1 Name 2 3 CHROMIUM_texture_mailbox 4 5 Name Strings 6 7 GL_CHROMIUM_texture_mailbox 8 9 Version 10 11 Last Modifed Date: June 2, 2014 12 13 Dependencies 14 15 OpenGL ES 2.0 is required. 16 17 Overview 18 19 This extension defines a way of sharing texture image data between texture 20 objects in different contexts where the contexts would not normally share 21 texture resources. Five new functions are exported. glGenMailboxCHROMIUM 22 generates a name that can be used to identify texture image data outside 23 the scope of a context group. glProduceMailboxCHROMIUM and 24 glProduceTextureDirectCHROMIUM associate a texture object with a global 25 mailbox name. glConsumeMailboxCHROMIUM and glCreateAndConsumeTextureCHROMIUM 26 associate the texture object referenced by a mailbox name to a texture name. 27 28 New Procedures and Functions 29 30 void glGenMailboxCHROMIUM (GLbyte *mailbox) 31 32 Generates a unique name identifying a mailbox. The name is generated using 33 a cryptographic random number generator and is intended to be difficult to 34 guess. The scope of the name is implementation specific, for example it 35 might not span multiple displays. 36 37 <mailbox> returns a GL_MAILBOX_SIZE_CHROMIUM byte sized name 38 39 40 void glProduceTextureCHROMIUM (GLenum target, const GLbyte *mailbox) 41 42 Associates the currently bound texture object with the mailbox name. A 43 given texture object can be associated with several mailbox names. If a 44 mailbox name was previously associated with a texture object, that 45 previous association is broken. The currently bound texture object is not 46 modified by the operation. 47 48 If glProduceTextureCHROMIUM generates an error, the mailbox name keeps its 49 current association, if any. 50 51 The mailbox does not keep a reference to the texture object. When the 52 texture object is destroyed (deleted from all context groups, and unbound 53 from all texture units and framebuffer attachments), the mailbox is 54 disassociated from the texture object. 55 56 <target> uses the same parameters as TexImage2D. 57 58 <mailbox> identifies a GL_MAILBOX_SIZE_CHROMIUM byte sized name returned by 59 glGenMailboxCHROMIUM. 60 61 INVALID_OPERATION is generated if <target> is not a valid target. 62 63 INVALID_OPERATION is generated if <mailbox> is invalid. 64 65 66 void glProduceTextureDirectCHROMIUM (GLuint texture, GLenum target, 67 const GLbyte *mailbox) 68 69 Associates the specified texture object with the mailbox name. Performs 70 identically to glProduceTextureCHROMIUM except that the texture specified by 71 <texture> is used instead of the currently bound texture. This operation 72 does not change the texture bindings or alter the bound texture in any way. 73 74 <texture> Specifies the name of a texture. 75 76 77 void glConsumeTextureCHROMIUM (GLenum target, const GLbyte *mailbox) 78 79 <target> uses the same parameters as TexImage2D. 80 81 <mailbox> identifies a GL_MAILBOX_SIZE_CHROMIUM byte sized name returned by 82 glGenMailboxCHROMIUM. 83 84 Deletes the currently bound texture object, and redefines its texture name 85 to point to the texture object associated with the mailbox name. All the 86 contexts that have consumed the texture object, as well as produced it share 87 the texture object, as if the contexts were part of the share group. The 88 texture object is deleted once all contexts have deleted the texture name 89 associated with the texture object, and detached it from all framebuffer 90 objects as well as texture unit bindings. See Appendix C of the OpenGL ES 91 2.0 specification for details relative to visibility in one context of 92 changes to the shared texture object in another context. 93 94 If glConsumeTextureCHROMIUM generates an error, the currently bound texture 95 object is preserved. 96 97 INVALID_OPERATION is generated if <target> is not a valid target. 98 99 INVALID_OPERATION is generated if <mailbox> is invalid. 100 101 INVALID_OPERATION is generated if <mailbox> is not associated with a texture 102 object. 103 104 INVALID_OPERATION is generated if the texture object associated with 105 <mailbox> has a different target than <target>. 106 107 INVALID_OPERATION is generated if the currently bound texture was previously 108 deleted (for example in another context), hence doesn't have a name. 109 110 111 GLuint glCreateAndConsumeTextureCHROMIUM (GLenum target, 112 const GLbyte *mailbox) 113 114 Returns a new texture name associated with the given target pointing to the 115 texture object associated with the mailbox name. Does not alter the texture 116 bindings or alter the currently bound texture in any way. Otherwise performs 117 identically to glConsumeTextureCHROMIUM. 118 119 New Tokens 120 121 The size of a mailbox name in bytes. 122 123 GL_MAILBOX_SIZE_CHROMIUM 64 124 125 Errors 126 127 None. 128 129 New Tokens 130 131 None. 132 133 New State 134 135 None. 136 137 Revision History 138 139 4/25/2011 Documented the extension 140 5/23/2013 Major revision in Produce/Consume semantics, introducing 141 sharing. 142 6/02/2014 Added glProduceTextureDirectCHROMIUM and 143 glCreateAndConsumeTextureCHROMIUM definitions. 144
