Hello,

 

I am trying to draw line between two points using GL11, But I get this error message

FATAL ERROR in native method: Thread[Render thread,10,main]: No context is current or a function that is not available in the current context was called. The JVM will abort execution.
	at org.lwjgl.opengl.GL11.glPushMatrix(org.lwjgl.opengl@3.3.1+7/Native Method)

 

My Code:

@SubscribeEvent
  public void playerTick(TickEvent.PlayerTickEvent event) {
  double posX = event.player.position().x;
  double posY = event.player.position().y;
  double posZ = event.player.position().z;
  event.player.level.addParticle(ParticleTypes.SMOKE, posX, posY, posZ, 0.0D, 0.0D, 0.0D);

  event.player.setGlowingTag(true);

  Vec3 pos1= new Vec3 (0,5,0);  // [b]Vector from 0,0,0 to 0,5,0 -> Blockcoords[/b]
  Vec3 pos2= new Vec3 (5,5,0);  // [b]Vector from 0,0,0 to 5,5,0 -> Blockcoords[/b]

  // Draw line
  drawLineWithGL(pos1, pos2);
}

private void drawLineWithGL(Vec3 blockA, Vec3 blockB)
{
  System.out.println("REACHED HERE");
  
  // Here it returns error and crash
  GL11.glPushMatrix();
  GL11.glPushAttrib(GL11.GL_ENABLE_BIT);
  GL11.glDisable(GL11.GL_LIGHTING);
  GL11.glDisable(GL11.GL_TEXTURE_2D);
  GL11.glDisable(GL11.GL_DEPTH_TEST);
  GL11.glDisable(GL11.GL_CULL_FACE);
  GL11.glDisable(GL11.GL_LIGHTING);
  GL11.glBlendFunc(GL11.GL_SRC_ALPHA, GL11.GL_ONE_MINUS_SRC_ALPHA);

  GL11.glColor3f(0F, 1F, 0F);
  GL11.glBegin(GL11.GL_LINE_STRIP);

  //you will want to modify these offsets.
  GL11.glVertex3d(blockA.x + 0.5,blockA.y - 0.01,blockA.z + 0.5);
  GL11.glVertex3d(blockB.x + 0.5,blockB.y - 0.01,blockB.z + 0.5);

  GL11.glEnd();
}

 

You don't do rendering in PlayerTick. And you don't use opengl directly you use mojang's Blaze3d library.

See my original response to your other question: https://forums.minecraftforge.net/topic/117495-1192-trying-to-draw-a-line-behind-player/

Edited October 16, 20222 yr by warjort

You are also still not checking the side or phase of PlayerTick.

16 minutes ago, warjort said:

You don't do rendering in PlayerTick. And you don't use opengl directly you use mojang's Blaze3d library.

See my original response to your other question: https://forums.minecraftforge.net/topic/117495-1192-trying-to-draw-a-line-behind-player/

 

I am really having a serious problem doing that.

Can you please share a demo code that renders line behind player when he moves ?

I've checked tutorials and many sites and still no success

Why would there be a demo or tutorial for this?

I can't think of a vanilla process or mod that does anything similar to what you are doing.

The closest things I can think of (that shows where an entity has been) are the sprint particles and the particles generated for arrow trails - see Arrow.tick()

Which is why I suggested spawning particles for your feature in your other thread.

 

If you do want to continue to do it through rendering, you are going to need to store some state for each player that remembers where they have been, e.g. using a client side player capability

See DataStorage here: https://forge.gemwire.uk/wiki/Main_Page