override fun onRender()

in skiko/src/awtMain/kotlin/org/jetbrains/skiko/swing/LinuxOpenGLSwingRedrawer.kt [44:87]
40 lines of code
3 McCabe index (conditional complexity)

    override fun onRender(g: Graphics2D, width: Int, height: Int, nanoTime: Long) {
        offScreenBufferPtr = makeOffScreenBuffer(offScreenContextPtr, offScreenBufferPtr, width, height)
        if (offScreenBufferPtr == 0L) {
            throw RenderException("Cannot create offScreen OpenGL buffer")
        }
        startRendering(offScreenContextPtr, offScreenBufferPtr)
        try {
            autoCloseScope {
                // TODO: reuse texture
                val texturePtr = createAndBindTexture(width, height)
                if (texturePtr == 0L) {
                    throw RenderException("Cannot create offScreen OpenGL texture")
                }
                val fbId = getFboId(texturePtr)
                val renderTarget = makeGLRenderTarget(
                    width,
                    height,
                    0,
                    8,
                    fbId,
                    FramebufferFormat.GR_GL_RGBA8
                ).autoClose()

                // TODO: may be it is possible to reuse [makeGLContext]
                val directContext = makeGLContext().configureContext().autoClose()
                val surface = Surface.makeFromBackendRenderTarget(
                    directContext,
                    renderTarget,
                    SurfaceOrigin.TOP_LEFT,
                    SurfaceColorFormat.BGRA_8888,
                    ColorSpace.sRGB,
                    SurfaceProps(pixelGeometry = PixelGeometry.UNKNOWN)
                )?.autoClose() ?: throw RenderException("Cannot create surface")

                val canvas = surface.canvas
                canvas.clear(Color.TRANSPARENT)
                renderDelegate.onRender(canvas, width, height, nanoTime)
                flush(surface, g)
                unbindAndDisposeTexture(texturePtr)
            }
        } finally {
            finishRendering(offScreenContextPtr)
        }
    }