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[1.17.1] Trying to draw a simple line overlay


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Hi all. New to modding so this is probably a silly question but I've searched and searched but cannot find any guides or sample code that works for 1.17.1
I have successfully created a client-side only mod that displays the player's coordinates on the screen and am now trying to draw a simple line in the world. Unfortunately, everything I have tried results in nothing displaying or a crash.
My latest crash is

Cannot invoke "net.minecraft.client.renderer.ShaderInstance.setSampler(String, Object)" because "shaderinstance" is null

Here is the code I have so far

public class MyRenderType extends RenderType {
    public MyRenderType(String p_173178_, VertexFormat p_173179_, VertexFormat.Mode p_173180_, int p_173181_, boolean p_173182_, boolean p_173183_, Runnable p_173184_, Runnable p_173185_) {
        super(p_173178_, p_173179_, p_173180_, p_173181_, p_173182_, p_173183_, p_173184_, p_173185_);

    private static final LineStateShard THICK_LINES = new LineStateShard(OptionalDouble.of(3.0));

    public static final RenderType OVERLAY_LINES = create("overlay_lines",


public static void drawLast(RenderWorldLastEvent event) {
    MultiBufferSource.BufferSource buffer = MultiBufferSource.immediate(Tesselator.getInstance().getBuilder());
    VertexConsumer builder = buffer.getBuffer(MyRenderType.OVERLAY_LINES);
    PoseStack matrixStack = event.getMatrixStack();
    Vec3 pos = minecraft.player.position();
    matrixStack.translate(-pos.x, -pos.y, -pos.z);

    Matrix4f matrix = matrixStack.last().pose();

    // There's also a version of the vertex method that doesn't take matrixStack, I tried that too but it made no difference.
    builder.vertex(matrixStack, (float)-5 + 0.5f, (float)0 + 0.5f, (float)5 + 0.5f)
    builder.vertex(matrixStack, (float)5 + 0.5f, (float)0 + 0.5f, (float)5 + 0.5f)
        .color(1, 0, 0, 1f)

    // I tried adding these lines but it made no difference.
    //RenderSystem.setShaderColor(1.0F, 1.0F, 1.0F, 1.0F);

    buffer.endBatch(); // crashes here

Any help is much appreciated

Edited by Marshall7
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  • Marshall7 changed the title to [1.17.1] Trying to draw a simple line overlay

I am trying to find the class you mentioned but StructureBlockEntityRenderer doesn't appear to exist in the vanilla code that I can see. I also cannot find any results on google for either class.
I can see LevelRenderer but so far haven't been able to figure out how to use it or what is wrong with my existing code.

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Thank you! I was able to make something appear using LevelRenderer and now I have determined the key thing that was wrong with my original code:
My custom render type needed to include


and for some reason I need one or both of


...if I want to see the line through other blocks.

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