jin.graphics = jin.graphics or {} 

local jg = jin.graphics

jg.RenderMode = {
  FILL = 1, 
  LINE = 2,
}

jg.SpriteOrigin = {
  TOPLEFT = 0,
  TOPCENTER = 1,
  TOPRIGHT = 2,
  MIDDLELEFT = 3,
  MIDDLECENTER = 4,
  MIDDLERIGHT = 5,
  BOTTOMLEFT = 6,
  BOTTOMCENTER = 7,
  BOTTOMRIGHT = 8
}

jg.SpriteMode = {
  SINGLE = 1,
  RANDOM = 2,
  ANIMATED = 3
}

jg.BlendMode = {
  DEFAULT = 1,
  ALPHA = 1, 
  ADDITIVE = 2,
  PREMULTIPLIEDALPHA = 3
}

-- Built in shaders.
jg.Shaders = nil
local function compileBuiltInShaders() 
  if jg.Shaders ~= nil then 
    return
  end
  jg.Shaders = {}
	jg.Shaders.Font = jg.newShader[[
		#VERTEX_SHADER
		Vertex vert(Vertex v)
		{
			return v;
		}
		#END_VERTEX_SHADER
		#FRAGMENT_SHADER
		Color frag(Color col, Texture tex, Vertex v)
		{
			return Color(col.rgb, texel(tex, v.uv).a);
		}
		#END_FRAGMENT_SHADER
	]]
	jg.Shaders.Texture = jg.newShader[[
		#VERTEX_SHADER
		Vertex vert(Vertex v)
		{
			return v;
		}
		#END_VERTEX_SHADER
		#FRAGMENT_SHADER
		Color frag(Color col, Texture tex, Vertex v)
		{
			return col * texel(tex, v.uv);
		}
		#END_FRAGMENT_SHADER
	]]
	jg.Shaders.Sprite = jg.newShader[[
		#VERTEX_SHADER
		Vertex vert(Vertex v)
		{
			return v;
		}
		#END_VERTEX_SHADER
		#FRAGMENT_SHADER
		Color frag(Color col, Texture tex, Vertex v)
		{
			return col * texel(tex, v.uv);
		}
		#END_FRAGMENT_SHADER
	]]
	jg.Shaders.SpriteBatch = jg.newShader[[
		#VERTEX_SHADER
		Vertex vert(Vertex v)
		{
			return v;
		}
		#END_VERTEX_SHADER
		#FRAGMENT_SHADER
		Color frag(Color col, Texture tex, Vertex v)
		{
			return col * texel(tex, v.uv);
		}
		#END_FRAGMENT_SHADER
	]]
  jg.Shaders.Shape = jg.newShader[[
    #VERTEX_SHADER
	  Vertex vert(Vertex v)
	  {
		  return v;
	  }
	  #END_VERTEX_SHADER
	  #FRAGMENT_SHADER
	  Color frag(Color col, Texture tex, Vertex v)
	  {
		  return col;
	  }
	  #END_FRAGMENT_SHADER
  ]]
  jg.Shaders.Mesh = jg.newShader[[ 
     	#VERTEX_SHADER
    in Vec4 color;
		Vertex vert(Vertex v)
		{
			return v;
		}
		#END_VERTEX_SHADER
		#FRAGMENT_SHADER
		Color frag(Color col, Texture tex, Vertex v)
		{
			return col * texel(tex, v.uv) * v.color;
		}
		#END_FRAGMENT_SHADER 
  ]]
	jg.Shaders.Default = jg.newShader[[
		#VERTEX_SHADER
		Vertex vert(Vertex v)
		{
			return v;
		}
		#END_VERTEX_SHADER
		#FRAGMENT_SHADER
		Color frag(Color col, Texture tex, Vertex v)
		{
			return col * texel(tex, v.uv);
		}
		#END_FRAGMENT_SHADER
	]]
  jg.Shaders.Error = jg.newShader[[
  	#VERTEX_SHADER
		Vertex vert(Vertex v)
		{
			return v;
		}
		#END_VERTEX_SHADER
		#FRAGMENT_SHADER
		Color frag(Color col, Texture tex, Vertex v)
		{
			return Color(1, 0, 1, 1);
		}
		#END_FRAGMENT_SHADER
  ]]
end

local _init = jg.init
local initialized = false
jg.init = function(setting) 
  if initialized then 
    return initialized
  end
  initialized = _init(setting)
  if initialized then 
    compileBuiltInShaders()
    jg.useShader(jg.Shaders.Default)
  end
  return initialized 
end

-- Reset all attributes to default value.
jg.reset = function()
  jg.setColor(255, 255, 255, 255)
  jg.setClearColor(0, 0, 0, 0)
  jg.clear()
  jg.unsetFont()
  jg.unuseShader()
end

jg.unuseShader = function()
  jg.useShader(jg.Shaders.Default)
end

local _newShader = jg.newShader

jg.newShader = function(program) 
  local shader = _newShader(program)
  if shader == nil then 
    jin.log.error("Compile shader failed:\n" .. debug.traceback())
    return jg.Shaders.Error
  else
    return shader
  end
end

local _newShaderf = jg.newShaderf

jg.newShaderf = function(file)
  local shader = _newShaderf(file)
  if shader == nil then 
    jin.log.error("Compile shader failed:\n" .. debug.traceback())
    return jg.Shaders.Error
  else
    return shader
  end
end