mieki256's diary

function love.conf(t)
  t.window.title = "Shader test 06 sin cos"
  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 06 sin cos
--
-- love.graphics.newShader - LOVE
-- https://love2d.org/wiki/love.graphics.newShader

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("hsvbar.png")

  -- make shader
  myshader = love.graphics.newShader("shader.fs")
  myshader:send("factor", 0.0)

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

function love.update(dt)
  angle = (angle + 30 * dt) % 360.0;
  myshader:send("factor", 1.0 * (1.0 - math.sin(math.rad(angle))))
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

extern number factor;
varying vec4 vpos;

#ifdef VERTEX
vec4 position( mat4 transform_projection, vec4 vertex_position ) {
  vpos = vertex_position;
  return transform_projection * vertex_position;
}
#endif

#ifdef PIXEL
vec4 effect( vec4 color, Image texture, vec2 texture_coords, vec2 screen_coords ) {
  texture_coords += vec2(factor * cos(0.1 * vpos.x), factor * sin(0.075 * vpos.y));
  vec4 texcolor = Texel(texture, texture_coords);
  return texcolor * color;
}
#endif