Question

I’m writing a game for Android using libgdx. Here is some code that draws a textured torus:

Gdx.gl10.glPushMatrix();
Gdx.gl10.glTranslatef(center.x, center.y, 0);
Gdx.gl10.glRotatef(0, 0, 1, angle * 360f / (2f * (float)Math.PI));
texture.bind();
mesh.render(GL10.GL_TRIANGLE_STRIP);
Gdx.gl10.glPopMatrix();

…and here is some code that draws a bit of text:

spriteBatch.begin();
spriteBatch.setColor(1, 1, 1, 1);
float fps = 1f / Gdx.graphics.getDeltaTime();
font.draw(spriteBatch, "fps: " + fps, 0, 50);
spriteBatch.end();

The first bit of code works, frame after frame, until the second bit of code runs. After that, the first bit’s triangle strip is rendered using only the latest glMaterial. Any idea why this is happening?

Update: Solved! It turns out SpriteBatch.end() calls glDisable(GL_TEXTURE_2D). Just had to read the source…

Answer 1

It actually says so in the Javadocs as well. Rule of thumb: all libgdx classes connected to OpenGL ES will change the minimum amount of states and most likely won’t reset things as querying GL for state is costly.