Transparent texture in OpenGL

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Hi every body
I have an texture in a quad. but it's picture have transparent. OpenGL show that like this :

http://upload.tehran98.com/img1/roc36xty7n84mavubhzj.png[^]

what can I do ? ( i work with sdl )

Posted 19-Dec-12 1:42am

mohammadali1375

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Abhishek Pant 19-Dec-12 10:54am

use photoshop!

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Santhosh G_ · Accepted Answer · 2012-12-19T07:06:00

In OpenGL texture mapping, Transparency can be implemented through alpha blending. You can use GL_RGBA8 texture format to create Alpha enabled texture. Provide proper alpha values to get transparency. To get get opaque image, provide 255 as alpha value and to get fully transparent pixel provide 0 as alpha value. For semi-transparent pixels provide 128 as the alpha value.

On texture mapping enable blending to get transparent effect to the drawn image.

C#

// This function render the image with alpha blending to display only the alpha pixels.
    glEnable( GL_BLEND );
    glBlendFunc( GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA );
// Texture mapping code... 
// On drawing texture image, color of texel will be multiplied with the existing image.
// and it will provide transparent effect.