Alpha blending with opengl

Mike · 2002-10-24T00:55:21

I''m just trying to draw a quad that is semi-transparent over what has already been drawn. I call glBlendFunc( GL_SRC_ALPHA, GL_ONE ); in my gl init code and when i go to draw the quad that i want to blend with what''s on the screen i call glEnable( GL_BLEND ) and after i''m done drawing that quad i call glDisable( GL_BLEND ). This kind of works. The quad blends with what''s there but very poorly. I expected to be able to control the alpha blending with the fourth parameter in glColor4f() which I call like so: glBindTexture( GL_TEXTURE_2D, m_texture[1] ); if( m_bBlend ) { glEnable( GL_BLEND ); glDisable( GL_DEPTH_TEST ); } glBegin( (m_bWireFrame)? GL_LINE_LOOP : GL_QUADS ); glNormal3f( 0.0f, 0.0f, 1.0f ); glColor4f( 1.0f, 1.0f, 1.0f, 0.5f ); glTexCoord2f( 0, 0 ); glVertex3f( -60, -10, -95); glTexCoord2f( 10, 0 ); glVertex3f( 60, -10, -95); glTexCoord2f( 10, 1 ); glVertex3f( 60, 10, -95); glTexCoord2f( 0, 1 ); glVertex3f( -60, 10, -95); glEnd(); if( m_bBlend ) { glEnable( GL_DEPTH_TEST ); glDisable( GL_BLEND ); } What is wrong with what i have done?