Method _promoteToFramebuffer

src/webgpu/p5.RendererWebGPU.js:1383–1464

* Promotes the current frame to use mainFramebuffer. * Copies current canvas content to mainFramebuffer, then switches to rendering there. * @private

()

     * @private
     */
    _promoteToFramebuffer() {
      // Already promoted this frame
      if (this._frameState === FRAME_STATE.PROMOTED) {
        return;
      }

      // Already drawing to a custom framebuffer, no promotion needed
      if (this.activeFramebuffer()) {
        return;
      }

      // Flush any pending draws to canvas first
      this.flushDraw();

      // Mark as promoted
      this._frameState = FRAME_STATE.PROMOTED;

      // Get current canvas texture
      const canvasTexture = this.drawingContext.getCurrentTexture();

      // Ensure mainFramebuffer matches canvas size
      if (this.mainFramebuffer.width !== this.width ||
          this.mainFramebuffer.height !== this.height) {
        this.mainFramebuffer.resize(this.width, this.height);
      }

      // Copy canvas textures to mainFramebuffer
      const commandEncoder = this.device.createCommandEncoder();

      // Copy color texture
      commandEncoder.copyTextureToTexture(
        {
          texture: canvasTexture,
          origin: { x: 0, y: 0, z: 0 },
          mipLevel: 0,
        },
        {
          texture: this.mainFramebuffer.colorTexture,
          origin: { x: 0, y: 0, z: 0 },
          mipLevel: 0,
        },
        {
          width: Math.ceil(this.width * this._pixelDensity),
          height: Math.ceil(this.height * this._pixelDensity),
          depthOrArrayLayers: 1,
        }
      );

      // Copy depth texture
      commandEncoder.copyTextureToTexture(
        {
          texture: this.depthTexture,
          origin: { x: 0, y: 0, z: 0 },
          mipLevel: 0,
        },
        {
          texture: this.mainFramebuffer.depthTexture,
          origin: { x: 0, y: 0, z: 0 },