1XXX - Obsolete; implemented as part of GL_SGIX_igloo_interface 2 3Name 4 5 IGLOO_viewport_offsetXXX 6 7 This not an EXT, SGI, SGIS, or SGIX extension. It violates the prefix rules. 8 Also the XXX violates the no-caps in the body of the name rule. 9 10Name Strings 11 12 GL_IGLOO_viewport_offsetXXX 13 14 These strings should never be returned by glGetString, 15 because I don't expect the get in this extension to be implemented 16 The extension should remain incomplete. 17 The name string here is used solely in the registry. 18 19Version 20 21 $Date: 1999/04/03 08:40:52 $ $Revision: 1.2 $ 22 23Number 24 25 None 26 27 Do we number these??? 28 29 30Dependencies 31 32 33 This extension has *NO* dependencies. 34 35Overview 36 37 When Viewport_Offset is enabled then the viewport transformation is becomes 38 39 40 x_w = (p_x/2) x_d + o_x + 0.5 41 y_w = (p_y/2) y_d + o_y + 0.5 42 z_w = . . . same as before. 43 44 I believe that this is only useful for emulating IrisGL on top of OpenGL. 45 46 47New Procedures and Functions 48 49 50 There are no new Procedures for this extension 51New Tokens 52 53* This list should be complete. It should separate the new tokens 54* based on which procedures and parameters accept them, and explicitly 55* list those procedures and parameters. Token suffixes must match the 56* prefix chosen for the extension name. For example: 57* 58* Accepted by the <pname> parameters of GetBooleanv, GetIntegerv, 59* GetFloatv, and GetDoublev: 60* 61* NEW_TOKEN_SGI 62 63 IGLOO_OFFSET_VIEWPORT_XXX Is accepted by glEnable and glDisable. 64 65 Probably not accepted by the <pname> parameter of glGetBooleanv, and 66 glIsEnabled. 67 68 (I do not expect glGet to accept this in most implementations, 69 but techically it should since this is user state.) 70 71 If glEnable or glDisable generates an INVALID_ENUM then 72 this extension is not available. 73 74Additions to Chapter 2 of the 1.0 Specification (OpenGL Operation) 75 76 77 78 Section 2.9.1 (Controlling the viewport) 79 now reads: 80 81 "The vertex's window coordinates, (x_w) are given by 82 (y_w) 83 (z_w), 84 85 (x_w) ((p_x/2)x_d + o_x + offset) ) 86 (y_w) = ((p_y/2)y_d + o_y + offset) ) 87 (z_w) ([unchanged from versions 1.0]) ) 88 89 where offset equals 0.5 if IGLOO_OFFSET_VIEWPORT_XXX is enabled, and 0.0 if it is 90 disabled. 91 92Additions to Chapter 3 of the 1.0 Specification (Rasterization) 93 94 NONE 95 96Additions to Chapter 4 of the 1.0 Specification (Per-Fragment Operations 97and the Frame Buffer) 98 99 NONE 100 101Additions to Chapter 5 of the 1.0 Specification (Special Functions) 102 103* List commands that are not included in display lists (typically Get* 104* commands) 105 106 glGet(IGLOO_OFFSET_VIEWPORT_XXX) will probably not be part of any real implementation. 107 glEnable is already display listable and remains so. 108 109Additions to Chapter 6 of the 1.0 Specification (State and State Requests) 110 111 112 There is one new bit of state. 113 This bit is TRUE if IGLOO_OFFSET_VIEWPORT_XXX is enabled 114 and FALSE otherwise. While this is technically user state, it is not 115 needed by IGLOO. . . 116 It's default value is FALSE. 117 118Additions to the GLX Specification 119 No additions are needed for the GLX Specification 120 121Errors 122 There is no new Error state, but glEnable/glDisable now accepts a the new token. 123 124 125 126New State 127 128* Description of all state values in table format. Note that client 129* state should have "client" listed in the Attrib column. 130 131 Initial 132 Get Value Get Command Type Value Attrib 133 --------- ----------- ---- ------- ------ 134 IGLOO_OFFSET_VIEWPORT_XXX glGetBooleanv Bool FALSE enable 135 136