[MC-219894] Powder snow fog effect is still applied to spectators

While to a much lesser extent as of the latest snapshot due to the fixing of MC-213743, it still poses slightly problematic with visibility at high distances. Spectator players aren't supposed to be impaired visually by the game like survival players are, so the fog here probably shouldn't exist in this case.

Code Analysis:

Code analysis by @unknown can be found in this comment.

Related issues

relates to

MC-219893 Lava fog effect is still applied to spectators

testing discovered

MC-219895 Powder snow z-fighting with distant block faces from within

Attachments

MC-219894.mp4

Comments

migrated 2021-03-17T20:16:46Z

[media][media][media]

Avoma 2021-03-18T09:15:40Z

Can confirm however, it appears that the density of the fog has been dramatically reduced whilst in spectator mode, so this may be intended.

Avoma 2021-03-20T13:55:28Z

Video attached.

Avoma 2021-03-31T17:54:35Z

Can confirm in 21w13a.

Avoma 2021-04-08T14:39:24Z

Can confirm in 21w14a.

Avoma 2021-04-14T18:23:02Z

Can confirm in 21w15a.

Avoma 2021-04-22T08:57:20Z

Can confirm in 21w16a.

Avoma 2021-04-28T18:01:15Z

Can confirm in 21w17a.

Avoma 2021-07-09T09:13:08Z

Can confirm in 1.17.1.

ampolive 2021-11-18T12:30:22Z

Can confirm in 1.18 Pre-release 4.

Avoma 2021-12-17T20:16:22Z

Can confirm in 1.18.1.

Avoma 2022-03-06T18:40:40Z

Can confirm in 1.18.2.

Avoma 2022-09-04T15:56:23Z

Can confirm in 1.19.2.

Apollo30 2023-07-20T01:33:42Z

Code Analysis:

The following is based on a decompiled version of Minecraft 1.20.1 using MCP-Reborn.

net.minecraft.client.Camera.java // Original

public class Camera {
    ...
    public FogType getFluidInCamera() {
            if (!this.initialized) {
                return FogType.NONE;
            } else {
                FluidState fluidstate = this.level.getFluidState(this.blockPosition);
                if (fluidstate.is(FluidTags.WATER) && this.position.y < (double)((float) this.blockPosition.getY() + fluidstate.getHeight(this.level, this.blockPosition))) {
                    return FogType.WATER;
                } else {
                    Camera.NearPlane camera$nearplane = this.getNearPlane();                    for (Vec3 vec3: Arrays.asList(camera$nearplane.forward, camera$nearplane.getTopLeft(), camera$nearplane.getTopRight(), camera$nearplane.getBottomLeft(), camera$nearplane.getBottomRight())) {
                        Vec3 vec31 = this.position.add(vec3);
                        BlockPos blockpos = BlockPos.containing(vec31);
                        FluidState fluidstate1 = this.level.getFluidState(blockpos);
                        if (fluidstate1.is(FluidTags.LAVA)) {
                            if (vec31.y <= (double)(fluidstate1.getHeight(this.level, blockpos) + (float) blockpos.getY())) {
                                return FogType.LAVA;
                            }
                        } else {
                            BlockState blockstate = this.level.getBlockState(blockpos);
                            if (blockstate.is(Blocks.POWDER_SNOW)) {
                                return FogType.POWDER_SNOW;
                            }
                        }
                    }                    return FogType.NONE;
                }
            }
        }
        ...
}

As we can see, this is the method that determines which fog to product to an entity's camera. As a result of this inspection, we can see that there is no conditions to determine whether a player is in spectator or not.

Fix:

net.minecraft.client.Camera.java // Updated

public class Camera {
    ...
    public FogType getFluidInCamera() {
            if (!this.initialized || (this.entity instanceof Player player) && player.isSpectator()) {
                return FogType.NONE;
            } else {
                FluidState fluidstate = this.level.getFluidState(this.blockPosition);
                if (fluidstate.is(FluidTags.WATER) && this.position.y < (double)((float) this.blockPosition.getY() + fluidstate.getHeight(this.level, this.blockPosition))) {
                    return FogType.WATER;
                } else {
                    Camera.NearPlane camera$nearplane = this.getNearPlane();                    for (Vec3 vec3: Arrays.asList(camera$nearplane.forward, camera$nearplane.getTopLeft(), camera$nearplane.getTopRight(), camera$nearplane.getBottomLeft(), camera$nearplane.getBottomRight())) {
                        Vec3 vec31 = this.position.add(vec3);
                        BlockPos blockpos = BlockPos.containing(vec31);
                        FluidState fluidstate1 = this.level.getFluidState(blockpos);
                        if (fluidstate1.is(FluidTags.LAVA)) {
                            if (vec31.y <= (double)(fluidstate1.getHeight(this.level, blockpos) + (float) blockpos.getY())) {
                                return FogType.LAVA;
                            }
                        } else {
                            BlockState blockstate = this.level.getBlockState(blockpos);
                            if (blockstate.is(Blocks.POWDER_SNOW)) {
                                return FogType.POWDER_SNOW;
                            }
                        }
                    }                    return FogType.NONE;
                }
            }
        }
        ...
}

This fix removes any sort of fog whenever the player is in spectator. Giving spectators free reign to look around at anything without any disturbance.