
[partitioning("integer")]
[outputtopology("triangle_cw")]
[outputcontrolpoints(3)]
[patchconstantfunc("DeferredPatchConstantFunction")]

HullOutputType DeferredHullShader(InputPatch<HullInputType, 3> patch, uint pointId: SV_OutputControlPointID, uint patchId : SV_PrimitiveID)
{
	HullOutputType output;

	//...more hull (point) shader stuff
	return output;
}

//Domain Shader
[domain("tri")]
PixelInputType DeferredDomainShader(ConstantOutputType input, float3 uvwCoord: SV_DomainLocation, const OutputPatch<HullOutputType, 3> patch)
{
	float3 vertexPosition;
	PixelInputType output;
	//does the new pixel location calculation, as well as multiplying against the view / proj / world matricies and setting it to the output struct

	return output;
}

//Pixel Shader
PixelOutputType DeferredPixelShader(PixelInputType input) 
{
	PixelOutputType output;
	float4 color;
	color = input.color;
	color = tex.Sample(SamplerType, input.tex);
	color.w = 1.0f;	//this is just to force the alpha value, for testing
	
	output.color = color;
	return output;
}

Thanks for your help so far guys, I'm really stumped....

wow...finally solved the issue.

I'm such a fool....here's what went wrong, and its pretty freaking obvious...

When switching shaders from the deferred shader to the regular texture shader that outputs to the "screen," I call the PS and VS set shader functions...but i wasn't clearing out the HS and DS shaders...in essence they were still in place while only the PS and VS shaders had changed....wow....

Thanks as always guys for your help. just chalk it up as one of the many learning experiences out there....

Thanks for sharing the solution - it often happens that people solve the issue and don't post it, but since you did then someone else might find this post as an answer to their question! So you get rated up for coming back and finishing it off :)

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