FTexture2DRHIRef texture and vertex shader about unrealengineshaderplugindemo

[Temaran]

Hello there :) If you want to draw to the texture, you need to set it as the render target. I do this in the demo, although I would strongly reading a book or tutorial on DirectX and/or OpenGL to learn these parts, since it has nothing to do with UE4 :) To simply draw it black, check out the RHICmdList->Clear function; you can fill a texture with any uniform color very quickly this way. The reason I suspect the size didn't change was most likely because you are still drawing it to the render target I supplied. If you had been drawing a model in world space, the model would indeed have been scaled 3 times by your addition, but as it is drawn to a 2D target, that has the same (unscaled) UV coordinates, you will not see any change as the sampling will be the same. Best regards, Temaran 2017-05-23 12:49 GMT+02:00 andakkino <[email protected]>:

…

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, — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#8>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AE025MdfAQzR1NEqwn1JNAiBbHtToJvOks5r8rm1gaJpZM4Njgnh> .

[andakkino]

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]

Hello there :) Not sure about what the best resource for DirectX is right now, I'm sure there are lots to be found though :) As for the second question; kind of, but not quite, render targets are shared terminology between most API's. When issuing a draw call you basically have a few different components: Render target: This is the target buffer that you bind in a very special way. Resources: Can be structured, constant or texture buffers. You bind these to the shader. This binding is done by the shader classes in UE4 (see the XXXShader stuff in my tutorial) Shaders: You bind these to the API before issuing the call (VS/PS/CS etc.). When you issue the draw call, the API will load your resources for the shaders you have bound, then run the shaders which will then write to the render target(s). The best way to start looking into this would be RHICmdList->SetRenderTarget in UE4. /Temaran 2017-05-23 16:21 GMT+02:00 andakkino <[email protected]>:

…

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. — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#8 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AE025AJntjqYsbFzmJP0CTDbG79BsxgXks5r8utUgaJpZM4Njgnh> .

[andakkino]

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]

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]

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]

The enqueue command will indeed schedule the block to execute on the render thread. In that block you will also have access to the RHICmdList. The arguments to the macro are the types and variables you want to send from your call site. You can check my examples or the engine for samples on how to call it :) As for reading a pixel, I'm pretty sure I have some function in the demo somewhere that dumps a texture to a png file, I would look at that code as a starting point (or the screenshot function in the engine code, I think I modelled my code after that function). Also, if you want to sample a texture in the pixel shader, I would recommend using a texture sampler instead of the load function. From the looks of it you're reading a uint type, are you sure that the texture you're using is of a uint format? /Temaran 2017-05-24 12:39 GMT+02:00 andakkino <[email protected]>:

…

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 `Texture2D TextureParameter; 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... — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#8 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AE025DIyAc6BQU7JauIMfRdx9O91bqX7ks5r9Aj4gaJpZM4Njgnh> .

[andakkino]

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]

I think it might be good to first practice DirectX using the DirectX SDK before you tackle it inside a large engine like UE4. That way you will be able to figure out what UE4-stuff isn't working vs. what DX stuff isn't working. When you feel confident in DX-vanilla, I would suggest studying the shaders (USF HLSL code and C++ backend code) in the main engine. Also, if you're not using Visual Assist X yet, I would strongly suggest getting it as it makes navigating and searching the engine for code templates much easier. I wish you much success in your endeavors! Best regards, Temaran 2017-05-24 15:16 GMT+02:00 andakkino <[email protected]>:

…

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 (also when before calling the pixel shader I do something like this) 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()); } ); maybe I still miss something that I don't understand :( — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#8 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AE025FOSDQZ_mU8fpdg9KR9DqCE4KY7Iks5r9C2RgaJpZM4Njgnh> .

[andakkino]

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?