Method copyTexture

core/src/processing/opengl/Texture.java:1212–1253

(Texture tex, int x, int y, int w, int h,
                             boolean scale)

  // Copies source texture tex into this.
  protected void copyTexture(Texture tex, int x, int y, int w, int h,
                             boolean scale) {
    if (tex == null) {
      throw new RuntimeException("Source texture is null");
    }

    if (tempFbo == null) {
      tempFbo = new FrameBuffer(pg, glWidth, glHeight);
    }

    // This texture is the color (destination) buffer of the FBO.
    tempFbo.setColorBuffer(this);
    tempFbo.disableDepthTest();

    // FBO copy:
    pg.pushFramebuffer();
    pg.setFramebuffer(tempFbo);
    // Replaces anything that this texture might contain in the area being
    // replaced by the new one.
    pg.pushStyle();
    pg.blendMode(REPLACE);
    if (scale) {
      // Rendering tex into "this", and scaling the source rectangle
      // to cover the entire destination region.
      pgl.drawTexture(tex.glTarget, tex.glName, tex.glWidth, tex.glHeight,
                      0, 0, tempFbo.width, tempFbo.height, 1,
                      x, y, x + w, y + h, 0, 0, width, height);

    } else {
      // Rendering tex into "this" but without scaling so the contents
      // of the source texture fall in the corresponding texels of the
      // destination.
      pgl.drawTexture(tex.glTarget, tex.glName, tex.glWidth, tex.glHeight,
                      0, 0, tempFbo.width, tempFbo.height, 1,
                      x, y, x + w, y + h, x, y, x + w, y + h);
    }
    pgl.flush(); // Needed to make sure that the change in this texture is
                 // available immediately.
    pg.popStyle();
    pg.popFramebuffer();
    updateTexels(x, y, w, h);
  }


  // Copies source texture tex into this.