• Announcements

    • khawk

      Download the Game Design and Indie Game Marketing Freebook   07/19/17

      GameDev.net and CRC Press have teamed up to bring a free ebook of content curated from top titles published by CRC Press. The freebook, Practices of Game Design & Indie Game Marketing, includes chapters from The Art of Game Design: A Book of Lenses, A Practical Guide to Indie Game Marketing, and An Architectural Approach to Level Design. The GameDev.net FreeBook is relevant to game designers, developers, and those interested in learning more about the challenges in game development. We know game development can be a tough discipline and business, so we picked several chapters from CRC Press titles that we thought would be of interest to you, the GameDev.net audience, in your journey to design, develop, and market your next game. The free ebook is available through CRC Press by clicking here. The Curated Books The Art of Game Design: A Book of Lenses, Second Edition, by Jesse Schell Presents 100+ sets of questions, or different lenses, for viewing a game’s design, encompassing diverse fields such as psychology, architecture, music, film, software engineering, theme park design, mathematics, anthropology, and more. Written by one of the world's top game designers, this book describes the deepest and most fundamental principles of game design, demonstrating how tactics used in board, card, and athletic games also work in video games. It provides practical instruction on creating world-class games that will be played again and again. View it here. A Practical Guide to Indie Game Marketing, by Joel Dreskin Marketing is an essential but too frequently overlooked or minimized component of the release plan for indie games. A Practical Guide to Indie Game Marketing provides you with the tools needed to build visibility and sell your indie games. With special focus on those developers with small budgets and limited staff and resources, this book is packed with tangible recommendations and techniques that you can put to use immediately. As a seasoned professional of the indie game arena, author Joel Dreskin gives you insight into practical, real-world experiences of marketing numerous successful games and also provides stories of the failures. View it here. An Architectural Approach to Level Design This is one of the first books to integrate architectural and spatial design theory with the field of level design. The book presents architectural techniques and theories for level designers to use in their own work. It connects architecture and level design in different ways that address the practical elements of how designers construct space and the experiential elements of how and why humans interact with this space. Throughout the text, readers learn skills for spatial layout, evoking emotion through gamespaces, and creating better levels through architectural theory. View it here. Learn more and download the ebook by clicking here. Did you know? GameDev.net and CRC Press also recently teamed up to bring GDNet+ Members up to a 20% discount on all CRC Press books. Learn more about this and other benefits here.
Sign in to follow this  
Followers 0
  • entries
    6
  • comments
    0
  • views
    7900

Arkanong part 1: Porting for the sake of sanity

Sign in to follow this  
Followers 0
molehill mountaineer

786 views

Last year I decided that I had enough of my procrastrination (and several other bad habits) and began a process of self-reformation.
Part of this undertaking was the development of a small framework with which I could make a pong clone. The plan was to build the engine as an educational exercise, produce several small games and perhaps form a development partnership with somebody on this site down the road.

This is what I managed to put together:


solipsist_pong.png



It's pong meets breakout with several balls - touching the other player's balls (heh heh) will convert them to yours and vice versa. The paddle can move in eight directions up to a certain vertical limit and the bricks contain powerups (not yet implemented except a single "cheat key" which will cause the blue balls to move much faster).


This took a long time to make, as I have school and 'real world' projects competing for my time.
The real problem though, was that every single step of the way was new to me.
Drawing quads on screen, batching sprites, implementing physics for bouncing balls off each other, working with sound, writing code that generates textured quads because for some reason directX10 doesn't support drawing text on screen, etcetera.
Although the code works, the 'engine' and game quickly became a patchwork of messy amateur implementations. Check this out: (don't read the whole thing unless you're a masochist)void PongPrototype::performCollisionChecks(){ HitRegion* playerRegion = m_pHumanPlayer->getPaddle()->getHitRegion(); //HitRegion* enemyRegion = m_pEnemyPaddle->getHitRegion(); HitRegion* enemyRegion = m_pEnemyPlayer->getPaddle()->getHitRegion(); HitRegion* ballRegion = NULL; HitRegion* brickRegion = NULL; Ball* currentBall = NULL; // //check player collisions against level border and correct if necessary if(checkBorderCollision(playerRegion)) { correctPaddleOverschoot(m_pHumanPlayer->getPaddle()); } if(checkBorderCollision(enemyRegion)) { //correctPaddleOverschoot(m_pEnemyPaddle); correctPaddleOverschoot(m_pEnemyPlayer->getPaddle()); } //iterate over balls and perform collision checks std::vector::iterator it = m_balls.begin(); for(it; it != m_balls.end(); ++it) { currentBall = (*it); if(currentBall != NULL) //is there a ball to check? { ballRegion = (*it)->getHitRegion(); //check ball collision against border if(checkBorderCollision(ballRegion)) { correctBallovershoot(currentBall); bounceBallOffWall(currentBall); } // // //it's important that we check the ball against paddle (in checkRegionCollision) and not the other way around // //-> because of the way that the collision is calculated a larger hitregion checked against a // //smaller one will not return true. // //check ball collision against players if(m_pParentProject->checkRegionCollision(ballRegion, playerRegion)) //did ball hit player paddle? { bounceBallOffPaddle(currentBall, m_pHumanPlayer->getPaddle()); } if(m_pParentProject->checkRegionCollision(ballRegion, enemyRegion)) //did ball hit player paddle? { //bounceBallOffPaddle((*it), m_pEnemyPaddle); bounceBallOffPaddle(currentBall, m_pEnemyPlayer->getPaddle()); } // //iterate over bricks and perform checks //iterate over bricks and perform collision checks std::vector::iterator brickIt = m_bricks.begin(); for(brickIt; brickIt != m_bricks.end(); ++brickIt) { if((*brickIt) != NULL) //is there a brick to check? { brickRegion = (*brickIt)->getHitRegion(); if(m_pParentProject->checkRegionCollision(ballRegion, brickRegion)) { bounceBallOffBrick((*brickIt), currentBall); } } } //finally iterate over entire ball vector to perform collision checks with other balls std::vector::iterator it2 = m_balls.begin(); for(it2; it2 != m_balls.end(); ++it2) { //we've got to make sure that there is a ball to collide and that //we don't "collide" with ourself if((*it2 != NULL) && (it2 != it)) { HitRegion* otherBallRegion = (*it2)->getHitRegion(); //did the balls hit each other? if(m_pParentProject->checkRegionCollision(ballRegion, otherBallRegion)) bounceBallsOffEachOther(currentBall, *it2); } } } }}//this function moves the ball back a little if it's gone past the window edgesvoid PongPrototype::correctBallovershoot(Ball* p_ball){ floatRect region = p_ball->getHitRegion()->getRegion(); XMFLOAT2 offset; offset.x = 0.0f; offset.y = 0.0f; if(region.left <= 0) offset.x -= region.left; //negative number so we subtract if(region.right > SOLIPSIST.getWindowWidth()) offset.x -= (region.right - SOLIPSIST.getWindowWidth()); //hit top or bottom? adjust overshoot and flip y direction if(region.bottom <= 0) offset.y -= region.bottom; if(region.top > SOLIPSIST.getWindowHeight()) offset.y -= (region.top - SOLIPSIST.getWindowHeight()); //adjust overshoot p_ball->move(offset);}void PongPrototype::bounceBallsOffEachOther(Ball* p_ballOne, Ball* p_ballTwo){ //hitregion is a bit smaller than the actual ball so we add a margin int ballOneRadius = (p_ballOne->getHitRegion()->getRegionWidth() / 2) + 2; int ballTwoRadius = (p_ballTwo->getHitRegion()->getRegionWidth() / 2) + 2; //find out the normal to the collision plane (by normalizing the distance between the centerpoints //position = centerpoint XMFLOAT2 ballOnePosition = p_ballOne->getBitmap()->getPosition(); XMFLOAT2 ballTwoPosition = p_ballTwo->getBitmap()->getPosition(); XMFLOAT2 normalVector; normalVector.x = ballOnePosition.x - ballTwoPosition.x; normalVector.y = ballOnePosition.y - ballTwoPosition.y; //find out magnitude (=length) of directional vector by taking square root of squared components //(brush up on vector math if you don't understand this bit) float normalMagnitude = sqrt((normalVector.x * normalVector.x) + (normalVector.y * normalVector.y)); if(normalMagnitude <= (ballOneRadius + ballTwoRadius)) //collision? { //move balls back a little to correct any overshoot so the hitregions don't get stuck inside eachother float overshoot = (ballOneRadius + ballTwoRadius) - normalMagnitude; XMFLOAT2 overshootCorrection; overshootCorrection.x = (-p_ballOne->getDirection().x * overshoot); overshootCorrection.y = (-p_ballOne->getDirection().y * overshoot); p_ballOne->move(overshootCorrection); overshootCorrection.x = (-p_ballTwo->getDirection().x * overshoot); overshootCorrection.y = (-p_ballTwo->getDirection().y * overshoot); p_ballTwo->move(overshootCorrection); //make normal to collision plane a unit vector XMFLOAT2 unitNormal; unitNormal.x = normalVector.x / normalMagnitude; unitNormal.y = normalVector.y / normalMagnitude; //find unit tangent to collision plane //since tangent is perpendicular to collision plane we can //get the unit tangent from the unit normal XMFLOAT2 unitTangent; unitTangent.x = -unitNormal.y; unitTangent.y = unitNormal.x; //project velocity onto normal and tangent (= decomposing the velocity vector into tangent & normal) XMFLOAT2 ball1Velocity; ball1Velocity.x = p_ballOne->getDirection().x * p_ballOne->getSpeed(); ball1Velocity.y = p_ballOne->getDirection().y * p_ballOne->getSpeed(); float normalSpeed1, tangentSpeed1; float xDot, yDot; //project velocity onto normal xDot = ball1Velocity.x * unitNormal.x; yDot = ball1Velocity.y * unitNormal.y; normalSpeed1 = xDot + yDot; //project velocity onto tangent xDot = ball1Velocity.x * unitTangent.x; yDot = ball1Velocity.y * unitTangent.y; tangentSpeed1 = xDot + yDot; //preserve tangent and normal velocities (unlike pool, where normal velocity would be affected from collision) XMFLOAT2 newDirection1; newDirection1.x = -(unitNormal.x * normalSpeed1) + (unitTangent.x * tangentSpeed1); newDirection1.y = -(unitNormal.y * normalSpeed1) + (unitTangent.y * tangentSpeed1); float directionalMagnitude = sqrt((newDirection1.x * newDirection1.x) + (newDirection1.y * newDirection1.y)); newDirection1.x /= directionalMagnitude; newDirection1.y /= directionalMagnitude; p_ballOne->setDirection(newDirection1); //project velocity onto normal and tangent (= decomposing the velocity vector into tangent & normal) XMFLOAT2 ball2Velocity; ball2Velocity.x = p_ballTwo->getDirection().x * p_ballTwo->getSpeed(); ball2Velocity.y = p_ballTwo->getDirection().y * p_ballTwo->getSpeed(); float normalSpeed2, tangentSpeed2; //project velocity onto normal xDot = ball2Velocity.x * unitNormal.x; yDot = ball2Velocity.y * unitNormal.y; normalSpeed2 = xDot + yDot; //project velocity onto tangent xDot = ball2Velocity.x * unitTangent.x; yDot = ball2Velocity.y * unitTangent.y; tangentSpeed2 = xDot + yDot; //preserve tangent and normal velocities (unlike pool, where normal velocity would be affected from collision) XMFLOAT2 newDirection2; newDirection2.x = (unitNormal.x * normalSpeed1) + (unitTangent.x * tangentSpeed2); newDirection2.y = (unitNormal.y * normalSpeed1) + (unitTangent.y * tangentSpeed2); directionalMagnitude = sqrt((newDirection2.x * newDirection2.x) + (newDirection2.y * newDirection2.y)); newDirection2.x /= directionalMagnitude; newDirection2.y /= directionalMagnitude; p_ballTwo->setDirection(newDirection2); }}void PongPrototype::bounceBallOffWall(Ball* &p_ball){ //bool markedForDeletion = false; XMFLOAT2 direction = p_ball->getDirection(); floatRect region = p_ball->getHitRegion()->getRegion(); //hit left or right? adjust overshoot and flip x direction if(region.left <= 0) { direction.x = -direction.x; } if(region.right >= SOLIPSIST.getWindowWidth()) { direction.x = -direction.x; } //hit top or bottom? adjust overshoot and flip y direction + check scoring conditions if(region.bottom <= 0) { //player ball bounces of bottom, otherwise score if(p_ball->isFriendly()) direction.y = -direction.y; //else //ball wasn't friendly, score ball //{ // m_enemyScore++; // markedForDeletion = true; //} } if(region.top >= SOLIPSIST.getWindowHeight()) { /*if(p_ball->isFriendly()) { m_playerScore++; markedForDeletion = true; }*/ if(!p_ball->isFriendly()) { direction.y = -direction.y; } } //change direction p_ball->setDirection(direction); //if(markedForDeletion) //{ // //TODO: let pass pass through hitregion before deleting // delete p_ball; // p_ball = 0; //}}//check which balls are in the score zone, remove them and mark up the scorevoid PongPrototype::removeOvershotBalls(){ m_playerScore += m_pHumanPlayer->removeOvershotBalls(m_pParentProject->getWindowHeight() - 20); m_enemyScore += m_pEnemyPlayer->removeOvershotBalls(20);}//this function is only called when a collision is already detected, so //we just have to check which side of the paddle was hitvoid PongPrototype::bounceBallOffPaddle(Ball* p_ball, Paddle* p_paddle){ //these boolean are used to determine which part of the brick the ball hit bool top = false; bool bottom = false; bool left = false; bool right = false; //these floats are used to determine have far the "overshoot" is (that is, how deep one hitregion penetrated into another // - we need this value to make sure things don't get stuck to each other when a collision has occured) float ballRadius = p_ball->getHitRegion()->getRegionWidth() / 2; float paddleWidth = p_paddle->getHitRegion()->getRegionWidth(); float paddleHeight = p_paddle->getHitRegion()->getRegionHeight(); XMFLOAT2 overshootNudge; overshootNudge.x = 0.0f; overshootNudge.y = 0.0f; //centerpoints of colliding objects XMFLOAT2 paddlePosition = p_paddle->getPosition(); XMFLOAT2 ballPosition = p_ball->getPosition(); //direction of ball after hitting paddle (we "flip" these values) XMFLOAT2 ballDirectionPrime; ballDirectionPrime.x = p_ball->getDirection().x; ballDirectionPrime.y = p_ball->getDirection().y; //distance of the impact from the centrepoint of the brick // x > 0 = ball is on right side of brick centre // x < 0 = ball is on left side of brick centre // y > 0 = ball is above brick centre // y < 0 = ball is below brick centre XMFLOAT2 impactDistance; impactDistance.x = ballPosition.x - paddlePosition.x; impactDistance.y = ballPosition.y - paddlePosition.y; if(impactDistance.x > 0) right = true; if(impactDistance.x < 0) left = true; if(impactDistance.y > 0) top = true; if(impactDistance.y < 0) bottom = true; float paddleWidthHalved = paddleWidth/2; float paddleHeightHalved = paddleHeight/2; if(left) //impact distance is a negative number (x < 0 -> left) { //if the centre of the ball isn't positioned past the left wall of the brick we can assume it's a top or bottom hit if((impactDistance.x + paddleWidthHalved) > 0) left = false; } if(right) //impact distance is a positive number (x > 0 -> right) { if((impactDistance.x - paddleWidthHalved) < 0) right = false; } if(bottom) //distance is negative (y < 0 -> bottom) { if((impactDistance.y + paddleHeightHalved) > 0) bottom = false; } if(top) { if((impactDistance.y - paddleHeightHalved) < 0) top = false; } if(top || bottom) { ballDirectionPrime.y *= -1; float yNudge = 0.0f; if(top) yNudge = (paddleHeightHalved + ballRadius) - impactDistance.y; if(bottom) yNudge = (paddleHeightHalved + ballRadius + impactDistance.y) * -1; if(yNudge < 0) overshootNudge.y = floor(yNudge); if(yNudge > 0) overshootNudge.y = ceil(yNudge); } if(left || right) { ballDirectionPrime.x *= -1; float xNudge = 0.0f; //x-nudge only for hit on the sides if(right && !(top || bottom)) xNudge = (paddleWidthHalved + ballRadius) - impactDistance.x; if(left && !(top ||bottom)) xNudge = (impactDistance.x + paddleWidthHalved + ballRadius) * -1; if(xNudge < 0) overshootNudge.x = floor(xNudge); if(xNudge > 0) overshootNudge.x = ceil(xNudge); } Paddle* AIPaddle = m_pEnemyPlayer->getPaddle(); Paddle* humanPaddle = m_pHumanPlayer->getPaddle(); if(p_ball->isFriendly() && p_paddle == AIPaddle) { //remove reference to ball from player vector m_pHumanPlayer->popBall(p_ball); p_ball->setFriendly(false); XMFLOAT2 position; position.x = p_ball->getPosition().x; position.y = p_ball->getPosition().y; p_ball->cleanup(); p_ball->initialize(SOLIPSIST.getGraphics(), _T("Graphics/Sprites/enemyBall.dds")); p_ball->move(position); m_pEnemyPlayer->pushBall(p_ball); } if(!(p_ball->isFriendly()) && p_paddle == humanPaddle) { //remove reference to ball from enemy vector m_pEnemyPlayer->popBall(p_ball); p_ball->setFriendly(true); XMFLOAT2 position; position.x = p_ball->getPosition().x; position.y = p_ball->getPosition().y; p_ball->cleanup(); p_ball->initialize(SOLIPSIST.getGraphics(), _T("Graphics/Sprites/playerBall.dds")); p_ball->move(position); m_pHumanPlayer->pushBall(p_ball); } p_ball->move(overshootNudge); p_ball->setDirection(ballDirectionPrime);}//TODO: dit heeft eigenlijk geen aparte functie nodigvoid PongPrototype::bounceBallOffBrick(PowerupBrick* p_brick, Ball* p_ball){ //these boolean are used to determine which part of the brick the ball hit bool top = false; bool bottom = false; bool left = false; bool right = false; //these floats are used to determine have far the "overshoot" is (that is, how deep one hitregion penetrated into another // - we need this value to make sure things don't get stuck to each other when a collision has occured) float ballRadius = p_ball->getHitRegion()->getRegionWidth() / 2; float brickWidth = p_brick->getHitRegion()->getRegionWidth(); float brickHeight = p_brick->getHitRegion()->getRegionHeight(); XMFLOAT2 overshootNudge; overshootNudge.x = 0.0f; overshootNudge.y = 0.0f; //centerpoints of colliding objects XMFLOAT2 brickPosition = p_brick->getPosition(); XMFLOAT2 ballPosition = p_ball->getPosition(); //direction of ball after hitting paddle (we "flip" these values) XMFLOAT2 ballDirectionPrime; ballDirectionPrime.x = p_ball->getDirection().x; ballDirectionPrime.y = p_ball->getDirection().y; //distance of the impact from the centrepoint of the brick // x > 0 = ball is on right side of brick centre // x < 0 = ball is on left side of brick centre // y > 0 = ball is above brick centre // y < 0 = ball is below brick centre XMFLOAT2 impactDistance; impactDistance.x = (ballPosition.x - brickPosition.x); impactDistance.y = ballPosition.y - brickPosition.y; if(impactDistance.x > 0) right = true; if(impactDistance.x < 0) left = true; if(impactDistance.y > 0) top = true; if(impactDistance.y < 0) bottom = true; float brickWidthHalved = brickWidth/2; float brickHeightHalved = brickHeight/2; if(left) //impact distance is a negative number (x < 0 -> left) { //if the centre of the ball isn't positioned past the left wall of the brick we can assume it's a top or bottom hit if((impactDistance.x + brickWidthHalved) > 0) left = false; } if(right) //impact distance is a positive number (x > 0 -> right) { if((impactDistance.x - brickWidthHalved) < 0) right = false; } if(bottom) //distance is negative (y < 0 -> bottom) { if((impactDistance.y + brickHeightHalved) > 0) bottom = false; } if(top) { if((impactDistance.y - brickHeightHalved) < 0) top = false; } if(top || bottom) { ballDirectionPrime.y *= -1; float yNudge = 0.0f; if(top) yNudge = (brickHeightHalved + ballRadius) - impactDistance.y; if(bottom) yNudge = (brickHeightHalved + ballRadius + impactDistance.y) * -1; if(yNudge < 0) overshootNudge.y = floor(yNudge); if(yNudge > 0) overshootNudge.y = ceil(yNudge); } if(left || right) { ballDirectionPrime.x *= -1; float xNudge = 0.0f; //x-nudge only for hit on the sides if(right && !(top || bottom)) xNudge = (brickWidthHalved + ballRadius) - impactDistance.x; if(left && !(top ||bottom)) xNudge = (impactDistance.x + brickWidthHalved + ballRadius) * -1; if(xNudge < 0) overshootNudge.x = floor(xNudge); if(xNudge > 0) overshootNudge.x = ceil(xNudge); } p_ball->move(overshootNudge); p_ball->setDirection(ballDirectionPrime); p_brick->decreaseHitCounter();}//The purpose of this function is to keep the paddle within the confines of the WIN32 window //and prevent the player from moving his paddle out of sightvoid PongPrototype::correctPaddleOverschoot(Paddle* p_paddle){ XMFLOAT2 offset; offset.x = 0.0f; offset.y = 0.0f; int windowWidth = SOLIPSIST.getWindow()->getWidth(); int windowHeight = SOLIPSIST.getWindow()->getHeight(); floatRect region = p_paddle->getHitRegion()->getRegion(); float margin = 0.4f; //store overshoot corrections if(region.left < 0) offset.x -= (region.left - margin); //subtract because region.left is a negative value if(region.bottom < 0) offset.y -= (region.bottom - margin); //same here, subtract because it's a negative value if(region.right > windowWidth) offset.x -= (region.right - windowWidth) - margin; if(region.top > windowHeight) offset.y -= (region.top - windowHeight) - margin; p_paddle->move(offset); XMFLOAT2 nullDirection; nullDirection.x = 0.0f; nullDirection.y = 0.0f; p_paddle->setDirection(nullDirection);}//check collision against edges of window bool PongPrototype::checkBorderCollision(HitRegion* p_region){ bool collision = false; floatRect rect = p_region->getRegion(); //retrieve the location of the hitregion (HitRegion is a wrapper for floatRect) //check the border of the map and adjust any overshoots if( rect.bottom <= 0 || rect.top >= SOLIPSIST.getWindow()->getHeight() || rect.left <= 0 || rect.right >= SOLIPSIST.getWindow()->getWidth()) collision = true; return collision;}
Ugh - that is alot of ugly code just for bouncing a bunch of balls and sticks around.
So, to make a long story short I've decided to kill project solipsist (yes my engine had a name that snooty) and decided to remake the game in SFML.

Don't get me wrong - I'm happy I did it because I learned a ton of stuff BUT:
1) I would like the game to be finished sometime before 2020
2) I would like a modicum of portability
3) I would like to see the inner workings of a properly coded framework
4) the prospect of clean code appeals to me
5) I'm a sucker for reputation points and am going to blog about making this game (and maybe refactoring solipsist).


So yesterday I spent the whole day following this SFML tutorial and have gotten up to this point:

reloaded_pong.png



...and now I'm about to work on the collision detection. This is where my code will being to diverge since my paddles move up and down and the player will have multiple balls bouncing around (heh heh again) .

Obviously I'm hoping to avoid the messy code you saw earlier - that's why I'm currently teaching myself trigonometry - if you want to do the same thing I suggest you check out udacity or khan academy.



I'll try to post code and explanations as new things are added. Hopefully newbies can follow along and learn a thing or two.
I didn't do that for this post since it would pretty much be a rip off from the tutorial I posted a link to.

Also, since I am quite busy some patience will be required - Thanks for reading!

0
Sign in to follow this  
Followers 0


0 Comments


There are no comments to display.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now