fglColorPointerEXT(3G)
fglColorPointerEXT - define a array of colors
As shipped in IRIX 6.5.15. Last changed in IRIX 6.5.15.
NAME fglColorPointerEXT - define a array of colors FORTRAN SPECIFICATION SUBROUTINE fglColorPointerEXT( INTEGER*4 size, INTEGER*4 type, INTEGER*4 stride, INTEGER*4 count, CHARACTER*8 pointer ) PARAMETERS size Specifies the number of components per color. It must be 3 or 4. type Specifies the data type of each color component in the array. Symbolic constants GL_BYTE, GL_UNSIGNED_BYTE, GL_SHORT, GL_UNSIGNED_SHORT, GL_INT, GL_UNSIGNED_INT, GL_FLOAT, or GL_DOUBLE_EXT, are accepted. stride Specifies the byte offset between consecutive colors. If stride is zero the colors are understood to be tightly packed in the array. count Specifies the number of colors, counting from the first, that are static. pointer Specifies a pointer to the first component of the first color element in the array. DESCRIPTION fglColorPointerEXT specifies the location and data format of an array of color components to use when rendering using the vertex array extension. size specifies the number of components per color, and must be 3 or 4. type specifies the data type of each color component and stride gives the byte stride from one color to the next allowing vertices and attributes to be packed into a single array or stored in separate arrays. (Single- array storage may be more efficient on some implementations.) count indicates the number of array elements (counting from the first) that are static. Static elements may be modified by the application, but once they are modified, the application must explicitly respecify the array before using it for any rendering. When a color array is specified, size, type, stride, count and pointer are saved as client-side state, and static array elements may be cached by the implementation. The color array is enabled and disabled using fglEnable and fglDisable with the argument GL_COLOR_ARRAY_EXT. If enabled, the color array is used when fglDrawArraysEXT or fglArrayElementEXT is called. Use fglDrawArraysEXT to define a sequence of primitives (all of the same type) from pre-specified vertex and vertex attribute arrays. Use fglArrayElementEXT to specify primitives by indexing vertices and vertex attributes. NOTES Non-static array elements are not accessed until fglArrayElementEXT or fglDrawArraysEXT is executed. By default the color array is disabled and it won't be accessed when fglArrayElementEXT or fglDrawArraysEXT is called. Although it is not an error to call fglColorPointerEXT between the execution of fglBegin and the corresponding execution of fglEnd, the results are undefined. fglColorPointerEXT will typically be implemented on the client side with no protocol. Since the color array parameters are client side state, they are not saved or restored by fglPushAttrib and fglPopAttrib. fglColorPointerEXT commands are not entered into display lists. fglColorPointerEXT is part of the EXT_vertex_array extension, not part of the core GL command set. If GL_EXT_vertex_array is included in the string returned by fglGetString, when called with argument GL_EXTENSIONS, extension EXT_vertex_array is supported. ERRORS GL_INVALID_VALUE is generated if size is not 3 or 4. GL_INVALID_ENUM is generated if type is not an accepted value. GL_INVALID_VALUE is generated if stride or count is negative. ASSOCIATED GETS fglIsEnabled with argument GL_COLOR_ARRAY_EXT fglGet with argument GL_COLOR_ARRAY_SIZE_EXT fglGet with argument GL_COLOR_ARRAY_TYPE_EXT fglGet with argument GL_COLOR_ARRAY_STRIDE_EXT fglGet with argument GL_COLOR_ARRAY_COUNT_EXT fglGetPointervEXT with argument GL_COLOR_ARRAY_POINTER_EXT 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 fglArrayElementEXT, fglDrawArraysEXT, fglEdgeFlagPointerEXT, fglEnable, fglGetPointervEXT, fglIndexPointerEXT, fglNormalPointerEXT, fglTexCoordPointerEXT, fglVertexPointerEXT