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Why does the RGB value always equal to (0, 0, 0) when I use gl2.glReadPixels(e.x, viewport[3] - e.y, 1, 1, GL2.GL_RGB, GL2.GL_FLOAT, FloatBuffer.wrap(color));

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Irene Tang

Mar 18, 2016; 6:38am

Why does the RGB value always equal to (0, 0, 0) when I use gl2.glReadPixels(e.x, viewport[3] - e.y, 1, 1, GL2.GL_RGB, GL2.GL_FLOAT, FloatBuffer.wrap(color));

SceneObject.java
BasicObject.java
Draw.java

elect

Mar 18, 2016; 7:53am

Re: Why does the RGB value always equal to (0, 0, 0) when I use gl2.glReadPixels(e.x, viewport[3] - e.y, 1, 1, GL2.GL_RGB, GL2.GL_FLOAT, FloatBuffer.wrap(color));

Because it means at that moment when you read that pixel that is its value.

You should read this to understand problems of deprecated (fixed function) opengl and benefits of the current one