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 Nirs_allocation in_alloc; 185ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Nistatic rs_sampler sampler; 195ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni 205ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Nistatic float2 center, neg_center, inv_dimensions, axis_scale; 215ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Nistatic float alpha, radius2, factor; 225ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni 235ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Nivoid init_filter(uint32_t dim_x, uint32_t dim_y, float center_x, float center_y, float k, 245ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni rs_sampler sam) { 255ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni sampler = sam; 265ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni center.x = center_x; 275ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni center.y = center_y; 285ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni neg_center = -center; 295ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni inv_dimensions.x = 1.f / (float)dim_x; 305ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni inv_dimensions.y = 1.f / (float)dim_y; 315ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni alpha = k * 2.0f + 0.75f; 325ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni 335ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni axis_scale = (float2)1.f; 345ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni if (dim_x > dim_y) 355ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni axis_scale.y = (float)dim_y / (float)dim_x; 365ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni else 375ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni axis_scale.x = (float)dim_x / (float)dim_y; 385ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni 395ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni const float bound2 = 0.25f * (axis_scale.x*axis_scale.x + axis_scale.y*axis_scale.y); 405ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni const float bound = sqrt(bound2); 415ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni const float radius = 1.15f * bound; 425ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni radius2 = radius*radius; 435ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni const float max_radian = M_PI_2 - atan(alpha / bound * sqrt(radius2 - bound2)); 445ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni factor = bound / max_radian; 455ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni} 465ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni 475ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Nifloat4 __attribute__((kernel)) fisheye(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 float2 scaledCoord = axis_scale * coord; 525ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni const float dist2 = scaledCoord.x*scaledCoord.x + scaledCoord.y*scaledCoord.y; 535ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni const float inv_dist = half_rsqrt(dist2); 545ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni const float radian = M_PI_2 - atan((alpha * half_sqrt(radius2 - dist2)) * inv_dist); 555ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni const float scalar = radian * factor * inv_dist; 565ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni const float2 new_coord = mad(coord, scalar, center); 578e607f39757174d088cbc9703ef051b378c6018fYang Ni // TODO: rsSample does not work with element type float4. 585ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni const float4 fout = rsSample(in_alloc, sampler, new_coord); 595ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni return fout; 605ab5155f7e0e0904f8c11cd0dbdbf7832e3ac948Yang Ni} 61