Distorted Android

//////////////////////////////////////////////////////////////////////////////////////////////

// Copyright 2018 Leszek Koltunski                                                          //

//                                                                                          //

// This file is part of Distorted.                                                          //

//                                                                                          //

// Distorted is free software: you can redistribute it and/or modify                        //

// it under the terms of the GNU General Public License as published by                     //

// the Free Software Foundation, either version 2 of the License, or                        //

// (at your option) any later version.                                                      //

//                                                                                          //

// Distorted is distributed in the hope that it will be useful,                             //

// but WITHOUT ANY WARRANTY; without even the implied warranty of                           //

// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the                            //

// GNU General Public License for more details.                                             //

//                                                                                          //

// You should have received a copy of the GNU General Public License                        //

// along with Distorted.  If not, see <http://www.gnu.org/licenses/>.                       //

//////////////////////////////////////////////////////////////////////////////////////////////

precision highp float;

out vec4 fragColor;           // The output color

in vec2 v_TexCoordinate;      // Interpolated texture coordinate per fragment.

uniform sampler2D u_Texture;

uniform sampler2D u_DepthTexture;

//////////////////////////////////////////////////////////////////////////////////////////////

// why -0.0003 ? On some drivers (for example Qualcomm's V@331, V@415 on Adreno 308 - also on

// some Mali devices ) without it the depth test - when postprocessing a flat 2D object - does

// not pass (for unknown reasons) and we don't see the Glow halo.  See for example the 'Glowing

// Leaf' test app.

// Why exactly 0.0003? Testing of the Cube app on the SM-A315F. ( Mali G52, drivr r20p0 )

// 0.0003 shouldn't hurt anyway.

void main()                    		

  {

  gl_FragDepth = texture(u_DepthTexture,v_TexCoordinate).r -0.0003;

  fragColor    = texture(u_Texture     ,v_TexCoordinate);

  }