Direct light is just that: direct. Direct light always has direction and color, and it is a factor for shading algorithms, such as Gouraud shading. Different types of lights emit direct light in different ways, creating special attenuation effects. You create a sets of light parameters for direct light by calling the IDirect3DDevice7::SetLight method. For more information, see Lights.

Ambient light is effectively everywhere in a scene. You can think of it as a general level of light that fills an entire scene, regardless of the objects and their locations within that scene. Ambient light, being everywhere, has no position or direction, only color and intensity. Set the ambient light level with a call to the IDirect3DDevice7::SetRenderState method, specifying D3DRENDERSTATE_AMBIENT as the dwRenderStateType parameter, and the desired RGBA color as the dwRenderState parameter.

Ambient light color takes the form of an RGBA value, where each component is an integer value from 0 to 255. (This is unlike most color values in Direct3D Immediate Mode. For more information, see Color Values for Lights and Materials.) You can use the RGBA_MAKE macro to generate RGBA values from integers. The red, green, and blue components combine to make the final color of the ambient light. The alpha component controls the transparency of the color. In ramp emulation, ambient light doesn't have color, so the alpha component is used for brightness. When using hardware acceleration or RGB emulation, the alpha component is ignored.

Direct light is just that: direct. Direct light always has direction and color, and it is a factor for shading algorithms, such as Gouraud shading. Different types of lights emit direct light in different ways, creating special attenuation effects. You create a sets of light parameters for direct light by calling the Direct3DDevice7.SetLight method. For more information, see Lights.

Ambient light is effectively everywhere in a scene. You can think of it as a general level of light that fills an entire scene, regardless of the objects and their locations within that scene. Ambient light, being everywhere, has no position or direction, only color and intensity. Set the ambient light level with a call to the Direct3DDevice7.SetRenderState method, specifying D3DRENDERSTATE_AMBIENT as the state parameter, and the desired RGBA color as the renderstate parameter.

You can use the DirectX7.CreateColorRGBA method to generate RGBA values from values of type Single. The red, green, and blue components combine to make the final color of the ambient light. The alpha component controls the transparency of the color. In ramp emulation, ambient light doesn't have color, so the alpha component is used for brightness. When using hardware acceleration or RGB emulation, the alpha component is ignored.