15ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni/* 25ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni * Copyright (C) 2012 The Android Open Source Project 35ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni * 45ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni * Licensed under the Apache License, Version 2.0 (the "License"); 55ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni * you may not use this file except in compliance with the License. 65ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni * You may obtain a copy of the License at 75ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni * 85ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni * http://www.apache.org/licenses/LICENSE-2.0 95ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni * 105ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni * Unless required by applicable law or agreed to in writing, software 115ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni * distributed under the License is distributed on an "AS IS" BASIS, 125ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 135ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni * See the License for the specific language governing permissions and 145ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni * limitations under the License. 155ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni */ 165ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni 175ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Nistatic float2 neg_center, axis_scale, inv_dimensions; 185ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Nistatic float sloped_neg_range, sloped_inv_max_dist, shade, opp_shade; 195ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni 205ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Nivoid init_vignette(uint32_t dim_x, uint32_t dim_y, float center_x, float center_y, 215ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni float desired_scale, float desired_shade, float desired_slope) { 225ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni 235ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni neg_center.x = -center_x; 245ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni neg_center.y = -center_y; 255ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni inv_dimensions.x = 1.f / (float)dim_x; 265ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni inv_dimensions.y = 1.f / (float)dim_y; 275ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni 285ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni axis_scale = (float2)1.f; 295ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni if (dim_x > dim_y) 305ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni axis_scale.y = (float)dim_y / (float)dim_x; 315ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni else 325ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni axis_scale.x = (float)dim_x / (float)dim_y; 335ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni 345ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni const float max_dist = 0.5f * length(axis_scale); 355ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni sloped_inv_max_dist = desired_slope * 1.f/max_dist; 365ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni 375ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni // Range needs to be between 1.3 to 0.6. When scale is zero then range is 385ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni // 1.3 which means no vignette at all because the luminousity difference is 395ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni // less than 1/256. Expect input scale to be between 0.0 and 1.0. 405ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni const float neg_range = 0.7f*sqrt(desired_scale) - 1.3f; 415ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni sloped_neg_range = exp(neg_range * desired_slope); 425ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni 435ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni shade = desired_shade; 445ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni opp_shade = 1.f - desired_shade; 455ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni} 465ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni 475ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Nifloat4 __attribute__((kernel)) vignette(float4 in, uint32_t x, uint32_t y) { 485ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni // Convert x and y to floating point coordinates with center as origin 495ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni const float2 inCoord = {(float)x, (float)y}; 505ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni const float2 coord = mad(inCoord, inv_dimensions, neg_center); 515ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni const float sloped_dist_ratio = fast_length(axis_scale * coord) * sloped_inv_max_dist; 525ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni const float lumen = opp_shade + shade * half_recip(1.f + sloped_neg_range * native_exp(sloped_dist_ratio)); 535ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni float4 fout; 545ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni fout.rgb = in.rgb * lumen; 555ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni fout.w = in.w; 565ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni return fout; 575ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni} 585ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni 59