Boundary-Handling Methods
You use a boundary-handling method specifier to indicate how you want a shader to handle
uv
values that are outside the valid range (namely, 0 to 1). For example, you pass one of these constants to the
Q3Shader_SetUBoundary
function to indicate how to handle values in the
u
parametric direction that lie outside the valid range.
For a fuller description of boundary-handling methods, see
"Handling uv Values Outside the Valid Range"
.
typedef enum TQ3ShaderUVBoundary {
kQ3ShaderUVBoundaryWrap,
kQ3ShaderUVBoundaryClamp
} TQ3ShaderUVBoundary;
Constant descriptions
-
kQ3ShaderUVBoundaryWrap
-
Values outside the valid range are to be wrapped. To wrap a shader effect is to replicate the entire effect across the mapped area. For example, for a texture shader, wrapping causes the entire image to be replicated across the surface onto which the texture is mapped.
-
kQ3ShaderUVBoundaryClamp
-
Values outside the valid range are to be clamped. To clamp a shader effect is to replicate the boundaries of the effect across the portion of the mapped area that lies outside the valid range. For example, for a texture shader, clamping causes boundaries of the image to be smeared across the portion of the surface onto which the texture is mapped that lies outside the valid range.
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