java - LWJGL 倾斜纹理

Question

我试图将纹理与 LWJGL 一起使用，结果发现 RBG-png 有点倾斜。例子: Original picture/Texture

加载代码是 lwjgl wiki Space Invaders 示例的 98%。纹理.java:

public int target, textureID, height, width, texWidth, texHeight;
private float widthRatio, heightRatio;

public Texture(int target, int textureID) {

    this.target = target;
    this.textureID = textureID;
}

public void bind() {

    GL11.glBindTexture(target, textureID);
}

public void setWidth(int width) {

    this.width = width;
    setWidth();
}

public void setHeight(int height) {

    this.height = height;
    setHeight();
}

public int getImageWidth() {

    return width;
}

public int getImageHeight() {

    return height;
}

public float getWidth() {

    return widthRatio;
}

public float getHeight() {

    return heightRatio;
}

public void setTextureWidth(int texWidth) {

    this.texWidth = texWidth;
    setWidth();
}

public void setTextureHeight(int texHeight) {

    this.texHeight = texHeight;
    setHeight();
}

private void setWidth() {

    if (texWidth != 0)
        widthRatio = ((float) width) / texWidth;
}

private void setHeight() {

    if (texHeight != 0)
        heightRatio = ((float) height) / texHeight;
}

TextureLoader.java:

private static HashMap<String, Texture> table = new HashMap<String, Texture>();

    private static ColorModel glAlphaColorModel, glColorModel;
    private static IntBuffer textureIDBuffer = BufferUtils.createIntBuffer(1);

    static {
        glAlphaColorModel = new ComponentColorModel(
                ColorSpace.getInstance(ColorSpace.CS_sRGB), new int[] { 8, 8,
                        8, 8 }, true, false, ComponentColorModel.TRANSLUCENT,
                DataBuffer.TYPE_BYTE);

        glColorModel = new ComponentColorModel(
                ColorSpace.getInstance(ColorSpace.CS_sRGB), new int[] { 8, 8,
                        8, 0 }, false, false, ComponentColorModel.OPAQUE,
                DataBuffer.TYPE_BYTE);
    }

    private static int createTextureID() {

        GL11.glGenTextures(textureIDBuffer);
        return textureIDBuffer.get(0);
    }

    public static Texture getTexture(String name, BufferedImage image)
            throws IOException {

        Texture tex = table.get(name);

        if (tex != null)
            return tex;

        tex = getTexture(image, GL11.GL_TEXTURE_2D, GL11.GL_RGBA,
                GL11.GL_LINEAR, GL11.GL_LINEAR);

        table.put(name, tex);

        return tex;
    }

    public static Texture getTexture(BufferedImage image, int target,
            int dstPixelFormat, int minFilter, int magFilter)
            throws IOException {

        int srcPixelFormat;

        int textureID = createTextureID();
        Texture texture = new Texture(target, textureID);

        GL11.glBindTexture(target, textureID);

        texture.setWidth(image.getWidth());
        texture.setHeight(image.getHeight());

        if (image.getColorModel().hasAlpha())
            srcPixelFormat = GL11.GL_RGBA;
        else
            srcPixelFormat = GL11.GL_RGB;

        ByteBuffer textureBuffer = convertImageData(image, texture);

        if (target == GL11.GL_TEXTURE_2D) {

            GL11.glTexParameteri(target, GL11.GL_TEXTURE_MIN_FILTER, minFilter);
            GL11.glTexParameteri(target, GL11.GL_TEXTURE_MAG_FILTER, magFilter);
        }

        GL11.glTexImage2D(target, 0, dstPixelFormat, image.getWidth(),
                image.getHeight(), 0, srcPixelFormat,
                GL11.GL_UNSIGNED_BYTE, textureBuffer);

        return texture;
    }

    private static ByteBuffer convertImageData(BufferedImage bufferedImage,
            Texture texture) {

        ByteBuffer imageBuffer;
        WritableRaster raster;
        BufferedImage texImage;

        int texWidth = bufferedImage.getWidth();
        int texHeight = bufferedImage.getHeight();

        texture.setTextureHeight(texHeight);
        texture.setTextureWidth(texWidth);

        if (bufferedImage.getColorModel().hasAlpha()) {
            raster = Raster.createInterleavedRaster(DataBuffer.TYPE_BYTE,
                    texWidth, texHeight, 4, null);
            texImage = new BufferedImage(glAlphaColorModel, raster, false,
                    new Hashtable());
        } else {
            raster = Raster.createInterleavedRaster(DataBuffer.TYPE_BYTE,
                    texWidth, texHeight, 3, null);
            texImage = new BufferedImage(glColorModel, raster, false,
                    new Hashtable());
        }

        Graphics g = texImage.getGraphics();
        g.setColor(new Color(0f, 0f, 0f, 0f));
        g.fillRect(0, 0, texWidth, texHeight);
        g.drawImage(bufferedImage, 0, 0, null);

        // texImage is NOT skewed at this point

        byte[] data = ((DataBufferByte) texImage.getRaster().getDataBuffer())
                .getData();

        imageBuffer = ByteBuffer.allocateDirect(data.length);
        imageBuffer.order(ByteOrder.nativeOrder());
        imageBuffer.put(data, 0, data.length);
        imageBuffer.flip();

        return imageBuffer;
    }

Answer 1

我知道这是一个老问题，但我自己刚才也遇到了这个问题。假设您已经自己解决了这个问题，希望其他人也会受益。

纹理倾斜和变色的原因是它与您的 UNPACK_ALIGNMENT 没有正确对齐。据我了解，每行中的字节数必须是 UNPACK_ALIGNMENT 设置的倍数(默认为 4)。

对于 4 分量格式，这不是问题，因为每个像素由 4 个字节组成，因此任何尺寸的图像都会正确对齐。但对于其他格式，数据会被填充以保持正确对齐，这会导致这样的问题。

您可以更改图像的大小以使其正确对齐 ((width * formatComponents) % 4 == 0) 、将格式更改为 4 分量格式，或者更改UNPACK_ALIGNMENT 到不会使用以下方式填充图像的内容:

glPixelStore(GL_UNPACK_ALIGNMENT, 对齐);//对齐方式必须为 1、2、4 或 8。

http://www.opengl.org/wiki/Common_Mistakes#Texture_upload_and_pixel_reads