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.

 

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)

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?

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.