Temaran/UnrealEngineShaderPluginDemo

FTexture2DRHIRef texture and vertex shader

Closed this issue · 10 comments

andakkino commented

Hello, I need a little help about two points.

I'm testing the plugin and I want to create a FTexture2DRHIRef texture to give as input directly to the pixel shader, How Can I do it? I did:

FRHIResourceCreateInfo CreateInfo;
InputTexture = RHICreateTexture2D(960, 540, PF_R32_UINT, 1, 1, TexCreate_ShaderResource | TexCreate_UAV, CreateInfo);

but then how can I fill the data? for example how to obtain a black texture?

Second question is, in the PixelShaderExample I found out the MainVertexShader function.
How can I use it? because if for example I set
OutPosition = InPosition*3;

nothing change! instead I was expecting to see cubes in the example enlarge three time themselves. So how I can use properly the vertex shader?

I’m sorry for the newby question,
I’m very grateful for your help,

Temaran commented
andakkino commented

Thank you for the (unexpected) quick reply!
OK, regarding the FRHI command I found this:
https://docs.unrealengine.com/latest/INT/API/Runtime/RHI/FRHICommandList/index.html

I will look to the functions listed here.
Can you suggest a more verbose documentation or simple related tutorial?

Regarding DirectX/OpenGL. I know a little of OpenGL. In fact, I wrote some (working) shaders in OpenGL but now I have the task to implement the same here in UE4 (and so googling and searching I found your plugin!). UE4 is so big that I'm confused!

So, I will try the functions as soon as possible and I will let you know (and I will write a reply here hoping to be help for someone in future). Unfortunately I can't access the working station now so I think I will try in the next days.

For what regards the second question, the render target one, I will read something about that. Just to be sure we have the same vocabulary, with "render target" are we speaking about "buffers" like in OpenGL?

Again thank you, I will write results and/or new doubts when I will read something more about the topic or tried solutions. Sorry for my bad English I'm not a native speaker.

Temaran commented
andakkino commented

Hello again, Sorry if I bore you, If I do this please tell me and I will write these question on the ue4 general forum.

So I tried to use the ClearColorTexture() function but in order to use it I need a RHICmdList, Which I create in the line above.

	//MY STUFF
	FRHIResourceCreateInfo CreateInfo;
	FLinearColor my_color = FLinearColor(1, 1, 0, 1);
	InputTexture = RHICreateTexture2D(960, 540, PF_R32_UINT, 1, 1, TexCreate_ShaderResource | TexCreate_UAV, CreateInfo);
	/* Get global RHI command list */
	FRHICommandListImmediate& myRHICmdList = GRHICommandList.GetImmediateCommandList();
	myRHICmdList.ClearColorTexture(InputTexture, my_color, FIntRect());
	//end my stuff

If I try to do something like this (this code is placed between the execution of the compute shader and the pixel shader).. ue4 crashes.

If I try to access single pixel like in this example_https://answers.unrealengine.com/questions/25594/accessing-pixel-values-of-texture2d.html

	//my stuff due
	FColor my_FColor = FColor(1, 0, 0, 1);
	FTexture2DMipMap* MyMipMap = &InputTexture->GetTexture2D()->PlatformData->Mips[0];
	FByteBulkData* RawImageData = &MyMipMap->BulkData;
	FColor* FormatedImageData = static_cast<FColor*>(RawImageData->Lock(LOCK_READ_ONLY));
	
	uint32 TextureWidth = MyMipMap->SizeX, TextureHeight = MyMipMap->SizeY;
	FColor PixelColor;
	for (int i = 0; i < TextureWidth*TextureHeight; i++) {
		FormatedImageData[i] = my_FColor;
	}
	
	/*
	uint8 PixelX = 5, PixelY = 10;
	if (PixelX >= 0 && PixelX < TextureWidth && PixelY >= 0 && PixelY < TextureHeight)
	{
		PixelColor = FormatedImageData[PixelY * TextureWidth + PixelX];
	}*/
	RawImageData->Unlock();
	InputTexture->GetTexture2D()->PlatformData->Mips[0].BulkData.Unlock();
	//end my stuff due

The compiler tells me that FRHITexture2D does not contain any member callded “Platform Data”.

Now I will study the target buffer to solve the vertex shader issue. thanks you.

andakkino commented

maybe should I execute that code in Render thread?
I see also from your example that I should use
ENQUEUE_UNIQUE_RENDER_COMMAND_ONEPARAMETER macro.
but I dont understand the params I should pass to this macro for apply these operation.

andakkino commented

Ok, maybe I'm near,

I use this code

	//MY STUFF
		ENQUEUE_UNIQUE_RENDER_COMMAND_ONEPARAMETER(void, FTexture2DRHIRef, InputTexture, InputTexture ,
			{	
				FRHIResourceCreateInfo CreateInfo;
				InputTexture = RHICreateTexture2D(960, 540, PF_R32_UINT, 1, 1, TexCreate_ShaderResource | TexCreate_UAV, CreateInfo);
				// Write the contents of the texture.
				uint32 DestStride;
				uint32* DestBuffer = (uint32*)RHILockTexture2D(InputTexture, 0, RLM_WriteOnly, DestStride, false);
				int BufferSize = 960 * 540 * 4;
				uint8 * SourceBuffer = new uint8[BufferSize];
				for (int i = 0; i < BufferSize; i++) {
					SourceBuffer[i] = 20;
				}
				FMemory::Memcpy(DestBuffer, SourceBuffer, BufferSize);
				RHIUnlockTexture2D(InputTexture, 0, false);
			}
		);

I'm not sure about the macro parameter.
after this code I exectute

       PixelShading->ExecutePixelShader(RenderTarget, InputTexture,
                                         FColor(EndColorBuildup * 255, 0, 0, 255), ComputeShaderBlend);

My Pixel shader is


void MainPixelShader(
	in float2 uv : TEXCOORD0,
	out float4 OutColor : SV_Target0
	)
{
	//First we need to unpack the uint material and retrieve the underlying R8G8B8A8_UINT values.
	float sizeX, sizeY;
	TextureParameter.GetDimensions(sizeX, sizeY);
	uint packedValue = TextureParameter.Load(int3(sizeX * uv.x, sizeY * uv.y, 0));
	uint r = (packedValue & 0x000000FF);
	uint g = (packedValue & 0x0000FF00) >> 8;
	uint b = (packedValue & 0x00FF0000) >> 16;
	uint a = (packedValue & 0xFF000000) >> 24;
	
    OutColor =  float4(r,g,b,a) ;
	}

So I'm sampling from the texture I wrote right?
unfortunatly is not working because I can see only black cubes whatever values I put inside texture elements...

Temaran commented
andakkino commented

Well,
Onestly I'm quite disoriented,
I'm creating the texture like I wrote above. So I have this 960*540 resolution texture where each textel is 4 bytes.

I tried to sample in this way in the hlsl shader
OutColor = TextureParameter.Sample(mySampler, float2(sizeX * uv.x, sizeY * uv.y));
having the foresight to change the input from
Texture2D <uint> TextureParameter;
to
Texture2D TextureParameter;

unfortunatly I still see black cubes.

I've asket another method to write into the texture, I received help in the forum, here is my code now, as you can see after I modify the texture I call the pixel shader.

 //MY STUFF
			 //Create Texture
			ENQUEUE_UNIQUE_RENDER_COMMAND_ONEPARAMETER(FCreateActorsTexure,
				FTexture2DRHIRef, TexurePtr, InputTexture,
				{
					FRHIResourceCreateInfo CreateInfo;
					TexurePtr = RHICreateTexture2D(960, 540, PF_R32_UINT, 1, 1, TexCreate_ShaderResource | TexCreate_UAV, CreateInfo);
					//FRHICommandListImmediate& RHICmdList = GRHICommandList.GetImmediateCommandList();
					//RHICmdList.ClearColorTexture(TexurePtr, FLinearColor::Red, FIntRect());
				}
			);

			//Update Texture
			uint32 BufferSize = 960 * 540 * 4;
			uint8 * SourceBuffer = new uint8[BufferSize];

			for (uint32 i = 0; i < BufferSize; i++)
			{
				SourceBuffer[i] = 20;
			}

			ENQUEUE_UNIQUE_RENDER_COMMAND_THREEPARAMETER(FUpdateActorsTexure,
				FTexture2DRHIRef, TexurePtr, InputTexture,
				uint8*, NewData, SourceBuffer,
				uint32, Size, BufferSize,
				{
					uint32 DestStride;
					uint32* DestBuffer = (uint32*)RHILockTexture2D(TexurePtr, 0, RLM_WriteOnly, DestStride, false);
					FMemory::Memcpy(DestBuffer, NewData, Size);
					RHIUnlockTexture2D(TexurePtr, 0, false);
					delete[] NewData;
				}
			);

			PixelShading->ExecutePixelShader(RenderTarget, InputTexture, FColor(EndColorBuildup * 255, 0, 0, 255), ComputeShaderBlend);
Temaran commented
andakkino commented

Hello,
As promised I'll put something working hoping that can be usefull to someone. the code is not clean. This Is the original one in the Demo + some lines that load a custom texture to the pixel shader.

 FTexture2DRHIRef InputTexture = NULL;

		if (ComputeShading) {
			ComputeShading->ExecuteComputeShader(TotalElapsedTime);
			InputTexture =
				ComputeShading->GetTexture(); //This is the output texture from the compute shader that we will pass to the pixel shader.
		}

		ENQUEUE_UNIQUE_RENDER_COMMAND_ONEPARAMETER(FCreateActorsTexure,
		FTexture2DRHIRef, TexurePtr, InputTexture,
			{
				FRHIResourceCreateInfo CreateInfo;
		TexurePtr = RHICreateTexture2D(960, 540, PF_R8G8B8A8, 1, 1, TexCreate_ShaderResource | TexCreate_UAV, CreateInfo);
			}
		);

		//Update Texture
		uint32 BufferSize = 960 * 540 * 4;
		uint8 * SourceBuffer = new uint8[BufferSize];
		uint8 myrand = (FMath::RandRange(0, 255));
		for (uint32 i = 0; i < BufferSize; i=i+4)
		{
		SourceBuffer[i] = 0;
		SourceBuffer[i+1] = 255;
		SourceBuffer[i+2] = 0;
		SourceBuffer[i+3] = 255;
		}

		ENQUEUE_UNIQUE_RENDER_COMMAND_THREEPARAMETER(FUpdateActorsTexure,
		FTexture2DRHIRef, TexurePtr, InputTexture,
		uint8*, NewData, SourceBuffer,
		uint32, Size, BufferSize,
		{
		uint32 DestStride;
		uint8* DestBuffer = (uint8*)RHILockTexture2D(TexurePtr, 0, RLM_WriteOnly, DestStride, false);
		FMemory::Memcpy(DestBuffer, NewData, Size);
		RHIUnlockTexture2D(TexurePtr, 0, false);
		delete[] NewData;
		}
		);




        ComputeShaderBlend = FMath::Clamp(ComputeShaderBlend +
                                          ComputeShaderBlendScalar * DeltaSeconds, 0.0f, 1.0f);
        PixelShading->ExecutePixelShader(RenderTarget, InputTexture,
                                         FColor(EndColorBuildup * 255, 0, 0, 255), ComputeShaderBlend);
    }

for example above I create a green texture (0, 255, 0,255)

here the modified pixel shader

Texture2D <uint> TextureParameter;

SamplerState mySampler
{
    Filter = MIN_MAG_MIP_LINEAR;
    AddressU = Wrap;
    AddressV = Wrap;
};

void MainPixelShader(
	in float2 uv : TEXCOORD0,
	out float4 OutColor : SV_Target0
	)
{
	//First we need to unpack the uint material and retrieve the underlying R8G8B8A8_UINT values.
	float sizeX, sizeY;
	TextureParameter.GetDimensions(sizeX, sizeY);
	uint packedValue = TextureParameter.Load(int3(uv.x,uv.y, 0));
	uint r = (packedValue & 0x000000FF);
	uint g = (packedValue & 0x0000FF00) >> 8;
	uint b = (packedValue & 0x00FF0000) >> 16;
	uint a = (packedValue & 0xFF000000) >> 24;
    
    //sampling
   // OutColor = TextureParameter.Sample(mySampler, float2(sizeX * uv.x, sizeY * uv.y));

    
	OutColor = float4(r,g,b,a); 
    //OutColor = float4(255,255,0,255);	 //yellow
}

thanks for the help temaran.

I have a lot of doubts,
why if I execute

		ENQUEUE_UNIQUE_RENDER_COMMAND_ONEPARAMETER(FCreateActorsTexure,
		FTexture2DRHIRef, TexurePtr, InputTexture,
			{
				FRHIResourceCreateInfo CreateInfo;
		TexurePtr = RHICreateTexture2D(960, 540, PF_R8G8B8A8, 1, 1, TexCreate_ShaderResource | TexCreate_UAV, CreateInfo);
			}
		);

whitout before executing this:

		if (ComputeShading) {
			ComputeShading->ExecuteComputeShader(TotalElapsedTime);
			InputTexture =
				ComputeShading->GetTexture(); //This is the output texture from the compute shader that we will pass to the pixel shader.
		}

It crashes?

Then, How to bind new parameters to the shaders?