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#ActualChris_F

Posted 17 January 2013 - 04:13 PM

So I've looked around, and there is a lot of info to be found on this subject, but it is only for encoding floats in the range [0, 1], and I want to encode floats of arbitrary magnitude. Can you tell me if my method is sound?

 

On the CPU:

glm::ivec4 FloatToRGBA(float input)
{
    int exponent;
    float significand = frexp(input, &exponent);
    int sig_int = glm::round(significand * 16777215.0f);
    glm::vec4 output;
    output.x = exponent + 128;
    output.y = sig_int & 0x000000FF;
    output.z = (sig_int & 0x0000FF00) >> 8;
    output.w = (sig_int & 0x00FF0000) >> 16;
    return output;
}

 

On the GPU:

float RGBAtoFloat(float4 input)
{
    float significand = dot(input.yzw, float3(16711680.0f, 65280.0f, 255.0f)) / 16777215.0f;
    return ldexp(significand, input.x * 255.0f - 128.0f);
}

#1Chris_F

Posted 17 January 2013 - 04:10 PM

So I've looked around, and there is a lot of info to be found on this subject, but it is only for encoding floats in the range [0, 1], and I want to encode floats of arbitrary magnitude. Can you tell me if my method is sound?

 

 

glm::ivec4 FloatToRGBA(float input)
{
    int exponent;
    float significand = frexp(input, &exponent);
    int sig_int = glm::round(significand * 16777215.0f);
    glm::vec4 output;
    output.x = exponent + 128;
    output.y = sig_int & 0x000000FF;
    output.z = (sig_int & 0x0000FF00) >> 8;
    output.w = (sig_int & 0x00FF0000) >> 16;
    return output;
}

 

 

 

float RGBAtoFloat(float4 input)
{
    float significand = dot(input.yzw, float3(16711680.0f, 65280.0f, 255.0f)) / 16777215.0f;
    return ldexp(significand, input.x * 255.0f - 128.0f);
}

 


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