• Announcements

    • khawk

      Download the Game Design and Indie Game Marketing Freebook   07/19/17

      GameDev.net and CRC Press have teamed up to bring a free ebook of content curated from top titles published by CRC Press. The freebook, Practices of Game Design & Indie Game Marketing, includes chapters from The Art of Game Design: A Book of Lenses, A Practical Guide to Indie Game Marketing, and An Architectural Approach to Level Design. The GameDev.net FreeBook is relevant to game designers, developers, and those interested in learning more about the challenges in game development. We know game development can be a tough discipline and business, so we picked several chapters from CRC Press titles that we thought would be of interest to you, the GameDev.net audience, in your journey to design, develop, and market your next game. The free ebook is available through CRC Press by clicking here. The Curated Books The Art of Game Design: A Book of Lenses, Second Edition, by Jesse Schell Presents 100+ sets of questions, or different lenses, for viewing a game’s design, encompassing diverse fields such as psychology, architecture, music, film, software engineering, theme park design, mathematics, anthropology, and more. Written by one of the world's top game designers, this book describes the deepest and most fundamental principles of game design, demonstrating how tactics used in board, card, and athletic games also work in video games. It provides practical instruction on creating world-class games that will be played again and again. View it here. A Practical Guide to Indie Game Marketing, by Joel Dreskin Marketing is an essential but too frequently overlooked or minimized component of the release plan for indie games. A Practical Guide to Indie Game Marketing provides you with the tools needed to build visibility and sell your indie games. With special focus on those developers with small budgets and limited staff and resources, this book is packed with tangible recommendations and techniques that you can put to use immediately. As a seasoned professional of the indie game arena, author Joel Dreskin gives you insight into practical, real-world experiences of marketing numerous successful games and also provides stories of the failures. View it here. An Architectural Approach to Level Design This is one of the first books to integrate architectural and spatial design theory with the field of level design. The book presents architectural techniques and theories for level designers to use in their own work. It connects architecture and level design in different ways that address the practical elements of how designers construct space and the experiential elements of how and why humans interact with this space. Throughout the text, readers learn skills for spatial layout, evoking emotion through gamespaces, and creating better levels through architectural theory. View it here. Learn more and download the ebook by clicking here. Did you know? GameDev.net and CRC Press also recently teamed up to bring GDNet+ Members up to a 20% discount on all CRC Press books. Learn more about this and other benefits here.
Sign in to follow this  
Followers 0
Migi0027

DX11
DX11 - HLSL - Billboarding

6 posts in this topic

Hi guys! happy.png

 

This is my current issue, I'm trying to create 3d billboards, now this is how I think I should do it:

 

(Sample: Render thousands of grass instances)

 

Create Instance Buffer ( -> Position, Rotation)

Send Mesh Stuff + Instance Buffer

 

Shader:

{
  float4x4 rMatrix = generateRotationMatrix(instanceRot);
  position = mul(position, rMatrix);
  position += instancepos;

  ...apply World, View, Proj matrices here.
  ...
}

But is this the best way? Because I don't think passing a constant buffer with thousands of rotation matrices would be so good, am I wrong?

 

What does you're experience tell you to do here?

 

So the real question is: How can I individually rotate thousands of instances to the cameras view?

 

Thank You, like always! wink.png

0

Share this post


Link to post
Share on other sites

You don't rotate billboards. Billboards always face the camera because they are just 2-D sprites. The only matrix you need to store per instance in your instance buffer is the world matrix. This matrix will have the position and scale of the billboards, such that the further it is the smaller it gets.

 

Anyway for instancing models this is what I do:

#define NUM_MAX_INSTANCES 128

struct InstanceBuffer
{
	XMFLOAT4X4 InstanceWorld[NUM_MAX_INSTANCES];
};

Then my shaders (note this is a normal model, not a billboard) look something like this:

PS_INPUT VS( VS_INPUT input, uint iid : SV_InstanceID)
{
    PS_INPUT output = (PS_INPUT)0;
    output.Pos = mul( input.Pos, InstanceWorld[iid] );
    output.Pos = mul( output.Pos, View );
    output.Pos = mul( output.Pos, Projection );
    output.Norm = mul(float4(input.Norm, 0), InstanceWorld[iid] ).xyz;
	output.Tex = input.Tex;
    
    return output;
}
#define NUM_MAX_INSTANCES 128

cbuffer InstanceBuffer : register(b1)
{
	matrix InstanceWorld[NUM_MAX_INSTANCES];
}

Someone else can chime in with the max size of the instance buffer. I just guessed 128 for now.

 

Any time I need to render a batch of instanced models I call UpdateSubresource() with my new instance buffer and then DrawInstanced(). For drawing thousands of models I would probably have multiple DrawInstanced() calls, but I don't know if there is a better way.

1

Share this post


Link to post
Share on other sites

You don't even need to store a matrix in your per-instance buffer (which I'd use a dynamic vertex buffer for, with D3D11_INPUT_PER_INSTANCE_DATA in the corresponding input layout so that you won't run into cbuffer space limits); you can just store a combined MVP in your per-frame cbuffer, then the position of each instance in your per-instance buffer.

 

In your per-frame cbuffer you also store a couple of vectors which you can extract from your view matrix, and that gives you everything you need to do billboarding, at a significantly reduced data cost and much higher ceiling on how many instances you can have per draw call.

 

A discussion of the technique (implemented in software, but which you should be easily able to convert to shader code) is available here: http://www.mvps.org/directx/articles/view_oriented_billboards.htm

0

Share this post


Link to post
Share on other sites

Thank you mhagain and menohack!

 

mhagain, I followed your link and it is actually working now, and now I'm translating it into shader code, but here is my worry:

 

How can I translate the vertices individually, as each vertex has it's own location.

 

I guess I could use the SV_VertexID and then use some if's, but would that be slow?

 

I'm not asking for you to write the shader code, just guide me.

0

Share this post


Link to post
Share on other sites

The easiest way would be to use a geometry shader.  Input one point, output a 4-vert tristrip, and just lift it from the software version.  You don't need to use instancing with this method, although having the GS stage active will introduce some (small) additional overhead.  If that's acceptable, then go do it.

 

Another method would be to use an additional per-vertex buffer, containing 4 verts.  This buffer can be static, and each vertex is 2 floats: {{-1, -1}, {1, -1}, {-1, 1}, {1, 1}} works well for one tristrip ordering (other tristrip orderings will be different, of course).  Let's assume that this is called "offset" in your VS input struct, that "position" is a float3, and you get the following:

vs_out.position = mul (float4 (vs_in.position + right * offset.x + up * offset.y, 1.0f), globalMVP);

If you want each billboard to have a variable scale ("scale" in your input struct) modify like so:

vs_out.position = mul (float4 (vs_in.position + (right * offset.x + up * offset.y) * vs_in.scale, 1.0f), globalMVP)

This isn't exactly the same as the example in the link I posted; that one produces a diamond shape, this one is a square.

 

These "offsets" can alternatively be indexed via SV_VertexID and also be reused for texcoords, by the way.

Edited by mhagain
0

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0

  • Similar Content

    • By lonewolff
      Hi Guys,
      I am revisiting an old DX11 framework I was creating a while back and am scratching my head with a small issue.
      I am trying to set the pixel shader resources and am getting the following error on every loop.
      As you can see in the below code, I am clearing out the shader resources as per the documentation. (Even going overboard and doing it both sides of the main PSSet call). But I just can't get rid of the error. Which results in the render target not being drawn.
      ID3D11ShaderResourceView* srv = { 0 }; d3dContext->PSSetShaderResources(0, 1, &srv); for (std::vector<RenderTarget>::iterator it = rtVector.begin(); it != rtVector.end(); ++it) { if (it->szName == name) { //std::cout << it->srv <<"\r\n"; d3dContext->PSSetShaderResources(0, 1, &it->srv); break; } } d3dContext->PSSetShaderResources(0, 1, &srv);  
      I am storing the RT's in a vector and setting them by name. I have tested the it->srv and am retrieving a valid pointer.
      At this stage I am out of ideas.
      Any help would be greatly appreciated
       
    • By bowerbirdcn
      hi, guys, how to understand the math used in CDXUTDirectionWidget ::UpdateLightDir 
      the  following code snippet is taken from MS DXTU source code
       
        D3DXMATRIX mInvView;
          D3DXMatrixInverse( &mInvView, NULL, &m_mView );
          mInvView._41 = mInvView._42 = mInvView._43 = 0;
          D3DXMATRIX mLastRotInv;
          D3DXMatrixInverse( &mLastRotInv, NULL, &m_mRotSnapshot );
          D3DXMATRIX mRot = *m_ArcBall.GetRotationMatrix();
          m_mRotSnapshot = mRot;
          // Accumulate the delta of the arcball's rotation in view space.
          // Note that per-frame delta rotations could be problematic over long periods of time.
          m_mRot *= m_mView * mLastRotInv * mRot * mInvView;
          // Since we're accumulating delta rotations, we need to orthonormalize 
          // the matrix to prevent eventual matrix skew
          D3DXVECTOR3* pXBasis = ( D3DXVECTOR3* )&m_mRot._11;
          D3DXVECTOR3* pYBasis = ( D3DXVECTOR3* )&m_mRot._21;
          D3DXVECTOR3* pZBasis = ( D3DXVECTOR3* )&m_mRot._31;
          D3DXVec3Normalize( pXBasis, pXBasis );
          D3DXVec3Cross( pYBasis, pZBasis, pXBasis );
          D3DXVec3Normalize( pYBasis, pYBasis );
          D3DXVec3Cross( pZBasis, pXBasis, pYBasis );
       
       
      https://github.com/Microsoft/DXUT/blob/master/Optional/DXUTcamera.cpp
    • By YixunLiu
      Hi,
      I have a surface mesh and I want to use a cone to cut a hole on the surface mesh.
      Anybody know a fast method to calculate the intersected boundary of these two geometries?
       
      Thanks.
       
      YL
       
    • By hiya83
      Hi, I tried searching for this but either I failed or couldn't find anything. I know there's D11/D12 interop and there are extensions for GL/D11 (though not very efficient). I was wondering if there's any Vulkan/D11 or Vulkan/D12 interop?
      Thanks!
    • By lonewolff
      Hi Guys,
      I am just wondering if it is possible to acquire the address of the backbuffer if an API (based on DX11) only exposes the 'device' and 'context' pointers?
      Any advice would be greatly appreciated
  • Popular Now