shader_type canvas_item;
uniform sampler2D glyph_atlas : hint_normal;
uniform vec2 tilemap_size = vec2(32.0, 20.0);  // Update this to match the texture size

// tile_atlas hardcoded to 64x4 tiles for now

void fragment() {
	// GLES2
	vec2 xy = UV * tilemap_size;  // Texel-space coord of our texture
	float t = texture(TEXTURE, UV).r;
	int tile_idx = int(t * 255.0);  // Luminosity channel (any RGB channel works)
	// Convert tile_idx to a texel coordinate, then to a UV coordinate
	ivec2 tile_xy = ivec2(tile_idx%64, tile_idx/64);
	vec2 tile_uv = vec2(tile_xy)/64.0;
	// Get sub-tile UV
	vec2 sub_tile_uv = fract(xy);
	vec2 uv = tile_uv + (sub_tile_uv/64.0);

	COLOR = texture(glyph_atlas, uv);
}