__DEVICE__ float apply_contrast(float in, float contrast, float pivot) { float out; out = (in - pivot) * contrast + pivot; return out; } DEFINE_UI_PARAMS(contrast, Contrast, DCTLUI_SLIDER_FLOAT, 1.0, 0.0, 2.0, 0.1) DEFINE_UI_PARAMS(pivot, Pivot, DCTLUI_SLIDER_FLOAT, .435, 0.0, 1.0, 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 in = {p_R, p_G, p_B}; float3 out; out.x = apply_contrast(in.x, contrast, pivot); out.y = apply_contrast(in.y, contrast, pivot); out.z = apply_contrast(in.z, contrast, pivot); return out; }