Grain_Blend.dctl

// Grain Blend DCTL


#define RGB_GRAIN			// alternative monochromatic
#define SOFTLIGHT			// alternative is overlay blend
#define INTENSITY 12		// grain contrast


__DEVICE__ float fract(float A)
{
float B;
B = A - _floor(A);
return B;
}

__DEVICE__ float rand(float x)
{
return fract(_sinf(x) * 100000.0f);
}

__DEVICE__ float intensity(float grain, float contrast)
{
return (grain - 0.5f) * contrast + 0.5f;
}

__DEVICE__ float softLight(float col, float grain)
{
return grain < 0.5f ? 2.0f * col * grain + (col * col) * (1.0f - 2.0f * grain) : 2.0f * col * (1.0f - grain) + _sqrtf(col) * (2.0f * grain - 1.0f);
}

__DEVICE__ float3 softLight(float3 col, float3 grain)
{
return make_float3(softLight(col.x, grain.x), softLight(col.y, grain.y), softLight(col.z, grain.z));
}

__DEVICE__ float overlay(float col, float grain)
{
return col < 0.5f ? (2 * col * grain) : (1 - 2 * (1 - col) * (1 - grain));
}

__DEVICE__ float3 overlay(float3 col, float3 grain)
{
return make_float3(overlay(col.x, grain.x), overlay(col.y, grain.y), overlay(col.z, grain.z));
}

__DEVICE__ float3 transform(int p_Width, int p_Height, int p_X, int p_Y, __TEXTURE__ p_TexR, __TEXTURE__ p_TexG, __TEXTURE__ p_TexB)
{

float3 col = make_float3(_tex2D(p_TexR, p_X, p_Y), _tex2D(p_TexG, p_X, p_Y), _tex2D(p_TexB, p_X, p_Y));

float contrast = (float)INTENSITY * 0.01f;
float iTime = _tex2D(p_TexR, 500, 500) * 20.0f;
float X = (float)p_X + 1.0f;
float Y = (float)(p_Height - p_Y) + 1.0f;
float2 resolution = make_float2((float)p_Width, (float)p_Height);
float2 position = make_float2(X/resolution.x, Y/resolution.y);
float x = position.x * position.y * 100000.0f + iTime;
float f = fract(x);
float i = _floor(x);
x *= 100.0f;

float3 grain;
grain.x = rand(x);
grain.x = intensity(grain.x, contrast);
#ifdef RGB_GRAIN
grain.y = rand(x * iTime);
grain.y = intensity(grain.y, contrast);
grain.z = rand(x + iTime);
grain.z = intensity(grain.z, contrast);
#else
grain.z = grain.y = grain.x;
#endif

#ifdef SOFTLIGHT
col = softLight(col, grain);
#else
col = overlay(col, grain);
#endif

return col;
 
}