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spectral
Adept II

cl_float4 ... and co...

Hi,

I try to play with float4, float8 etc.... in c++ so I use cl_float4 by example.

Here is the definition in the cl files.

typedef union
{
cl_float CL_ALIGNED(16) s[4];
#if defined( __GNUC__) && ! defined( __STRICT_ANSI__ )
__extension__ struct{ cl_float x, y, z, w; };
__extension__ struct{ cl_float s0, s1, s2, s3; };
__extension__ struct{ cl_float2 lo, hi; };
#endif
#if defined( __CL_FLOAT2__)
__cl_float2 v2[2];
#endif
#if defined( __CL_FLOAT4__)
__cl_float4 v4;
#endif
}cl_float4;

What is strange is that I have to access the cl_float4 like this :

cl_float4 val;

val.s[0] = 1.f;
val.s[1] = 2.f;
val.s[2] = 3.f;

And I have no ".x" , ".y", ... under MSVC

Except form GNUC where there is the x,y,z,x and s0, s1, s2, s3 !

Why we don't have this for all platforms ?

 

Thx

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8 Replies
nou
Exemplar

cl_float4 ... and co...

question is if MSVC support that. try remove that #define __GNUC__ if  MSVC it will compile.

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spectral
Adept II

cl_float4 ... and co...

Thanks Nou,

But why I don' t have this directly ? Will it be fixed in a next version of the SDK ?

Or it is better to use s[0]... to be portable ?

Thx

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spectral
Adept II

cl_float4 ... and co...

Also, there is no function and no operator for cl_float_4 etc... like we have in the kernels.

I can't do :

cl_float4 a, b;

a = b;

if (a == b)

c = a / b; 

...

It will be useful

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nou
Exemplar

cl_float4 ... and co...

yes usefull but not possible. plain C don't support such operator over struct. in C++ you can overload operators so you get a desired functionality. it is a limitation of the language.

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spectral
Adept II

cl_float4 ... and co...

Thanks Nou,

Now I have problems to transfer some cl_float4 to the kernel.

Before I was using a struct like this { float x,y,z; } and have replace it with cl_float3;

In the kernel I have replace with "float3".

But the values I retreive in the kernel are wrong !!!!

Here are my structures, they are aligned (I think) !!! So, what can be the problem ?

KERNEL VERSION -------------- typedef struct { float x,y,z; } Vector3; typedef struct { float turbidity; float thetaSun, phiSun; float zenith_x, zenith_y, zenith_Y; float perez_x[5]; float perez_y[5]; float perez_Y[5]; Vector3 sunDirection; Vector3 sunXaxis; Vector3 sunYaxis; float3 sunSpectralRadiance; float sunSolidAngle; float sunCosThetaMax; float overcast; float atmosphereAttenuation; float g1[2]; // Align float8 riS0Spectrum; float8 riS1Spectrum; float8 riS2Spectrum; float8 X; float8 Y; float8 Z; float8 beta_p; float8 beta_m; float yint; float skyPowerFactor; float sunPowerFactor; int isSunRendered; float g2[4]; // Align } PhysicalSkyLight; C++ VERSION ----------- typedef struct { float x,y,z; } clVector3; typedef struct { float turbidity; float thetaSun, phiSun; float zenith_x, zenith_y, zenith_Y; float perez_x[5]; float perez_y[5]; float perez_Y[5]; clVector3 sunDirection; clVector3 sunXaxis; clVector3 sunYaxis; cl_float3 sunSpectralRadiance; float sunSolidAngle; float sunCosThetaMax; float overcast; float atmosphereAttenuation; float g1[2]; cl_float8 riS0Spectrum; cl_float8 riS1Spectrum; cl_float8 riS2Spectrum; cl_float8 X; cl_float8 Y; cl_float8 Z; cl_float8 beta_p; cl_float8 beta_m; float yint; float skyPowerFactor; float sunPowerFactor; int isSunRendered; float g2[4]; } CLPhysicalSkyLight;

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spectral
Adept II

cl_float4 ... and co...

In fact, I do this :

printf("%f\n", physical.sunSpectralRadiance.x);

and it display the value of physical.sunSpectralRadiance[2] !!!

NB: I work on a 64 bits machine CPU

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nou
Exemplar

cl_float4 ... and co...

didn't i write you how to check proper aligment of data types? check a starting offset of sunSpectralRadiance. in fact cl_float3 is just a retyped cl_float4 that mean it has 4*float aligment and size.

before sunSpectralRadiance you have 33 float values. that mean sunSpectralRadiance should start at 36*4 bytes offset. but i don't know if MSVC proper align cl_float* types at C++ side as a gcc does.

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spectral
Adept II

cl_float4 ... and co...

Right... I've forgot some alignment 😛

Sorry and thx

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