GLata is an Android library for creating multi-object and resource-heavy animations using OpenGL for Embedded Systems.

I bet you’re familiar with Canvas, ObjectAnimator, and MotionLayout. These standard Android solutions are undeniably great for creating simple animations. However, they may not always be enough for drawing massive animations with loads of moving objects and/or large images. This may be a task for OpenGL ES. However, setting up OpenGL usually takes a lot of time, especially if you’ve never done it before. GLata not only does the initial setup for you but suggests tools to start drawing complex animations right away. These include tools for:

• Creating a rectangle and applying an image to it
• Setting up a camera and specifying the visible area
• Applying a bunch of shaders including blur and tint
• Applying basic animations: movement, scaling, rotation, texture switching
• Using the ETC1 compressed texture format for faster loading

And one more thing: GLata lets you use native OpenGL ES calls and tricks, which is not usually the case for large graphics frameworks. Consider this library a lightweight wrapper for OpenGL ES and your launching pad for creating complex animations.

Add jitpack repo in your root build.gradle at the end of repositories:

	allprojects {
		repositories {
			...
			maven { url 'https://jitpack.io' }
		}
	}

And add dependency in your app module

	dependencies {
	        implementation 'com.github.Yalantis:GLata:0.1.1'
	}

Now you can add android.opengl.GLSurfaceView to the xml layout. You can specify any width and height. Also you can use MotionableGLSurfaceView if you need your animation to react to gestures.

<?xml version="1.0" encoding="utf-8"?>
<android.opengl.GLSurfaceView
        android:id="@+id/surfaceView"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

Now, you have to extend Scene class and override onAttach method. This is where the initialization of your animation scene happens. Here you create shaders and objects, set up camera and specify the animations.

    class MyScene() : Scene(sp) {
          override fun onAttach(rp: RendererParams) {
                super.onAttach(rp)
                rendererParams.managers.shaderManager.apply {
			add(Shaders.DEFAULT_COLOR_SHADER)
			add(Shaders.DEFAULT_TEXTURE_SHADER)
		}
                sceneParams.camera.apply {
            		setMaximumVisibleArea(10f, 10f)
            		setPivot(Align.CENTER)
            		setProjectionMatrix()
       		 }
        
                ...
            }

    }

You have to create a rectangle, specify its color or texture (you can use R.drawable... or just pass an image name as a string), attach a shader and create animation. Currently you can choose only movement, scale, rotation or texture switching animation (or all at once and wrap them into AnimationList). Most of the time this is enough but you can implement an IAnimation interface and create your own.

        val rect1 = Rectangle.builder()
                .setGradientColor(Color(1f, 0f, 0f, 1f), Color(0f, 1f, 0f, 1f),
                        Color(0f, 0f, 1f, 1f), Color(0.6f, 0.6f, 0.6f, 1f))
                .build()
        rect1.animation = ScalingAnimation(
                startScalingFrom = 0.8f, 
                scaleTo = 1f, 
                scaleTimeMillis = 1000f).apply {
            isInfinite = true
            interpolator = AccelerateDecelerateInterpolator()
        }
        rect1.modelParams.apply {
            setShader(Shaders.DEFAULT_COLOR_SHADER)
            transform.position.x = -1f
        }
        addChild(rect1)
            
        val rect2 = Rectangle
                .builder()
                .setTexture(rendererParams.managers.textureManager.add(Texture(rendererParams, "ava_2")))
                .build()
        rect2.animation = AxisMovementAnimation(
                axis = Axis.Y,
                initialPosition = -1f,
                destinationPosition = 1f,
                travelTimeMillis = 1000f).apply {
                    isInfinite = true
                    returnToInitialAfterFinished = true
                }
        rect2.modelParams.apply {
            setShader(Shaders.DEFAULT_TEXTURE_SHADER)
            transform.position.x = 1f
        }
        addChild(rect2)

Then you just need to initialize this surfaceView by calling initSurface and pass there context and your animation scene.

    surfaceView.initSurface(context, MyScene())

That's all for start. For some complex stuff please check out the demo application.

We’d be really happy if you sent us links to your projects where you use our library. Just send an email to [email protected] and do let us know if you have any questions or suggestions.

The MIT License (MIT)

Copyright © 2019 Yalantis, https://yalantis.com

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