// mcpro24fps mLog 80% to Rec.709
// ver. 2020-04-13

__CONSTANT__ float BLACK = 0.0784;
__CONSTANT__ float BRIGHTNESS = 0.1;

__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;
 
	rgb.x = p_R;
    rgb.y = p_G;
    rgb.z = p_B;
	
	if(rgb.x < BLACK)
		rgb.x = 0.0;
	else {
		rgb.x = (rgb.x - BLACK)/(1.0 - BLACK);
		rgb.x = (-1.0 * _powf(_clampf((1.0 - rgb.x),0.0,1.0), (BRIGHTNESS + 0.5)) + 1.0);
		rgb.x = (2.0 * (BRIGHTNESS - 0.5)) * (0.25 - (rgb.x - 0.5)*(rgb.x - 0.5)) + rgb.x;
	}
	if(rgb.y < BLACK)
		rgb.y = 0.0;
	else {
		rgb.y = (rgb.y - BLACK)/(1.0 - BLACK);
		rgb.y = (-1.0 * _powf(_clampf((1.0 - rgb.y),0.0,1.0), (BRIGHTNESS + 0.5)) + 1.0);
		rgb.y = (2.0 * (BRIGHTNESS - 0.5)) * (0.25 - (rgb.y - 0.5)*(rgb.y - 0.5)) + rgb.y;
	}
	if(rgb.z < BLACK)
		rgb.z = 0.0;
	else {
		rgb.z = (rgb.z - BLACK)/(1.0 - BLACK);
		rgb.z = (-1.0 * _powf(_clampf((1.0 - rgb.z),0.0,1.0), (BRIGHTNESS + 0.5)) + 1.0);
		rgb.z = (2.0 * (BRIGHTNESS - 0.5)) * (0.25 - (rgb.z - 0.5)*(rgb.z - 0.5)) + rgb.z;
	}
	
	//Rec.709
	rgb.x = rgb.x < 0.018 ? 4.5*rgb.x : 1.099*_powf(rgb.x, 0.45f) - 0.099;
    rgb.y = rgb.y < 0.018 ? 4.5*rgb.y : 1.099*_powf(rgb.y, 0.45f) - 0.099;
    rgb.z = rgb.z < 0.018 ? 4.5*rgb.z : 1.099*_powf(rgb.z, 0.45f) - 0.099;

    return rgb;
}