绘制到纹理不起作用 LWJGL

Posted 2023-02-22

【中文标题】绘制到纹理不起作用 LWJGL

【英文标题】：Drawing to Textures does not work LWJGL

【发布时间】：2015-07-12 18:37:54

【问题描述】：

我正在尝试绘制 2d 纹理并在 3D 场景中绘制该纹理。

初始化帧缓冲对象和纹理的代码：

public static void initFBO()

    renderEngine.framebuffers = new int[7];
    renderEngine.monitorTextures = new int[7];

    for(int i = 0;i < 7;i++)
    
        renderEngine.framebuffers[i] = glGenFramebuffers();
        renderEngine.monitorTextures[i] = glGenTextures();

        glBindFramebuffer(GL_FRAMEBUFFER, renderEngine.framebuffers[i]);
        glBindTexture(GL_TEXTURE_2D, renderEngine.monitorTextures[i]);
        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 512, 512, 0, GL_RGBA, GL_UNSIGNED_BYTE, (ByteBuffer)null);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
        glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, renderEngine.monitorTextures[i], 0);
           

    if(glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE)
        System.err.println("Error while creating FBO");

    glBindFramebuffer(GL_FRAMEBUFFER, 0);
    glBindTexture(GL_TEXTURE_2D, 0);

将四边形渲染到帧缓冲区的代码： glUseProgram(0);

    for(int i = 0;i < 6;i++)
    
        glBindFramebuffer(GL_FRAMEBUFFER, framebuffers[i]);
        glPushAttrib(GL_VIEWPORT_BIT);
        glViewport(0, 0, 512, 512);
        glClearColor(0f, 0f, 0f, 1f);
        glClear(GL_COLOR_BUFFER_BIT);

        //glActiveTexture(GL_TEXTURE0);
        //glEnable(GL_TEXTURE_2D);

        glMatrixMode(GL_PROJECTION);
        glLoadIdentity();
        glOrtho(0, 512, 512, 0, 1, -1);
        glMatrixMode(GL_MODELVIEW);

        glUseProgram(0);

        glColor4f(1f, 0f, 0f, 1f);
        glBegin(GL_QUADS);
        glVertex2f(20, 20);
        glVertex2f(420, 20);
        glVertex2f(420, 420);
        glVertex2f(20, 420);
        glEnd();

        glBindFramebuffer(GL_FRAMEBUFFER, 0);
        glPopAttrib();
    

如果我更改透明颜色，纹理在我的 3D 场景中渲染时会获得该颜色。但我看不到四边形。我做错了什么吗？

【参考方案1】：

如果找到解决方案。因为我使用的是 3D 环境并启用了 GL_CULL_FACE 并设置为 CCW（逆时针），所以未显示顺时针绘制的四边形。

我只是在绘制到帧缓冲区之前禁用了它，然后重新启用它。

glDisable(GL_CULL_FACE);
glEnable(GL_CULL_FACE);