/* Minetest-c55 Copyright (C) 2010-2012 celeron55, Perttu Ahola <celeron55@gmail.com> This program is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. This program 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 Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. */ #include "numeric.h" #include "../log.h" #include "../constants.h" // BS, MAP_BLOCKSIZE #include <iostream> // Calculate the borders of a "d-radius" cube void getFacePositions(core::list<v3s16> &list, u16 d) { if(d == 0) { list.push_back(v3s16(0,0,0)); return; } if(d == 1) { /* This is an optimized sequence of coordinates. */ list.push_back(v3s16( 0, 1, 0)); // top list.push_back(v3s16( 0, 0, 1)); // back list.push_back(v3s16(-1, 0, 0)); // left list.push_back(v3s16( 1, 0, 0)); // right list.push_back(v3s16( 0, 0,-1)); // front list.push_back(v3s16( 0,-1, 0)); // bottom // 6 list.push_back(v3s16(-1, 0, 1)); // back left list.push_back(v3s16( 1, 0, 1)); // back right list.push_back(v3s16(-1, 0,-1)); // front left list.push_back(v3s16( 1, 0,-1)); // front right list.push_back(v3s16(-1,-1, 0)); // bottom left list.push_back(v3s16( 1,-1, 0)); // bottom right list.push_back(v3s16( 0,-1, 1)); // bottom back list.push_back(v3s16( 0,-1,-1)); // bottom front list.push_back(v3s16(-1, 1, 0)); // top left list.push_back(v3s16( 1, 1, 0)); // top right list.push_back(v3s16( 0, 1, 1)); // top back list.push_back(v3s16( 0, 1,-1)); // top front // 18 list.push_back(v3s16(-1, 1, 1)); // top back-left list.push_back(v3s16( 1, 1, 1)); // top back-right list.push_back(v3s16(-1, 1,-1)); // top front-left list.push_back(v3s16( 1, 1,-1)); // top front-right list.push_back(v3s16(-1,-1, 1)); // bottom back-left list.push_back(v3s16( 1,-1, 1)); // bottom back-right list.push_back(v3s16(-1,-1,-1)); // bottom front-left list.push_back(v3s16( 1,-1,-1)); // bottom front-right // 26 return; } // Take blocks in all sides, starting from y=0 and going +-y for(s16 y=0; y<=d-1; y++) { // Left and right side, including borders for(s16 z=-d; z<=d; z++) { list.push_back(v3s16(d,y,z)); list.push_back(v3s16(-d,y,z)); if(y != 0) { list.push_back(v3s16(d,-y,z)); list.push_back(v3s16(-d,-y,z)); } } // Back and front side, excluding borders for(s16 x=-d+1; x<=d-1; x++) { list.push_back(v3s16(x,y,d)); list.push_back(v3s16(x,y,-d)); if(y != 0) { list.push_back(v3s16(x,-y,d)); list.push_back(v3s16(x,-y,-d)); } } } // Take the bottom and top face with borders // -d<x<d, y=+-d, -d<z<d for(s16 x=-d; x<=d; x++) for(s16 z=-d; z<=d; z++) { list.push_back(v3s16(x,-d,z)); list.push_back(v3s16(x,d,z)); } } /* myrand */ static unsigned long next = 1; /* RAND_MAX assumed to be 32767 */ int myrand(void) { next = next * 1103515245 + 12345; return((unsigned)(next/65536) % 32768); } void mysrand(unsigned seed) { next = seed; } int myrand_range(int min, int max) { if(max-min > MYRAND_MAX) { errorstream<<"WARNING: myrand_range: max-min > MYRAND_MAX"<<std::endl; max = min + MYRAND_MAX; } if(min > max) { errorstream<<"WARNING: myrand_range: min > max"<<std::endl; return max; } return (myrand()%(max-min+1))+min; } /* blockpos: position of block in block coordinates camera_pos: position of camera in nodes camera_dir: an unit vector pointing to camera direction range: viewing range */ bool isBlockInSight(v3s16 blockpos_b, v3f camera_pos, v3f camera_dir, f32 camera_fov, f32 range, f32 *distance_ptr) { v3s16 blockpos_nodes = blockpos_b * MAP_BLOCKSIZE; // Block center position v3f blockpos( ((float)blockpos_nodes.X + MAP_BLOCKSIZE/2) * BS, ((float)blockpos_nodes.Y + MAP_BLOCKSIZE/2) * BS, ((float)blockpos_nodes.Z + MAP_BLOCKSIZE/2) * BS ); // Block position relative to camera v3f blockpos_relative = blockpos - camera_pos; // Distance in camera direction (+=front, -=back) f32 dforward = blockpos_relative.dotProduct(camera_dir); // Total distance f32 d = blockpos_relative.getLength(); if(distance_ptr) *distance_ptr = d; // If block is very close, it is always in sight if(d < 1.44*1.44*MAP_BLOCKSIZE*BS/2) return true; // If block is far away, it's not in sight if(d > range) return false; // Maximum radius of a block f32 block_max_radius = 0.5*1.44*1.44*MAP_BLOCKSIZE*BS; // If block is (nearly) touching the camera, don't // bother validating further (that is, render it anyway) if(d < block_max_radius) return true; // Cosine of the angle between the camera direction // and the block direction (camera_dir is an unit vector) f32 cosangle = dforward / d; // Compensate for the size of the block // (as the block has to be shown even if it's a bit off FOV) // This is an estimate, plus an arbitary factor cosangle += block_max_radius / d * 0.5; // If block is not in the field of view, skip it if(cosangle < cos(camera_fov / 2)) return false; return true; }