[1.19.2] Rendering "ghost" blocks

[zskamljic]

I was looking into this topic, and trying to update it to 1.19.2, and came up with this so far.

As it happens, it seems like the block is rendered at camera origin, despite my intention to render it in a specific block position. Am I even using the right event? Am I rendering the block correctly? 

Translating the poseStack to all 0 does not seem to be helping either.

Edited November 6, 2022 by zskamljic

[warjort]

If you look at LevelRender.renderHitOutline() it uses (pseudo code)

blockPos - camera.getPosition()

So, the PoseStack must be at the camera position when that event is called.

 

You can't translate to anywhere. PoseStack.translate() is a relative operation so passing all 0 does nothing. 🙂 

 

Try something like:

                var target = event.getTarget();
                var cpos = event.getCamera().getPosition(); // camera
                var bpos = target.getBlockPos().relative(target.getDirection()); // block

                var poseStack = event.getPoseStack();
                poseStack.pushPose();
                poseStack.translate(bpos.getX() - cpos.x, bpos.getY() - cpos.y, bpos.getZ() - cpos.z);
                // your code here
                poseStack.popPose();

 

Edited November 6, 2022 by warjort

[zskamljic]

That works perfectly! Thanks! Is there a similar way to also change the alpha of the block? The following does not appear to work:

	RenderSystem.setShaderColor(1f, 1f, 1f, 0.1f);
	

Edited November 6, 2022 by zskamljic

[warjort]

If you look at the code for the method you are using, it uses the BlockAndTintGetter (the player.level) you pass to do its calculations of light levels.

If you want to alter things, you will probably need to create a wrapper/delegate implementation of that interface that changes the values returned by the real ClientLevel?

[zskamljic]

I have tried creating a "proxy" BlockAndTintGetter, based on my debugging only getShade, getLightEngine and getBlockState are called, changing values returned by getShade seems to darken the block (closer to 0f) or use default color (closer to 1f), getBlockTint (which I expected to return ARGB int does not seem to get called at all.

I have also tried changing buffer color, but it appears to be ignored there.

[warjort]

You know as much as about this as I do.  It's not really my area of expertise.

I do know there is some caching code in there. So maybe you are hitting that? See for example AmbientOcclusionFace.calculate() and BlockModelRenderer.Cache

I've tried a couple of times to understand how minecraft's lighting code works, but it is spaghetti. 🙂 

 

Maybe you can use your debugger to disable the cache to see if that is your problem? 

[zskamljic]

I have tried creating a "proxy" BlockAndTintGetter, based on my debugging only getShade, getLightEngine and getBlockState are called, changing values returned by getShade seems to darken the block (closer to 0f) or use default color (closer to 1f), getBlockTint (which I expected to return ARGB int does not seem to get called at all.

I have also tried changing buffer color, but it appears to be ignored there.

By digging through the code, I have discovered that in VertexConsumer interface, one of the overloads of putBulkData is used, with alpha set to 1. The answer was to proxy the VertextConsumer and override the default method putBulkData, using custom alpha value.

I have updated the original gist with the "solution", but it still feels like there should be a cleaner way to achieve this.