INSTANCE_CUSTOM preventing shader from being compiled

Help Shaders
1

Godot Version

4.4

Question

Im trying to pass data to instances in a multi mesh shader on Mac but my shader keeps getting an error and not compiling the shader resulting in the color being lost and the data not being passed through. This is my shader code
shader_type spatial;
uniform vec4 grass_color : source_color;
void vertex() {
// Called for every vertex the material is visible on.
}

void fragment() {
// At runtime, INSTANCE_CUSTOM.x is valid
float cut_height = INSTANCE_CUSTOM.x;

ALBEDO = grass_color.rgb;

}

And this is my code where I set custom data
tall_grass.multimesh.instance_count = 0
tall_grass.multimesh.use_custom_data = true
tall_grass.multimesh.instance_count = grass_count

2

Typing “Godot INSTANCE_CUSTOM” into Google gave this as the top result INSTANCE_CUSTOM information regarding accesibility only in vertex shader. · Issue #10604 · godotengine/godot-docs · GitHub

3

Instance custom is only available in vertex function. If you need it in fragment, pass it from vertex function via a varying.