Error when making the game go to the next shader

[The_Fireplace]

Hey guys, I am trying to make my code cause the player to go to the next shader, but it gives me the following error(and the nearby chunks vanish then re-render) when activated:

 

 

[15:15:30] [Netty Local Client IO #0/WARN]: Failed to load shader: minecraft:shaders/post/notch.json
net.minecraft.client.util.JsonException: Invalid shaders/post/notch.json targets[0]: No OpenGL context found in the current thread.
at net.minecraft.client.util.JsonException.func_151379_a(JsonException.java:61) ~[JsonException.class:?]
at net.minecraft.client.shader.ShaderGroup.parseGroup(ShaderGroup.java:81) ~[shaderGroup.class:?]
at net.minecraft.client.shader.ShaderGroup.<init>(ShaderGroup.java:54) ~[shaderGroup.class:?]
at net.minecraft.client.renderer.EntityRenderer.loadShader(EntityRenderer.java:261) [EntityRenderer.class:?]
at net.minecraft.client.renderer.EntityRenderer.activateNextShader(EntityRenderer.java:247) [EntityRenderer.class:?]
at the_fireplace.unlogicii.proxy.ClientProxy.changeShader(ClientProxy.java:53) [ClientProxy.class:?]
at the_fireplace.unlogicii.network.ChangeShaderMessage$Handler.handleClientMessage(ChangeShaderMessage.java:33) [ChangeShaderMessage$Handler.class:?]
at the_fireplace.unlogicii.network.ChangeShaderMessage$Handler.handleClientMessage(ChangeShaderMessage.java:27) [ChangeShaderMessage$Handler.class:?]
at the_fireplace.unlogicii.network.AbstractMessageHandler.onMessage(AbstractMessageHandler.java:18) [AbstractMessageHandler.class:?]
at net.minecraftforge.fml.common.network.simpleimpl.SimpleChannelHandlerWrapper.channelRead0(SimpleChannelHandlerWrapper.java:37) [simpleChannelHandlerWrapper.class:?]
at net.minecraftforge.fml.common.network.simpleimpl.SimpleChannelHandlerWrapper.channelRead0(SimpleChannelHandlerWrapper.java:17) [simpleChannelHandlerWrapper.class:?]
at io.netty.channel.SimpleChannelInboundHandler.channelRead(SimpleChannelInboundHandler.java:105) [simpleChannelInboundHandler.class:4.0.23.Final]
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:333) [AbstractChannelHandlerContext.class:4.0.23.Final]
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:319) [AbstractChannelHandlerContext.class:4.0.23.Final]
at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:103) [MessageToMessageDecoder.class:4.0.23.Final]
at io.netty.handler.codec.MessageToMessageCodec.channelRead(MessageToMessageCodec.java:111) [MessageToMessageCodec.class:4.0.23.Final]
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:333) [AbstractChannelHandlerContext.class:4.0.23.Final]
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:319) [AbstractChannelHandlerContext.class:4.0.23.Final]
at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:787) [DefaultChannelPipeline.class:4.0.23.Final]
at io.netty.channel.embedded.EmbeddedChannel.writeInbound(EmbeddedChannel.java:169) [EmbeddedChannel.class:4.0.23.Final]
at net.minecraftforge.fml.common.network.internal.FMLProxyPacket.processPacket(FMLProxyPacket.java:90) [FMLProxyPacket.class:?]
at net.minecraft.network.NetworkManager.channelRead0(NetworkManager.java:158) [NetworkManager.class:?]
at net.minecraft.network.NetworkManager.channelRead0(NetworkManager.java:54) [NetworkManager.class:?]
at io.netty.channel.SimpleChannelInboundHandler.channelRead(SimpleChannelInboundHandler.java:105) [simpleChannelInboundHandler.class:4.0.23.Final]
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:333) [AbstractChannelHandlerContext.class:4.0.23.Final]
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:319) [AbstractChannelHandlerContext.class:4.0.23.Final]
at net.minecraftforge.fml.common.network.handshake.NetworkDispatcher.handleClientSideCustomPacket(NetworkDispatcher.java:389) [NetworkDispatcher.class:?]
at net.minecraftforge.fml.common.network.handshake.NetworkDispatcher.channelRead0(NetworkDispatcher.java:255) [NetworkDispatcher.class:?]
at net.minecraftforge.fml.common.network.handshake.NetworkDispatcher.channelRead0(NetworkDispatcher.java:53) [NetworkDispatcher.class:?]
at io.netty.channel.SimpleChannelInboundHandler.channelRead(SimpleChannelInboundHandler.java:105) [simpleChannelInboundHandler.class:4.0.23.Final]
at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:333) [AbstractChannelHandlerContext.class:4.0.23.Final]
at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:319) [AbstractChannelHandlerContext.class:4.0.23.Final]
at io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:787) [DefaultChannelPipeline.class:4.0.23.Final]
at io.netty.channel.local.LocalChannel.finishPeerRead(LocalChannel.java:326) [LocalChannel.class:4.0.23.Final]
at io.netty.channel.local.LocalChannel.access$400(LocalChannel.java:45) [LocalChannel.class:4.0.23.Final]
at io.netty.channel.local.LocalChannel$5.run(LocalChannel.java:312) [LocalChannel$5.class:4.0.23.Final]
at io.netty.channel.local.LocalEventLoop.run(LocalEventLoop.java:33) [LocalEventLoop.class:4.0.23.Final]
at io.netty.util.concurrent.SingleThreadEventExecutor$2.run(SingleThreadEventExecutor.java:116) [singleThreadEventExecutor$2.class:4.0.23.Final]
at java.lang.Thread.run(Thread.java:745) [?:1.8.0_65]
Caused by: java.lang.RuntimeException: No OpenGL context found in the current thread.
at org.lwjgl.opengl.GLContext.getCapabilities(GLContext.java:124) ~[lwjgl-2.9.4-nightly-20150209.jar:?]
at org.lwjgl.opengl.GL11.glEnable(GL11.java:1012) ~[lwjgl-2.9.4-nightly-20150209.jar:?]
at net.minecraft.client.renderer.GlStateManager$BooleanState.setState(GlStateManager.java:590) ~[GlStateManager$BooleanState.class:?]
at net.minecraft.client.renderer.GlStateManager$BooleanState.setEnabled(GlStateManager.java:579) ~[GlStateManager$BooleanState.class:?]
at net.minecraft.client.renderer.GlStateManager.enableDepth(GlStateManager.java:109) ~[GlStateManager.class:?]
at net.minecraft.client.shader.Framebuffer.createBindFramebuffer(Framebuffer.java:51) ~[Framebuffer.class:?]
at net.minecraft.client.shader.Framebuffer.<init>(Framebuffer.java:39) ~[Framebuffer.class:?]
at net.minecraft.client.shader.ShaderGroup.addFramebuffer(ShaderGroup.java:312) ~[shaderGroup.class:?]
at net.minecraft.client.shader.ShaderGroup.initTarget(ShaderGroup.java:128) ~[shaderGroup.class:?]
at net.minecraft.client.shader.ShaderGroup.parseGroup(ShaderGroup.java:77) ~[shaderGroup.class:?]
... 37 more

 

 

And so you can trace the issue, here is the ClientProxy, where it is being changed from:

ClientProxy

And the packet class that calls the method to change the shader:

ChangeShaderMessage

 

I don't understand how no OpenGL context can be found in the thread when it is being called on the client side, so I am stumped on this one.

 

If you have any questions or comments, let me know. Any help is appreciated.

 

[N247S]

This might be caused becuase your code is handled by a non opengl thread. Meaning that opengl will complain about that. And from the top of my head, messages/packets are handled in a side thread in MC 1.8. So maybe bringing it back to the mainThread would work? (Im not sure wich thread you need)

[The_Fireplace]

This might be caused becuase your code is handled by a non opengl thread. Meaning that opengl will complain about that. And from the top of my head, messages/packets are handled in a side thread in MC 1.8. So maybe bringing it back to the mainThread would work? (Im not sure wich thread you need)

I figured as much. I still don't know which thread to switch it to and how to switch it. Or perhaps, there is a better solution. Anyone know?

[Choonster]

Packets are handled on a Netty thread, as N247S said. You need to schedule a task to run on the main thread before you can safely interact with normal Minecraft classes.

 

This tutorial explains how to schedule the task.