如何将 bufferedImage 加载为 opengl 纹理？

Question

我正在尝试从加载的缓冲图像创建纹理，如下所示：

public static long loadTexture(String img) throws IOException{


     File imgPath = new File(img);
     BufferedImage bufferedImage = ImageIO.read(imgPath);


    byte[] pixels = ((DataBufferByte) bufferedImage.getRaster().getDataBuffer()).getData();
    int id = glGenTextures();

    glBindTexture(GL_TEXTURE_2D, id);

    glPixelStorei(GL_UNPACK_ALIGNMENT, 1);

    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, bufferedImage.getWidth(), bufferedImage.getHeight(), 0, GL_RGBA, GL_UNSIGNED_BYTE, ByteBuffer.wrap(pixels));

    glGenerateMipmap(GL_TEXTURE_2D);

    return id; 
}

但是这段代码给我一个 java sigsegv 错误。我正在使用 Java.nio.Bytebuffer，因为 java 11 不支持 sun。那我做错了什么？图片加载正确，4bpp:

//last 2 digits are lenght
FF-AD-6F-CB-FF-FF-FF-00-FF-FF-FF-00-FF-FF-FF-00-FF-FF-FF-00-FF-00-00-FF-FF-00-00-FF-FF-FF-FF-00-FF-FF-FF-00-FF-00-00-FF-FF-00-00-FF-FF-FF-FF-00-FF-FF-FF-00-FF-FF-FF-00-FF-FF-FF-00-FF-FF-FF-00-64

图片如下：它当然很小，但数据是正确的。

那么为什么我会收到 sigsegv？日志很无用而且很长所以我不能 post 它。

以及如何从 4bpp 字节数组创建 opengl 纹理？

Answer 1

按照 Java Code Examples for org.lwjgl.opengl.GL11.glTexImage2D()（示例 5）中的建议，您必须在循环中将数据复制到 ByteBuffer：

public static long loadTexture(String img) throws IOException{

    File imgPath = new File(img);
    BufferedImage image = ImageIO.read(imgPath);

    int[] pixels = new int[image.getWidth() * image.getHeight()];
    image.getRGB(0, 0, image.getWidth(), image.getHeight(), pixels, 0, image.getWidth());
    ByteBuffer buffer = ByteBuffer.allocateDirect(image.getWidth() * image.getHeight() * 4);

    for(int h = 0; h < image.getHeight(); h++) {
        for(int w = 0; w < image.getWidth(); w++) {
            int pixel = pixels[h * image.getWidth() + w];

            buffer.put((byte) ((pixel >> 16) & 0xFF));
            buffer.put((byte) ((pixel >> 8) & 0xFF));
            buffer.put((byte) (pixel & 0xFF));
            buffer.put((byte) ((pixel >> 24) & 0xFF));
        }
    }

    buffer.flip();

    int id = glGenTextures();
    glBindTexture(GL_TEXTURE_2D, id);
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, image.getWidth(), image.getHeight(),
                 0, GL_RGBA, GL_UNSIGNED_BYTE, buffer);
    glGenerateMipmap(GL_TEXTURE_2D);

    return id; 
}

注意，glPixelStorei(GL_UNPACK_ALIGNMENT, 1)在这种情况下是不必要的，因为RGBA像素的大小是4个字节，所以每行对齐到4个字节，GL_UNPACK_ALIGNMENT默认为4。

此外，如果你想使用Mipmaps (glGenerateMipmap), then the minifying function (GL_TEXTURE_MIN_FILTER) has to be GL_NEAREST_MIPMAP_NEAREST, GL_LINEAR_MIPMAP_NEAREST, GL_NEAREST_MIPMAP_LINEAR or GL_LINEAR_MIPMAP_LINEAR. (See glTexParameter)

如何将 bufferedImage 加载为 opengl 纹理？

How can I load bufferedImage as opengl texture?

java

opengl

png

textures

bytebuffer