io.stdout:setvbuf("no")
local shader
local img
local img2
local canvas
local sw, sh = jin.graphics.getSize()
function jin.core.onLoad()
    local str = jin.filesystem.read("metaball.shader")
    shader = jin.graphics.newShader(str)
    local w, h = 256, 240
	local bitmap = jin.graphics.newBitmap(w, h, {255, 255, 0, 255})
	local b = bitmap:clone()
	bitmap = nil
	-- local bitmap2 = jin.graphics.newBitmap("img2.bmp")
    img = jin.graphics.newTexture(b)
    -- img2 = jin.graphics.newTexture(bitmap2)
    canvas = jin.graphics.newCanvas(200, 200)
end
-- extern vec3 iResolution;
-- extern number iGlobalTime;
-- extern vec4 iMouse;
local mx, my = 0, 0
function jin.core.onEvent(e)
    if e.type == "Quit" then 
        jin.core.stop()
    end
    if e.type == "KeyDown" then 
        if e.key == "Escape" then 
            jin.core.stop()
        end
    end
    if e.type == "MouseMotion" then 
        -- if e.button == "left" then 
            mx = e.x 
            my = e.y
        -- end
    end
end

local dt = 0
function jin.core.onDraw()
    dt = dt + 0.1
    jin.graphics.bindCanvas(canvas)
    jin.graphics.useShader(shader)
    shader:sendNumber("iGlobalTime", dt )
    shader:sendVec3("iResolution", {sw, sh, 1})
    shader:sendVec4("iMouse", {mx, my, mx, my})
    jin.graphics.draw(img, 0, 0, 1, 1)
    jin.graphics.unuseShader()
    jin.graphics.unbindCanvas()
    jin.graphics.draw(canvas, 0, 0, 2, 2)
end