LWJGL png纹理透明度（textureColour.a白色代替黑色）

Question

我有PNG图片纹理的草模型。我得到白色背景颜色而不是黑色，这是我想要的。为什么会这样，我该怎么做才能解决这个问题？我正在使用 LWJGL 3 和 PNGDecoder.jar

纹理加载器代码：

public int loadTexture(String fileName) {
    ByteBuffer buf = null;
    int tWidth = 0;
    int tHeight = 0;

    try {
        // Open the PNG file as an InputStream
        InputStream in = new FileInputStream("res/" + fileName + ".png");
        // Link the PNG decoder to this stream
        PNGDecoder decoder = new PNGDecoder(in);

        // Get the width and height of the texture
        tWidth = decoder.getWidth();
        tHeight = decoder.getHeight();

        // Decode the PNG file in a ByteBuffer
        buf = ByteBuffer.allocateDirect(
                4 * decoder.getWidth() * decoder.getHeight());
        decoder.decode(buf, decoder.getWidth() * 4, Format.RGBA);
        buf.flip();

        in.close();
    } catch (IOException e) {
        e.printStackTrace();
        System.exit(-1);
    }

    // Create a new texture object in memory and bind it
    int textureId = GL11.glGenTextures();
    GL13.glActiveTexture(textureId);
    GL11.glBindTexture(GL11.GL_TEXTURE_2D, textureId);

    // All RGB bytes are aligned to each other and each component is 1 byte
    GL11.glPixelStorei(GL11.GL_UNPACK_ALIGNMENT, 1);

    // Upload the texture data and generate mip maps (for scaling)
    GL11.glTexImage2D(GL11.GL_TEXTURE_2D, 0, GL11.GL_RGB, tWidth, tHeight, 0,
            GL11.GL_RGBA, GL11.GL_UNSIGNED_BYTE, buf);
    GL30.glGenerateMipmap(GL11.GL_TEXTURE_2D);

    // Setup the ST coordinate system
    GL11.glTexParameteri(GL11.GL_TEXTURE_2D, GL11.GL_TEXTURE_WRAP_S, GL11.GL_REPEAT);
    GL11.glTexParameteri(GL11.GL_TEXTURE_2D, GL11.GL_TEXTURE_WRAP_T, GL11.GL_REPEAT);

    // Setup what to do when the texture has to be scaled
    GL11.glTexParameteri(GL11.GL_TEXTURE_2D, GL11.GL_TEXTURE_MAG_FILTER,
            GL11.GL_NEAREST);
    GL11.glTexParameteri(GL11.GL_TEXTURE_2D, GL11.GL_TEXTURE_MIN_FILTER,
            GL11.GL_LINEAR_MIPMAP_LINEAR);

    return textureId;
}

Answer 1

如果希望透明纹理看起来透明，则必须先启用混合。将以下内容放在OpenGL初始化代码中。

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

您还在内部以RGB而非RGBA格式存储纹理。

GL11.glTexImage2D(GL11.GL_TEXTURE_2D, 0, GL11.GL_RGB, tWidth, tHeight, 0,
    GL11.GL_RGBA, GL11.GL_UNSIGNED_BYTE, buf);

应该成为

GL11.glTexImage2D(GL11.GL_TEXTURE_2D, 0, GL11.GL_RGBA8, tWidth, tHeight, 0,
    GL11.GL_RGBA, GL11.GL_UNSIGNED_BYTE, buf);