Amulet.xyz Sprite Editor

main.lua

-- Sprite Editor

-- Paste any sized sprite into this block to edit it.
-- After drawing, copy the text from the console.
img = [[
...cc.ccc.
.cccccccc.
.cYYcYYYc.
YYgWYYgWcY
YYYYYYYYYY
.YRYYYYRY.
.YYRRRRY..
....YY....
.MmMYYmMm.
.MmMmMmMm.
]]

sprite = am.sprite(img)
pixels = sprite.spec.texture.image_buffer.buffer:view('uint')
size = vec2(sprite.width, sprite.height)

win = am.window{
    title = "Sprite Editor",
    width = size.x,
    height = size.y,
    clear_color = vec4(0, 0, 0, 1)
}

win.scene = sprite

function rgba2uint(color)
    return
        math.floor(color.a * 255) * 16777216 + 
        math.floor(color.b * 255) * 65536 + 
        math.floor(color.g * 255) * 256 + 
        math.floor(color.r * 255)
end

function uint2rgba(uint)
    local a = math.floor(uint / 16777216) / 255
    uint = uint - math.floor(a * 255) * 16777216
    
    local b = math.floor(uint / 65536) / 255
    uint = uint - math.floor(b * 255) * 65536

    local g = math.floor(uint / 256) / 255
    uint = uint - math.floor(g * 255) * 256

    local r = math.floor(uint) / 255

    return vec4(r,g,b,a)
end

-- add clear into the map, so we can draw with it
am.ascii_color_map['.'] = vec4(0,0,0,0)

-- starting color
color = rgba2uint(am.ascii_color_map['W'])

function lookup_color(c)
    local cuint = rgba2uint(c)
    for k,v in pairs(am.ascii_color_map) do
        if rgba2uint(v) == cuint then
            return k
        end
    end
    return "?"
end

function handle_key(k)
    if k == 'escape' then
        pixels:set(0)
        return
    end
    if k == 'period' then
        k = '.'
    end
    if win:key_down("lshift") or win:key_down("rshift") then
        k = string.upper(k)
    end
    local c = am.ascii_color_map[k]
    if c ~= nil then
        color = rgba2uint(c)
        print("color", k, "=", c, string.format("%x",color))
        return
    else
        print("unrecognized key:", k)
    end
end

print("Available colors:")
print(table.tostring(am.ascii_color_map))
print("Press any of these keys to pick a color.")
print("Press ESCAPE to clear.")

sprite:action(function()
    for _,k in ipairs(win:keys_pressed()) do
        handle_key(k)
    end
    if win:mouse_down"left" then
        local p = win:mouse_position() + size/2
        p = vec2(math.floor(p.x), math.floor(p.y))
        local i = p.x + p.y * win.width + 1
        if i>=1 and i<=size.x*size.y then
            pixels[i] = color
        end
    end
    if win:mouse_released"left" then
        print("img = [[")
        for y = 0,size.y-1 do
            local row=""
            for x = 0,size.x-1 do
                local i = x + (size.y - y - 1) * size.x + 1
                local pix = pixels[i]
                row = row .. lookup_color(uint2rgba(pix))
            end
            print(row)
        end
        print("]]")
    end
end)