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Chapter 3: Sprites

What are Sprites

A Sprite is a 2D graphic. A Sprite is a single Texture.

Creating Sprites

Creating a Textured Sprite

auto mySprite = Sprite::create("mysprite.png");

Creating an Untextured Sprite

auto mySprite = Sprite::create();

Creating a Sprite From a SpriteFrame

auto frame = SpriteFrame::createWithTexture(texture, rect, offset);
    
auto mysprite = Sprite::createWithSpriteFrame(frame);

Creating a Sprite From SpriteCache

auto mysprite = Sprite::createWithSpriteFrameName("mysprite.png");

Creating a Sprite From a Rect

auto mySprite = Sprite::create("mysprite.png", Rect(0,0,40,40));

Sprite Manipulation

After creating a Sprite, there are a variety of functions that can be applied to it.

Given:

auto mySprite = Sprite::create("mysprite.png");

Resizing

// increases X and Y size by 4.0 uniformly
mySprite->setScale(4.0);

// increases just X scale by 4.0
mySprite->setScaleX(4.0);

// increases just Y scale by 4.0
mySprite->setScaleY(4.0);

Anchor Point and Position

// bottom left
mySprite->setAnchorPoint(0, 0);

// middle
mySprite->setAnchorPoint(0.5, 0.5);

// top right
mySprite->setAnchorPoint(1, 1);

Skew

// adjusts the X and Y skew by 4.0 uniformly
mySprite->setSkew(4.0);

// adjusts the X skew by 4.0
mySprite->setSkewX(4.0);

// adjusts the Y skew by 4.0
mySprite->setSkewY(4.0);

Sprite Sheets

A sprite sheet a way to combine sprites into a single texture while reducing the overall size compared to loading each Sprite individually. Why does this matter? When loading a Sprite each hardware platform has constraints of a minimum texture size that it will need to load. As you can imagine there is a lot of unused space and this increases memory consumption, draw times and lowers your games frame rate. Using a sprite sheet allows all of your sprites to be condensed filing unused space. Now only the entire spritesheet must meet the hardwares constraints and can be loaded all at the same time. This means you will significantly reduce memory usage, reduce the time it takes OpenGL to draw your sprites and keep the frame rate of your game high.

Here is an example sprite sheet:

Load your sprite sheet into the SpriteFrameCache, probably in AppDelegate:

auto spritecache = SpriteFrameCache::getInstance();
spritecache->addSpriteFramesWithFile("sprites.plist");

A few examples of working with a sprite sheet:

Creating a Sprite from the SpriteFrameCache

auto mySprite = Sprite::createWithSpriteFrameName("mysprite.png");

Creating an Animation from SpriteFrameCache

auto anim1 = Animation::create();
anim1->addSpriteFrameWithFile("enemystand.png");
anim1->addSpriteFrameWithFile("enemymove1.png");
anim1->addSpriteFrameWithFile("enemymove2.png");
anim1->addSpriteFrameWithFile("enemymove3.png");
anim1->addSpriteFrameWithFile("enemymove4.png");
anim1->addSpriteFrameWithFile("enemymove5.png");
anim1->addSpriteFrameWithFile("enemyjump.png");
  
auto animation = Animate::create(anim1);
animation->setDuration(0.2f);
sprite->runAction(RepeatForever::create(animation));

Tools for creating Sprite Sheets

Coco Studio

Texture Packer

Zwoptex