FBO lwjgl大于屏幕尺寸-我在做什么错? [英] FBO lwjgl bigger than Screen Size - What I'm doing wrong?

问题描述

我再次需要您的帮助.我想使用大于屏幕尺寸的帧缓冲对象.当我按以下方式进行操作时，FBO的尺寸1024 x 1024从分辨率1024 x 768的顶部开始被截断.我自己找不到解决方案-这就是我要问的原因.

I need your help again. I wanna use Frame Buffer Object bigger than the Screen size. When I do it as below FBO size 1024 x 1024 is cut off from the top in resolution 1024 x 768. I couldn't find the solution on my own - that's why I'm asking.

代码的第一部分是创建FBO的方法，即在激活和停用之间进行渲染.后来我使用纹理.

First part of code is the way I create FBO, I do the rendering between activate, and deactivate. Later I use texture.

我在做什么错了?

清除帧缓冲区对象以进行重用的最快方法是什么?

What is the fastest way to clear Frame Buffer Object for reuse?

public FrameBufferObject(int width, int height) {
    this.width = width;
    this.height = height;
    texture = glGenTextures();
    frameBufferObject = GL30.glGenFramebuffers();
    activate();
    glBindTexture(GL_TEXTURE_2D, texture);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_BYTE, BufferUtils.createByteBuffer(4 * width * height));
    GL30.glFramebufferTexture2D(GL30.GL_FRAMEBUFFER, GL30.GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, texture, 0);
    deactivate();
}

public void activate() {
    GL30.glBindFramebuffer(GL30.GL_FRAMEBUFFER, frameBufferObject);
}

public void deactivate();
    GL30.glBindFramebuffer(GL30.GL_FRAMEBUFFER, 0);
}

OpenGL设置:

private static void initializeOpenGL() {
    glDisable(GL_DEPTH_TEST);
    glEnable(GL_TEXTURE_2D);
    glEnable(GL_MULTISAMPLE);
    glEnable(GL_BLEND);
    glEnable(GL_SCISSOR_TEST);
    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
    glOrtho(0, Display.getWidth(), Display.getHeight(), 0, 1, -1);
    glMatrixMode(GL_MODELVIEW);
    glClearColor(0, 0, 0, 0);
}

推荐答案

在绑定后和开始渲染之前，需要使用FBO尺寸调用glViewport().请注意，视口尺寸是全局状态，而不是每个帧缓冲区状态，因此，当您再次渲染到默认帧缓冲区时，还必须将它们重新设置.

You need to call glViewport() with the FBO dimensions after binding it, and before starting to render. Note that the viewport dimensions are global state, not per-framebuffer state, so you also have to set them back when you render to the default framebuffer again.

使用您在问题中使用的数字(您显然不希望在实际代码中使用硬编码的数字):

With the numbers you use in the question (you obviously wouldn't want to use hardcoded numbers in real code):

public void activate() {
    GL30.glBindFramebuffer(GL30.GL_FRAMEBUFFER, frameBufferObject);
    glViewport(0, 0, 1024, 1024);
}

public void deactivate();
    GL30.glBindFramebuffer(GL30.GL_FRAMEBUFFER, 0);
    glViewport(0, 0, 1024, 768);
}

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