| // Copyright (C) 2011 The Android Open Source Project |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| #pragma version(1) |
| #pragma rs java_package_name(com.android.rs.image) |
| |
| uint32_t gMaxIteration = 500; |
| uint32_t gDimX = 1024; |
| uint32_t gDimY = 1024; |
| |
| float lowerBoundX = -2.f; |
| float lowerBoundY = -2.f; |
| float scaleFactor = 4.f; |
| |
| uchar4 __attribute__((kernel)) root(uint32_t x, uint32_t y) { |
| float2 p; |
| p.x = lowerBoundX + ((float)x / gDimX) * scaleFactor; |
| p.y = lowerBoundY + ((float)y / gDimY) * scaleFactor; |
| |
| float2 t = 0; |
| float2 t2 = t * t; |
| int iter = 0; |
| while((t2.x + t2.y < 4.f) && (iter < gMaxIteration)) { |
| float xtemp = t2.x - t2.y + p.x; |
| t.y = 2 * t.x * t.y + p.y; |
| t.x = xtemp; |
| iter++; |
| t2 = t * t; |
| } |
| |
| if(iter >= gMaxIteration) { |
| // write a non-transparent black pixel |
| return (uchar4){0, 0, 0, 0xff}; |
| } else { |
| float mi3 = gMaxIteration / 3.f; |
| if (iter <= (gMaxIteration / 3)) |
| return (uchar4){0xff * (iter / mi3), 0, 0, 0xff}; |
| else if (iter <= (((gMaxIteration / 3) * 2))) |
| return (uchar4){0xff - (0xff * ((iter - mi3) / mi3)), |
| (0xff * ((iter - mi3) / mi3)), 0, 0xff}; |
| else |
| return (uchar4){0, 0xff - (0xff * ((iter - (mi3 * 2)) / mi3)), |
| (0xff * ((iter - (mi3 * 2)) / mi3)), 0xff}; |
| } |
| } |