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keep getting error

c5121 multiple bindings to output semantic "ATTR1"

while trying to create a shader for Minecraft with the latest version of iris and fabric.

this is my code:

#version 330 compatibility
#extension GL_ARB_separate_shader_objects : enable

out vec2 lmcoord;
out vec2 texcoord;
out vec4 glcolor;
out vec3 normal;

uniform mat4 gbufferModelViewInverse;

/* DRAWBUFFERS:012 */

layout(location = 0) out vec4 color;
layout(location = 1) out vec4 lightmapData;
layout(location = 2) out vec4 encodedNormal;

void main() {

gl_Position = ftransform();
texcoord = (gl_TextureMatrix[0] * gl_MultiTexCoord0).xy;
lmcoord = (gl_TextureMatrix[1] * gl_MultiTexCoord1).xy;
lmcoord = (lmcoord * 33.05 / 32.0) - (1.05 / 32.0);
glcolor = gl_Color;
normal = gl_NormalMatrix * gl_Normal;
normal = mat3(gbufferModelViewInverse) * normal;
lightmapData = vec4(lmcoord, 0.0, 1.0);
encodedNormal = vec4(normal * 0.5 + 0.5, 1.0);

}

has to do with lightmapData = vec4(lmcoord, 0.0, 1.0);
and layout(location = 1) out vec4 lightmapData;
because when I delete them it works just fine. I’m on windows ten with a gtx 1660ti with updated drivers.

The c5121 message usually pops up when two outputs end up sharing the same location, even if the code doesn’t make that obvious. I’d try giving each out variable a manual layout location to force the linker to stop guessing. Something like layout(location = 0) for texcoord, 1 for lmcoord, etc. I had fewer headaches doing that while working on shaders for a map I grabbed through ModsCraft.