/***************************************************************************** The Dark Mod GPL Source Code This file is part of the The Dark Mod Source Code, originally based on the Doom 3 GPL Source Code as published in 2011. The Dark Mod Source Code 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 3 of the License, or (at your option) any later version. For details, see LICENSE.TXT. Project: The Dark Mod (http://www.thedarkmod.com/) ******************************************************************************/ // returns surface normal in tangent space // should handle all the specifics of normalmap format vec3 unpackSurfaceNormal(vec4 normalTexColor, bool useNormalTexture, bool RGTC) { if (useNormalTexture) { // fetch RGB, convert from [0, 1] to [-1, 1] range vec3 bumpTexel = normalTexColor.xyz * 2.0 - 1.0; if (RGTC) { // RGTC compression: add positive Z value float xyNormSqr = dot(bumpTexel.xy, bumpTexel.xy); return vec3(bumpTexel.x, bumpTexel.y, sqrt(max(1.0 - xyNormSqr, 0))); } else { // full RGB texture return normalize(bumpTexel.xyz); } } else { // flat surface return vec3(0, 0, 1); } }