3D Graphics Programming with QuickDraw 3D 1.5.4

Creating a Light

You create a light by filling in the fields of the data structure for the type of light you want to create and then by calling a QuickDraw 3D function to create the light. For example, to create a point light, you fill in a data structure of type TQ3PointLightData and then call Q3PointLight_New , as shown in Listing 1 .

Listing 1 Creating a new point light



 
TQ3LightObject MyNewPointLight (void)

{

    TQ3LightData                    myLightData;

    TQ3PointLightData               myPointLightData;

    TQ3LightObject                  myPointLight;

    TQ3Point3D                      pointLocation = {-20.0, 0.0, 20.0};

    TQ3ColorRGB                     WhiteLight = { 1.0, 1.0, 1.0 };



    /*Set up light data for a point light.*/

    myLightData.isOn = kQ3True;

    myLightData.brightness = 1.0;

    myLightData.color = WhiteLight;

    myPointLightData.lightData = myLightData;

    myPointLightData.castsShadows = kQ3False;

    myPointLightData.attenuation = kQ3AttenuationTypeNone;

    myPointLightData.location = pointLocation;



    /*Create a point light.*/

    myPointLight = Q3PointLight_New(&myPointLightData);

    return (myPointLight);

}

As you can see, the MyNewPointLight function defined in Listing 1 simply fills in the myPointLight structure and then calls Q3PointLight_New . MyNewPointLight returns to its caller either a reference to the new light (if Q3PointLight_New succeeds) or the value NULL (if Q3PointLight_New fails).