fake perspective shader in Godot

fake_perspective.gdshader

shader_type canvas_item;
// displays a texture but distorts it based on the size of the top and bottom

uniform sampler2D main_texture:source_color, repeat_disable;

// scale the bottom of the image
uniform float scale_x_bottom = 1.0;

// scale the top of the image
uniform float scale_x_top = 1.0;

void fragment() {
	vec2 uv = (UV - vec2(0.5, 0.5)) * mix(scale_x_top, scale_x_bottom, UV.y) + vec2(0.5, 0.5);
	COLOR = texture(main_texture, uv);
	if (uv.x < 0.0 || uv.x > 1.0 || uv.y > 1.0 || uv.y < 0.0)
		COLOR.a = 0.0;
}