i-mic-fps/lib/texture.rb

class IMICFPS
  class Texture
    DEFAULT_TEXTURE = "#{IMICFPS.assets_path}/base/shared/textures/default.png"
    include CommonMethods

    CACHE = {}

    def self.release_textures
      CACHE.values.each do |id|
        glDeleteTextures(id)
      end
    end

    def self.from_cache(path, retro)
      return CACHE.dig("#{path}?retro=#{retro}")
    end

    attr_reader :id
    def initialize(path: nil, image: nil, retro: false)
      raise "keyword :path or :image must be provided!" if path.nil? && image.nil?
      @retro = retro

      if path.is_a?(Array)
        if path.size > 1
          path = "#{GAME_ROOT_PATH}/assets/#{path.join("/")}"
        else
          path = path.first
        end
      end

      @path = path

      if @path
        unless File.exist?(@path)
          warn "Missing texture at: #{@path}" if window.config.get(:debug_options, :stats)
          @retro = true # override retro setting
          @path = DEFAULT_TEXTURE
        end

        if texture = Texture.from_cache(@path, @retro)
          @id = texture.id
          puts "Using cached texture: #{@path}" if window.config.get(:debug_options, :stats)
          return
        end

        puts "Allocating texture for: #{@path}" if window.config.get(:debug_options, :stats)
        image = load_image(@path)
        @id = create_from_image(image)
      else
        puts "Allocating texture for: #{image}" if window.config.get(:debug_options, :stats)
        @id = create_from_image(image)
      end
    end

    def load_image(path)
      CACHE["#{path}?retro=#{@retro}"] = self
      Gosu::Image.new(path, retro: @retro)
    end

    def create_from_image(image)
      array_of_pixels = image.to_blob

      tex_names_buf = ' ' * 4
      glGenTextures(1, tex_names_buf)
      texture_id = tex_names_buf.unpack('L2').first

      glBindTexture(GL_TEXTURE_2D, texture_id)
      glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, image.width, image.height, 0, GL_RGBA, GL_UNSIGNED_BYTE, array_of_pixels)
      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT)
      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT)
      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST) if @retro
      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR) unless @retro
      glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR)
      glGenerateMipmap(GL_TEXTURE_2D)
      gl_error?

      return texture_id
    end
  end
end