diff --git a/doc/tutorials/raster-reprojection.md b/doc/tutorials/raster-reprojection.md
index e771d50d67..3f88f3647b 100644
--- a/doc/tutorials/raster-reprojection.md
+++ b/doc/tutorials/raster-reprojection.md
@@ -107,7 +107,7 @@ In case you are creating a custom build of OpenLayers and do not need the reproj
 See [Custom builds](custom-builds.html#defines) tutorial on how to do this.
 
 ### Triangulation precision threshold
-The default [triangulation error threshold](#dynamic-triangulation) in pixels is given by `DEFAULT_RASTER_REPROJECTION_ERROR_THRESHOLD` (0.5 pixel).
+The default [triangulation error threshold](#dynamic-triangulation) in pixels is given by `ERROR_THRESHOLD` (0.5 pixel).
 In case a different threshold needs to be defined for different sources, the `reprojectionErrorThreshold` option can be passed when constructing the tile image source.
 
 ###Limiting visibility of reprojected map by extent
diff --git a/externs/olx.js b/externs/olx.js
index 65bcf571c9..f1e2320d35 100644
--- a/externs/olx.js
+++ b/externs/olx.js
@@ -7443,7 +7443,7 @@ olx.source.ZoomifyOptions.prototype.transition;
 
 /**
  * Tile size. Same tile size is used for all zoom levels. Default value is
- * `OpenLayers.DEFAULT_TILE_SIZE`.
+ * `256`.
  * @type {number|undefined}
  * @api
  */
@@ -8612,8 +8612,7 @@ olx.style.AtlasManagerOptions;
 
 
 /**
- * The size in pixels of the first atlas image. If no value is given the
- * `ol.INITIAL_ATLAS_SIZE` compile-time constant will be used.
+ * The size in pixels of the first atlas image. Default is `256`.
  * @type {number|undefined}
  * @api
  */
@@ -8621,11 +8620,8 @@ olx.style.AtlasManagerOptions.prototype.initialSize;
 
 
 /**
- * The maximum size in pixels of atlas images. If no value is given then
- * the `ol.MAX_ATLAS_SIZE` compile-time constant will be used. And if
- * `ol.MAX_ATLAS_SIZE` is set to `-1` (the default) then
- * `ol.WEBGL_MAX_TEXTURE_SIZE` will used if WebGL is supported. Otherwise
- * 2048 is used.
+ * The maximum size in pixels of atlas images. Default is
+ * `WEBGL_MAX_TEXTURE_SIZE` or 2048 if WebGL is not supported.
  * @type {number|undefined}
  * @api
  */
diff --git a/src/ol/Map.js b/src/ol/Map.js
index 5987b2f158..40b7cd33e5 100644
--- a/src/ol/Map.js
+++ b/src/ol/Map.js
@@ -1,7 +1,7 @@
 /**
  * @module ol/Map
  */
-import {ENABLE_CANVAS, ENABLE_WEBGL, inherits} from './index.js';
+import {inherits} from './index.js';
 import _ol_PluggableMap_ from './PluggableMap.js';
 import _ol_PluginType_ from './PluginType.js';
 import _ol_control_ from './control.js';
@@ -19,24 +19,21 @@ import _ol_renderer_webgl_TileLayer_ from './renderer/webgl/TileLayer.js';
 import _ol_renderer_webgl_VectorLayer_ from './renderer/webgl/VectorLayer.js';
 
 
-if (ENABLE_CANVAS) {
-  _ol_plugins_.register(_ol_PluginType_.MAP_RENDERER, _ol_renderer_canvas_Map_);
-  _ol_plugins_.registerMultiple(_ol_PluginType_.LAYER_RENDERER, [
-    _ol_renderer_canvas_ImageLayer_,
-    _ol_renderer_canvas_TileLayer_,
-    _ol_renderer_canvas_VectorLayer_,
-    _ol_renderer_canvas_VectorTileLayer_
-  ]);
-}
+_ol_plugins_.register(_ol_PluginType_.MAP_RENDERER, _ol_renderer_canvas_Map_);
+_ol_plugins_.registerMultiple(_ol_PluginType_.LAYER_RENDERER, [
+  _ol_renderer_canvas_ImageLayer_,
+  _ol_renderer_canvas_TileLayer_,
+  _ol_renderer_canvas_VectorLayer_,
+  _ol_renderer_canvas_VectorTileLayer_
+]);
 
-if (ENABLE_WEBGL) {
-  _ol_plugins_.register(_ol_PluginType_.MAP_RENDERER, _ol_renderer_webgl_Map_);
-  _ol_plugins_.registerMultiple(_ol_PluginType_.LAYER_RENDERER, [
-    _ol_renderer_webgl_ImageLayer_,
-    _ol_renderer_webgl_TileLayer_,
-    _ol_renderer_webgl_VectorLayer_
-  ]);
-}
+// TODO: move these to new ol-webgl package
+_ol_plugins_.register(_ol_PluginType_.MAP_RENDERER, _ol_renderer_webgl_Map_);
+_ol_plugins_.registerMultiple(_ol_PluginType_.LAYER_RENDERER, [
+  _ol_renderer_webgl_ImageLayer_,
+  _ol_renderer_webgl_TileLayer_,
+  _ol_renderer_webgl_VectorLayer_
+]);
 
 
 /**
diff --git a/src/ol/View.js b/src/ol/View.js
index 88212a3699..6d1bbe8eb4 100644
--- a/src/ol/View.js
+++ b/src/ol/View.js
@@ -1,7 +1,8 @@
 /**
  * @module ol/View
  */
-import {DEFAULT_MIN_ZOOM, DEFAULT_TILE_SIZE, inherits, getUid, nullFunction} from './index.js';
+import {DEFAULT_TILE_SIZE} from './tilegrid/common.js';
+import {inherits, getUid, nullFunction} from './index.js';
 import _ol_CenterConstraint_ from './CenterConstraint.js';
 import _ol_Object_ from './Object.js';
 import _ol_ResolutionConstraint_ from './ResolutionConstraint.js';
@@ -21,6 +22,13 @@ import _ol_obj_ from './obj.js';
 import _ol_proj_ from './proj.js';
 import _ol_proj_Units_ from './proj/Units.js';
 
+
+/**
+ * @type {number} Default min zoom level for the map view.
+ */
+var DEFAULT_MIN_ZOOM = 0;
+
+
 /**
  * @classdesc
  * An ol.View object represents a simple 2D view of the map.
diff --git a/src/ol/control/OverviewMap.js b/src/ol/control/OverviewMap.js
index 0fc75f9325..b3c0104fee 100644
--- a/src/ol/control/OverviewMap.js
+++ b/src/ol/control/OverviewMap.js
@@ -1,7 +1,7 @@
 /**
  * @module ol/control/OverviewMap
  */
-import {OVERVIEWMAP_MAX_RATIO, OVERVIEWMAP_MIN_RATIO, inherits} from '../index.js';
+import {inherits} from '../index.js';
 import _ol_Collection_ from '../Collection.js';
 import _ol_PluggableMap_ from '../PluggableMap.js';
 import _ol_MapEventType_ from '../MapEventType.js';
@@ -19,6 +19,21 @@ import _ol_events_ from '../events.js';
 import _ol_events_EventType_ from '../events/EventType.js';
 import _ol_extent_ from '../extent.js';
 
+
+/**
+ * @type {number} Maximum width and/or height extent ratio that determines
+ * when the overview map should be zoomed out.
+ */
+var MAX_RATIO = 0.75;
+
+
+/**
+ * @type {number} Minimum width and/or height extent ratio that determines
+ * when the overview map should be zoomed in.
+ */
+var MIN_RATIO = 0.1;
+
+
 /**
  * Create a new control with a map acting as an overview map for an other
  * defined map.
@@ -336,10 +351,10 @@ _ol_control_OverviewMap_.prototype.validateExtent_ = function() {
   var ovmapWidth = ovmapSize[0];
   var ovmapHeight = ovmapSize[1];
 
-  if (boxWidth < ovmapWidth * OVERVIEWMAP_MIN_RATIO ||
-      boxHeight < ovmapHeight * OVERVIEWMAP_MIN_RATIO ||
-      boxWidth > ovmapWidth * OVERVIEWMAP_MAX_RATIO ||
-      boxHeight > ovmapHeight * OVERVIEWMAP_MAX_RATIO) {
+  if (boxWidth < ovmapWidth * MIN_RATIO ||
+      boxHeight < ovmapHeight * MIN_RATIO ||
+      boxWidth > ovmapWidth * MAX_RATIO ||
+      boxHeight > ovmapHeight * MAX_RATIO) {
     this.resetExtent_();
   } else if (!_ol_extent_.containsExtent(ovextent, extent)) {
     this.recenter_();
@@ -353,7 +368,7 @@ _ol_control_OverviewMap_.prototype.validateExtent_ = function() {
  * @private
  */
 _ol_control_OverviewMap_.prototype.resetExtent_ = function() {
-  if (OVERVIEWMAP_MAX_RATIO === 0 || OVERVIEWMAP_MIN_RATIO === 0) {
+  if (MAX_RATIO === 0 || MIN_RATIO === 0) {
     return;
   }
 
@@ -371,8 +386,8 @@ _ol_control_OverviewMap_.prototype.resetExtent_ = function() {
   // box sizes using the min and max ratio, pick the step in the middle used
   // to calculate the extent from the main map to set it to the overview map,
   var steps = Math.log(
-      OVERVIEWMAP_MAX_RATIO / OVERVIEWMAP_MIN_RATIO) / Math.LN2;
-  var ratio = 1 / (Math.pow(2, steps / 2) * OVERVIEWMAP_MIN_RATIO);
+      MAX_RATIO / MIN_RATIO) / Math.LN2;
+  var ratio = 1 / (Math.pow(2, steps / 2) * MIN_RATIO);
   _ol_extent_.scaleFromCenter(extent, ratio);
   ovview.fit(extent);
 };
diff --git a/src/ol/has.js b/src/ol/has.js
index 7428ec4c60..182eaea2ea 100644
--- a/src/ol/has.js
+++ b/src/ol/has.js
@@ -1,7 +1,7 @@
 /**
  * @module ol/has
  */
-import {ENABLE_CANVAS, ASSUME_TOUCH, HAS_WEBGL} from './index.js';
+import {HAS_WEBGL} from './index.js';
 
 var _ol_has_ = {};
 
@@ -51,13 +51,12 @@ _ol_has_.CANVAS_LINE_DASH = false;
 
 
 /**
- * True if both the library and browser support Canvas.  Always `false`
- * if `ol.ENABLE_CANVAS` is set to `false` at compile time.
+ * True if the and browsers support Canvas.
  * @const
  * @type {boolean}
  * @api
  */
-_ol_has_.CANVAS = ENABLE_CANVAS && (
+_ol_has_.CANVAS = (
   /**
    * @return {boolean} Canvas supported.
    */
@@ -105,7 +104,7 @@ _ol_has_.GEOLOCATION = 'geolocation' in navigator;
  * @type {boolean}
  * @api
  */
-_ol_has_.TOUCH = ASSUME_TOUCH || 'ontouchstart' in window;
+_ol_has_.TOUCH = 'ontouchstart' in window;
 
 
 /**
diff --git a/src/ol/index.js b/src/ol/index.js
index 5c04cec288..f6aced6ae8 100644
--- a/src/ol/index.js
+++ b/src/ol/index.js
@@ -6,174 +6,15 @@ import webgl from './webgl.js';
 
 
 /**
- * Constants defined with the define tag cannot be changed in application
- * code, but can be set at compile time.
- * Some reduce the size of the build in advanced compile mode.
- */
-
-
-/**
- * @type {boolean} Assume touch.  Default is `false`.
- */
-export var ASSUME_TOUCH = false;
-
-
-/**
- * TODO: rename this to something having to do with tile grids
- * see https://github.com/openlayers/openlayers/issues/2076
- * @type {number} Default maximum zoom for default tile grids.
- */
-export var DEFAULT_MAX_ZOOM = 42;
-
-
-/**
- * @type {number} Default min zoom level for the map view.  Default is `0`.
- */
-export var DEFAULT_MIN_ZOOM = 0;
-
-
-/**
- * @type {number} Default maximum allowed threshold  (in pixels) for
- *     reprojection triangulation. Default is `0.5`.
- */
-export var DEFAULT_RASTER_REPROJECTION_ERROR_THRESHOLD = 0.5;
-
-
-/**
- * @type {number} Default tile size.
- */
-export var DEFAULT_TILE_SIZE = 256;
-
-
-/**
- * @type {string} Default WMS version.
- */
-export var DEFAULT_WMS_VERSION = '1.3.0';
-
-
-/**
- * @type {boolean} Enable the Canvas renderer.  Default is `true`. Setting
- *     this to false at compile time in advanced mode removes all code
- *     supporting the Canvas renderer from the build.
- */
-export var ENABLE_CANVAS = true;
-
-
-/**
- * @type {boolean} Enable integration with the Proj4js library.  Default is
- *     `true`.
- */
-export var ENABLE_PROJ4JS = true;
-
-
-/**
- * @type {boolean} Enable automatic reprojection of raster sources. Default is
- *     `true`.
- */
-export var ENABLE_RASTER_REPROJECTION = true;
-
-
-/**
- * @type {boolean} Enable the WebGL renderer.  Default is `true`. Setting
- *     this to false at compile time in advanced mode removes all code
- *     supporting the WebGL renderer from the build.
- */
-export var ENABLE_WEBGL = true;
-
-
-/**
+ * TODO: move to a separate ol-webgl package
  * @type {boolean} Include debuggable shader sources.  Default is `true`.
- *     This should be set to `false` for production builds (if `ENABLE_WEBGL`
- *     is `true`).
+ *     This should be set to `false` for production builds.
  */
 export var DEBUG_WEBGL = true;
 
 
 /**
- * TODO: get rid of this or move it to AtlasManager.js
- * @type {number} The size in pixels of the first atlas image. Default is
- * `256`.
- */
-export var INITIAL_ATLAS_SIZE = 256;
-
-
-/**
- * TODO: get rid of this or move it to AtlasManager.js
- * @type {number} The maximum size in pixels of atlas images. Default is
- * `-1`, meaning it is not used (and `WEBGL_MAX_TEXTURE_SIZE` is
- * used instead).
- */
-export var MAX_ATLAS_SIZE = -1;
-
-
-/**
- * TODO: move this to MouseWheelZoom.js
- * @type {number} Maximum mouse wheel delta.
- */
-export var MOUSEWHEELZOOM_MAXDELTA = 1;
-
-
-/**
- * TODO: move this to OverviewMap.js
- * @type {number} Maximum width and/or height extent ratio that determines
- * when the overview map should be zoomed out.
- */
-export var OVERVIEWMAP_MAX_RATIO = 0.75;
-
-
-/**
- * TODO: move this to OverviewMap.js
- * @type {number} Minimum width and/or height extent ratio that determines
- * when the overview map should be zoomed in.
- */
-export var OVERVIEWMAP_MIN_RATIO = 0.1;
-
-
-/**
- * TODO: move this to Triangulation.js
- * @type {number} Maximum number of subdivision steps during raster
- *     reprojection triangulation. Prevents high memory usage and large
- *     number of proj4 calls (for certain transformations and areas).
- *     At most `2*(2^this)` triangles are created for each triangulated
- *     extent (tile/image). Default is `10`.
- */
-export var RASTER_REPROJECTION_MAX_SUBDIVISION = 10;
-
-
-/**
- * TODO: move this to Triangulation.js
- * @type {number} Maximum allowed size of triangle relative to world width.
- *     When transforming corners of world extent between certain projections,
- *     the resulting triangulation seems to have zero error and no subdivision
- *     is performed.
- *     If the triangle width is more than this (relative to world width; 0-1),
- *     subdivison is forced (up to `RASTER_REPROJECTION_MAX_SUBDIVISION`).
- *     Default is `0.25`.
- */
-export var RASTER_REPROJECTION_MAX_TRIANGLE_WIDTH = 0.25;
-
-
-/**
- * TODO: move this to renderer/vector.js
- * @type {number} Tolerance for geometry simplification in device pixels.
- */
-export var SIMPLIFY_TOLERANCE = 0.5;
-
-
-/**
- * TODO: move this to webgl/Map.js
- * @type {number} Texture cache high water mark.
- */
-export var WEBGL_TEXTURE_CACHE_HIGH_WATER_MARK = 1024;
-
-
-/**
- * @type {string} OpenLayers version.
- */
-export var VERSION = 'v4.6.4';
-
-
-/**
+ * TODO: move to a separate ol-webgl package
  * The maximum supported WebGL texture size in pixels. If WebGL is not
  * supported, the value is set to `undefined`.
  * @const
@@ -183,6 +24,7 @@ var WEBGL_MAX_TEXTURE_SIZE; // value is set below
 
 
 /**
+ * TODO: move to a separate ol-webgl package
  * List of supported WebGL extensions.
  * @const
  * @type {Array.<string>}
@@ -191,13 +33,14 @@ var WEBGL_EXTENSIONS; // value is set below
 
 
 /**
+ * TODO: move to a separate ol-webgl package
  * WebGL is available.
  * @type {boolean}
  */
 var HAS_WEBGL = false;
 
 
-if (ENABLE_WEBGL && 'WebGLRenderingContext' in window) {
+if ('WebGLRenderingContext' in window) {
   try {
     var canvas = /** @type {HTMLCanvasElement} */
         (document.createElement('CANVAS'));
@@ -216,6 +59,12 @@ if (ENABLE_WEBGL && 'WebGLRenderingContext' in window) {
 export {HAS_WEBGL, WEBGL_MAX_TEXTURE_SIZE, WEBGL_EXTENSIONS};
 
 
+/**
+ * @type {string} OpenLayers version.
+ */
+export var VERSION = 'v4.6.4';
+
+
 /**
  * Inherit the prototype methods from one constructor into another.
  *
@@ -277,27 +126,8 @@ export default {
   nullFunction: nullFunction,
   inherits: inherits,
   VERSION: VERSION,
-  ASSUME_TOUCH: ASSUME_TOUCH,
-  DEFAULT_MAX_ZOOM: DEFAULT_MAX_ZOOM,
-  DEFAULT_MIN_ZOOM: DEFAULT_MIN_ZOOM,
-  DEFAULT_RASTER_REPROJECTION_ERROR_THRESHOLD: DEFAULT_RASTER_REPROJECTION_ERROR_THRESHOLD,
-  DEFAULT_TILE_SIZE: DEFAULT_TILE_SIZE,
-  DEFAULT_WMS_VERSION: DEFAULT_WMS_VERSION,
-  ENABLE_CANVAS: ENABLE_CANVAS,
-  ENABLE_PROJ4JS: ENABLE_PROJ4JS,
-  ENABLE_RASTER_REPROJECTION: ENABLE_RASTER_REPROJECTION,
-  ENABLE_WEBGL: ENABLE_WEBGL,
   DEBUG_WEBGL: DEBUG_WEBGL,
-  INITIAL_ATLAS_SIZE: INITIAL_ATLAS_SIZE,
-  MAX_ATLAS_SIZE: MAX_ATLAS_SIZE,
-  MOUSEWHEELZOOM_MAXDELTA: MOUSEWHEELZOOM_MAXDELTA,
-  OVERVIEWMAP_MAX_RATIO: OVERVIEWMAP_MAX_RATIO,
-  OVERVIEWMAP_MIN_RATIO: OVERVIEWMAP_MIN_RATIO,
-  RASTER_REPROJECTION_MAX_SUBDIVISION: RASTER_REPROJECTION_MAX_SUBDIVISION,
-  RASTER_REPROJECTION_MAX_TRIANGLE_WIDTH: RASTER_REPROJECTION_MAX_TRIANGLE_WIDTH,
-  SIMPLIFY_TOLERANCE: SIMPLIFY_TOLERANCE,
   HAS_WEBGL: HAS_WEBGL,
-  WEBGL_TEXTURE_CACHE_HIGH_WATER_MARK: WEBGL_TEXTURE_CACHE_HIGH_WATER_MARK,
   WEBGL_MAX_TEXTURE_SIZE: WEBGL_MAX_TEXTURE_SIZE,
   WEBGL_EXTENSIONS: WEBGL_EXTENSIONS
 };
diff --git a/src/ol/interaction/MouseWheelZoom.js b/src/ol/interaction/MouseWheelZoom.js
index 16e16dc7cc..18d93663cc 100644
--- a/src/ol/interaction/MouseWheelZoom.js
+++ b/src/ol/interaction/MouseWheelZoom.js
@@ -1,7 +1,7 @@
 /**
  * @module ol/interaction/MouseWheelZoom
  */
-import {MOUSEWHEELZOOM_MAXDELTA, inherits} from '../index.js';
+import {inherits} from '../index.js';
 import _ol_ViewHint_ from '../ViewHint.js';
 import _ol_easing_ from '../easing.js';
 import _ol_events_EventType_ from '../events/EventType.js';
@@ -9,6 +9,13 @@ import _ol_has_ from '../has.js';
 import _ol_interaction_Interaction_ from '../interaction/Interaction.js';
 import _ol_math_ from '../math.js';
 
+
+/**
+ * @type {number} Maximum mouse wheel delta.
+ */
+var MAX_DELTA = 1;
+
+
 /**
  * @classdesc
  * Allows the user to zoom the map by scrolling the mouse wheel.
@@ -252,7 +259,7 @@ _ol_interaction_MouseWheelZoom_.prototype.handleWheelZoom_ = function(map) {
   if (view.getAnimating()) {
     view.cancelAnimations();
   }
-  var maxDelta = MOUSEWHEELZOOM_MAXDELTA;
+  var maxDelta = MAX_DELTA;
   var delta = _ol_math_.clamp(this.delta_, -maxDelta, maxDelta);
   _ol_interaction_Interaction_.zoomByDelta(view, -delta, this.lastAnchor_,
       this.duration_);
diff --git a/src/ol/proj.js b/src/ol/proj.js
index d28c2616d1..dd5a47e98f 100644
--- a/src/ol/proj.js
+++ b/src/ol/proj.js
@@ -1,7 +1,6 @@
 /**
  * @module ol/proj
  */
-import {ENABLE_PROJ4JS} from './index.js';
 import _ol_Sphere_ from './Sphere.js';
 import _ol_extent_ from './extent.js';
 import _ol_math_ from './math.js';
@@ -32,23 +31,21 @@ _ol_proj_.METERS_PER_UNIT = _ol_proj_Units_.METERS_PER_UNIT;
 _ol_proj_.SPHERE_ = new _ol_Sphere_(_ol_Sphere_.DEFAULT_RADIUS);
 
 
-if (ENABLE_PROJ4JS) {
-  /**
-   * Register proj4. If not explicitly registered, it will be assumed that
-   * proj4js will be loaded in the global namespace. For example in a
-   * browserify ES6 environment you could use:
-   *
-   *     import ol from 'openlayers';
-   *     import proj4 from 'proj4';
-   *     ol.proj.setProj4(proj4);
-   *
-   * @param {Proj4} proj4 Proj4.
-   * @api
-   */
-  _ol_proj_.setProj4 = function(proj4) {
-    _ol_proj_proj4_.set(proj4);
-  };
-}
+/**
+ * Register proj4. If not explicitly registered, it will be assumed that
+ * proj4js will be loaded in the global namespace. For example in a
+ * browserify ES6 environment you could use:
+ *
+ *     import ol from 'openlayers';
+ *     import proj4 from 'proj4';
+ *     ol.proj.setProj4(proj4);
+ *
+ * @param {Proj4} proj4 Proj4.
+ * @api
+ */
+_ol_proj_.setProj4 = function(proj4) {
+  _ol_proj_proj4_.set(proj4);
+};
 
 
 /**
@@ -311,7 +308,7 @@ _ol_proj_.get = function(projectionLike) {
   } else if (typeof projectionLike === 'string') {
     var code = projectionLike;
     projection = _ol_proj_projections_.get(code);
-    if (ENABLE_PROJ4JS && !projection) {
+    if (!projection) {
       var proj4js = _ol_proj_proj4_.get();
       if (typeof proj4js == 'function' &&
           proj4js.defs(code) !== undefined) {
@@ -380,7 +377,7 @@ _ol_proj_.getTransformFromProjections = function(sourceProjection, destinationPr
   var sourceCode = sourceProjection.getCode();
   var destinationCode = destinationProjection.getCode();
   var transform = _ol_proj_transforms_.get(sourceCode, destinationCode);
-  if (ENABLE_PROJ4JS && !transform) {
+  if (!transform) {
     var proj4js = _ol_proj_proj4_.get();
     if (typeof proj4js == 'function') {
       var sourceDef = proj4js.defs(sourceCode);
diff --git a/src/ol/proj/Projection.js b/src/ol/proj/Projection.js
index 6a08d1a8ac..6e925544ed 100644
--- a/src/ol/proj/Projection.js
+++ b/src/ol/proj/Projection.js
@@ -1,7 +1,6 @@
 /**
  * @module ol/proj/Projection
  */
-import {ENABLE_PROJ4JS} from '../index.js';
 import _ol_proj_Units_ from '../proj/Units.js';
 import _ol_proj_proj4_ from '../proj/proj4.js';
 
@@ -108,20 +107,18 @@ var _ol_proj_Projection_ = function(options) {
   this.metersPerUnit_ = options.metersPerUnit;
 
   var code = options.code;
-  if (ENABLE_PROJ4JS) {
-    var proj4js = _ol_proj_proj4_.get();
-    if (typeof proj4js == 'function') {
-      var def = proj4js.defs(code);
-      if (def !== undefined) {
-        if (def.axis !== undefined && options.axisOrientation === undefined) {
-          this.axisOrientation_ = def.axis;
-        }
-        if (options.metersPerUnit === undefined) {
-          this.metersPerUnit_ = def.to_meter;
-        }
-        if (options.units === undefined) {
-          this.units_ = def.units;
-        }
+  var proj4js = _ol_proj_proj4_.get();
+  if (typeof proj4js == 'function') {
+    var def = proj4js.defs(code);
+    if (def !== undefined) {
+      if (def.axis !== undefined && options.axisOrientation === undefined) {
+        this.axisOrientation_ = def.axis;
+      }
+      if (options.metersPerUnit === undefined) {
+        this.metersPerUnit_ = def.to_meter;
+      }
+      if (options.units === undefined) {
+        this.units_ = def.units;
       }
     }
   }
diff --git a/src/ol/renderer/canvas/ImageLayer.js b/src/ol/renderer/canvas/ImageLayer.js
index ab01e9a8a1..3e36728ef4 100644
--- a/src/ol/renderer/canvas/ImageLayer.js
+++ b/src/ol/renderer/canvas/ImageLayer.js
@@ -1,7 +1,8 @@
 /**
  * @module ol/renderer/canvas/ImageLayer
  */
-import {ENABLE_RASTER_REPROJECTION, inherits} from '../../index.js';
+import {ENABLE_RASTER_REPROJECTION} from '../../reproj/common.js';
+import {inherits} from '../../index.js';
 import _ol_ImageCanvas_ from '../../ImageCanvas.js';
 import _ol_LayerType_ from '../../LayerType.js';
 import _ol_ViewHint_ from '../../ViewHint.js';
diff --git a/src/ol/renderer/vector.js b/src/ol/renderer/vector.js
index dd9003b7dd..9d18b05175 100644
--- a/src/ol/renderer/vector.js
+++ b/src/ol/renderer/vector.js
@@ -1,13 +1,19 @@
 /**
  * @module ol/renderer/vector
  */
-import {SIMPLIFY_TOLERANCE, getUid} from '../index.js';
+import {getUid} from '../index.js';
 import _ol_ImageState_ from '../ImageState.js';
 import _ol_geom_GeometryType_ from '../geom/GeometryType.js';
 import _ol_render_ReplayType_ from '../render/ReplayType.js';
 var _ol_renderer_vector_ = {};
 
 
+/**
+ * @type {number} Tolerance for geometry simplification in device pixels.
+ */
+var SIMPLIFY_TOLERANCE = 0.5;
+
+
 /**
  * @param {ol.Feature|ol.render.Feature} feature1 Feature 1.
  * @param {ol.Feature|ol.render.Feature} feature2 Feature 2.
diff --git a/src/ol/renderer/webgl/ImageLayer.js b/src/ol/renderer/webgl/ImageLayer.js
index d67457c8c2..9b29331f77 100644
--- a/src/ol/renderer/webgl/ImageLayer.js
+++ b/src/ol/renderer/webgl/ImageLayer.js
@@ -1,7 +1,8 @@
 /**
  * @module ol/renderer/webgl/ImageLayer
  */
-import {ENABLE_RASTER_REPROJECTION, inherits, nullFunction} from '../../index.js';
+import {ENABLE_RASTER_REPROJECTION} from '../../reproj/common.js';
+import {inherits, nullFunction} from '../../index.js';
 import _ol_LayerType_ from '../../LayerType.js';
 import _ol_ViewHint_ from '../../ViewHint.js';
 import _ol_dom_ from '../../dom.js';
diff --git a/src/ol/renderer/webgl/Map.js b/src/ol/renderer/webgl/Map.js
index 7515e47673..642eb73d06 100644
--- a/src/ol/renderer/webgl/Map.js
+++ b/src/ol/renderer/webgl/Map.js
@@ -1,9 +1,8 @@
 /**
  * @module ol/renderer/webgl/Map
  */
-// FIXME check against gl.getParameter(webgl.MAX_TEXTURE_SIZE)
 
-import {WEBGL_TEXTURE_CACHE_HIGH_WATER_MARK, inherits} from '../../index.js';
+import {inherits} from '../../index.js';
 import _ol_array_ from '../../array.js';
 import _ol_css_ from '../../css.js';
 import _ol_dom_ from '../../dom.js';
@@ -22,6 +21,13 @@ import _ol_webgl_ from '../../webgl.js';
 import _ol_webgl_Context_ from '../../webgl/Context.js';
 import _ol_webgl_ContextEventType_ from '../../webgl/ContextEventType.js';
 
+
+/**
+ * @type {number} Texture cache high water mark.
+ */
+var WEBGL_TEXTURE_CACHE_HIGH_WATER_MARK = 1024;
+
+
 /**
  * @constructor
  * @extends {ol.renderer.Map}
diff --git a/src/ol/reproj/Image.js b/src/ol/reproj/Image.js
index cf843e2bdc..ec94824ce9 100644
--- a/src/ol/reproj/Image.js
+++ b/src/ol/reproj/Image.js
@@ -1,7 +1,8 @@
 /**
  * @module ol/reproj/Image
  */
-import {DEFAULT_RASTER_REPROJECTION_ERROR_THRESHOLD, inherits} from '../index.js';
+import {ERROR_THRESHOLD} from './common.js';
+import {inherits} from '../index.js';
 import _ol_ImageBase_ from '../ImageBase.js';
 import _ol_ImageState_ from '../ImageState.js';
 import _ol_events_ from '../events.js';
@@ -48,7 +49,7 @@ var _ol_reproj_Image_ = function(sourceProj, targetProj,
   var sourceResolution = _ol_reproj_.calculateSourceResolution(
       sourceProj, targetProj, targetCenter, targetResolution);
 
-  var errorThresholdInPixels = DEFAULT_RASTER_REPROJECTION_ERROR_THRESHOLD;
+  var errorThresholdInPixels = ERROR_THRESHOLD;
 
   /**
    * @private
diff --git a/src/ol/reproj/Tile.js b/src/ol/reproj/Tile.js
index d0e7be6530..10d5ddcdfe 100644
--- a/src/ol/reproj/Tile.js
+++ b/src/ol/reproj/Tile.js
@@ -1,7 +1,8 @@
 /**
  * @module ol/reproj/Tile
  */
-import {DEFAULT_RASTER_REPROJECTION_ERROR_THRESHOLD, inherits} from '../index.js';
+import {ERROR_THRESHOLD} from './common.js';
+import {inherits} from '../index.js';
 import _ol_Tile_ from '../Tile.js';
 import _ol_TileState_ from '../TileState.js';
 import _ol_events_ from '../events.js';
@@ -136,7 +137,7 @@ var _ol_reproj_Tile_ = function(sourceProj, sourceTileGrid,
   }
 
   var errorThresholdInPixels = opt_errorThreshold !== undefined ?
-    opt_errorThreshold : DEFAULT_RASTER_REPROJECTION_ERROR_THRESHOLD;
+    opt_errorThreshold : ERROR_THRESHOLD;
 
   /**
    * @private
diff --git a/src/ol/reproj/Triangulation.js b/src/ol/reproj/Triangulation.js
index d70031a88b..954153633a 100644
--- a/src/ol/reproj/Triangulation.js
+++ b/src/ol/reproj/Triangulation.js
@@ -1,11 +1,33 @@
 /**
  * @module ol/reproj/Triangulation
  */
-import {RASTER_REPROJECTION_MAX_SUBDIVISION, RASTER_REPROJECTION_MAX_TRIANGLE_WIDTH} from '../index.js';
 import _ol_extent_ from '../extent.js';
 import _ol_math_ from '../math.js';
 import _ol_proj_ from '../proj.js';
 
+
+/**
+ * @type {number} Maximum number of subdivision steps during raster
+ *     reprojection triangulation. Prevents high memory usage and large
+ *     number of proj4 calls (for certain transformations and areas).
+ *     At most `2*(2^this)` triangles are created for each triangulated
+ *     extent (tile/image).
+ */
+var MAX_SUBDIVISION = 10;
+
+
+/**
+ * @type {number} Maximum allowed size of triangle relative to world width.
+ *     When transforming corners of world extent between certain projections,
+ *     the resulting triangulation seems to have zero error and no subdivision
+ *     is performed.
+ *     If the triangle width is more than this (relative to world width; 0-1),
+ *     subdivison is forced (up to `MAX_SUBDIVISION`).
+ *     Default is `0.25`.
+ */
+var MAX_TRIANGLE_WIDTH = 0.25;
+
+
 /**
  * @classdesc
  * Class containing triangulation of the given target extent.
@@ -112,7 +134,7 @@ var _ol_reproj_Triangulation_ = function(sourceProj, targetProj, targetExtent,
       destinationTopLeft, destinationTopRight,
       destinationBottomRight, destinationBottomLeft,
       sourceTopLeft, sourceTopRight, sourceBottomRight, sourceBottomLeft,
-      RASTER_REPROJECTION_MAX_SUBDIVISION);
+      MAX_SUBDIVISION);
 
   if (this.wrapsXInSource_) {
     var leftBound = Infinity;
@@ -213,11 +235,11 @@ _ol_reproj_Triangulation_.prototype.addQuad_ = function(a, b, c, d,
       var targetCoverageX =
           _ol_extent_.getWidth(targetQuadExtent) / this.targetWorldWidth_;
       needsSubdivision |=
-          targetCoverageX > RASTER_REPROJECTION_MAX_TRIANGLE_WIDTH;
+          targetCoverageX > MAX_TRIANGLE_WIDTH;
     }
     if (!wrapsX && this.sourceProj_.isGlobal() && sourceCoverageX) {
       needsSubdivision |=
-          sourceCoverageX > RASTER_REPROJECTION_MAX_TRIANGLE_WIDTH;
+          sourceCoverageX > MAX_TRIANGLE_WIDTH;
     }
   }
 
diff --git a/src/ol/reproj/common.js b/src/ol/reproj/common.js
new file mode 100644
index 0000000000..524358e314
--- /dev/null
+++ b/src/ol/reproj/common.js
@@ -0,0 +1,12 @@
+/**
+ * @type {number} Default maximum allowed threshold  (in pixels) for
+ *     reprojection triangulation.
+ */
+export var ERROR_THRESHOLD = 0.5;
+
+/**
+ * TODO: decide if we want to expose this as a build flag or remove it
+ * @type {boolean} Enable automatic reprojection of raster sources. Default is
+ *     `true`.
+ */
+export var ENABLE_RASTER_REPROJECTION = true;
diff --git a/src/ol/source/Image.js b/src/ol/source/Image.js
index 1f9dc15919..db0fb79b6e 100644
--- a/src/ol/source/Image.js
+++ b/src/ol/source/Image.js
@@ -1,7 +1,8 @@
 /**
  * @module ol/source/Image
  */
-import {ENABLE_RASTER_REPROJECTION, inherits} from '../index.js';
+import {ENABLE_RASTER_REPROJECTION} from '../reproj/common.js';
+import {inherits} from '../index.js';
 import _ol_ImageState_ from '../ImageState.js';
 import _ol_array_ from '../array.js';
 import _ol_events_Event_ from '../events/Event.js';
diff --git a/src/ol/source/ImageWMS.js b/src/ol/source/ImageWMS.js
index 74a7d46274..98fa89fab9 100644
--- a/src/ol/source/ImageWMS.js
+++ b/src/ol/source/ImageWMS.js
@@ -2,7 +2,8 @@
  * @module ol/source/ImageWMS
  */
 
-import {DEFAULT_WMS_VERSION, inherits} from '../index.js';
+import {DEFAULT_WMS_VERSION} from './common.js';
+import {inherits} from '../index.js';
 import _ol_Image_ from '../Image.js';
 import _ol_asserts_ from '../asserts.js';
 import _ol_events_ from '../events.js';
diff --git a/src/ol/source/TileImage.js b/src/ol/source/TileImage.js
index 56ae68cd6d..c827ef15c0 100644
--- a/src/ol/source/TileImage.js
+++ b/src/ol/source/TileImage.js
@@ -1,7 +1,8 @@
 /**
  * @module ol/source/TileImage
  */
-import {ENABLE_RASTER_REPROJECTION, getUid, inherits} from '../index.js';
+import {ENABLE_RASTER_REPROJECTION} from '../reproj/common.js';
+import {getUid, inherits} from '../index.js';
 import _ol_ImageTile_ from '../ImageTile.js';
 import _ol_TileCache_ from '../TileCache.js';
 import _ol_TileState_ from '../TileState.js';
diff --git a/src/ol/source/TileWMS.js b/src/ol/source/TileWMS.js
index 1a63818b98..a03a4f718e 100644
--- a/src/ol/source/TileWMS.js
+++ b/src/ol/source/TileWMS.js
@@ -2,7 +2,8 @@
  * @module ol/source/TileWMS
  */
 
-import {DEFAULT_WMS_VERSION, inherits} from '../index.js';
+import {DEFAULT_WMS_VERSION} from './common.js';
+import {inherits} from '../index.js';
 import _ol_asserts_ from '../asserts.js';
 import _ol_extent_ from '../extent.js';
 import _ol_obj_ from '../obj.js';
diff --git a/src/ol/source/Zoomify.js b/src/ol/source/Zoomify.js
index d9e1179252..807fa0fd55 100644
--- a/src/ol/source/Zoomify.js
+++ b/src/ol/source/Zoomify.js
@@ -1,7 +1,8 @@
 /**
  * @module ol/source/Zoomify
  */
-import {DEFAULT_TILE_SIZE, inherits} from '../index.js';
+import {DEFAULT_TILE_SIZE} from '../tilegrid/common.js';
+import {inherits} from '../index.js';
 import _ol_ImageTile_ from '../ImageTile.js';
 import _ol_TileState_ from '../TileState.js';
 import _ol_TileUrlFunction_ from '../TileUrlFunction.js';
diff --git a/src/ol/source/common.js b/src/ol/source/common.js
new file mode 100644
index 0000000000..a20bbd8c85
--- /dev/null
+++ b/src/ol/source/common.js
@@ -0,0 +1,4 @@
+/**
+ * @type {string} Default WMS version.
+ */
+export var DEFAULT_WMS_VERSION = '1.3.0';
diff --git a/src/ol/style/AtlasManager.js b/src/ol/style/AtlasManager.js
index 26b01aeaeb..9d67ff1a2d 100644
--- a/src/ol/style/AtlasManager.js
+++ b/src/ol/style/AtlasManager.js
@@ -1,9 +1,21 @@
 /**
  * @module ol/style/AtlasManager
  */
-import {INITIAL_ATLAS_SIZE, MAX_ATLAS_SIZE, WEBGL_MAX_TEXTURE_SIZE, nullFunction} from '../index.js';
+import {WEBGL_MAX_TEXTURE_SIZE, nullFunction} from '../index.js';
 import _ol_style_Atlas_ from '../style/Atlas.js';
 
+
+/**
+ * @type {number} The size in pixels of the first atlas image.
+ */
+var INITIAL_ATLAS_SIZE = 256;
+
+/**
+ * @type {number} The maximum size in pixels of atlas images.
+ */
+var MAX_ATLAS_SIZE = -1;
+
+
 /**
  * Manages the creation of image atlases.
  *
diff --git a/src/ol/tilegrid.js b/src/ol/tilegrid.js
index 30fcb5fd11..4c9e7ba0e6 100644
--- a/src/ol/tilegrid.js
+++ b/src/ol/tilegrid.js
@@ -1,7 +1,7 @@
 /**
  * @module ol/tilegrid
  */
-import {DEFAULT_MAX_ZOOM, DEFAULT_TILE_SIZE} from './index.js';
+import {DEFAULT_MAX_ZOOM, DEFAULT_TILE_SIZE} from './tilegrid/common.js';
 import _ol_size_ from './size.js';
 import _ol_extent_ from './extent.js';
 import _ol_extent_Corner_ from './extent/Corner.js';
diff --git a/src/ol/tilegrid/TileGrid.js b/src/ol/tilegrid/TileGrid.js
index e57728e603..edab2d53de 100644
--- a/src/ol/tilegrid/TileGrid.js
+++ b/src/ol/tilegrid/TileGrid.js
@@ -1,7 +1,7 @@
 /**
  * @module ol/tilegrid/TileGrid
  */
-import {DEFAULT_TILE_SIZE} from '../index.js';
+import {DEFAULT_TILE_SIZE} from './common.js';
 import _ol_asserts_ from '../asserts.js';
 import _ol_TileRange_ from '../TileRange.js';
 import _ol_array_ from '../array.js';
diff --git a/src/ol/tilegrid/common.js b/src/ol/tilegrid/common.js
new file mode 100644
index 0000000000..e003fba738
--- /dev/null
+++ b/src/ol/tilegrid/common.js
@@ -0,0 +1,9 @@
+/**
+ * @type {number} Default maximum zoom for default tile grids.
+ */
+export var DEFAULT_MAX_ZOOM = 42;
+
+/**
+ * @type {number} Default tile size.
+ */
+export var DEFAULT_TILE_SIZE = 256;
diff --git a/test/spec/ol/source/zoomify.test.js b/test/spec/ol/source/zoomify.test.js
index 3d21657ca7..a6b7d364b3 100644
--- a/test/spec/ol/source/zoomify.test.js
+++ b/test/spec/ol/source/zoomify.test.js
@@ -1,4 +1,4 @@
-import {DEFAULT_TILE_SIZE} from '../../../../src/ol/index.js';
+import {DEFAULT_TILE_SIZE} from '../../../../src/ol/tilegrid/common.js';
 import _ol_events_ from '../../../../src/ol/events.js';
 import _ol_proj_Projection_ from '../../../../src/ol/proj/Projection.js';
 import _ol_source_Zoomify_ from '../../../../src/ol/source/Zoomify.js';
diff --git a/test/spec/ol/tilegrid/tilegrid.test.js b/test/spec/ol/tilegrid/tilegrid.test.js
index 346c9d8b95..86a6bf3886 100644
--- a/test/spec/ol/tilegrid/tilegrid.test.js
+++ b/test/spec/ol/tilegrid/tilegrid.test.js
@@ -1,4 +1,4 @@
-import {DEFAULT_MAX_ZOOM, DEFAULT_TILE_SIZE} from '../../../../src/ol/index.js';
+import {DEFAULT_MAX_ZOOM, DEFAULT_TILE_SIZE} from '../../../../src/ol/tilegrid/common.js';
 import _ol_TileRange_ from '../../../../src/ol/TileRange.js';
 import _ol_extent_ from '../../../../src/ol/extent.js';
 import _ol_proj_ from '../../../../src/ol/proj.js';