IDirect3DDevice9::SetLight method (d3d9helper.h)

Article
08/19/2022

Assigns a set of lighting properties for this device.

Syntax

HRESULT SetLight(
  [in] DWORD           Index,
  [in] const D3DLIGHT9 *unnamedParam2
);

Parameters

[in] Index

Type: DWORD

Zero-based index of the set of lighting properties to set. If a set of lighting properties exists at this index, it is overwritten by the new properties specified in pLight.

[in] unnamedParam2

Type: const D3DLIGHT9*

Pointer to a D3DLIGHT9 structure, containing the lighting parameters to set.

Return value

Type: HRESULT

If the method succeeds, the return value is D3D_OK. If the method fails, the return value can be D3DERR_INVALIDCALL.

Remarks

Set light properties by preparing a D3DLIGHT9 structure and then calling the IDirect3DDevice9::SetLight method. The IDirect3DDevice9::SetLight method accepts the index at which the device should place the set of light properties to its internal list of light properties, and the address of a prepared D3DLIGHT9 structure that defines those properties. You can call IDirect3DDevice9::SetLight with new information as needed to update the light's illumination properties.

The system allocates memory to accommodate a set of lighting properties each time you call the IDirect3DDevice9::SetLight method with an index that has never been assigned properties. Applications can set a number of lights, with only a subset of the assigned lights enabled at a time. Check the MaxActiveLights member of the D3DCAPS9 structure when you retrieve device capabilities to determine the maximum number of active lights supported by that device. If you no longer need a light, you can disable it or overwrite it with a new set of light properties.

The following example prepares and sets properties for a white point-light whose emitted light will not attenuate over distance.


// Assume d3dDevice is a valid pointer to an IDirect3DDevice9 interface.
D3DLIGHT9 d3dLight;
HRESULT   hr;
    
// Initialize the structure.
ZeroMemory(&d3dLight, sizeof(d3dLight));
    
// Set up a white point light.
d3dLight.Type = D3DLIGHT_POINT;
d3dLight.Diffuse.r  = 1.0f;
d3dLight.Diffuse.g  = 1.0f;
d3dLight.Diffuse.b  = 1.0f;
d3dLight.Ambient.r  = 1.0f;
d3dLight.Ambient.g  = 1.0f;
d3dLight.Ambient.b  = 1.0f;
d3dLight.Specular.r = 1.0f;
d3dLight.Specular.g = 1.0f;
d3dLight.Specular.b = 1.0f;
    
// Position it high in the scene and behind the user.
// Remember, these coordinates are in world space, so
// the user could be anywhere in world space, too. 
// For the purposes of this example, assume the user
// is at the origin of world space.
d3dLight.Position.x = 0.0f;
d3dLight.Position.y = 1000.0f;
d3dLight.Position.z = -100.0f;
    
// Don't attenuate.
d3dLight.Attenuation0 = 1.0f; 
d3dLight.Range        = 1000.0f;
    
// Set the property information for the first light.
hr = d3dDevice->SetLight(0, &d3dLight);
if (SUCCEEDED(hr))
    // Handle Success
else
    // Handle failure

Enable a light source by calling the IDirect3DDevice9::LightEnable method for the device.

Requirements

Requirement	Value
Target Platform	Windows
Header	d3d9helper.h (include D3D9.h)
Library	D3D9.lib