Useful%20Tools%20for%20Making%20Video%20Games

1
Useful Tools for Making Video Games

• Part I
• An overview of Ogre

2
Sample Games

• Thunder Wheels
• Kong
• Masterplan
• Pacific Storm
• Trampoline

3
Features

• Graphics API independent 3D implementation
• Platform independence
• Material Shader support
• Well known texture formats png, jpeg, tga, bmp,
  dds, dxt
• Mesh support Milkshape3D, 3D Studio Max, Maya,
  Blender
• Scene features
• BSP, Octree plugins, hierarchical scene graph
• Special effects
• Particle systems, skyboxes, billboarding, HUD,
  cube mapping, bump mapping, post-processing
  effects
• Easy integration with physics libraries
• ODE, Tokamak, Newton, OPCODE
• Open source!

4
Core Objects
5
Startup Sequence

• ExampleApplication
• Go()
• Setup()
• Configure()
• setupResources()
• chooseSceneManager()
• createCamera()
• createViewport()
• createResourceListener()
• loadResources()
• createScene()
• frameStarted/Ended()
• createFrameListener()
• destroyScene()

6
Basic Scene

• Entity, SceneNode
• Camera, lights, shadows
• BSP map
• Integrated ODE physics
• BSP map
• Frame listeners

7
Terrain, sky, fog
8
CEGUI

• Window, panel, scrollbar, listbox, button, static
  text
• Media/gui/ogregui.layout
• CEGUIWindow sheet
• CEGUIWindowManagergetSingleton().loadWindowLay
  out( (CEGUIutf8)"ogregui.layout")
• mGUISystem-gtsetGUISheet(sheet)

9
Animation

• Node animation (camera, light sources)
• Skeletal Animation
• AnimationState mAnimationState
• mAnimationState ent-gtgetAnimationState("Idle")
• mAnimationState-gtsetLoop(true)
• mAnimationState-gtsetEnabled(true)
• mAnimationState-gtaddTime(evt.timeSinceLastFrame)
  
• mNode-gtrotate(quat)

10
Animation

• Crowd (instancing vs single entity)
• InstancedGeometry batch
• new InstancedGeometry(mCamera-gtgetSceneManager
  (), "robots" )
• batch-gtaddEntity(ent, Vector3ZERO)
• batch-gtbuild()
• Facial animation
• VertexPoseKeyFrame manualKeyFrame
• manualKeyFrame-gtaddPoseReference()
• manualKeyFrame-gtupdatePoseReference
  ( ushort poseIndex, Real influence) 

11
Picking
12
Picking

• CEGUIPoint mousePos CEGUIMouseCursorgetSi
  ngleton().getPosition()
• Ray mouseRay
• mCamera-gtgetCameraToViewportRay(mo
  usePos.d_x/float(arg.state.width),
• 
  mousePos.d_y/float(arg.state.height))
• mRaySceneQuery-gtsetRay(mouseRay)
• mRaySceneQuery-gtsetSortByDistance(fals
  e)
• RaySceneQueryResult result
  mRaySceneQuery-gtexecute()
• RaySceneQueryResultiterator
  mouseRayItr
• Vector3 nodePos
• for (mouseRayItr result.begin()
  mouseRayItr ! result.end() mouseRayItr)
• if (mouseRayItr-gtworldFragment)
• nodePos mouseRayItr-gtworldFr
  agment-gtsingleIntersection
• break
• // if

13
Particle Effects

• mSceneMgr-gtgetRootSceneNode()-gtcreateChildSceneNod
  e()-gtattachObject(
• mSceneMgr-gtcreateParticleSystem("s
  il", "Examples/sil"))
• Examples/sil
• material Examples/Flare2
• particle_width 75
• particle_height 100
• cull_each false
• quota 1000
• billboard_type oriented_self
• // Area emitter
• emitter Point
• angle 30
• emission_rate 75
• time_to_live 2
• direction 0 1 0

14
Particle Effects
Particle system attributes quota material particle_width particle_height cull_each billboard_type billboard_origin billboard_rotation_type common_direction common_up_vector renderer sorted local_space point_rendering accurate_facing iteration_interval nonvisible_update_timeout Emitter attributes (point, box, clyinder, ellipsoid, hollow ellipsoid, ring) angle colour colour_range_start colour_range_end direction emission_rate position velocity velocity_min velocity_max time_to_live time_to_live_min time_to_live_max duration duration_min duration_max repeat_delay repeat_delay_min repeat_delay_max Affectors (LinearForce, ColorFader) Linear Force Affector ColourFader Affector ColourFader2 Affector Scaler Affector Rotator Affector ColourInterpolator Affector ColourImage Affector DeflectorPlane Affector DirectionRandomiser Affector
15
Fire and Smoke

• affector Rotator
• rotation_range_start 0
• rotation_range_end 360
• rotation_speed_range_start -60
• rotation_speed_range_end 200

16
Cel Shading

• vertex_program Ogre/CelShadingVP cg
• source Example_CelShading.cg
• entry_point main_vp
• default_params
• material Examples/CelShading
• vertex_program_ref Ogre/CelShadingVP
• fragment_program_ref Ogre/CelShadingFP

17
Cube Mapping

• With Perlin noise to distort vertices
• void morningcubemap_fp (
• float3 uv TEXCOORD0,
• out float4 colour COLOR,
• uniform samplerCUBE tex register(s0) )
• colour texCUBE(tex, uv)
• // blow out the light a bit
• colour 1.7

18
Bump Mapping


19
Reflections Refractions

• // Noise
• texture_unit
• // Perlin noise volume
• texture waves2.dds
• // min / mag filtering, no mip
• filtering linear linear none
• // Reflection
• texture_unit
• // Will be filled in at runtime
• texture Reflection
• tex_address_mode clamp
• // needed by ps.1.4
• tex_coord_set 1
• // Refraction
• texture_unit

20
Reflections Refractions
21
Grass

• Each grass section is 3 planes at 60 degrees to
  each other
• Normals point straight up to simulate correct
  lighting

22
Post-Processing Effects
23
Supporting tools (add-ons)

• Blender, Autodesk 3DS, Milkshape3D, Softimage XSI
  importers/exporters
• Particle editors, mesh viewers
• GUI editors
• Physics bindings
• Scene exporters and lots more
• Add-on site

24
References

• http//www.ogre3d.org/