GLINDEXPOINTER(3G)

GLINDEXPOINTER 💅

okay bestie, sit down, hydrate, because we're about to talk about glIndexPointer — that's the 3G manual page, OpenGL family, and she's a lil client-side icon 🎀

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✨ NAME ✨

glIndexPointer — define an array of color indexes 🌈

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✨ C SPECIFICATION ✨

void glIndexPointer( GLenum type,
                     GLsizei stride,
                     const GLvoid *ptr )

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✨ PARAMETERS ✨

• type — tells you the data type of each color index in the array. The symbolic constants she accepts are GL_UNSIGNED_BYTE, GL_SHORT, GL_INT, GL_FLOAT, and GL_DOUBLE. Her initial value is GL_FLOAT. 🦋
• stride — the byte offset between consecutive color indexes. If stride is 0 (which is the initial value, slay), then the color indexes are understood to be tightly packed in the array. Initial value is 0. 💫
• ptr — a pointer to the first index in the array. Initial value is 0. 🫶

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✨ DESCRIPTION ✨

So glIndexPointer specifies the location and data of an array of color indexes to use when rendering. type specifies the data type of each color index, and stride gives the byte stride from one color index to the next — which is the whole reason vertices and attributes can be packed into a single array, or stored in separate arrays. (Single-array storage may be more efficient on some implementations; go look at glInterleavedArrays, she's right there.) 👑

type, stride, and ptr are saved as client-side state. no cap.

The color index array is initially disabled. To enable and disable the array, call glEnableClientState and glDisableClientState with the argument GL_INDEX_ARRAY. If enabled, the color index array is used when glDrawArrays, glDrawElements or glArrayElement is called. periodt. 💅

Use glDrawArrays to construct a sequence of primitives (all of the same type) from prespecified vertex and vertex attribute arrays. Use glArrayElement to specify primitives by indexing vertices and vertex attributes, and glDrawElements to construct a sequence of primitives by indexing vertices and vertex attributes. three sisters, all iconic. 🌸

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✨ NOTES ✨

• glIndexPointer is available only if the GL version is 1.1 or greater. iykyk.
• The color index array is initially disabled, and it isn't accessed when glArrayElement, glDrawElements, or glDrawArrays is called.
• Execution of glIndexPointer is not allowed between glBegin and the corresponding glEnd, but an error may or may not be generated. If an error is not generated, the operation is undefined. 💀 bestie please do not test this.
• glIndexPointer is typically implemented on the client side.
• Since the color index array parameters are client-side state, they are not saved or restored by glPushAttrib and glPopAttrib. Use glPushClientAttrib and glPopClientAttrib instead. different functions, different vibe. 🙈

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✨ ERRORS ✨

• GL_INVALID_ENUM is generated if type is not an accepted value. 🚫
• GL_INVALID_VALUE is generated if stride is negative. 😭

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✨ ASSOCIATED GETS ✨

• glIsEnabled with argument GL_INDEX_ARRAY
• glGet with argument GL_INDEX_ARRAY_TYPE
• glGet with argument GL_INDEX_ARRAY_STRIDE
• glGetPointerv with argument GL_INDEX_ARRAY_POINTER

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✨ SEE ALSO ✨

glArrayElement(3G), glColorPointer(3G), glDrawArrays(3G), glDrawElements(3G), glEdgeFlagPointer(3G), glEnable(3G), glGetPointerv(3G), glInterleavedArrays(3G), glNormalPointer(3G), glPopClientAttrib(3G), glPushClientAttrib(3G), glTexCoordPointer(3G), glVertexPointer(3G) ⭐

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💖 that's the whole page, no notes, every single detail intact, we ate and left no crumbs.

and that's the sign-off, bestie — this was page <code>GLINDEXPOINTER(3G)</code> from the <code>3G</code> manual set, footer and all. mwah. 🧚💜