处理奇怪的空指针异常(与PGraphics有关)

Question

无论出于什么原因，当我运行我的程序时，我都会得到一个NullPointerException。以下是崩溃日志：

java.lang.NullPointerException
    at processing.awt.PGraphicsJava2D.getRaster(PGraphicsJava2D.java:2727)
    at processing.awt.PGraphicsJava2D.loadPixels(PGraphicsJava2D.java:2751)
    at processing.opengl.PGraphicsOpenGL.initCache(PGraphicsOpenGL.java:6471)
    at processing.opengl.PGraphicsOpenGL.getTexture(PGraphicsOpenGL.java:6424)
    at processing.opengl.PGraphicsOpenGL$TexCache.getTexture(PGraphicsOpenGL.java:7464)
    at processing.opengl.PGraphicsOpenGL.flushPolys(PGraphicsOpenGL.java:2430)
    at processing.opengl.PGraphicsOpenGL.flush(PGraphicsOpenGL.java:2371)
    at processing.opengl.PGraphicsOpenGL.endDraw(PGraphicsOpenGL.java:1540)
    at processing.core.PApplet.handleDraw(PApplet.java:2436)
    at processing.opengl.PSurfaceJOGL$DrawListener.display(PSurfaceJOGL.java:884)
    at jogamp.opengl.GLDrawableHelper.displayImpl(GLDrawableHelper.java:692)
    at jogamp.opengl.GLDrawableHelper.display(GLDrawableHelper.java:674)
    at jogamp.opengl.GLAutoDrawableBase$2.run(GLAutoDrawableBase.java:443)
    at jogamp.opengl.GLDrawableHelper.invokeGLImpl(GLDrawableHelper.java:1293)
    at jogamp.opengl.GLDrawableHelper.invokeGL(GLDrawableHelper.java:1147)
    at com.jogamp.newt.opengl.GLWindow.display(GLWindow.java:759)
    at com.jogamp.opengl.util.AWTAnimatorImpl.display(AWTAnimatorImpl.java:81)
    at com.jogamp.opengl.util.AnimatorBase.display(AnimatorBase.java:452)
    at com.jogamp.opengl.util.FPSAnimator$MainTask.run(FPSAnimator.java:178)
    at java.util.TimerThread.mainLoop(Timer.java:555)
    at java.util.TimerThread.run(Timer.java:505)
Could not run the sketch (Target VM failed to initialize).
For more information, read revisions.txt and Help ? Troubleshooting.

只有当我使用P2D/P3D时才会发生这种情况。JAVA2D运行得很好，但我想使用P2D，因为否则程序就会变得很慢。

Answer 1

请仔细检查您的草图和PGraphics是否使用显式渲染器，特别是GL渲染器(例如P2D/P3D)。

例如：

PGraphics buffer;

void setup(){
  size(400,400,P3D);

  buffer = createGraphics(width,height,P3D);
  buffer.beginDraw();
  buffer.background(0);
  buffer.sphereDetail(4);
  buffer.noFill();
  buffer.endDraw();

}
void draw(){
  float size = map(sin(frameCount * .01),-1.0,1.0,0.0,100.0);  

  buffer.beginDraw();
  buffer.stroke(255,size * 0.5);
  buffer.translate(mouseX,mouseY,0);
  buffer.rotate(frameCount * 0.01,0.5,0.5,1.0);
  buffer.sphere(size);
  buffer.endDraw();

  image(buffer,0,0); 
}