FBO紋理翻轉/旋轉

我通過fbo捕獲了幾個圖像。然後我重新使用這些圖像，添加一些東西（使用fbo和着色器）。現在，出於某種原因，圖像旋轉，我不知道它發生了什麼。FBO紋理翻轉/旋轉

下面的錯誤可能會連接到一些代碼。我可以根據要求提供更多的代碼。

我省像這樣的圖片：

glReadBuffer(GL_COLOR_ATTACHMENT0_EXT); 
      int bpp = 4; // Assuming a 32-bit display with a byte each for red, green, blue, and alpha. 
      ByteBuffer buffer = BufferUtils.createByteBuffer(SAVE_WIDTH * SAVE_HEIGHT * bpp); 
      glReadPixels(0, 0, SAVE_WIDTH, SAVE_HEIGHT, GL_RGBA, GL_UNSIGNED_BYTE, buffer); 

      File file = new File("picture" + k + ".png"); // The file to save to. 
      String format = "png"; // Example: "PNG" or "JPG" 
      BufferedImage image = new BufferedImage(SAVE_WIDTH, SAVE_HEIGHT, BufferedImage.TYPE_INT_ARGB); 

      for(int x = 0; x < SAVE_WIDTH; x++) 
       for(int y = 0; y < SAVE_HEIGHT; y++) 
       { 
         int i = (x + (SAVE_WIDTH * y)) * bpp; 
         int r = buffer.get(i) & 0xFF; 
         int g = buffer.get(i + 1) & 0xFF; 
         int b = buffer.get(i + 2) & 0xFF; 
         int a = buffer.get(i + 3) & 0xFF; 
         image.setRGB(x, SAVE_HEIGHT - (y + 1), (a << 24) | (r << 16) | (g << 8) | b); 
       } 


      try { 
       ImageIO.write(image, format, file); 
      } catch (IOException e) { 
       e.printStackTrace(); 
      }

我加載它們是這樣的：

ByteBuffer buf = null; 
     File file = new File(filename); 

     if (file.exists()) { 

      try { 
       BufferedImage image = ImageIO.read(file); 

       buf = Util.getImageDataFromImage(image); 
      } catch (IOException ex) { 
       Logger.getLogger(SkyBox.class.getName()).log(Level.SEVERE, null, ex); 
      } 
     } else { 
      int length = SAVE_WIDTH * SAVE_HEIGHT * 4; 
      buf = ByteBuffer.allocateDirect(length); 
      for (int i = 0; i < length; i++) 
       buf.put((byte)0xFF); 
      buf.rewind(); 
     } 

     // Create a new texture object in memory and bind it 
     glBindTexture(GL_TEXTURE_2D, pictureTextureId); 

     // All RGB bytes are aligned to each other and each component is 1 byte 
     glPixelStorei(GL_UNPACK_ALIGNMENT, 1); 

     // Upload the texture data and generate mip maps (for scaling) 
     glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, SAVE_WIDTH, SAVE_HEIGHT, 0, 
         GL_RGBA, GL_UNSIGNED_BYTE, buf);  

     // Setup what to do when the texture has to be scaled 
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, 
         GL_NEAREST); 
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, 
         GL_NEAREST);

getImageDataFromImage（）

WritableRaster wr = bufferedImage.getRaster(); 
    DataBuffer db = wr.getDataBuffer(); 
    DataBufferByte dbb = (DataBufferByte) db; 
    ByteBuffer byteBuffer = ByteBuffer.allocateDirect(dbb.getData().length); 

    byte[] bytes = dbb.getData(); 

    for(int i=0; i<bytes.length; i+=4) { 
     byteBuffer.put(bytes[i+3]); 
     byteBuffer.put(bytes[i+2]); 
     byteBuffer.put(bytes[i+1]); 
     byteBuffer.put(bytes[i]); 
    } 

    byteBuffer.flip(); 
    return byteBuffer;

來源

2013-01-03 RobotRock

旋轉或垂直翻轉？如果它們被翻轉了，那是因爲OpenGL和圖像文件格式並不是必須同意座標系的原點。使用OpenGL和通常的投影設置，原點位於左下角。大多數圖像文件格式和IO庫假定左上角的原點。

來源

2013-01-03 11:06:54 datenwolf

FBO紋理翻轉/旋轉

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