Game Programming:Programming Lab 2

2008/9/24Kim, HyungSeok

HyungSeok Kim, Konkuk University

Programming Labs

• Part I: Framework– 1. Windows creation– 2. Renderer– 3. Lights and Objects/Model loading– 4. GUI design/Input system/Sound

• Part II: Simulation– 5. Math libs– 6. Collision detection– 7. Basic scripting– 8. Model animation

• Part III: Advanced rendering– 9. Special effects– 10. Textures

• Part IV: Final– 11. Game final

HyungSeok Kim, Konkuk University

Game Engine

• Rendering– Video– Audio– Haptic, …

• Simulation– AI– Math calculation

• User interface– Input

• Scene graph

HyungSeok Kim, Konkuk University

What we have done in Lab #1

• Create a frame for an engine– Game Engine• Main loop

• Class Renderer• Class Simulator• …

HyungSeok Kim, Konkuk University

Lab #2

• Create a basic scene graph structures– Which object to create?– Which structure to hold?

• Create a basic renderer– How to put renderer into the framework?– Which functionality the renderer will have?

HyungSeok Kim, Konkuk University

Scene Definition

• Task 1: Following the last Homework– Create a scene database

– How?• Requirement analysis• Specification• Implementation

HyungSeok Kim, Konkuk University

Scene Definition

• Common properties of objects– Position– Orientation• Transform matrix

– Shape• Mesh

– … and more

HyungSeok Kim, Konkuk University

Scene Definition

• Scene structure– Why?

– How?• Array?• Tree?• Any others?

– Your proposition• Pros and cons

HyungSeok Kim, Konkuk University

Scene Definition

• Scene Graph– Tree-like approach

HyungSeok Kim, Konkuk University

Scene Definition

• 1. Class hierarchy definition

• 2. Data definition– Position/Orientation?– Shape?

HyungSeok Kim, Konkuk University

Transform Matrix

• Transform Matrix– Matrix for specifying position and orientation– Translation– Rotation

– Matrix concatenation and storage

HyungSeok Kim, Konkuk University

Hierarchical Transform

• Hierarchical transform– World matrix stack– Why stack?

HyungSeok Kim, Konkuk University

Exemplar Code in D3D

ID3DXMatrixStack* pMatrixStack;D3DXCreateMatrixStack(0,&pMatrixStack); pMatrixStack->LoadMatrix(<Hand matrix>);<Draw Hand>For childrens

– pMatrixStack->Push();– pMatrixStack->MultMatrix(<Finger 1 matrix>);– <Draw Finger 1>

• For childrens if any– …

– pMatrixStack->Pop();

HyungSeok Kim, Konkuk University

Exemplar Code in OpenGL

glLoadMatrix(<Hand matrix>);<Draw Hand>For childrens

– glPushMatrix();– glMultMatrix(<Finger 1 matrix>);– <Draw Finger 1>

• For childrens if any– …

– glPopMatrix();

HyungSeok Kim, Konkuk University

What to Store?

• Matrix

• Translation (x,y,z)• Rotation– How?– Quaternion

HyungSeok Kim, Konkuk University

D3D functions

• Mesh– Container for a shape• Shape-wise representation: an object

– Use a container instead of separated elements– Easy representation and control of multiple shapes

• Store/load of a shape

– OpenGL: vertex array, index array, …– D3D: class ID3DXMesh;

HyungSeok Kim, Konkuk University

Displaying a Mesh

• D3D– HRESULT ID3DXBaseMesh::DrawSubset(DWORD

AttribId ); – Subset• A group of triangles which has the same material and

states

• OpenGL– glDrawPrimitives, glDrawElements, …

HyungSeok Kim, Konkuk University

Scene Definition

• class Scene { … };– Singleton– Access scene definition• Array case: able to get array• Tree case: able to get tree root• …

HyungSeok Kim, Konkuk University

Lab #2 – Task 1

• Create Box or Sphere and add it to your scene– OpenGL• GLUquadricObj* gluNewQuadric( void );• void gluSphere( GLUquadricObj *qobj, GLdouble ra-

dius, GLint slices, GLint stacks );– D3D• HRESULT D3DXCreateBox(LPDIRECT3DDEVICE9 pDevice,

FLOAT width, FLOAT height, FLOAT depth, LPD3DXMESH *ppMesh, LPD3DXBUFFER *ppAdjacency);• Draw

HyungSeok Kim, Konkuk University

Renderer

• Render scene periodically– Should be called in main loop

– Event-based update vs. Continuous update

HyungSeok Kim, Konkuk University

Renderer

• Functions– Traverse scene database• Scene graph• Scene array?• …

– Render each object• Optimization

HyungSeok Kim, Konkuk University

Lab #2 – Task 2

• Add another box or sphere to the scene graph– Render all

HyungSeok Kim, Konkuk University

Conclusion