io.stdout:setvbuf("no")
local texture_shader_source = [[
#VERTEX_SHADER
Vertex vert(Vertex v)
{
    return v; 
}
#END_VERTEX_SHADER

#FRAGMENT_SHADER
Color frag(Color c, Texture tex, Vertex v)
{
    return c * texel(tex, v.uv);
}
#END_FRAGMENT_SHADER
]] 
local texture_shader = nil
local font = nil
function jin.core.onLoad() 
    texture_shader = jin.graphics.newShader(texture_shader_source)
    local fontData = jin.graphics.newBitmap("font.png")
    font = jin.graphics.newTexture(fontData)
    fontData = nil
end

function jin.core.onEvent(e)
    if e.type == "Quit" then 
        jin.core.stop()
    end
    if e.type == "KeyDown" and e.key == "Escape" then 
        jin.core.stop()
    end
end
function jin.core.onUpdate(dt)

end
local t = 0
function jin.core.onDraw()
    jin.graphics.setClearColor(255, 255, 255, 255)
    t = t + 0.01
    jin.graphics.setColor(255*math.sin(t), 255*math.cos(t), 255*math.sin(t)*math.cos(t), 255)
    jin.graphics.useShader(texture_shader)
    jin.graphics.drawq(font, {16, 16, 32, 16}, 10, 10, 5, 5)
    --jin.graphics.draw(font, 0, 0, 3, 3)
    jin.graphics.unuseShader()
end