I have a bit of trouble getting transparency and depth to work properly.
I have an image which has a transparent background (transparency in the image below shown with color). So only part of the image is actually opaque. Now I want to draw another object(the blue circle) so that it looks like its behind the first object(the rectangle).
In the image, the first two frames shows what I have got so far. I wish to achieve the effect shown in the 3rd frame. The circle image also has a transparent background like the rectangle.
No matter what I try, I just cant get it to work properly. The circle either ends up behind the rectangle or completely in the front.
Any help or pointers will be much appreciated.
Here is a small part of the code I’ve written so far:
/**When cirlce_z > rectangle_z, it is drawn in front and behind otherwise **/ glEnable(GL_DEPTH_TEST); .... .... glEnable(GL_TEXTURE_2D); /*Drawing the circle first*/ glBindTexture(GL_TEXTURE_2D, circleImage); glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); glEnable(GL_BLEND); glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA); //drawing code ... ... ... /*drawing the rectangle last (I've tried the reverse order as well)*/ glBindTexture(GL_TEXTURE_2D, rectImage); glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR); glBlendFunc(GL_ONE, GL_ONE_MINUS_SRC_ALPHA); //drawing code ... glDisable(GL_BLEND); glDisable(GL_TEXTURE_2D);