fglVertexPointer(3G)
fglVertexPointer - define an array of vertex data
As shipped in IRIX 6.5.5. Unchanged since IRIX 6.5.
NAME fglVertexPointer - define an array of vertex data FORTRAN SPECIFICATION SUBROUTINE fglVertexPointer( INTEGER*4 size, INTEGER*4 type, INTEGER*4 stride, CHARACTER*8 pointer ) PARAMETERS size Specifies the number of coordinates per vertex; must be 2, 3, or 4. The initial value is 4. type Specifies the data type of each coordinate in the array. Symbolic constants GL_SHORT, GL_INT, GL_FLOAT, and GL_DOUBLE are accepted. The initial value is GL_FLOAT. stride Specifies the byte offset between consecutive vertexes. If stride is 0, the vertexes are understood to be tightly packed in the array. The initial value is 0. pointer Specifies a pointer to the first coordinate of the first vertex in the array. DESCRIPTION fglVertexPointer specifies the location and data format of an array of vertex coordinates to use when rendering. size specifies the number of coordinates per vertex and type the data type of the coordinates. stride specifies the byte stride from one vertex to the next allowing vertexes and attributes to be packed into a single array or stored in separate arrays. (Single-array storage may be more efficient on some implementations; see fglInterleavedArrays.) When a vertex array is specified, size, type, stride, and pointer are saved as client-side state. To enable and disable the vertex array, call fglEnableClientState and fglDisableClientState with the argument GL_VERTEX_ARRAY. If enabled, the vertex array is used when fglDrawArrays, fglDrawElements, or fglArrayElement is called. Use fglDrawArrays to construct a sequence of primitives (all of the same type) from prespecified vertex and vertex attribute arrays. Use fglArrayElement to specify primitives by indexing vertexes and vertex attributes and fglDrawElements to construct a sequence of primitives by indexing vertexes and vertex attributes. NOTES fglVertexPointer is available only if the GL version is 1.1 or greater. The vertex array is initially disabled and isn't accessed when fglArrayElement, fglDrawElements or fglDrawArrays is called. Execution of fglVertexPointer is not allowed between the execution of fglBegin and the corresponding execution of fglEnd, but an error may or may not be generated. If no error is generated, the operation is undefined. fglVertexPointer is typically implemented on the client side. Vertex array parameters are client-side state and are therefore not saved or restored by fglPushAttrib and fglPopAttrib. Use fglPushClientAttrib and fglPopClientAttrib instead. ERRORS GL_INVALID_VALUE is generated if size is not 2, 3, or 4. GL_INVALID_ENUM is generated if type is is not an accepted value. GL_INVALID_VALUE is generated if stride is negative. ASSOCIATED GETS fglIsEnabled with argument GL_VERTEX_ARRAY fglGet with argument GL_VERTEX_ARRAY_SIZE fglGet with argument GL_VERTEX_ARRAY_TYPE fglGet with argument GL_VERTEX_ARRAY_STRIDE fglGetPointerv with argument GL_VERTEX_ARRAY_POINTER MACHINE DEPENDENCIES On RealityEngine, RealityEngine2, and VTX systems, do not enable or disable GL_VERTEX_ARRAY, GL_VERTEX_ARRAY_EXT, GL_NORMAL_ARRAY, GL_NORMAL_ARRAY_EXT, GL_COLOR_ARRAY, GL_COLOR_ARRAY_EXT, GL_INDEX_ARRAY,GL_INDEX_ARRAY_EXT, GL_TEXTURE_COORD_ARRAY, GL_TEXTURE_COORD_ARRAY_EXT, GL_EDGE_FLAG_ARRAY or GL_EDGE_FLAG_ARRAY_EXT between a call to fglNewList and the corresponding call to fglEndList. Instead, enable or disable before the call to fglNewList. On InfiniteReality systems it is particularly important to minimize the amount of data transferred from the application to the graphics pipe, since the host-to-pipe bandwidth limit can cause a performance bottleneck. One way to reduce the amount of data transferred per vertex is to use properly-aligned byte and short data types whenever possible. Accordingly, the EXT_vertex_array extension on InfiniteReality systems has been optimized for vertex information packed into the following data structures. (Note: v represents vertex coordinates, c represents color components, n represents normal coordinates, and t represents texture coordinates. Normals must have unit length.) struct {GLfloat v[3];} struct {GLubyte c[4]; GLfloat v[3];} struct {GLshort n[3]; GLfloat v[3];} struct {GLubyte c[4]; GLshort n[3]; GLfloat v[3];} struct {GLshort t[2]; GLfloat v[3];} struct {GLshort t[2]; GLubyte c[4]; GLfloat v[3];} struct {GLshort t[2]; GLshort n[3]; GLfloat v[3];} struct {GLshort t[2]; GLubyte c[4]; GLshort n[3]; GLfloat v[3];} struct {GLfloat t[2]; GLfloat v[3];} struct {GLfloat t[2]; GLubyte c[4]; GLfloat v[3];} struct {GLfloat t[2]; GLshort n[3]; GLfloat v[3];} struct {GLfloat t[2]; GLubyte c[4]; GLshort n[3]; GLfloat v[3];} Application-specific fields may be added to these structures, provided that all the fields described above retain their relative order and word alignment. An additional constraint applies when fglTexGen is being used. The implementation normally generates all four texture coordinates in parallel, and must take special action to generate just a subset of the four coordinates. Therefore performance is best when none of the texture coordinates are being generated, or when all of them are being generated. For example, when using 2D texturing (generating s and t coordinates) it will be faster to enable texture coordinate generation for the r and q coordinates as well as s and t. Choose a texture generation mode of GL_OBJECT_LINEAR and use the plane equations (0,0,0,0) and (0,0,0,1) for r and q, respectively. Using these structures on InfiniteReality systems can improve performance considerably, compared to structures in which all values are single- precision floating point. SEE ALSO fglArrayElement, fglColorPointer, fglDrawArrays, fglDrawElements, fglEdgeFlagPointer, fglEnable, fglGetPointerv, fglIndexPointer, fglInterleavedArrays, fglNormalPointer, fglPopClientAttrib, fglPushClientAttrib, fglTexCoordPointer