ACES_DLog_DGamut.dctl

// D-Log D-Gamut to ACES AP0 DCTL

typedef struct
{
float3 r0, r1, r2;
} mat3;

__DEVICE__ mat3 make_mat3( float3 A, float3 B, float3 C);
__DEVICE__ float3 mult_f3_f33 (float3 In, mat3 A);
__DEVICE__ float dlog_to_lin(float in);
__DEVICE__ float3 dlog_to_lin3(float3 in);

__DEVICE__ mat3 make_mat3( float3 A, float3 B, float3 C)
{
mat3 D;
D.r0 = A;
D.r1 = B;
D.r2 = C;
return D;
}

__DEVICE__ float3 mult_f3_f33 (float3 In, mat3 A)
{
float out[3];
float in[3] = {In.x, In.y, In.z};
float a[3][3] =    {{A.r0.x, A.r0.y, A.r0.z},
	  {A.r1.x, A.r1.y, A.r1.z},
	  {A.r2.x, A.r2.y, A.r2.z}};
for( int i = 0; i < 3; ++i)
{
out[i] = 0.0f;
for( int j = 0; j < 3; ++j)
{
out[i] = out[i] + in[j] * a[i][j];
}
}
return make_float3(out[0], out[1], out[2]);
}

#define dgamut_to_AP0			make_mat3(make_float3(0.691279f, 0.214383f, 0.094338f), make_float3(0.066222f, 1.011616f, -0.077838f), make_float3(-0.017299f, -0.077379f, 1.094677f))

__DEVICE__ float dlog_to_lin( float in)
{
float out = in <= 0.14f ? (in - 0.0929f) / 6.025f : (_exp10f(3.89616 * in - 2.27752f) - 0.0108f) / 0.9892f;
return out;
}

__DEVICE__ float3 dlog_to_lin3( float3 in)
{
float3 out;
out.x = dlog_to_lin(in.x);
out.y = dlog_to_lin(in.y);
out.z = dlog_to_lin(in.z);
return out;
}

__DEVICE__ float3 transform(int p_Width, int p_Height, int p_X, int p_Y, float p_R, float p_G, float p_B)
{
float3 rgb = make_float3(p_R, p_G, p_B);

rgb = dlog_to_lin3(rgb);

rgb = mult_f3_f33(rgb, dgamut_to_AP0);

return rgb;
}