-- sample for termfx
-- Gunnar Zötl <gz@tset.de>, 2014-2015
-- Released under the terms of the MIT license. See file LICENSE for details.
tfx = require "termfx"

tfx.init()

function makespr(s, fg, bg)
    local c = "-:+=%ZXH#"
    local spr = tfx.newbuffer(s, s / 2)
    spr:attributes(fg, bg)
    for y = 1, s / 2 do
        for x = 1, s do
            local lx, ly = (x - 0.5) / s, (2 * y - 1) / s
            local v = math.floor((math.sin(lx * math.pi) + math.sin(ly * math.pi)) / 2 * #c)
            local ch = string.sub(c, v, v)
            spr:setcell(x, y, ch)
        end
    end
    return spr
end

tfx.outputmode(tfx.output.NORMAL)

ok, err = pcall(function()
    local sprites = {}
    local blit2screen = true

    for i = 1, 5 do
        sprites[i] = makespr(2 ^ (i + 2), i + 1, tfx.color.BLACK)
    end

    local snum = 1
    local spr = sprites[snum]
    local sw, sh = spr:width(), spr:height()
    local x, y = 1 - sw, 1 - sh
    local xo, yo = 1, 1
    local fw, fh = tfx.width(), tfx.height()
    local target = tfx.newbuffer(fw - 2, fh - 2)
    local w, h = target:width(), target:height()

    repeat

        if blit2screen then
            tfx.clear(tfx.color.WHITE, tfx.color.BLACK)
            tfx.blit(x, y, spr)
        else
            tfx.clear(tfx.color.WHITE, tfx.color.RED)
            target:clear(tfx.color.WHITE, tfx.color.BLACK)
            target:blit(x, y, spr)
            tfx.blit(2, 2, target)
        end

        x = x + xo
        if x > w or x < 1 - sw then
            xo = -xo
        end
        y = y + yo
        if y > h or y < 1 - sh then
            yo = -yo
        end

        tfx.printat(1, tfx.height(),
            "print 1.." .. #sprites .. " for sprite size, t to toggle blit to screen or buffer, q to quit")
        tfx.printat(1, 1, "Current size: " .. snum .. " (" .. spr:width() .. "x" .. spr:height() .. ")")

        tfx.present()
        evt = tfx.pollevent(333)
        snum = evt and tonumber(evt.char) or snum
        if snum >= 1 and snum <= #sprites then
            spr = sprites[snum]
            sw, sh = spr:width(), spr:height()
            if x < 1 - sw then
                x = 1 - sw
                xo = 1
            end
            if y < 1 - sh then
                y = 1 - sh
                yo = 1
            end
        end

        if evt and evt.char == 't' then
            blit2screen = not blit2screen
        end

    until evt and evt.type == "key" and evt.char == "q"
end)

tfx.shutdown()
if not ok then
    print("Error: " .. err)
end