I am attempting to implement chunks/octrees to speed up my render times. However, sometimes the walls show horizontal or vertical lines (rays hitting the inside of voxels?) or some blocks disappear altogether, although sometimes everything renders fine.

Edit: Yes, the chunks are stored fine. OctrA stands for OctreeA, which is the chunk.

 float cameraX = x/(float)HALFRESX -1;// -1 to 1 struct Point3D rayd; rayd.x = dir.x + plane.x * cameraX; rayd.y = dir.y + plane.y * cameraX; struct Point3D delta; delta.x = fabsf(1/rayd.x); delta.y = fabsf(1/rayd.y); int zy = -HALFRESY; struct pos map; map.x = (char)pos.x; map.y = (char)pos.y; float sdistX; float sdistY; struct pos s; struct pos step; struct Point3D sdist; if(rayd.x < 0) { step.x = -1; s.x = 1; sdistX = (pos.x - map.x) * delta.x; } else { step.x = 1; s.x = 0; sdistX = (map.x + 1 - pos.x) * delta.x; } if(rayd.y < 0) { step.y = -1; s.y = 1; sdistY = (pos.y - map.y) * delta.y; } else { step.y = 1; s.y = 0; sdistY = (map.y + 1 - pos.y) * delta.y; } for(int y = 0; y < RESY; y += 1) { zy++; float cameraY = y/(float)HALFRESY - 1; rayd.z = dir.z + plane.z * cameraY; delta.z = fabsf(1/rayd.z); map.x = (char)pos.x; map.y = (char)pos.y; map.z = (char)pos.z; sdist.x = sdistX; sdist.y = sdistY; if(rayd.z < 0) { step.z = -1; s.z = 1; sdist.z = (pos.z - map.z) * delta.z; } else { step.z = 1; s.z = 0; sdist.z = (map.z + 1 - pos.z) * delta.z; } #ifdef USE_OCTREE while( !octrA[map.x/2][map.y/2][map.z/2]) { if(sdist.y < sdist.x ) { if(sdist.y < sdist.z) { sdist.y += delta.y*2; map.y += step.y*2; } else { sdist.z += delta.z*2; map.z += step.z*2; } } else { if(sdist.x < sdist.z) { sdist.x += delta.x*2; map.x += step.x*2; } else { sdist.z += delta.z*2; map.z += step.z*2; } } } #endif char side; //either 0 (NS), or 1 (EW), or 2(UD) while( !MAP[map.x][map.y][map.z]) { if(sdist.y < sdist.x ) { if(sdist.y < sdist.z) { sdist.y += delta.y; map.y += step.y; side = 1; // y } else { sdist.z += delta.z; map.z += step.z; side = 2; } } else { if(sdist.x < sdist.z) { sdist.x += delta.x; map.x += step.x; side = 0; } else { sdist.z += delta.z; map.z += step.z; side = 2; } } }