mieki256's diary

function love.conf(t)
  t.window.title = "Shader test 07 raster"
  t.window.vsync = true
  t.window.resizable = true
  t.window.width = 640
  t.window.height = 480
  -- t.window.fullscreen = true
  -- t.window.fullscreentype = "exclusive"
end

-- Shader test 07 raster

function love.load()
  love.graphics.setDefaultFilter("nearest", "nearest")
  scr_w, scr_h = 640, 480
  canvas = love.graphics.newCanvas(scr_w, scr_h)
  img = love.graphics.newImage("bg_ras_c.png")

  -- make shader
  local shadercode = [[
    extern vec2 imgsize;
    extern number factor;

    vec4 effect( vec4 color, Image texture, vec2 texture_coords, vec2 screen_coords ) {
      texture_coords.x = mod(texture_coords.x + ((factor + (factor * texture_coords.y)) / imgsize.x), 1.0);
      vec4 texcolor = Texel(texture, texture_coords);
      return texcolor * color;
    }
  ]]
  myshader = love.graphics.newShader(shadercode)
  myshader:send("imgsize", {img:getWidth(), img:getHeight()})
  myshader:send("factor", 0.0)

  v = 0.0
  px = (scr_w - img:getWidth()) / 2
  py = scr_h - img:getHeight()
end

function love.update(dt)
  v = v + 128 * dt
  myshader:send("factor", v % 64.0)
end

function love.draw()
  love.graphics.setCanvas(canvas)
  love.graphics.clear(0, 0, 0, 255)

  love.graphics.setColor(255, 255, 255)
  love.graphics.setShader(myshader)
  love.graphics.draw(img, px, py)
  love.graphics.setShader()

  love.graphics.setCanvas()

  -- draw canvas to window
  wdw_w, wdw_h = love.graphics.getDimensions()
  scr_scale = math.min((wdw_w / scr_w), (wdw_h / scr_h))
  scr_ox = (wdw_w - (scr_w * scr_scale)) / 2
  scr_oy = (wdw_h - (scr_h * scr_scale)) / 2
  love.graphics.setColor(255, 255, 255)
  love.graphics.draw(canvas, scr_ox, scr_oy, 0, scr_scale, scr_scale)

  love.graphics.print("FPS: "..tostring(love.timer.getFPS()), 10, 10)
end

function love.keypressed(key, isrepeat)
  if key == "escape" then
    -- ESC to exit
    love.event.quit()
  end
end