Deprecated: Creation of dynamic property wpdb::$categories is deprecated in /var/www/twodee/blog/wp-includes/wp-db.php on line 668

Deprecated: Creation of dynamic property wpdb::$post2cat is deprecated in /var/www/twodee/blog/wp-includes/wp-db.php on line 668

Deprecated: Creation of dynamic property wpdb::$link2cat is deprecated in /var/www/twodee/blog/wp-includes/wp-db.php on line 668

Deprecated: Return type of WP_Theme::offsetExists($offset) should either be compatible with ArrayAccess::offsetExists(mixed $offset): bool, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /var/www/twodee/blog/wp-includes/class-wp-theme.php on line 554

Deprecated: Return type of WP_Theme::offsetGet($offset) should either be compatible with ArrayAccess::offsetGet(mixed $offset): mixed, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /var/www/twodee/blog/wp-includes/class-wp-theme.php on line 595

Deprecated: Return type of WP_Theme::offsetSet($offset, $value) should either be compatible with ArrayAccess::offsetSet(mixed $offset, mixed $value): void, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /var/www/twodee/blog/wp-includes/class-wp-theme.php on line 535

Deprecated: Return type of WP_Theme::offsetUnset($offset) should either be compatible with ArrayAccess::offsetUnset(mixed $offset): void, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /var/www/twodee/blog/wp-includes/class-wp-theme.php on line 544

Deprecated: Return type of WP_REST_Request::offsetExists($offset) should either be compatible with ArrayAccess::offsetExists(mixed $offset): bool, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /var/www/twodee/blog/wp-includes/rest-api/class-wp-rest-request.php on line 960

Deprecated: Return type of WP_REST_Request::offsetGet($offset) should either be compatible with ArrayAccess::offsetGet(mixed $offset): mixed, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /var/www/twodee/blog/wp-includes/rest-api/class-wp-rest-request.php on line 980

Deprecated: Return type of WP_REST_Request::offsetSet($offset, $value) should either be compatible with ArrayAccess::offsetSet(mixed $offset, mixed $value): void, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /var/www/twodee/blog/wp-includes/rest-api/class-wp-rest-request.php on line 992

Deprecated: Return type of WP_REST_Request::offsetUnset($offset) should either be compatible with ArrayAccess::offsetUnset(mixed $offset): void, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /var/www/twodee/blog/wp-includes/rest-api/class-wp-rest-request.php on line 1003

Deprecated: Return type of WP_Block_List::current() should either be compatible with Iterator::current(): mixed, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /var/www/twodee/blog/wp-includes/class-wp-block-list.php on line 151

Deprecated: Return type of WP_Block_List::next() should either be compatible with Iterator::next(): void, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /var/www/twodee/blog/wp-includes/class-wp-block-list.php on line 175

Deprecated: Return type of WP_Block_List::key() should either be compatible with Iterator::key(): mixed, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /var/www/twodee/blog/wp-includes/class-wp-block-list.php on line 164

Deprecated: Return type of WP_Block_List::valid() should either be compatible with Iterator::valid(): bool, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /var/www/twodee/blog/wp-includes/class-wp-block-list.php on line 186

Deprecated: Return type of WP_Block_List::rewind() should either be compatible with Iterator::rewind(): void, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /var/www/twodee/blog/wp-includes/class-wp-block-list.php on line 138

Deprecated: Return type of WP_Block_List::offsetExists($index) should either be compatible with ArrayAccess::offsetExists(mixed $offset): bool, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /var/www/twodee/blog/wp-includes/class-wp-block-list.php on line 75

Deprecated: Return type of WP_Block_List::offsetGet($index) should either be compatible with ArrayAccess::offsetGet(mixed $offset): mixed, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /var/www/twodee/blog/wp-includes/class-wp-block-list.php on line 89

Deprecated: Return type of WP_Block_List::offsetSet($index, $value) should either be compatible with ArrayAccess::offsetSet(mixed $offset, mixed $value): void, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /var/www/twodee/blog/wp-includes/class-wp-block-list.php on line 110

Deprecated: Return type of WP_Block_List::offsetUnset($index) should either be compatible with ArrayAccess::offsetUnset(mixed $offset): void, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /var/www/twodee/blog/wp-includes/class-wp-block-list.php on line 127

Deprecated: Return type of WP_Block_List::count() should either be compatible with Countable::count(): int, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /var/www/twodee/blog/wp-includes/class-wp-block-list.php on line 199

Deprecated: Creation of dynamic property Automattic\Jetpack\Connection\Manager::$error_handler is deprecated in /var/www/twodee/blog/wp-content/plugins/jetpack/vendor/automattic/jetpack-connection/src/class-manager.php on line 91

Deprecated: Creation of dynamic property WPCOM_REST_API_V2_Endpoint_Instagram_Gallery::$is_wpcom is deprecated in /var/www/twodee/blog/wp-content/plugins/jetpack/_inc/lib/core-api/wpcom-endpoints/class-wpcom-rest-api-v2-endpoint-instagram-gallery.php on line 23

Deprecated: Creation of dynamic property WPCOM_REST_API_V2_Endpoint_Mailchimp::$wpcom_is_wpcom_only_endpoint is deprecated in /var/www/twodee/blog/wp-content/plugins/jetpack/_inc/lib/core-api/wpcom-endpoints/class-wpcom-rest-api-v2-endpoint-mailchimp.php on line 17

Deprecated: Creation of dynamic property WPCOM_REST_API_V2_Endpoint_Tweetstorm_Gather::$wpcom_is_wpcom_only_endpoint is deprecated in /var/www/twodee/blog/wp-content/plugins/jetpack/_inc/lib/core-api/wpcom-endpoints/class-wpcom-rest-api-v2-endpoint-tweetstorm-gather.php on line 21

Deprecated: Creation of dynamic property WPCOM_REST_API_V2_Endpoint_Tweetstorm_Gather::$is_wpcom is deprecated in /var/www/twodee/blog/wp-content/plugins/jetpack/_inc/lib/core-api/wpcom-endpoints/class-wpcom-rest-api-v2-endpoint-tweetstorm-gather.php on line 22

Deprecated: Creation of dynamic property WPCOM_REST_API_V2_Endpoint_Gutenberg_Available_Extensions::$wpcom_is_site_specific_endpoint is deprecated in /var/www/twodee/blog/wp-content/plugins/jetpack/_inc/lib/core-api/wpcom-endpoints/gutenberg-available-extensions.php on line 20

Deprecated: Creation of dynamic property WPCOM_REST_API_V2_Endpoint_Memberships::$wpcom_is_wpcom_only_endpoint is deprecated in /var/www/twodee/blog/wp-content/plugins/jetpack/_inc/lib/core-api/wpcom-endpoints/memberships.php on line 23

Deprecated: Creation of dynamic property WPCOM_REST_API_V2_Endpoint_Memberships::$wpcom_is_site_specific_endpoint is deprecated in /var/www/twodee/blog/wp-content/plugins/jetpack/_inc/lib/core-api/wpcom-endpoints/memberships.php on line 24

Deprecated: Creation of dynamic property WPCOM_REST_API_V2_Endpoint_Subscribers::$wpcom_is_wpcom_only_endpoint is deprecated in /var/www/twodee/blog/wp-content/plugins/jetpack/_inc/lib/core-api/wpcom-endpoints/subscribers.php on line 15

Deprecated: Creation of dynamic property Automattic\Jetpack\Sync\Queue::$random_int is deprecated in /var/www/twodee/blog/wp-content/plugins/jetpack/vendor/automattic/jetpack-sync/src/class-queue.php on line 38

Deprecated: Creation of dynamic property Automattic\Jetpack\Sync\Queue::$random_int is deprecated in /var/www/twodee/blog/wp-content/plugins/jetpack/vendor/automattic/jetpack-sync/src/class-queue.php on line 38

Deprecated: Creation of dynamic property WPCOM_Widget_Goodreads::$shelves is deprecated in /var/www/twodee/blog/wp-content/plugins/jetpack/modules/widgets/goodreads.php on line 33

Deprecated: DateTime::__construct(): Passing null to parameter #1 ($datetime) of type string is deprecated in /var/www/twodee/blog/wp-includes/script-loader.php on line 348

Deprecated: Creation of dynamic property Advanced_Editor_Tools::$toolbar_classic_block is deprecated in /var/www/twodee/blog/wp-content/plugins/tinymce-advanced/tinymce-advanced.php on line 347

Deprecated: Creation of dynamic property Advanced_Editor_Tools::$toolbar_block is deprecated in /var/www/twodee/blog/wp-content/plugins/tinymce-advanced/tinymce-advanced.php on line 349

Deprecated: Creation of dynamic property Advanced_Editor_Tools::$toolbar_block_side is deprecated in /var/www/twodee/blog/wp-content/plugins/tinymce-advanced/tinymce-advanced.php on line 350

Deprecated: Creation of dynamic property Advanced_Editor_Tools::$panels_block is deprecated in /var/www/twodee/blog/wp-content/plugins/tinymce-advanced/tinymce-advanced.php on line 351

Deprecated: Creation of dynamic property Advanced_Editor_Tools::$used_block_buttons is deprecated in /var/www/twodee/blog/wp-content/plugins/tinymce-advanced/tinymce-advanced.php on line 354

Deprecated: Creation of dynamic property WP_Block_Type::$plan_check is deprecated in /var/www/twodee/blog/wp-includes/class-wp-block-type.php on line 333

Deprecated: Creation of dynamic property WP_Block_Type::$plan_check is deprecated in /var/www/twodee/blog/wp-includes/class-wp-block-type.php on line 333

Deprecated: Creation of dynamic property WP_Block_Type::$plan_check is deprecated in /var/www/twodee/blog/wp-includes/class-wp-block-type.php on line 333

Deprecated: Creation of dynamic property WP_Block_Type::$plan_check is deprecated in /var/www/twodee/blog/wp-includes/class-wp-block-type.php on line 333

Deprecated: Creation of dynamic property WP_Block_Type::$plan_check is deprecated in /var/www/twodee/blog/wp-includes/class-wp-block-type.php on line 333

Deprecated: Creation of dynamic property WP_Block_Type::$plan_check is deprecated in /var/www/twodee/blog/wp-includes/class-wp-block-type.php on line 333

Deprecated: Creation of dynamic property WP_Term::$object_id is deprecated in /var/www/twodee/blog/wp-includes/class-wp-term.php on line 198

Deprecated: Creation of dynamic property WP_Term::$object_id is deprecated in /var/www/twodee/blog/wp-includes/class-wp-term.php on line 198

Deprecated: Creation of dynamic property WP_Term::$object_id is deprecated in /var/www/twodee/blog/wp-includes/class-wp-term.php on line 198
» CS 145 Lecture 14 – Testing and conditionals via collision detection

teaching machines

CS 145 Lecture 14 – Testing and conditionals via collision detection

October 28, 2011 by . Filed under
Deprecated: Creation of dynamic property WP_Term::$cat_ID is deprecated in /var/www/twodee/blog/wp-includes/category.php on line 378

Deprecated: Creation of dynamic property WP_Term::$category_count is deprecated in /var/www/twodee/blog/wp-includes/category.php on line 379

Deprecated: Creation of dynamic property WP_Term::$category_description is deprecated in /var/www/twodee/blog/wp-includes/category.php on line 380

Deprecated: Creation of dynamic property WP_Term::$cat_name is deprecated in /var/www/twodee/blog/wp-includes/category.php on line 381

Deprecated: Creation of dynamic property WP_Term::$category_nicename is deprecated in /var/www/twodee/blog/wp-includes/category.php on line 382

Deprecated: Creation of dynamic property WP_Term::$category_parent is deprecated in /var/www/twodee/blog/wp-includes/category.php on line 383

Deprecated: Creation of dynamic property WP_Term::$cat_ID is deprecated in /var/www/twodee/blog/wp-includes/category.php on line 378

Deprecated: Creation of dynamic property WP_Term::$category_count is deprecated in /var/www/twodee/blog/wp-includes/category.php on line 379

Deprecated: Creation of dynamic property WP_Term::$category_description is deprecated in /var/www/twodee/blog/wp-includes/category.php on line 380

Deprecated: Creation of dynamic property WP_Term::$cat_name is deprecated in /var/www/twodee/blog/wp-includes/category.php on line 381

Deprecated: Creation of dynamic property WP_Term::$category_nicename is deprecated in /var/www/twodee/blog/wp-includes/category.php on line 382

Deprecated: Creation of dynamic property WP_Term::$category_parent is deprecated in /var/www/twodee/blog/wp-includes/category.php on line 383

Deprecated: Creation of dynamic property WP_Term::$cat_ID is deprecated in /var/www/twodee/blog/wp-includes/category.php on line 378

Deprecated: Creation of dynamic property WP_Term::$category_count is deprecated in /var/www/twodee/blog/wp-includes/category.php on line 379

Deprecated: Creation of dynamic property WP_Term::$category_description is deprecated in /var/www/twodee/blog/wp-includes/category.php on line 380

Deprecated: Creation of dynamic property WP_Term::$cat_name is deprecated in /var/www/twodee/blog/wp-includes/category.php on line 381

Deprecated: Creation of dynamic property WP_Term::$category_nicename is deprecated in /var/www/twodee/blog/wp-includes/category.php on line 382

Deprecated: Creation of dynamic property WP_Term::$category_parent is deprecated in /var/www/twodee/blog/wp-includes/category.php on line 383
cs145, fall 2011, lectures.

Agenda

Collision detection

  1. Suppose you have two horizontal line segments in the same line. (Or two pens.) When are they intersecting?
  2. Suppose you have two circles. When are they intersecting?
  3. Suppose you have two rectangles. When are they intersecting?

Code

CollisionUtilities.java

package lecture;

import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;

public class CollisionUtilities {

  public static void main(String[] args) throws FileNotFoundException {
    Scanner in = new Scanner(new File("/home/cjohnson/Desktop/lines.txt"));

    while (in.hasNextDouble()) {
      double leftA = in.nextDouble();
      double rightA = in.nextDouble();
      double leftB = in.nextDouble();
      double rightB = in.nextDouble();
      boolean expected = in.nextBoolean();

      boolean actual = isColliding(leftA, rightA, leftB, rightB);
      if (actual != expected) {
        System.out.printf("[%f, %f] vs. [%f, %f] expected: " + expected + ", actual: " + actual + "%n", leftA, rightA, leftB, rightB);
      }
    }

    in.close();
  }

  /**
   * Checks whether two 1-D line segments intersect.
   * 
   * @param leftA
   * Left bounds of line segment A, assumed < rightA
   * @param rightA
   * Right bounds of line segment A
   * @param leftB
   * Left bounds of line segment B, assumed < rightB
   * @param rightB
   * Right bounds of line segment B
   * @return True if they collide, false otherwise
   */
  public static boolean isColliding(double leftA,
                                    double rightA,
                                    double leftB,
                                    double rightB) {
    return !(leftB > rightA || rightB < leftA);
  }

}

Test-driven development

Here’s by far the best strategy for writing a method with minimal headache:

  1. Write its specification. What does it need to do? What does it needs from the outside world? What does it give back the outside world?
  2. Write its signature/interface.
  3. Write tests.
  4. Implement it.
  5. Execute your tests.