OpenGL-白色，纹理透明

Question

As you can see above there is white color where the image is transparent. The weird thing is that right next to the turret there also is transparency which is not white.

Here is the original image:

glEnable(GL_BLEND);
glBlendFunc(GL_ONE, GL_ONE_MINUS_SRC_ALPHA); 
glEnable(GL_TEXTURE_2D);

Loading the texture:

this.image = ImageIO.read(new File("res/textures/"+fileName);

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

ByteBuffer buffer = BufferUtils.createByteBuffer(image.getWidth() * image.getHeight() * 4); // 4 for RGBA, 3 for RGB


for (int y = 0; y < image.getHeight(); y++) {
    for (int x = 0; x < image.getWidth(); x++) {
        int pixel = pixels[y * image.getWidth() + x];
        buffer.put((byte) ((pixel >> 16) & 0xFF)); // Red component
        buffer.put((byte) ((pixel >> 8) & 0xFF)); // Green component
        buffer.put((byte) (pixel & 0xFF)); // Blue component
        buffer.put((byte) ((pixel >> 24) & 0xFF)); // Alpha component.
    }
}

buffer.flip();

int id = glGenTextures();
glBindTexture(GL_TEXTURE_2D, id);

// Setup wrap mode
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_BORDER);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_BORDER);

// Setup texture scaling filtering
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(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);

To display it I simply bind the texture and shader and render a mesh:

glBindTexture(GL_TEXTURE_2D, id);
shader.bind();
mesh.render();

EDIT:

I fixed the problem. I still don't know what the exact problem is though. I just opened the image in Pixelmator (Photoshop for Mac) and exported it. Then the white borders were gone.

Answer 1

I've just read a article about the transparent part that is displayed as white by windows in the MFC. Hope it will do help.It's said that the every pixel'value is its RGB value multiply the alpha value.The picture is transparent because its alpha value is 0,so the RGB*alpha value is 0.Your problem may be that the RGB value hasn't multiply with alpha value.In the article I read,the author do "RGB*alpha" by oneself.

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Here is some code:

for(int i = 0 ;i < m_pngImage.GetWidth();i++)
{
    unsigned char* pucColor = reinterpret_cast<unsigned char *>(m_pngImage.GetPixelAddress(i , j)); 
    pucColor[0] = pucColor[0] * pucColor[3] / 255;   
    pucColor[1] = pucColor[1] * pucColor[3] / 255;   
    pucColor[2] = pucColor[2] * pucColor[3] / 255;   
}