Spreads in shaders

vvvv beta question
1

i heard some rumours that it’s possible to access individual slices of spreads in shaders
is this true?
how so?
i’m feeding in matricies of data as transforms using SetMatrix.
It would be nice if i could access one specific matrix slice at a time.

I’m on the pixel shader, and generally I only need to access one slice per pixel (if that is a limitation)
anyone know the way to go?

2

p.s. i’m not feeding the matricies in on the ‘Transform’ pin, i’ve got seperate MAtrix4x4 inputs

3

as far as i know it works like this:
create a global array like this:

float4x4 transforms~091~10~093~;

then get a particular slice:

float4 newPos = mul(oldPos, transforms~091~i~093~);

4

you even can access single values of a matrix! see http://vvvv.org/tiki-index.php?page=shadersnippets#get_clipping_planes_of_a_Perspective_Projection

also take notice of this…

5

hhhm, just thinking loud:
would it also be possible to access a single value out of an ARRAY of transforms?

somehow like

float4x4 tArray10;
float FarPlane = 1/ ( tArrayi23 + tArrayi33 ) ; //

perhaps i check this later.

6

seems to work fine
example attached

also, spreading colours throws an error (about converting between structs and floats) maybe somebody else can get it working, i hacked here by putting things into floats before they get in the shader.

also, i dont seem to be able to be able to go higher than around 128 values per input

shader spread test.zip (3.1 kB)

7

float4 spreadcol~91~48~93~ : Color;

works for me…

8

yep, the array length is limited, see Arrays in the EX9.HLSL.Introduction.

color spreads work as tonfilm pointed out. where do you get the error thrown?