CodeSnippets

From Ogre Wiki

Contents 1 HOWTO's and Code Snippets 2 HOWTO 3 Geometry 3.1 Vertex and Index Buffers 3.2 Manual Object 3.3 General 4 Rendering 5 Non-Photorealistic Rendering 6 Materials & Textures 7 Particles 8 Shaders 9 Animation & Movement 10 Input 11 GUI 11.1 CEGUI 11.2 Other GUI Systems 11.3 General 11.4 Embedding OGRE in mainstream GUI libraries 12 Sound & multimedia 13 Physics 14 System 14.1 Minimal Ogre projects 14.2 Timer 14.3 Logging 14.4 Console 14.5 OS tricks 14.6 Scene manager 14.7 Render system 14.8 Script compilers (Shoggoth) 14.9 Misc 15 Miscellaneous 16 Useful Code Articles (w/code)

HOWTO

HOWTO - Collection of miscellaneous, smaller samples

HOWTO (II) - Part 2

Geometry

Vertex and Index Buffers

• Sharing buffers - Sharing vertex and index buffers across multiple meshes
• Generating a Mesh - Example of creating a mesh in memory using a index and vertex buffer
• Retrieving vertex data from a mesh
• Dynamically growing vertex buffers
• Creating a sphere mesh manually with nice texture coordinates and normals
• Using super ellipsoid for creating simple 3d primitives
• Creating various geometric/geodesic shapes
• Creates a set of tubes along a path
• Changing Coordinate Handedness - One way of using DirectX data

Manual Object

• ManualObject - A minimal example
• ManualObject 2D - A minimal example (Eihort only)
• ManualObject AxisObject - A simple Axis using box's.
• EditorGridSystem - A dynamically changing grid system for editors and such
• Create Tetrahedron with MOGRE (easy to port for Ogre)
• Loading from VRML - Load/create an entity from a VRML 2.0 / X3D format (using CyberX3D)

General

• Setting a vector's length
• Nearest point on a line - Find the nearest point on a line between two points
• 2D line intersection - do 2 lines described by 4 vertices in a plane intersect?
• Find Spline index - from global interpolation value
• Raycasting to the polygon level - how to see if a line intersects with a mesh's geometry
• Selection Buffer - pixel accurate entity selection
• Get Screenspace Coordinates - Get the screenspace (2D) coordinates of a MovableObject.
• Projecting 3D position and size to 2D
• Equal Length Spline - Generating new spline (based on SimpleSpline) which has equal distance between points.
• Nearest point on a Spline - From "Robust and Efficient Computation of the Closest Point on a Spline Curve"
• Get XZ coordinates - Retrieve XZ coordinates by a mouse ray

Rendering

• 2D Sprite Manager: A class for rendering 2D sprites, ie: the DirectDraw way.

MOGRE SpriteManager2d

• Drawing Lines in 3D
• Drawing lines in 3D revisited: Example of dynamic buffers code.
• Drawing Circles in 3D
• Displaying 2D Backgrounds
• Displaying a Lens Flare Effect
• HDR Effects Without Using Full Floating Point Textures
• Billboard-style Text in 3D: MovableText

MOGRE MovableText

• A More In-Depth Version of the 2D Sprite Manager
• Oriented Bounding Box

Non-Photorealistic Rendering

• Non-Photorealistic Rendering

Materials & Textures

• Loading resources from a URL - an Archive class for external resources.
• Merging and transforming archives - an Archive implementations that provide various transforms (resource overrides, file name prefixes).
• Creating dynamic textures - and materials using them.
• Saving dynamic textures
• Per renderable transparency - Utility classes to allow single renderables (Entities and SubEntities so far) to change their transparency without changing others that use the same material through a MaterialInstance utility class. See this forum thread
• Exporting 3D Textures - The (programmatic) generation of .dds and .raw 3D textures for use in Ogre.
• Material script examples - some example materials
• Rotating a texture using the getYaw() function - How to rotate a texture 360 degrees with the quaternion.getYaw() function
• Displaying 3D Object Text in 2D Without Using Billboards -- How to use the view transform to obtain 2D screen-space coordinates to draw overlay text above or near an object in the 3D scene.
• Displaying non-overlapping Text Overlays above Ogre MovableObjects -- Some enhancements to the Xavier's ObjectTextDisplay class resulted in 3 classes that do all the work for you. Enjoy!
• ObjectTitle - Display a title (text overlay) above a MovableObject
• Loading PGF Images -- Source code for loading PGF images using libPGF in Ogre
• Terrain Selection using a Mesh Decal -- using a mesh decal to show a marker on the terrain for terrain selection
• Light mapping -- A class used to do lightmapping in ogre.
• Reloading materials and parsing material scripts -- Ogre helper methods to reload all the materials found in a material script.
• Extending the Ogre GUI demo to reload textures on the fly -- A small extension to add a reload button to the Ogre GUI demo that makes customizing TaharezLook.tga faster.
• ColoredTextAreaOverlayElement -- A class to allow Quake 3 style color codes to be inserted into text overlay elements.
• Fade In/Out Effect Overlay -- Create an overlay that lets you create fade in/out effects in your scene.
• Crop Image -- Crop an Image into a smaller image.
• Creating transparency based on a key colour in code
• Merge exe with a media zip -- Embed a zip file of media within an ogre application executable.

Particles

• Sun Effect - An Example Particle Script
• Moving Space Dust Effect - A Space Dust Effect
• Interpolation Affector - A particle affector to vary size, rotation and velocity of particles.
• Iterated Fractals - Using ManualObjects as Point Sprites to create a Pickover attractor (updates in real-time with a million or more points!)
• ParticleExampleSun - particle code + how to use
• MeshEmitter - an emitter class + example

Shaders

• Introduction - How to submit a shader
• Getting Started With Ogre CG Materials
• How to compile CG code - How to check for errors in .cg code
• Orange Shader - A simple shader
• Fading Object Shader - A fade-to-dark effect
• Holographe Shader - An hologram effect
• PerPixel Lighting - Basic per-pixel, rather slow, texturing included
• PerPixel Lighting II
• The Monster - Tuneable parameters, feature-full, 1-pass, max 3 lights
• Normal AO Specular Mapping Shader - normal/diffuse/AO/specular mapping
• Shadows - How to start on Shadows
• Depth Shadow Mapping - How to implement depth shadow mapping in your own project as seen in the Shadows demo
• Custom Shadow Mapping - How to implement a custom shadow technique
• Parallel Split Shadow Mapping (PSSM) - A method for high-detail shadows
• Offset Bump Ambient Lightmap - Offset/Bump with added ambient and optional lightmap
• Ocean Fog - Basic underwater "depth" effect using the Ocean Shader
• Normal Mapping with Hardware Skinning and Specular - Combined normal mapping and hardware skinning
• Smoke Trails - Adding some turbulence to your ribbon trails
• Terrain Alpha Splatting - Basic terrain shader with up to 8 splat textures.
• Glow - A glow compositor method using 'Glow masks'
• GlowBalloon CG Shader - Another glowy shader, this time producing more of a bubble or balloon effect. (Also an example of translating from cgfx to cg)

Animation & Movement

• Rotating yaw while ignoring pitch and roll
• Manually Controlling Bones
• 3rd person camera system tutorial - How to create a basic, flexible camera system
• Integrating Physics and OGRE from XML - Creating and loading physical structures from XML and automatically linking them to Ogre models.
• How to limit the pitch of a camera
• Creating a simple first-person camera system
• Generic Manual Pose Loading
• Make a character look at the camera Using quaternions and SLERP to make a character look at a camera(or any other object for that matter) naturally, with constraints on head movement
• Euler Angle Class - An Ogre compatible class for euler angles.
• How to drive a car - You have a car, you have a point (i.e. waypoint), but you don't know how to determine side car should turn to drive to point(left or right).
• Controlling car on twisted track - Controlling car on crazy, twisted tracks using physics engine.
• Creating a camera control system - A plugin for managing and creating custom camera modes.

Input

• Head Tracking using the WiiMote
• 3D Object Picking - cTh (bad camel screen to 3D coord translation)
• Translate from english keyboard layout to any other, for instance german
• Using OGRE with GII Using OGRE with the GII input library
• Using OIS Using the Object-orientated Input System Library with OGRE
• Pick Drag Drop - How to make drag&drop objects
• Simple keyboard string editing - A small class to take key presses and edit a string.
• Auto Repeat Key Input - A small class to take key presses and auto repeat keyboard input for GUI.

GUI

• UOgreBrowser - Embedding uBrowser in an Ogre application
• Using Ogre with FLTK FLUID - Tutorial

CEGUI

• CEGUI Common File Dialog - CEGUI Common file dialog
• Initial Mouse Position With OIS and CEGUI - How to initialize the mouse cursor to a starting position
• CEGUI Build Dialog - CEGUI dialog which displays rotating 3D meshes on multiple buttons
• How To Show The Mouse Cursor - Showing the mouse using CEGUI
• Creating a good looking Confirm Dialog with CEGUI
• Update Ogre source code with latest Cegui source code

Other GUI Systems

• Comparison of GUIs - This page contains a comparison of the various GUI systems available
• Integrating OpenGUI - How to integrate OpenGUI in Ogre projects
• MyGUI quickstart - How to add a GUI with button

General

• Creating Overlays via Code
• PieSlice Overlay - Useful for pie charts, sniper scopes, rev counters and other such circular GUI elements.
• How to show the Mouse Cursor W/O CEGUI
• Simple Text Output - Simple text output using overlays.
• Scrolling Message - Scrolling messages which is based on the Simple Text Output above.
• OgreFontHelper utils for rendering text if Ogre::TextAreaOverlayElement is not enough
• Reading a Unicode Multi Language Translation Table - A How To with code for creating, reading, and using a Unicode translation table
• ColoredTextAreaOverlayElement - Extension for the TextAreaOverlayElement

Embedding OGRE in mainstream GUI libraries

• Using Ogre with FLTK - Here presented a way to embed Ogre into FLTK gui toolkit window
• wxOgre - A simple rendering widget for wxWindows (OGRE V1.0.1)
• wxOgre for OGRE v1.2 - A simple rendering widget for wxWindows (OGRE V1.2)
• wxOgre for OGRE v1.4 - A simple rendering widget for wxWindows 2.8 <- Most Recent.
• wxOgreView - A minimalistic C++ class providing Ogre render windows within wxWidgets
• GtkOgre - A GtkWidget for embedding Ogre render windows in GTK.
• GtkmmOgre - A GtkmmOgreWidget for embedding Ogre render windows in Gtkmm.
• qtOgre - Embedding Ogre into a qt application.

Sound & multimedia

• FMOD SoundManager - SoundManager using FMOD
• OpenAL SoundManager - SoundManager using OpenAl
• DirectShow video on a texture - how to play video with Direct Show in Ogre textures

Physics

• Mesh strider for bullet - Subclass from btStridingMeshInterface for sharing graphics and collision meshes
  
• Debug drawer for bullet - Subclass from btIDebugDraw that allows you to visualize collision shapes, contact points and more.
  
• Build a Manual TerrainHeightField with NxOgre - A simple function to get a Heightfield in NxOgre similar to an Ogre Terrain

System

Minimal Ogre projects

• Basic Ogre Framework A fully featured, yet clean base application.
• Project base - A blank project to use as the base of your own. Get all the messy initial details out of the way with this 1000+ line boilerplate.
• Minimal Application a minimal app without using exampleApplication.h
• Hello World with minimal Ogre init: Hello World without using ExampleApplication.h or resource scripts
• Minimal Practical Application a minimal application using it's own main loop and plugin loading
• One Function Ogre: Exploring how to start Ogre without using ExampleApplication.h or the built in Config Dialog

Timer

• TimerManager - Wrapping Ogre::Timer to issue callbacks
• Assaf Muller's Timer Manager - A timer manager to help you access timers from anywhere

Logging

• Dumping a node tree to the log
• Easy Logging Manager
• Logging Frequently Changing Variables

Console

• Creating a Scalable Console
• OgreConsole - A simple graphical console
• A Lua in game console, loosely based on the above "Creating a Scalable Console"

OS tricks

• Change of a icon and caption of the Application Simple way.
• Custom Icon and Cursor Even Simpler Way.
• Find path to executable to locate data files
• How to make your project paths cross platform
• Installing Video Drivers On Linux
• Solve *.material scripts parsing problems on Linux
• Detect AC power status on Windows

Scene manager

• Change the scenemanager at runtime

Render system

• How to safely load rendersystems without a crash (as in, fail gracefully on systems that lack DirectX or GL)
• How to flush the GPU command buffer regularly

Script compilers (Shoggoth)

• New Scripting Features
• Extending compiler with new scripting systems

Misc

• Controlling Particle Systems
• How to load a mesh without initialising the Ogre renderer
• How to load and play animations without initialising the Ogre renderer
• Parsing XML Files
• A simple camcorder class for recording & playing back camera paths
• A short example on how to create a plugin DLL that is loaded by Ogre at startup.
• How to load a mesh not under the predefined resource path.

Miscellaneous

• Easy debug text - uses the default ogre debug overlay text on the OgreDebugPanel overlay
• High resolution screenshots - how to make screenshots of unlimited size
• Printf with ogre - a simple class that lets you use printf with ogre.
• DotScene Loader with User Data - code for loading .scene files
• DotScene Loader with User Data Class - code for loading .scene files too
• Frustum Culling In Object Space - frustum culling using a custom SimpleFrustum class.
• Writing text on texture - how to write text onto a texture.
• All-purpose script parser - allows you to load your own custom data from Ogre-style scripts
• Query Ogre Version - a shell extension which allows to know the version of Ogre I'm working on
• MovableTextOverlay - display a text above an object (HUD / heads up display)
• Ogre Compatible HeightMap - get height of terrain at (x,z) positions
• Set icon of Window (Mogre)
• TinyXMLResource - use TinyXML documents via Ogres resource system
• AI Agent Control - AI Agent control code snippets

Useful Code Articles (w/code)

• std::map<> versus core::tree<> - Gamedev.net
• Soft Edge Shadows - Gamedev.net
• Callbacks - CodeGuru
• Function Pointers - Newty.DE
• Function Pointers - Eskimo.com
• Pointers to Member Functions - Parashift
• Fast Delegates - The Code Project