Issues with Push and Pop Matrix

Graphics and GPU Programming Programming

Started by gummby8 October 26, 2016 10:10 PM

1 comment, last by _WeirdCat_ 7 years, 5 months ago

gummby8

103

Author

October 26, 2016 10:10 PM

I am trying to rotate a player model in by 90 degrees

I do this in a pre and post render event


	@SideOnly(Side.CLIENT)
	@SubscribeEvent
	public void onRenderPlayer(RenderPlayerEvent.Pre event) {

		if (ModularBosses.instance.playerTarget != null && MBExtendedPlayer.get((EntityPlayer) event.entity).knockdownTime > 0) {
			EntityPlayer player = event.entityPlayer;
			GL11.glPushMatrix();
			GL11.glTranslatef(0, 0.15f, 0);
			GL11.glRotatef(-90, 1, 0, 0);
			GL11.glRotatef(-player.rotationYaw, 0, 0, 1);
			GL11.glRotatef(player.rotationYaw, 0, 1, 0);

			player.motionX = player.motionY = player.motionZ = 0;

		}

	}

	@SideOnly(Side.CLIENT)
	@SubscribeEvent
	public void onRenderPlayer(RenderPlayerEvent.Post event) {
		if (ModularBosses.instance.playerTarget != null && MBExtendedPlayer.get((EntityPlayer) event.entity).knockdownTime > 0) {
			GL11.glPopMatrix();
		}

	}

Problem is now when a spectator views the playor being affected, the affected player is moving all backwards in relation to the spectator.

Here is a video of the issue

Affected player is on the left and the spectator is on the right.

What can I add to the pre render event to counteract the odd movement on the spectator side. I can check if the client is spectator or affected so I just need to know how to translate the push matrix to look normal for the spectators.

Any help is appreciated.

Thank you,

Ashaman73

13,718

October 27, 2016 04:17 AM

If you want to use push/pop matrix, you should do it for each object you render like this


pushMatrix
do transformation
render
popMatrix

Don't mix this like this:


Call pre-render-event for all objects
Render all objects
Call post-render-event for all objects

The latter will not work.

But, the modern way don't use push/pop matrix at all. Today you have some matrix attached to the object representing its orientation and you do one of the following things:

1. (old way): glLoadMatrix to upload the model matrix

2. (better): upload the matrix as uniform to your shader

3. (even better): upload the matrix to uniform block/memory

The easiest way would be glLoadMatrix, as it seems that you are using ancient OpenGL (Version 1.1) now.

Ashaman

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