XGL™ Accelerator Guide for Reference Frame Buffers SunSoft, Inc. A Sun Microsystems, Inc. Business 2550 Garcia Avenue Mountain View, CA 94043 U.S.A. Copyright 1997 Sun Microsystems, Inc. 2550 Garcia Avenue, Mountain View, California 94043-1100 U.S.A. All rights reserved. This product or document is protected by copyright and distributed under licenses restricting its use, copying, distribution, and decompilation. No part of this product or document may be reproduced in any form by any means without prior written authorization of Sun and its licensors, if any. Third-party software, including font technology, is copyrighted and licensed from Sun suppliers. Parts of the product may be derived from Berkeley BSD systems, licensed from the University of California. UNIX is a registered trademark in the U.S. and other countries, exclusively licensed through X/Open Company, Ltd. 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CETTE PUBLICATION EST FOURNIE "EN L’ETAT" ET AUCUNE GARANTIE, EXPRESSE OU IMPLICITE, N’EST ACCORDEE, Y COMPRIS DES GARANTIES CONCERNANT LA VALEUR MARCHANDE, L’APTITUDE DE LA PUBLICATION A REPONDRE A UNE UTILISATION PARTICULIERE, OU LE FAIT QU’ELLE NE SOIT PAS CONTREFAISANTE DE PRODUIT DE TIERS. CE DENI DE GARANTIE NE S’APPLIQUERAIT PAS, DANS LA MESURE OU IL SERAIT TENU JURIDIQUEMENT NUL ET NON AVENU. Contents Preface. ix 1. General Acceleration Information . 1 Batching. 1 Color Type and Visual . 2 Tessellating Data . 4 XGL Data Types . 4 Using xgl_inquire(). 4 Use ASTI Deferral Mode . 5 Disable Error Checking . 5 Use of Backing Store . 5 Faster Rendering Into Memory Rasters and Unaccelerated Frame Buffers . 5 Faster Bounding Box Checking . 6 2. GX and GXplus Accelerators. 7 Device-Dependent Issues . 7 Accelerated Rendering Using Screen Coordinates (2D Only) 7 v Deferral Mode . 8 Backing Store . 8 Picking. 8 Line Join . 8 Hardware Double Buffering. 8 X Visuals . 9 Attributes That Affect Acceleration. 9 Reference Table of Primitives and Attributes. 13 3. Acceleration Across a Network With the Xpex Pipeline . 19 Rendering Across a Network . 19 General Acceleration Notes . 20 Depth Cueing . 21 Line Widths . 21 Use Gcache to Improve Performance . 21 Line Patterns. 21 Markers . 21 Lights. 21 Supported Point Types . 22 Attributes That Affect Acceleration. 22 Reference Table of Primitives and Attributes. 28 vi XGL™ Accelerator Guide for Reference Frame Buffers—August 1997 Tables Table 1-1 X Visual Class and XGL Color Type. 2 Table 2-1 Primitives and Related Attributes for the GX . 14 Table 3-1 Point Types Supported in the Xpex Pipeline. 22 Table 3-2 Primitives and Related Attributes for Xpex. 29 vii viii XGL™ Accelerator Guide for Reference Frame Buffers—August 1997 Preface The XGL Accelerator Guide for Reference Frame Buffers provides performance hints that you can use to write programs that use SunSoft hardware graphics accelerators. It lists attributes that are accelerated and shows how to make the most efficient use of XGL™ primitives. Who Should Use This Book This manual is intended for application programmers developing XGL applications. How This Book Is Organized This manual is organized as follow: • Chapter 1, “General Acceleration Information,” provides information on general techniques to improve performance on all XGL platforms. • Chapter 2, “GX and GXplus Accelerators,” gives specific hints and optimizations for the GX and GXplus accelerators. • Chapter 3, “Acceleration Across a Network With the Xpex Pipeline,” provides information on accelerating an application across a network. ix Related Books • XGL Programmer’s Guide • XGL Reference Manual Ordering Sun Documents The SunDocsSM program provides more than 250 manuals form Sun Microsystems, Inc. If you live in the United States, Canada, Europe, or Japan, you can purchase documentation sets or individual manuals using this program. For a list of documents and how to order them, see the catalog section of SunExpress™ On The Internet at http://www.sun.com/sunexpress. What Typographic Changes Mean The following table describes the typographic changes used in this book. Table P-1 Typographic Conventions Typeface or Symbol Meaning Example AaBbCc123 The names of commands, Edit your .login file. files, and directories; Use ls -a to list all files. on-screen computer output machine_name% You have mail. AaBbCc123 What you type, contrasted machine_name% su with on-screen computer Password: output AaBbCc123 Command-line placeholder: To delete a file, type rm filename. replace with a real name or value AaBbCc123 Book titles, new words or Read Chapter 6 in User’s Guide. terms, or words to be These are called class options. emphasized You must be root to do this. x XGL™ Accelerator Guide for Reference Frame Buffers—August 1997 General Acceleration Information 1 This chapter provides general acceleration information that will enable an XGL program to run in the most efficient way regardless of the targeted platform. For specific information on the GX and GXplus devices, see Chapter 2, “GX and GXplus Accelerators”. For information on accelerating XGL applications across a network, see Chapter 3, “Acceleration Across a Network With the Xpex Pipeline”. Note – Memory rasters are not accelerated on any device. Batching Due to the overhead involved in every XGL call, applications that use an XGL primitive to draw a single object per call do not achieve maximum performance. Applications run significantly faster through effective use of the multi primitives; drawing about 30 objects per call results in nearly peak performance. Note – Avoid using the primitive xgl_polygon() unless absolutely necessary, since it draws only one polygon per call. 1 1 Color Type and Visual For good performance, you should understand the color model of the targeted device and program accordingly. A visual is an Xlib concept that describes the way pixels are translated into colors. XGL supports these visual classes: PseudoColor, TrueColor, and DirectColor. Take care when selecting the visual because the visual class affects the XGL hardware color type, which in turn affects accelerator performance. Although XGL allows the mixing of visuals and color types, for best results PseudoColor visuals should be used with a raster color type of XGL_COLOR_INDEX, and TrueColor and DirectColor visuals should be used with XGL_COLOR_RGB. Table 1-1 shows these combinations. Table 1-1 X Visual Class and XGL Color Type Visual Class XGL Color Type PseudoColor XGL_COLOR_INDEX DirectColor XGL_COLOR_RGB TrueColor The following code segment shows the proper way to select the visual that gives the best performance on any frame buffer (8- or 24-bit).