Class: Quake::Renderer::GLSky

Inherits:
Object
  • Object
show all
Defined in:
lib/quake/renderer/gl_sky.rb

Overview

Renders Quake sky using the two-layer scrolling technique. Sky textures are 256x128, split into:

- Left half (128x128): solid background layer
- Right half (128x128): alpha foreground layer (index 0 = transparent)

Instance Method Summary collapse

Constructor Details

#initialize(level, palette, texture_manager) ⇒ GLSky

Returns a new instance of GLSky.



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# File 'lib/quake/renderer/gl_sky.rb', line 12

def initialize(level, palette, texture_manager)
  @level = level
  @palette = palette
  @texture_manager = texture_manager
  @sky_surfaces = []
  @solid_tex = nil
  @alpha_tex = nil
  @time = 0.0

  find_sky_texture
  precompute_sky_surfaces
end

Instance Method Details

#render(camera, visible_face_set: nil) ⇒ Object 



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# File 'lib/quake/renderer/gl_sky.rb', line 29

def render(camera, visible_face_set: nil)
  return if @sky_surfaces.empty? || @solid_tex.nil?

  # Filter to PVS-visible sky surfaces only. Without this, distant
  # sky polys (e.g. the level's outdoor exit area) draw even when the
  # camera is enclosed in a cave - and underwater they alpha-blend
  # through translucent water as bright cloud shapes.
  visible_surfaces = if visible_face_set
                       @sky_surfaces.select { |s| visible_face_set.include?(s[:face_index]) }
                     else
                       @sky_surfaces
                     end
  return if visible_surfaces.empty?

  # Render solid background layer
  GL.BindTexture(GL::TEXTURE_2D, @solid_tex)
  speed_scale = @time * 8.0
  speed_scale -= speed_scale.floor & ~127

  visible_surfaces.each do |surf|
    GL.Begin(GL::TRIANGLE_FAN)
    surf[:vertices].each do |v|
      s, t = sky_texcoord(v, camera.position, speed_scale)
      GL.TexCoord2f(s, t)
      GL.Vertex3f(v.x, v.y, v.z)
    end
    GL.End
  end

  # Render alpha foreground layer with blending
  GL.Enable(GL::BLEND)
  GL.BlendFunc(GL::SRC_ALPHA, GL::ONE_MINUS_SRC_ALPHA)
  GL.BindTexture(GL::TEXTURE_2D, @alpha_tex)
  speed_scale2 = @time * 16.0
  speed_scale2 -= speed_scale2.floor & ~127

  visible_surfaces.each do |surf|
    GL.Begin(GL::TRIANGLE_FAN)
    surf[:vertices].each do |v|
      s, t = sky_texcoord(v, camera.position, speed_scale2)
      GL.TexCoord2f(s, t)
      GL.Vertex3f(v.x, v.y, v.z)
    end
    GL.End
  end

  GL.Disable(GL::BLEND)
end

#update(dt) ⇒ Object 



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# File 'lib/quake/renderer/gl_sky.rb', line 25

def update(dt)
  @time += dt
end