3 replies to this topic

[Yann ALET]

Hi there !

When using instancing, is it possible to send a single float to a vertex shader like this ?

C++

struct InstanceData
{
XMFLOAT4X4 World;
float IsSelected;
};

HLSL

struct VertexIn
{
float3 PosL    : POSITION;
float3 NormalL : NORMAL;
float2 Tex	 : TEXCOORD0;
float isSelected	 : DEPTH;                  // Instance data
row_major float4x4 World  : WORLD;    // Instance data
};

I tried but it did not work, the only way i can have it working now is to put use something like TEXTCOORD1 and put my float in one of the two component, i thought DEPTH would be more appropriate as it seems to be just for a single float, but it does not seem to work with instancing.

So i guess my question is what is the most efficient way to send to each instance a single float ?

Thanks !

[Zaoshi Kaba]

Why you have different variable order in C++ and HLSL? Probably that's why it doesn't work.
float is 4 bytes in size, so use R32_FLOAT or similar format for this data.

[Yann ALET]

Wow, i did not know the order mattered
I guess this explains many things ... when i tried with the float2 TEXTCOORD, i probably declared it after the world matrix which made me think single float transfer was not possible.

Thanks a lot !

[GeniusPooh]

there is many bug(??) at declaration...

It's depend on hardware system..

I think it's suck..

If there is other problem at this issue..

I better recommend just using Tex or pack one float to other coordination..( like tex)