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KraftTextureView

⚠️ Important Note: In most cases, you usually don't need to use KraftTextureView directly. KraftEffectTextureView or AnimatedKraftTextureView provide higher-level functionality that is more suitable for most use cases. Only use KraftTextureView directly if you need very custom OpenGL rendering that doesn't fit the patterns of the specialized views.

KraftTextureView is the base class for all View implementations in KraftShade. It provides the fundamental OpenGL rendering capabilities that other specialized views build upon.

Overview​

KraftTextureView extends Android's TextureView and provides a foundation for OpenGL rendering in KraftShade. It manages the OpenGL environment (GlEnv) and window surface, handling the lifecycle of these components in sync with the view's lifecycle.

While you typically won't use KraftTextureView directly (instead using KraftEffectTextureView or AnimatedKraftTextureView), understanding its core functionality is important for advanced usage scenarios.

Key Features​

  • Manages the OpenGL environment lifecycle
  • Provides a window surface for rendering
  • Handles task scheduling for OpenGL operations
  • Synchronizes with the view's attachment/detachment lifecycle
  • Supports transparent rendering

Basic Usage​

Here's a simple example of using KraftTextureView to render a custom shader:

class MyActivity : AppCompatActivity() {
    private lateinit var kraftTextureView: KraftTextureView
    
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        
        // Create the view
        kraftTextureView = KraftTextureView(this)
        setContentView(kraftTextureView)
        
        // Run an OpenGL task when the view is ready
        kraftTextureView.runGlTask { windowSurface ->
            // Create and apply a custom shader
            val myShader = MyCustomShader()
            myShader.drawTo(windowSurface)
        }
    }
    
    override fun onDestroy() {
        // Clean up resources
        kraftTextureView.terminate()
        super.onDestroy()
    }
}

Important Methods​

runGlTask​

The most important method in KraftTextureView is runGlTask, which allows you to execute OpenGL operations:

fun runGlTask(task: KraftTextureViewTask): Job

This method:

  • Takes a suspend function that receives a GlEnvDslScope and WindowSurfaceBuffer
  • Returns a Kotlin coroutine Job that can be used to track or cancel the operation
  • Automatically queues tasks if the OpenGL environment isn't ready yet

terminate​

Call this method to clean up resources when you're done with the view:

fun terminate()

Considerations​

  • KraftTextureView operations run asynchronously in a coroutine context
  • Tasks submitted via runGlTask may be queued if the OpenGL environment isn't ready
  • Always call terminate() when you're done with the view to prevent memory leaks
  • For most use cases, consider using KraftEffectTextureView or AnimatedKraftTextureView instead

Next Steps​

For most applications, you'll want to use one of the specialized views that extend KraftTextureView: