java - LWJGL 透明度不起作用？

Question

知道为什么我无法使用 LWJGL 创建透明纹理吗？我使用 .gif 图像，因为 .PNG 图像会导致纹理出现奇怪的定位问题。我尝试了一些其他答案，但它没有解决我遇到的问题。我并不是最擅长 OpenGL，但我花了很多天试图弄清楚它。

<小时/>

纹理.java

public class Sprite {

/** The texture that stores the image for this sprite */
private Texture texture;

/** The width in pixels of this sprite */
private int         width;

/** The height in pixels of this sprite */
private int         height;

/**
 * Create a new sprite from a specified image.
 *
 * @param loader the texture loader to use
 * @param ref A reference to the image on which this sprite should be based
 */
public Sprite(TextureLoader loader, String ref) {
try {
        texture = loader.getTexture(ref);
  width = texture.getImageWidth();
  height = texture.getImageHeight();
} catch (IOException ioe) {
    ioe.printStackTrace();
  System.exit(-1);
}
}

/**
 * Get the width of this sprite in pixels
 *
 * @return The width of this sprite in pixels
 */
public int getWidth() {
    return texture.getImageWidth();
}

/**
 * Get the height of this sprite in pixels
 *
 * @return The height of this sprite in pixels
 */
public int getHeight() {
    return texture.getImageHeight();
}

/**
 * Draw the sprite at the specified location
 *
 * @param x The x location at which to draw this sprite
 * @param y The y location at which to draw this sprite
 */
public void draw(int x, int y) {
    // store the current model matrix

    glPushMatrix();

    // bind to the appropriate texture for this sprite
    texture.bind();

    // translate to the right location and prepare to draw
    glTranslatef(x, y, 0);

    // draw a quad textured to match the sprite
    glBegin(GL_QUADS);
    {
        glTexCoord2f(0, 0);
        glVertex2f(0, 0);

        glTexCoord2f(0, texture.getHeight());
        glVertex2f(0, height);

        glTexCoord2f(texture.getWidth(), texture.getHeight());
        glVertex2f(width, height);

        glTexCoord2f(texture.getWidth(), 0);
        glVertex2f(width, 0);
    }
    glEnd();

    // restore the model view matrix to prevent contamination
    glPopMatrix();
}
public void draw(int x, int y,int rotate) {
    // store the current model matrix
    glPushMatrix();

    // bind to the appropriate texture for this sprite
    texture.bind();

    // translate to the right location and prepare to draw
    //glTranslatef(x, y, 0);
    glTranslatef(x+getWidth()/2, y+getHeight()/2, 0); // M1 - 2nd translation
    glRotatef(rotate, 0.0f, 0.0f, 1.0f);                  // M2
    glTranslatef( -getWidth()/2, -getHeight()/2, 0);  // M3 - 1st translation
    // draw a quad textured to match the sprite

    glBegin(GL_QUADS);
    {
        glTexCoord2f(0, 0);
        glVertex2f(0, 0);

        glTexCoord2f(0, texture.getHeight());
        glVertex2f(0, height);

        glTexCoord2f(texture.getWidth(), texture.getHeight());
        glVertex2f(width, height);

        glTexCoord2f(texture.getWidth(), 0);
        glVertex2f(width, 0);
    }
    glEnd();

    // restore the model view matrix to prevent contamination
    glPopMatrix();
}

<小时/>

纹理.java

public class Texture {

/** The GL target type */
private int     target;

/** The GL texture ID */
private int     textureID;

/** The height of the image */
private int     height;

/** The width of the image */
private int     width;

/** The width of the texture */
private int     texWidth;

/** The height of the texture */
private int     texHeight;

/** The ratio of the width of the image to the texture */
private float   widthRatio;

/** The ratio of the height of the image to the texture */
private float   heightRatio;

/**
 * Create a new texture
 *
 * @param target The GL target
 * @param textureID The GL texture ID
 */
public Texture(int target, int textureID) {
    this.target = target;
    this.textureID = textureID;
}

/**
 * Bind the specified GL context to a texture
 */
public void bind() {
    glBindTexture(target, textureID);
}

/**
 * Set the height of the image
 *
 * @param height The height of the image
 */
public void setHeight(int height) {
    this.height = height;
    setHeight();
}

/**
 * Set the width of the image
 *
 * @param width The width of the image
 */
public void setWidth(int width) {
    this.width = width;
    setWidth();
}

/**
 * Get the height of the original image
 *
 * @return The height of the original image
 */
public int getImageHeight() {
    return height;
}

/**
 * Get the width of the original image
 *
 * @return The width of the original image
 */
public int getImageWidth() {
    return width;
}

/**
 * Get the height of the physical texture
 *
 * @return The height of physical texture
 */
public float getHeight() {
    return heightRatio;
}

/**
 * Get the width of the physical texture
 *
 * @return The width of physical texture
 */
public float getWidth() {
    return widthRatio;
}

/**
 * Set the height of this texture
 *
 * @param texHeight The height of the texture
 */
public void setTextureHeight(int texHeight) {
    this.texHeight = texHeight;
    setHeight();
}

/**
 * Set the width of this texture
 *
 * @param texWidth The width of the texture
 */
public void setTextureWidth(int texWidth) {
    this.texWidth = texWidth;
    setWidth();
}

/**
 * Set the height of the texture. This will update the
 * ratio also.
 */
private void setHeight() {
    if (texHeight != 0) {
        heightRatio = ((float) height) / texHeight;
    }
}

/**
 * Set the width of the texture. This will update the
 * ratio also.
 */
private void setWidth() {
    if (texWidth != 0) {
        widthRatio = ((float) width) / texWidth;
    }
}

<小时/>

textureLoader.java

public class TextureLoader {
/** The table of textures that have been loaded in this loader */
private HashMap<String, Texture> table = new HashMap<String, Texture>();

/** The colour model including alpha for the GL image */
private ColorModel glAlphaColorModel;

/** The colour model for the GL image */
private ColorModel glColorModel;

/** Scratch buffer for texture ID's */
private IntBuffer textureIDBuffer = BufferUtils.createIntBuffer(1);

/**
 * Create a new texture loader based on the game panel
 */
public TextureLoader() {
    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);
}

/**
 * Create a new texture ID
 *
 * @return A new texture ID
 */
private int createTextureID() {
  glGenTextures(textureIDBuffer);
  return textureIDBuffer.get(0);
}

/**
 * Load a texture
 *
 * @param resourceName The location of the resource to load
 * @return The loaded texture
 * @throws IOException Indicates a failure to access the resource
 */
public Texture getTexture(String resourceName) throws IOException {
    Texture tex = table.get(resourceName);

    if (tex != null) {
        return tex;
    }

    tex = getTexture(resourceName,
                     GL_TEXTURE_2D, // target
                     GL_RGBA,     // dst pixel format
                     GL_LINEAR, // min filter (unused)
                     GL_LINEAR);

    table.put(resourceName,tex);

    return tex;
}

/**
 * Load a texture into OpenGL from a image reference on
 * disk.
 *
 * @param resourceName The location of the resource to load
 * @param target The GL target to load the texture against
 * @param dstPixelFormat The pixel format of the screen
 * @param minFilter The minimising filter
 * @param magFilter The magnification filter
 * @return The loaded texture
 * @throws IOException Indicates a failure to access the resource
 */
public Texture getTexture(String resourceName,
                          int target,
                          int dstPixelFormat,
                          int minFilter,
                          int magFilter) throws IOException {
    int srcPixelFormat;

    // create the texture ID for this texture
    int textureID = createTextureID();
    Texture texture = new Texture(target,textureID);

    // bind this texture
    glBindTexture(target, textureID);

    BufferedImage bufferedImage = loadImage(resourceName);
    texture.setWidth(bufferedImage.getWidth());
    texture.setHeight(bufferedImage.getHeight());

    if (bufferedImage.getColorModel().hasAlpha()) {
        srcPixelFormat = GL_RGBA;
    } else {
        srcPixelFormat = GL_RGB;
    }

    // convert that image into a byte buffer of texture data
    ByteBuffer textureBuffer = convertImageData(bufferedImage,texture);

    if (target == GL_TEXTURE_2D) {
        glTexParameteri(target, GL_TEXTURE_MIN_FILTER, minFilter);
        glTexParameteri(target, GL_TEXTURE_MAG_FILTER, magFilter);
    }

    // produce a texture from the byte buffer
    glTexImage2D(target,
                  0,
                  dstPixelFormat,
                  get2Fold(bufferedImage.getWidth()),
                  get2Fold(bufferedImage.getHeight()),
                  0,
                  srcPixelFormat,
                  GL_UNSIGNED_BYTE,
                  textureBuffer );

    return texture;
}

/**
 * Get the closest greater power of 2 to the fold number
 *
 * @param fold The target number
 * @return The power of 2
 */
private static int get2Fold(int fold) {
    int ret = 2;
    while (ret < fold) {
        ret *= 2;
    }
    return ret;
}

/**
 * Convert the buffered image to a texture
 *
 * @param bufferedImage The image to convert to a texture
 * @param texture The texture to store the data into
 * @return A buffer containing the data
 */
private ByteBuffer convertImageData(BufferedImage bufferedImage,Texture texture) {
    ByteBuffer imageBuffer;
    WritableRaster raster;
    BufferedImage texImage;

    int texWidth = 2;
    int texHeight = 2;

    // find the closest power of 2 for the width and height
    // of the produced texture
    while (texWidth < bufferedImage.getWidth()) {
        texWidth *= 2;
    }
    while (texHeight < bufferedImage.getHeight()) {
        texHeight *= 2;
    }

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

    // create a raster that can be used by OpenGL as a source
    // for a texture
    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());
    }

    // copy the source image into the produced image
    Graphics g = texImage.getGraphics();
    g.setColor(new Color(0f,0f,0f,0f));
    g.fillRect(0,0,texWidth,texHeight);
    g.drawImage(bufferedImage,0,0,null);

    // build a byte buffer from the temporary image
    // that be used by OpenGL to produce a texture.
    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;
}

/**
 * Load a given resource as a buffered image
 *
 * @param ref The location of the resource to load
 * @return The loaded buffered image
 * @throws IOException Indicates a failure to find a resource
 */
private BufferedImage loadImage(String ref) throws IOException {
    URL url = TextureLoader.class.getClassLoader().getResource(ref);

    if (url == null) {
        throw new IOException("Cannot find: " + ref);
    }

    // due to an issue with ImageIO and mixed signed code
    // we are now using good oldfashioned ImageIcon to load
    // images and the paint it on top of a new BufferedImage
    Image img = new ImageIcon(url).getImage();
    BufferedImage bufferedImage = new BufferedImage(img.getWidth(null), img.getHeight(null), BufferedImage.TYPE_INT_ARGB);
    Graphics g = bufferedImage.getGraphics();
    g.drawImage(img, 0, 0, null);
    g.dispose();

    return bufferedImage;
}
}

Answer 1

为了便于阅读，我将其作为答案

初始化 openGL 调用后

glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

这将启用标准类型的混合

您不必在每次渲染调用时使用它，只需在开始时使用一次