Why is it that when I use set_shader_parameter, the sprite dissapears instead of changing to the state I set it to?

Question

Godot 4.2

I have a shader that changes the hue of an AnimatedSprite2D. Here is the shader:

shader_type canvas_item;

uniform vec4 color : source_color;

void fragment(){
    vec4 pixelColor = texture(TEXTURE, UV);
    float brightness = (0.299 * pixelColor.r + 0.587 * pixelColor.g + 0.114 * pixelColor.b);
    vec4 greyScale = vec4(brightness, brightness, brightness, pixelColor.a);
    COLOR = greyScale * color;

I would like to be able to change the color through code, so I've been looking into how to use set_shader_parameter. Just as a test, I've set up this code

func _on_button_pressed():
    material.set_shader_parameter("color", [Vector4(1.0, 0.3, 0.5, 1.0)])

However, once I click the button, the AnimatedSprite2D either disappears or becomes invisible.

I am new to shaders, so there may be a step I am missing!

Answer 1

Shader parameters in Godot 4 need to be set using the correct data type. In your code, the color parameter has a vec4. If this is the case, then it needs to pass it as a color, not a vector4.

Simply change Vector4 to Color for the shader parameter and reference it.