/extra/gpu/framebuffers/framebuffers-docs.factor

  1! (c)2009 Joe Groff bsd license
  2USING: alien byte-arrays gpu.buffers gpu.textures help.markup
  3help.syntax images kernel math math.rectangles sequences ;
  4IN: gpu.framebuffers
  5
  6HELP: <color-attachment>
  7{ $values
  8    { "index" integer }
  9    { "color-attachment" color-attachment }
 10}
 11{ $description "Constructs an " { $link attachment-ref } " referencing the " { $snippet "index" } "th " { $snippet "color-attachment" } " of a framebuffer." }
 12{ $notes "User-created framebuffer objects require OpenGL 3.0 or one of the " { $snippet "GL_ARB_framebuffer_object" } " or " { $snippet "GL_EXT_framebuffer_object" } " extensions." } ;
 13
 14HELP: <framebuffer-rect>
 15{ $values
 16    { "framebuffer" any-framebuffer } { "attachment" attachment-ref } { "rect" rect }
 17    { "framebuffer-rect" framebuffer-rect }
 18}
 19{ $description "Constructs a " { $link framebuffer-rect } " tuple that references a rectangular region of " { $snippet "attachment" } " in " { $snippet "framebuffer" } "." }
 20{ $notes "User-created framebuffer objects require OpenGL 3.0 or one of the " { $snippet "GL_ARB_framebuffer_object" } " or " { $snippet "GL_EXT_framebuffer_object" } " extensions." } ;
 21
 22{ framebuffer-rect <framebuffer-rect> <full-framebuffer-rect> } related-words
 23
 24HELP: <framebuffer>
 25{ $values
 26    { "color-attachments" sequence } { "depth-attachment" framebuffer-attachment } { "stencil-attachment" framebuffer-attachment } { "dim" { $maybe sequence } }
 27    { "framebuffer" framebuffer }
 28}
 29{ $description "Creates a new " { $link framebuffer } " object comprising the given set of " { $snippet "color-attachments" } ", " { $snippet "depth-attachment" } ", and " { $snippet "stencil-attachment" } ". If " { $snippet "dim" } " is not null, all of the attachments will be resized using " { $link resize-framebuffer } "; otherwise, each texture or renderbuffer being attached must have image memory allocated for the framebuffer creation to succeed." }
 30{ $notes "User-created framebuffer objects require OpenGL 3.0 or one of the " { $snippet "GL_ARB_framebuffer_object" } " or " { $snippet "GL_EXT_framebuffer_object" } " extensions. If only the " { $snippet "GL_EXT_framebuffer_object" } " is available, all framebuffer attachments must have the same size, and all color attachments must have the same " { $link component-order } " and " { $link component-type } "." } ;
 31
 32HELP: <full-framebuffer-rect>
 33{ $values
 34    { "framebuffer" any-framebuffer } { "attachment" attachment-ref }
 35    { "framebuffer-rect" framebuffer-rect }
 36}
 37{ $description "Constructs a " { $link framebuffer-rect } " tuple that spans the entire size of " { $snippet "attachment" } " in " { $snippet "framebuffer" } "." }
 38{ $notes "User-created framebuffer objects require OpenGL 3.0 or one of the " { $snippet "GL_ARB_framebuffer_object" } " or " { $snippet "GL_EXT_framebuffer_object" } " extensions." } ;
 39
 40HELP: <renderbuffer>
 41{ $values
 42    { "component-order" component-order } { "component-type" component-type } { "samples" { $maybe integer } } { "dim" { $maybe sequence } }
 43    { "renderbuffer" renderbuffer }
 44}
 45{ $description "Creates a new " { $link renderbuffer } " object. If " { $snippet "samples" } " is not " { $link f } ", it specifies the multisampling level to use. If " { $snippet "dim" } " is not " { $link f } ", image memory of the given dimensions will be allocated for the renderbuffer; otherwise, memory will have to be allocated separately with " { $link allocate-renderbuffer } "." } 
 46{ $notes "Renderbuffer objects require OpenGL 3.0 or one of the " { $snippet "GL_ARB_framebuffer_object" } " or " { $snippet "GL_EXT_framebuffer_object" } " extensions. Multisampled renderbuffers require OpenGL 3.0 or one of the " { $snippet "GL_ARB_framebuffer_object" } " or " { $snippet "GL_EXT_framebuffer_multisample" } " extensions." } ;
 47
 48HELP: <system-attachment>
 49{ $values
 50    { "side" { $maybe framebuffer-attachment-side } } { "face" { $maybe framebuffer-attachment-face } }
 51    { "system-attachment" system-attachment }
 52}
 53{ $description "Constructs an " { $link attachment-ref } " referencing a " { $link system-framebuffer } " color attachment." } ;
 54
 55HELP: <texture-1d-attachment>
 56{ $values
 57    { "texture" texture-data-target } { "level" integer }
 58    { "texture-1d-attachment" texture-1d-attachment }
 59}
 60{ $description "Constructs a " { $link framebuffer-attachment } " to the " { $snippet "level" } "th level of detail of one-dimensional texture " { $snippet "texture" } "." }
 61{ $notes "User-created framebuffer objects require OpenGL 3.0 or one of the " { $snippet "GL_ARB_framebuffer_object" } " or " { $snippet "GL_EXT_framebuffer_object" } " extensions." } ;
 62
 63HELP: <texture-2d-attachment>
 64{ $values
 65    { "texture" texture-data-target } { "level" integer }
 66    { "texture-2d-attachment" texture-2d-attachment }
 67}
 68{ $description "Constructs a " { $link framebuffer-attachment } " to the " { $snippet "level" } "th level of detail of two-dimensional texture " { $snippet "texture" } "." }
 69{ $notes "User-created framebuffer objects require OpenGL 3.0 or one of the " { $snippet "GL_ARB_framebuffer_object" } " or " { $snippet "GL_EXT_framebuffer_object" } " extensions." } ;
 70
 71HELP: <texture-3d-attachment>
 72{ $values
 73    { "texture" texture-data-target } { "z-offset" integer } { "level" integer }
 74    { "texture-3d-attachment" texture-3d-attachment }
 75}
 76{ $description "Constructs a " { $link framebuffer-attachment } " to the " { $snippet "z-offset" } "th plane of the " { $snippet "level" } "th level of detail of three-dimensional texture " { $snippet "texture" } "." }
 77{ $notes "User-created framebuffer objects require OpenGL 3.0 or one of the " { $snippet "GL_ARB_framebuffer_object" } " or " { $snippet "GL_EXT_framebuffer_object" } " extensions." } ;
 78
 79HELP: <texture-layer-attachment>
 80{ $values
 81    { "texture" texture-data-target } { "layer" integer } { "level" integer }
 82    { "texture-layer-attachment" texture-layer-attachment }
 83}
 84{ $description "Constructs a " { $link framebuffer-attachment } " to the " { $snippet "layer" } "th layer of the " { $snippet "level" } "th level of detail of three-dimensional texture or array texture " { $snippet "texture" } "." }
 85{ $notes "User-created framebuffer objects require OpenGL 3.0 or one of the " { $snippet "GL_ARB_framebuffer_object" } " or " { $snippet "GL_EXT_framebuffer_object" } " extensions. Array textures require OpenGL 3.0 or the " { $snippet "GL_EXT_texture_array" } " extension." } ;
 86
 87HELP: allocate-renderbuffer
 88{ $values
 89    { "renderbuffer" renderbuffer } { "dim" sequence }
 90}
 91{ $description "Allocates image memory for " { $snippet "renderbuffer" } " with dimension " { $snippet "dim" } "." }
 92{ $notes "Renderbuffer objects require OpenGL 3.0 or one of the " { $snippet "GL_ARB_framebuffer_object" } " or " { $snippet "GL_EXT_framebuffer_object" } " extensions." } ;
 93
 94HELP: any-framebuffer
 95{ $class-description "This class is a union of the " { $link framebuffer } " class, which represents user-created framebuffer objects, and the " { $link system-framebuffer } ". Words which accept " { $snippet "any-framebuffer" } " can operate on either the system framebuffer or user framebuffers." }
 96{ $notes "User-created framebuffer objects require OpenGL 3.0 or one of the " { $snippet "GL_ARB_framebuffer_object" } " or " { $snippet "GL_EXT_framebuffer_object" } " extensions." } ;
 97
 98HELP: attachment-ref
 99{ $class-description "An " { $snippet "attachment-ref" } " value references a particular color, depth, or stencil attachment to a " { $link framebuffer } " object."
100{ $list
101{ { $link system-attachment } " references one or more of the color attachments to the " { $link system-framebuffer } "." }
102{ { $link color-attachment } " references one of the indexed color attachments to a user-created " { $link framebuffer } "." }
103{ { $link default-attachment } " references the back buffer of the " { $snippet "system-framebuffer" } " or the first color attachment of a user " { $snippet "framebuffer" } "." }
104{ { $link depth-attachment } " references the depth buffer attachment to any framebuffer." }
105{ { $link stencil-attachment } " references the stencil buffer attachment to any framebuffer." }
106} }
107{ $notes "User-created framebuffer objects require OpenGL 3.0 or one of the " { $snippet "GL_ARB_framebuffer_object" } " or " { $snippet "GL_EXT_framebuffer_object" } " extensions." } ;
108
109HELP: back-face
110{ $class-description "Use this value in the " { $snippet "face" } " slot of a " { $link system-attachment } " reference to select the back face of a double-buffered " { $link system-framebuffer } "." } ;
111
112HELP: clear-framebuffer
113{ $values
114    { "framebuffer" any-framebuffer } { "alist" "a list of " { $link attachment-ref } "/value pairs" }
115}
116{ $description "Clears the active viewport area of the specified attachments to " { $snippet "framebuffer" } " to the associated values." }
117{ $notes "User-created framebuffer objects require OpenGL 3.0 or one of the " { $snippet "GL_ARB_framebuffer_object" } " or " { $snippet "GL_EXT_framebuffer_object" } " extensions." } ;
118
119HELP: clear-framebuffer-attachment
120{ $values
121    { "framebuffer" any-framebuffer } { "attachment-ref" attachment-ref } { "value" object }
122}
123{ $description "Clears the active viewport area of the given attachment to " { $snippet "framebuffer" } " to " { $snippet "value" } "." }
124{ $notes "User-created framebuffer objects require OpenGL 3.0 or one of the " { $snippet "GL_ARB_framebuffer_object" } " or " { $snippet "GL_EXT_framebuffer_object" } " extensions." } ;
125
126{ clear-framebuffer clear-framebuffer-attachment } related-words
127
128HELP: color-attachment
129{ $class-description "This " { $link attachment-ref } " type references a color attachment to a user-created " { $link framebuffer } " object. The " { $snippet "index" } " slot of the tuple indicates the color attachment referenced. Color attachments to the " { $link system-framebuffer } " are referenced by the " { $link system-attachment } " type." }
130{ $notes "User-created framebuffer objects require OpenGL 3.0 or one of the " { $snippet "GL_ARB_framebuffer_object" } " or " { $snippet "GL_EXT_framebuffer_object" } " extensions." } ;
131
132{
133    color-attachment system-attachment default-attachment depth-attachment stencil-attachment
134    attachment-ref color-attachment-ref
135} related-words
136
137HELP: color-attachment-ref
138{ $class-description "A " { $snippet "color-attachment-ref" } " value references a particular color attachment to a " { $link framebuffer } " object."
139{ $list
140{ { $link system-attachment } " references one or more of the color attachments to the " { $link system-framebuffer } "." }
141{ { $link color-attachment } " references one of the indexed color attachments to a user-created " { $link framebuffer } "." }
142{ { $link default-attachment } " references the back buffer of the " { $snippet "system-framebuffer" } " or the first color attachment of a user " { $snippet "framebuffer" } "." }
143} }
144{ $notes "User-created framebuffer objects require OpenGL 3.0 or one of the " { $snippet "GL_ARB_framebuffer_object" } " or " { $snippet "GL_EXT_framebuffer_object" } " extensions." } ;
145
146HELP: copy-framebuffer
147{ $values
148    { "to-fb-rect" framebuffer-rect } { "from-fb-rect" framebuffer-rect } { "depth?" boolean } { "stencil?" boolean } { "filter" texture-filter }
149}
150{ $description "Copies the rectangular region " { $snippet "from-fb-rect" } " to " { $snippet "to-fb-rect" } ". If " { $snippet "depth?" } " is true, depth values are also copied, and if " { $snippet "stencil?" } " is true, so are stencil values. If the rectangle sizes do not match, the region is scaled using nearest-neighbor or linear filtering based on " { $snippet "filter" } "." }
151{ $notes "This word requires OpenGL 3.0 or one of the " { $snippet "GL_ARB_framebuffer_object" } " or " { $snippet "GL_EXT_framebuffer_blit" } " extensions." } ;
152
153HELP: default-attachment
154{ $class-description "This " { $link attachment-ref } " references the back buffer of the " { $link system-framebuffer } " or the first color attachment of a user-created " { $link framebuffer } "." }
155{ $notes "User-created framebuffer objects require OpenGL 3.0 or one of the " { $snippet "GL_ARB_framebuffer_object" } " or " { $snippet "GL_EXT_framebuffer_object" } " extensions." } ;
156
157HELP: depth-attachment
158{ $class-description "This " { $link attachment-ref } " references the depth buffer attachment of a user-created " { $link framebuffer } " or the " { $link system-framebuffer } "." }
159{ $notes "User-created framebuffer objects require OpenGL 3.0 or one of the " { $snippet "GL_ARB_framebuffer_object" } " or " { $snippet "GL_EXT_framebuffer_object" } " extensions." } ;
160
161HELP: framebuffer
162{ $class-description "Objects of this class represent user-created framebuffer objects. These framebuffer objects provide an offscreen target for rendering operations and can send rendering output either to textures or to dedicated " { $link renderbuffer } "s. A framebuffer consists of a set of one or more color " { $link framebuffer-attachment } "s, an optional depth buffer " { $snippet "framebuffer-attachment" } ", and an optional stencil buffer " { $snippet "framebuffer-attachment" } "." }
163{ $notes "User-created framebuffer objects require OpenGL 3.0 or one of the " { $snippet "GL_ARB_framebuffer_object" } " or " { $snippet "GL_EXT_framebuffer_object" } " extensions." } ;
164
165HELP: framebuffer-attachment
166{ $class-description "This class is a union of the " { $link renderbuffer } " and " { $link texture-attachment } " classes, either of which can function as an attachment to a user-created " { $link framebuffer } " object." }
167{ $notes "User-created framebuffer objects require OpenGL 3.0 or one of the " { $snippet "GL_ARB_framebuffer_object" } " or " { $snippet "GL_EXT_framebuffer_object" } " extensions." } ;
168
169HELP: framebuffer-attachment-at
170{ $values
171    { "framebuffer" framebuffer } { "attachment-ref" attachment-ref }
172    { "attachment" framebuffer-attachment }
173}
174{ $description "Returns the " { $link texture-attachment } " or " { $link renderbuffer } " referenced by " { $snippet "attachment-ref" } " in " { $snippet "framebuffer" } "." }
175{ $notes "User-created framebuffer objects require OpenGL 3.0 or one of the " { $snippet "GL_ARB_framebuffer_object" } " or " { $snippet "GL_EXT_framebuffer_object" } " extensions." } ;
176
177HELP: framebuffer-attachment-face
178{ $class-description "The values " { $link front-face } " and " { $link back-face } " select a face of a double-buffered " { $link system-framebuffer } " when stored in the " { $snippet "face" } " slot of a " { $link system-attachment } " reference." } ;
179
180HELP: framebuffer-attachment-side
181{ $class-description "The values " { $link left-side } " and " { $link right-side } " select a face of a stereoscopic " { $link system-framebuffer } " when stored in the " { $snippet "side" } " slot of a " { $link system-attachment } " reference." } ;
182
183HELP: framebuffer-rect
184{ $class-description "This tuple class references a rectangular subregion of a color attachment of a " { $link framebuffer } " object."
185{ $list
186{ { $snippet "framebuffer" } " references either a user-created " { $link framebuffer } " or the " { $link system-framebuffer } "." }
187{ { $snippet "attachment" } " is a " { $link color-attachment-ref } " referencing the color attachment of interest in the framebuffer." }
188{ { $snippet "rect" } " is a " { $link rect } " referencing the rectangular region of interest of the attachment." }
189} }
190{ $notes "User-created framebuffer objects require OpenGL 3.0 or one of the " { $snippet "GL_ARB_framebuffer_object" } " or " { $snippet "GL_EXT_framebuffer_object" } " extensions." } ;
191
192HELP: front-face
193{ $class-description "Use this value in the " { $snippet "face" } " slot of a " { $link system-attachment } " reference to select the front face of a double-buffered " { $link system-framebuffer } "." } ;
194
195{ front-face back-face } related-words
196
197HELP: left-side
198{ $class-description "Use this value in the " { $snippet "side" } " slot of a " { $link system-attachment } " reference to select the left side of a stereoscopic " { $link system-framebuffer } "." } ;
199
200{ left-side right-side } related-words
201
202HELP: read-framebuffer
203{ $values
204    { "framebuffer-rect" framebuffer-rect }
205    { "byte-array" byte-array }
206}
207{ $description "Reads the rectangular region " { $snippet "framebuffer-rect" } " into a new " { $snippet "byte-array" } ". The format of the byte array is determined by the " { $link component-order } " and " { $link component-type } " of the associated " { $link framebuffer-attachment } "." }
208{ $notes "User-created framebuffer objects require OpenGL 3.0 or one of the " { $snippet "GL_ARB_framebuffer_object" } " or " { $snippet "GL_EXT_framebuffer_object" } " extensions." } ;
209
210HELP: read-framebuffer-image
211{ $values
212    { "framebuffer-rect" framebuffer-rect }
213    { "image" image }
214}
215{ $description "Reads the rectangular region " { $snippet "framebuffer-rect" } " into a new " { $snippet "image" } ". The format of the image is determined by the " { $link component-order } " and " { $link component-type } " of the associated " { $link framebuffer-attachment } "." }
216{ $notes "User-created framebuffer objects require OpenGL 3.0 or one of the " { $snippet "GL_ARB_framebuffer_object" } " or " { $snippet "GL_EXT_framebuffer_object" } " extensions." } ;
217
218HELP: read-framebuffer-to
219{ $values
220    { "framebuffer-rect" framebuffer-rect } { "gpu-data-ptr" gpu-data-ptr }
221}
222{ $description "Reads the rectangular region " { $snippet "framebuffer-rect" } " into " { $snippet "gpu-data-ptr" } ", which can reference either CPU memory (a " { $link byte-array } " or " { $link alien } ") or a GPU " { $link buffer-ptr } ". The format of the written data is determined by the " { $link component-order } " and " { $link component-type } " of the associated " { $link framebuffer-attachment } "." }
223{ $notes "User-created framebuffer objects require OpenGL 3.0 or one of the " { $snippet "GL_ARB_framebuffer_object" } " or " { $snippet "GL_EXT_framebuffer_object" } " extensions. Reading into a " { $snippet "buffer-ptr" } " requires OpenGL 2.1 or the " { $snippet "GL_ARB_pixel_buffer_object" } " extension." } ;
224
225{ read-framebuffer read-framebuffer-image read-framebuffer-to } related-words
226
227HELP: renderbuffer
228{ $class-description "Objects of this type represent renderbuffer objects, two-dimensional image buffers that can serve as " { $link framebuffer-attachment } "s to user-created " { $link framebuffer } " objects." }
229{ $notes "Renderbuffer objects require OpenGL 3.0 or one of the " { $snippet "GL_ARB_framebuffer_object" } " or " { $snippet "GL_EXT_framebuffer_object" } " extensions." } ;
230
231{ renderbuffer renderbuffer-dim allocate-renderbuffer <renderbuffer> } related-words
232{ framebuffer <framebuffer> resize-framebuffer } related-words
233
234HELP: renderbuffer-dim
235{ $values
236    { "renderbuffer" renderbuffer }
237    { "dim" sequence }
238}
239{ $description "Returns the dimensions of the allocated image memory for " { $snippet "renderbuffer" } "." }
240{ $notes "Renderbuffer objects require OpenGL 3.0 or one of the " { $snippet "GL_ARB_framebuffer_object" } " or " { $snippet "GL_EXT_framebuffer_object" } " extensions." } ;
241
242HELP: resize-framebuffer
243{ $values
244    { "framebuffer" framebuffer } { "dim" sequence }
245}
246{ $description "Reallocates the image memory for all of the textures and renderbuffers bound to " { $snippet "framebuffer" } " to be of the given dimensions." }
247{ $notes "User-created framebuffer objects require OpenGL 3.0 or one of the " { $snippet "GL_ARB_framebuffer_object" } " or " { $snippet "GL_EXT_framebuffer_object" } " extensions." } ;
248
249HELP: right-side
250{ $class-description "Use this value in the " { $snippet "side" } " slot of a " { $link system-attachment } " reference to select the right side of a stereoscopic " { $link system-framebuffer } "." } ;
251
252HELP: stencil-attachment
253{ $class-description "This " { $link attachment-ref } " references the stencil buffer attachment of a user-created " { $link framebuffer } " or the " { $link system-framebuffer } "." }
254{ $notes "User-created framebuffer objects require OpenGL 3.0 or one of the " { $snippet "GL_ARB_framebuffer_object" } " or " { $snippet "GL_EXT_framebuffer_object" } " extensions." } ;
255
256HELP: system-attachment
257{ $class-description "This " { $link attachment-ref } " references one or more of the color attachments to the " { $link system-framebuffer } ". Depending on the window system pixel format for the window, up to four attachments may be available:"
258{ $list
259{ "If double buffering is available, there is a " { $link back-face } ", which holds the screen image as it is drawn, and a " { $link front-face } ", which holds the current contents of the screen. The two buffers get swapped when a scene is completely drawn." }
260{ "If stereoscopic rendering is available, there is a " { $link left-side } " and " { $link right-side } ", representing the left and right eye viewpoints of a 3D viewing apparatus." }
261}
262"To select a subset of these attachments, the " { $snippet "system-attachment" } " tuple type has two slots:"
263{ $list
264{ { $snippet "side" } " selects either the " { $snippet "left-side" } " or " { $snippet "right-side" } ", or both if set to " { $link f } "." }
265{ { $snippet "face" } " selects either the " { $snippet "back-face" } " or " { $snippet "front-face" } ", or both if set to " { $link f } "." }
266}
267"If stereo or double buffering are not available, then both sides or faces respectively will be equivalent. All attachments can be selected by setting both slots to " { $link f } ", both attachments of a side or face can be selected by setting a single slot, and a single attachment can be targeted by setting both slots." } ;
268
269HELP: system-framebuffer
270{ $class-description "This symbol represents the framebuffer supplied by the window system to store the contents of the window on screen. Since this framebuffer is managed by the window system, it cannot have its attachments modified or resized; however, it is still a valid target for rendering, copying via " { $link copy-framebuffer } ", clearing via " { $link clear-framebuffer } ", and reading via " { $link read-framebuffer } "." } ;
271
272HELP: texture-1d-attachment
273{ $class-description "This class references a single level of detail of a one-dimensional texture for use as a " { $link framebuffer-attachment } "." }
274{ $notes "User-created framebuffer objects require OpenGL 3.0 or one of the " { $snippet "GL_ARB_framebuffer_object" } " or " { $snippet "GL_EXT_framebuffer_object" } " extensions." } ;
275
276HELP: texture-2d-attachment
277{ $class-description "This class references a single level of detail of a two-dimensional texture for use as a " { $link framebuffer-attachment } "." }
278{ $notes "User-created framebuffer objects require OpenGL 3.0 or one of the " { $snippet "GL_ARB_framebuffer_object" } " or " { $snippet "GL_EXT_framebuffer_object" } " extensions." } ;
279
280HELP: texture-3d-attachment
281{ $class-description "This class references a single plane and level of detail of a three-dimensional texture for use as a " { $link framebuffer-attachment } "." }
282{ $notes "User-created framebuffer objects require OpenGL 3.0 or one of the " { $snippet "GL_ARB_framebuffer_object" } " or " { $snippet "GL_EXT_framebuffer_object" } " extensions." } ;
283
284HELP: texture-attachment
285{ $class-description "This class is a union of the " { $link texture-1d-attachment } ", " { $link texture-2d-attachment } ", " { $link texture-3d-attachment } ", and " { $link texture-layer-attachment } " classes, which select layers and levels of detail of " { $link texture } " objects to serve as " { $link framebuffer } " attachments." }
286{ $notes "User-created framebuffer objects require OpenGL 3.0 or one of the " { $snippet "GL_ARB_framebuffer_object" } " or " { $snippet "GL_EXT_framebuffer_object" } " extensions." } ;
287
288HELP: texture-layer-attachment
289{ $class-description "This class references a single layer and level of detail of a three-dimensional texture or array texture for use as a " { $link framebuffer-attachment } "." }
290{ $notes "User-created framebuffer objects require OpenGL 3.0 or one of the " { $snippet "GL_ARB_framebuffer_object" } " or " { $snippet "GL_EXT_framebuffer_object" } " extensions. Array textures require OpenGL 3.0 or the " { $snippet "GL_EXT_texture_array" } " extension." } ;
291
292{ texture-1d-attachment <texture-1d-attachment> } related-words
293{ texture-2d-attachment <texture-2d-attachment> } related-words
294{ texture-3d-attachment <texture-3d-attachment> } related-words
295{ texture-layer-attachment <texture-layer-attachment> } related-words
296
297ARTICLE: "gpu.framebuffers" "Framebuffer objects"
298"The " { $vocab-link "gpu.framebuffers" } " vocabulary provides words for creating, allocating, and reading from framebuffer objects. Framebuffer objects are used as rendering targets; the " { $link system-framebuffer } " is supplied by the window system and contains the contents of the window on screen. User-created " { $link framebuffer } " objects can also be created to direct rendering output to offscreen " { $link texture } "s or " { $link renderbuffer } "s."
299{ $subsections
300    system-framebuffer
301    framebuffer
302    renderbuffer
303}
304"The contents of a framebuffer can be cleared to known values before rendering a scene:"
305{ $subsections
306    clear-framebuffer
307    clear-framebuffer-attachment
308}
309"The image memory for a renderbuffer can be resized, or the full set of textures and renderbuffers attached to a framebuffer can be resized to the same dimensions together:"
310{ $subsections
311    allocate-renderbuffer
312    resize-framebuffer
313}
314"Rectangular regions of framebuffers can be read into memory, read into GPU " { $link buffer } "s, and copied between framebuffers:"
315{ $subsections
316    framebuffer-rect
317    attachment-ref
318    read-framebuffer
319    read-framebuffer-to
320    read-framebuffer-image
321    copy-framebuffer
322} ;
323
324ABOUT: "gpu.framebuffers"