1572a5031a5d8602db0bec0b253428a034bd4dd59Jason Sams/* 2572a5031a5d8602db0bec0b253428a034bd4dd59Jason Sams * Copyright (C) 2012 The Android Open Source Project 3572a5031a5d8602db0bec0b253428a034bd4dd59Jason Sams * 4572a5031a5d8602db0bec0b253428a034bd4dd59Jason Sams * Licensed under the Apache License, Version 2.0 (the "License"); 5572a5031a5d8602db0bec0b253428a034bd4dd59Jason Sams * you may not use this file except in compliance with the License. 6572a5031a5d8602db0bec0b253428a034bd4dd59Jason Sams * You may obtain a copy of the License at 7572a5031a5d8602db0bec0b253428a034bd4dd59Jason Sams * 8572a5031a5d8602db0bec0b253428a034bd4dd59Jason Sams * http://www.apache.org/licenses/LICENSE-2.0 9572a5031a5d8602db0bec0b253428a034bd4dd59Jason Sams * 10572a5031a5d8602db0bec0b253428a034bd4dd59Jason Sams * Unless required by applicable law or agreed to in writing, software 11572a5031a5d8602db0bec0b253428a034bd4dd59Jason Sams * distributed under the License is distributed on an "AS IS" BASIS, 12572a5031a5d8602db0bec0b253428a034bd4dd59Jason Sams * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13572a5031a5d8602db0bec0b253428a034bd4dd59Jason Sams * See the License for the specific language governing permissions and 14572a5031a5d8602db0bec0b253428a034bd4dd59Jason Sams * limitations under the License. 15572a5031a5d8602db0bec0b253428a034bd4dd59Jason Sams */ 16572a5031a5d8602db0bec0b253428a034bd4dd59Jason Sams 17572a5031a5d8602db0bec0b253428a034bd4dd59Jason Samsstatic float2 neg_center, axis_scale, inv_dimensions; 18572a5031a5d8602db0bec0b253428a034bd4dd59Jason Samsstatic float sloped_neg_range, sloped_inv_max_dist, shade, opp_shade; 19572a5031a5d8602db0bec0b253428a034bd4dd59Jason Sams 20572a5031a5d8602db0bec0b253428a034bd4dd59Jason Samsvoid init_vignette(uint32_t dim_x, uint32_t dim_y, float center_x, float center_y, 21572a5031a5d8602db0bec0b253428a034bd4dd59Jason Sams float desired_scale, float desired_shade, float desired_slope) { 22572a5031a5d8602db0bec0b253428a034bd4dd59Jason Sams 23572a5031a5d8602db0bec0b253428a034bd4dd59Jason Sams neg_center.x = -center_x; 24572a5031a5d8602db0bec0b253428a034bd4dd59Jason Sams neg_center.y = -center_y; 25572a5031a5d8602db0bec0b253428a034bd4dd59Jason Sams inv_dimensions.x = 1.f / (float)dim_x; 26572a5031a5d8602db0bec0b253428a034bd4dd59Jason Sams inv_dimensions.y = 1.f / (float)dim_y; 27572a5031a5d8602db0bec0b253428a034bd4dd59Jason Sams 28572a5031a5d8602db0bec0b253428a034bd4dd59Jason Sams axis_scale = (float2)1.f; 29572a5031a5d8602db0bec0b253428a034bd4dd59Jason Sams if (dim_x > dim_y) 30572a5031a5d8602db0bec0b253428a034bd4dd59Jason Sams axis_scale.y = (float)dim_y / (float)dim_x; 31572a5031a5d8602db0bec0b253428a034bd4dd59Jason Sams else 32572a5031a5d8602db0bec0b253428a034bd4dd59Jason Sams axis_scale.x = (float)dim_x / (float)dim_y; 33572a5031a5d8602db0bec0b253428a034bd4dd59Jason Sams 34572a5031a5d8602db0bec0b253428a034bd4dd59Jason Sams const float max_dist = 0.5f * length(axis_scale); 35572a5031a5d8602db0bec0b253428a034bd4dd59Jason Sams sloped_inv_max_dist = desired_slope * 1.f/max_dist; 36572a5031a5d8602db0bec0b253428a034bd4dd59Jason Sams 37572a5031a5d8602db0bec0b253428a034bd4dd59Jason Sams // Range needs to be between 1.3 to 0.6. When scale is zero then range is 38572a5031a5d8602db0bec0b253428a034bd4dd59Jason Sams // 1.3 which means no vignette at all because the luminousity difference is 39572a5031a5d8602db0bec0b253428a034bd4dd59Jason Sams // less than 1/256. Expect input scale to be between 0.0 and 1.0. 40572a5031a5d8602db0bec0b253428a034bd4dd59Jason Sams const float neg_range = 0.7f*sqrt(desired_scale) - 1.3f; 41572a5031a5d8602db0bec0b253428a034bd4dd59Jason Sams sloped_neg_range = exp(neg_range * desired_slope); 42572a5031a5d8602db0bec0b253428a034bd4dd59Jason Sams 43572a5031a5d8602db0bec0b253428a034bd4dd59Jason Sams shade = desired_shade; 44572a5031a5d8602db0bec0b253428a034bd4dd59Jason Sams opp_shade = 1.f - desired_shade; 45572a5031a5d8602db0bec0b253428a034bd4dd59Jason Sams} 46572a5031a5d8602db0bec0b253428a034bd4dd59Jason Sams 47572a5031a5d8602db0bec0b253428a034bd4dd59Jason Samsuchar4 __attribute__((kernel)) root(uchar4 in, uint32_t x, uint32_t y) { 48572a5031a5d8602db0bec0b253428a034bd4dd59Jason Sams // Convert x and y to floating point coordinates with center as origin 49572a5031a5d8602db0bec0b253428a034bd4dd59Jason Sams const float4 fin = convert_float4(in); 50572a5031a5d8602db0bec0b253428a034bd4dd59Jason Sams const float2 inCoord = {(float)x, (float)y}; 51572a5031a5d8602db0bec0b253428a034bd4dd59Jason Sams const float2 coord = mad(inCoord, inv_dimensions, neg_center); 52572a5031a5d8602db0bec0b253428a034bd4dd59Jason Sams const float sloped_dist_ratio = length(axis_scale * coord) * sloped_inv_max_dist; 53572a5031a5d8602db0bec0b253428a034bd4dd59Jason Sams const float lumen = opp_shade + shade / ( 1.0f + sloped_neg_range * exp(sloped_dist_ratio) ); 54572a5031a5d8602db0bec0b253428a034bd4dd59Jason Sams float4 fout; 55572a5031a5d8602db0bec0b253428a034bd4dd59Jason Sams fout.rgb = fin.rgb * lumen; 56572a5031a5d8602db0bec0b253428a034bd4dd59Jason Sams fout.w = fin.w; 57572a5031a5d8602db0bec0b253428a034bd4dd59Jason Sams return convert_uchar4(fout); 58572a5031a5d8602db0bec0b253428a034bd4dd59Jason Sams} 59572a5031a5d8602db0bec0b253428a034bd4dd59Jason Sams 60