source: project/wiki/eggref/4/gl-utils @ 31368

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1== gl-utils
2[[toc:]]
3Provides a higher level interface to OpenGL. The following modules are included:
4
5* gl-utils: Exports all of the modules in this egg
6* gl-utils-core: Convenience procedures for OpenGL, abstracting over common tasks
7* gl-utils-bytevector: OpenGL-safe R7RS style bytevectors with extended accessors
8* gl-utils-mesh: Convenient vertex array interface for creation, modification, and use
9* gl-utils-ply: [[http://paulbourke.net/dataformats/ply/|PLY]] file loading
10* gl-utils-srfi-4: OpenGL-safe numeric vectors
11
12
13=== Requirements
14* z3
15* matchable
16* miscmacros
17* srfi-42
18* opengl-glew
19* gl-math
20* make
21
22
23=== Documentation
24
25==== gl-utils-core
26<procedure> (check-error)</procedure>
27
28Performs {{get-error}} ({{glGetError}}) and prints the error type when an error is returned.
29
30<procedure> (make-shader TYPE SOURCE)</procedure>
31
32Creates and compiles a shader object given the shader's type (e.g. {{+vertex-shader+}}, {{+geometry-shader+}}, {{+fragment-shader+}}), and a string containing the GLSL source. Returns an integer representing the ID of the shader.
33
34<procedure> (make-program SHADER-LIST [PROGRAM-ID])</procedure>
35
36Creates and links a program object, given a list of shader objects (i.e. the integers returned by {{make-shader}}. Returns an integer representing the ID of the program.
37
38Accepts an optional {{PROGRAM-ID}} argument. If given, {{make-program}} will use this ID rather than generating a new one.
39
40<procedure> (gen-buffer)</procedure>
41<procedure> (gen-framebuffer)</procedure>
42<procedure> (gen-program-pipeline)</procedure>
43<procedure> (gen-query)</procedure>
44<procedure> (gen-renderbuffer)</procedure>
45<procedure> (gen-sampler)</procedure>
46<procedure> (gen-texture)</procedure>
47<procedure> (gen-transform-feedback)</procedure>
48<procedure> (gen-vertex-array)</procedure>
49
50Analogous to their pluralized counterparts, but only generates and returns one (integer) object.
51
52<procedure> (delete-buffer BUFFER)</procedure>
53<procedure> (delete-framebuffer FRAMEBUFFER)</procedure>
54<procedure> (delete-program-pipeline PROGRAM-PIPELINE)</procedure>
55<procedure> (delete-query QUERY)</procedure>
56<procedure> (delete-renderbuffer RENDERBUFFER)</procedure>
57<procedure> (delete-sampler SAMPLER)</procedure>
58<procedure> (delete-texture TEXTURE)</procedure>
59<procedure> (delete-transform-feedback TRANSFORM-FEEDBACK)</procedure>
60<procedure> (delete-vertex-array VERTEX-ARRAY)</procedure>
61
62Analogous to their pluralized counterparts, but only accepts and deletes one (integer) object.
63
64<macro> (with-buffer TYPE BUFFER BODY ...)</macro>
65<macro> (with-framebuffer FRAMEBUFFER BODY ...)</macro>
66<macro> (with-program-pipeline PROGRAM-PIPELINE BODY ...)</macro>
67<macro> (with-renderbuffer RENDERBUFFER BODY ...)</macro>
68<macro> (with-sampler UNIT SAMPLER BODY ...)</macro>
69<macro> (with-texture TYPE TEXTURE BODY ...)</macro>
70<macro> (with-transform-feedback TRANSFORM-FEEDBACK BODY ...)</macro>
71<macro> (with-vertex-array VERTEX-ARRAY BODY ...)</macro>
72
73Equivalent to binding the object, executing the body, then binding 0. E.g. {{(bind-texture TYPE TEXTURE) BODY ... (bind-texture TYPE 0)}}.
74
75<procedure> (set-texture-properties ID type: TYPE mag: MAG min: MIN wrap: WRAP wrap-s: WRAP-S wrap-t: WRAP-T wrap-r: WRAP-R)</procedure>
76
77Conveniently set the most common properties of the texture {{ID}}. {{TYPE}} is the texture type, defaulting to {{+texture-2d+}}. {{MAG}} and {{MIN}} are the texture magnify and minifying functions, which default to {{+linear+}}. {{WRAP-S}}, {{WRAP-T}}, and {{WRAP-R}} set the wrapping parameters which default to {{+repeat+}}. {{WRAP}} sets all three wrapping parameters to the same value.
78
79<procedure> (create-framebuffer WIDTH HEIGHT channels: CHANNELS type: TYPE)</procedure>
80
81Create a framebuffer with a texture and depth renderbuffer attached. The texture and renderbuffer are given the dimensions {{WITH}} and {{HEIGHT}}. {{CHANNELS}} is the number of channels that the texture has: 1, 2, 3, or 4, corresponding to {{+red+}}, {{+rg+}}, {{+rgb+, and}}+rgba+ respectively, defaulting to 4. {{TYPE}} is the type of the texture data which defaults to {{+unsigned-byte+}}. Returns three values: The framebuffer, the texture, and the renderbuffer.
82
83<procedure> (->pointer VECTOR)</procedure>
84
85Returns the pointer to a srfi-4 vector or blob.
86
87<procedure> (size VECTOR)</procedure>
88
89Returns the size, in bytes, of a srfi-4 vector or blob.
90
91<procedure> (type->bytes TYPE)</procedure>
92
93Returns the size of {{TYPE}} (as accepted by {{type->gl}}) in number of bytes.
94
95<procedure> (type->gl TYPE)</procedure>
96
97Converts the keyword {{TYPE}} into a OpenGL type enum value. Accepted types (grouped by synonyms) are:
98
99* {{char:}} {{int8:}} {{byte:}}
100* {{uchar:}} {{uint8:}} {{unsigned-byte:}}
101* {{short:}} {{int16:}}
102* {{ushort:}} {{uint16:}} {{unsigned-short:}}
103* {{int:}} {{int32:}} {{integer:}} {{integer32:}}
104* {{uint:}} {{uint32:}} {{unsigned-int:}} {{unsigned-int32:}} {{unsigned-integer:}} {{unsigned-integer32:}}
105* {{float:}} {{float32:}}
106* {{double:}} {{float64:}}
107
108
109==== gl-utils-bytevector
110r7rs style bytevectors with unsafe accessors. As in gl-utils-srfi4, bytevectors are created in non-garbage-collected memory. They will still be freed when no longer used.
111
112<procedure> (bytevector BYTE ...)</procedure>
113
114Returns a newly allocated bytevector containing its arguments.
115
116<procedure> (make-bytevector K [BYTE] [NONGC] [FINALIZE])</procedure>
117
118Return a newly-allocated bytevector of length {{K}}. If the optional fill {{BYTE}} is specified, it specifies the initial value for each slot in the bytevector.
119
120The optional arguments {{NONGC}} and {{FINALIZE}} define whether the vector should be allocated in a memory area not subject to garbage collection and whether the associated storage should be automatically freed (using finalization) when there are no references from Scheme variables and data. {{NONGC}} defaults to #t (the vector will be located in non-garbage-collected memory) and {{FINALIZE}} defaults to #t. Note that the {{FINALIZE}} argument is only used when {{NONGC}} is true.
121
122<procedure> (bytevector-length BYTEVECTOR)</procedure>
123
124Return the length in bytes of {{BYTEVECTOR}}.
125
126<procedure> (bytevector? BYTEVECTOR)</procedure>
127
128Returns true if {{BYTEVECTOR}} is a bytevector, false otherwise.
129
130<procedure> (bytevector-u8-set! BYTEVECTOR K UNSIGNED-BYTE)</procedure>
131<procedure> (bytevector-s8-set! BYTEVECTOR K BYTE)</procedure>
132<procedure> (bytevector-u16-set! BYTEVECTOR K UNSIGNED-SHORT)</procedure>
133<procedure> (bytevector-s16-set! BYTEVECTOR K SHORT)</procedure>
134<procedure> (bytevector-u32-set! BYTEVECTOR K UNSIGNED-INT)</procedure>
135<procedure> (bytevector-s32-set! BYTEVECTOR K INT)</procedure>
136<procedure> (bytevector-u64-set! BYTEVECTOR K UNSIGNED-LONG)</procedure>
137<procedure> (bytevector-s64-set! BYTEVECTOR K LONG)</procedure>
138<procedure> (bytevector-f32-set! BYTEVECTOR K FLOAT)</procedure>
139<procedure> (bytevector-f64-set! BYTEVECTOR K DOUBLE)</procedure>
140
141Sets the byte {{K}} of the given bytevector to be the value of the given fixnum or flonum. These functions are unsafe, so be sure {{K}} is a valid location in the bytevector.
142
143<procedure> (bytevector-u8-ref BYTEVECTOR K)</procedure>
144<procedure> (bytevector-s8-ref BYTEVECTOR K)</procedure>
145<procedure> (bytevector-u16-ref BYTEVECTOR K)</procedure>
146<procedure> (bytevector-s16-ref BYTEVECTOR K)</procedure>
147<procedure> (bytevector-u32-ref BYTEVECTOR K)</procedure>
148<procedure> (bytevector-s32-ref BYTEVECTOR K)</procedure>
149<procedure> (bytevector-u64-ref BYTEVECTOR K)</procedure>
150<procedure> (bytevector-s64-ref BYTEVECTOR K)</procedure>
151<procedure> (bytevector-f32-ref BYTEVECTOR K)</procedure>
152<procedure> (bytevector-f64-ref BYTEVECTOR K)</procedure>
153
154Returns the fixnum or flonum of the given size located at byte {{K}} of the given bytevector. These functions are unsafe, so be sure {{K}} is a valid location in the bytevector.
155
156<procedure> (bytevector–>pointer BYTEVECTOR)</procedure>
157
158Returns the pointer to {{BYTEVECTOR}}’s data.usage
159
160<procedure> (bytevector-append BYTEVECTOR . BYTEVECTORSS)</procedure>
161
162Returns a newly allocated bytevector whose elements are the concatenation of the elements in the given bytevectors. If only one argument is passed to {{bytevector-append}}, it is assumed that it is a list of bytevectors.
163
164<procedure> (bytevector-copy BYTEVECTOR [START] [END])</procedure>
165
166Returns a newly allocated copy of the elements of the given bytevector between {{START}} and {{END}}.
167
168<procedure> (bytevector-copy! TO AT FROM [START] [END])</procedure>
169
170Copies the elements of bytevector {{FROM}} between {{START}} and {{END}} to bytevector {{TO}}, starting at {{AT}}. It is an error if {{AT}} is less than zero or greater than the length of {{TO}}. It is also an error if {{(- (bytevector-length TO) AT)}} is less than {{(- END START)}}.
171
172
173==== gl-utils-mesh
174<procedure> (make-mesh vertices: VERTICES [indices: INDICES] [mode: MODE])</procedure>
175
176Create a new mesh. {{VERTICES}} is a list of key value pairs that specifies the mesh’s vertex data. It should be in the form:
177
178    (attributes: ATTRIBUTES [initial-elements: INITIAL-ELEMENTS] [n-vertices: N-VERTICES])
179
180{{ATTRIBUTES}} is a list in the form:
181
182    (NAME TYPE N [normalized: NORMALIZED] [location: LOCATION])
183
184where {{NAME}} is the attribute name (as a symbol), {{TYPE}} is the type of the attribute as accepted by {{type->gl}}, {{N}} is the number of elements in the attribute, {{NORMALIZED}} is a boolean value indicating whether the attribute’s values should be normalized (defaulting to {{#f}}), and {{LOCATION}} is the shader attribute-location of the attribute (defaulting to -1 and settable by {{mesh-attribute-locations-set!}}).
185
186{{INITIAL-ELEMENTS}} is either a bytevector or a list of {{(NAME . VALUE)}} pairs where name is the name of the attribute to set (as per the name given in {{ATTRIBUTES}}) and {{VALUE}} is the initial contents of that attribute. When a list is given and more than one attribute is given initial-elements, the {{VALUE}}s should represent the same number of vertices. Values associated with attributes that are {{NORMALIZED}} should be provided as float between {{0.0}} and {{1.0}} (for unsigned types) or {{-1.0}} and {{1.0}}, which are then normalized. If {{INITIAL-ELEMENTS}} is given as a bytevector, that bytevector is used as the entire mesh’s vertex data and {{N-VERTICES}} – the number of vertices – must be provided.
187
188{{INDICES}} is an optional list of key value pairs that specifies the mesh’s index data, if it exists. It should be in the form:
189
190    (type: TYPE [initial-elements: INITIAL-ELEMENTS] [n-indices: N-INDICES])
191
192{{TYPE}} is a type keyword (as accepted by {{type->gl}}) that must be a valid type for an element array buffer (i.e. an unsigned fixnum). {{INITIAL-ELEMENTS}} is either a bytevector or a list of values. If {{INITIAL-ELEMENTS}} is given as a bytevector,  {{N-INDICES}} – the number of indices – must be provided.
193
194{{MODE}} is the keyword (as accepted by {{mode->gl}}) that defines what the mesh is supposed to represent. Defaults to {{#:triangles}}.
195
196<record> (mesh VERTEX-ATTRIBUTES INDEX-TYPE VERTEX-DATA INDEX-DATA N-VERTICES N-INDICES VERTEX-BUFFER INDEX-BUFFER VAO STRIDE MODE USAGE)</record>
197
198The type of record returned by {{make-mesh}}. {{VERTEX-ATTRIBUTES}} is a list of {{vertex-attribute}} records. {{INDEX-TYPE}} is the type given to the {{indices:}} argument of {{make-mesh}}. {{VERTEX-DATA}} and {{INDEX-DATA}} are the bytevectors representing the vertex and index data. {{N-VERTICES}} and {{N-INDICES}} are the number of vertices and indices present in the data. {{VERTEX-BUFFER}}, {{INDEX-BUFFER}} and {{VAO}} are the vertex buffers and VAO created by {{mesh-make-vao!}}. {{STRIDE}} is the number of bytes between the start of consecutive vertices. {{MODE}} is the value of the {{mode:}} argument provided to {{make-mesh}}. {{USAGE}} is the buffer usage that is set with {{make-mesh-vao!}}.
199
200<record> (vertex-attribute name type number normalized location)</record>
201
202The type of record returned by {{mesh-vertex-attributes}}. Getters for all of the fields are provided.
203
204<procedure> (mesh-attribute-locations-set! MESH LOCATIONS)</procedure>
205
206Set the shader attribute locations of the attributes of {{MESH}}. {{LOCATIONS}} is a list of {{(ATTRIBUTE-NAME . LOCATION)}} pairs.
207
208<procedure> (mesh-make-vao! MESH [USAGE])</procedure>
209
210Create a vertex attribute object (VAO) for {{MESH}}. {{USAGE}} is the buffer usage hint keyword as accepted by {{usage->gl}}, defaulting to {{#:static}}. Vertex buffer objects (VBOs) are created for the vertex and index data. The VAO binds these buffers, and sets the vertex attribute pointers. If the usage is one of the static types, the vertex and index data of the mesh are deleted, as are the vertex and index buffers. Attribute locations should be set for the mesh with {{mesh-attribute-locations-set!}} before calling {{mesh-make-vao!}}. The VBOs and VAO created by {{make-mesh-vao!}} are managed and should not be deleted.
211
212<procedure> (mesh-vertex-ref MESH ATTRIBUTE VERTEX)</procedure>
213
214Return a vector containing the values of the attribute named {{ATTRIBUTE}} corresponding to the {{VERTEX}}th vertex of the {{MESH}}. The result will be a srfi-4 numeric vector, corresponding to the type of the given attribute.
215
216<procedure> (mesh-vertex-set! MESH ATTRIBUTE VERTEX VALUE)</procedure>
217
218Set the {{VERTEX}}th vertex of the {{MESH}}’s attribute named {{ATTRIBUTE}} to the values provided by the srfi-4 numeric vector {{VALUE}}. {{VALUE}} must correspond to the type of the attribute, and should be the same length as the attribute. Using a {{VALUE}} that is too short is unsafe.
219
220If {{mesh-make-vao!}} has been called already, {{mesh-vertex-set!}} should be called inside a {{with-mesh}}. If {{mesh-make-vao!}} was called with a static usage, {{mesh-vertex-set!}} will result in an error, since there is no longer any vertex data to set.
221
222<procedure> (with-mesh MESH THUNK)</procedure>
223
224Calls {{THUNK}} with the VBO of the {{MESH}}’s vertex buffer bound. If the mesh has been modified by {{mesh-vertex-set!}}, the vertex buffer’s data will be updated before the VBO is unbound. When the usage hint given to {{mesh-make-vao!}} is dynamic, {{buffer-sub-data}} will be used to update the buffer data. When the usage hint is stream, {{buffer-data}} will be used.
225
226<procedure> (mesh-copy! TO AT FROM [START] [END])</procedure>
227
228Similar to {{bytevector-copy!}}, copies the vertices of mesh {{FROM}} between vertices {{START}} and {{END}} to mesh {{TO}}, starting at vertex {{AT}}.
229
230<procedure> (mesh-copy MESH)</procedure>
231
232Creates a fresh copy of {{MESH}}.
233
234<procedure> (mesh-append MESH . MESHES)</procedure>
235
236Creates a new mesh resulting from appending the vertices of the given meshes together. The indices are also appended and modified so they point to the same vertices. The attributes of all the meshes are assumed to be the same, otherwise bad things will probably happen. If only one argument is passed to {{mesh-append}} it is assumed that it is a list of meshes.
237
238<procedure> (mesh-transform! POSITION-NAME MESH TRANSFORM)</procedure>
239
240Destructively modifies the {{POSITION-NAME}} attribute of {{MESH}} by the [[http://wiki.call-cc.org/eggref/4/gl-math|gl-math]] matrix {{TRANSFORM}}. {{POSITION-NAME}} must be the name of a three element float attribute of {{MESH}}.
241
242<procedure> (mesh-transform-append POSITION-NAME MESH-TRANSFORM-PAIR . MESH-TRANSFORM-PAIRS)</procedure>
243
244Creates a new mesh resulting by appending all the given meshes together, then transforming the attribute named by {{POSITION-NAME}} by the given [[http://wiki.call-cc.org/eggref/4/gl-math|gl-math]] transform matrices. {{MESH-TRANSFORM-PAIR}} and {{MESH-TRANSFORM-PAIRS}} are {{(MESH . TRANFORM)}} pairs. {{POSITION-NAME}} must be the name of a three element float attribute of {{MESH}}. The attributes of all the meshes are assumed to be the same, otherwise bad things will probably happen. If only two arguments are passed to {{mesh-transform-append}} it is assumed that the second is a list of mesh/transform pairs.
245
246<procedure> (usage->gl USAGE)</procedure>
247
248Converts the keyword {{USAGE}} into a OpenGL usage enum value. Accepted usages (grouped by synonyms) are:
249
250* {{dynamic:}} {{dynamic-draw:}}
251* {{stream:}} {{stream-draw:}}
252* {{static:}} {{static-draw:}}
253* {{dynamic-read:}}
254* {{stream-read:}}
255* {{static-read:}}
256* {{dynamic-copy:}}
257* {{stream-copy:}}
258* {{static-copy:}}
259
260This line is here to prevent a Markdown parsing error :|
261
262<procedure> (mode->gl MODE)</procedure>
263
264Converts the keyword {{MODE}} into a OpenGL mode enum value. Accepted modes are:
265
266* {{points:}}
267* {{line-strip:}}
268* {{line-loop:}}
269* {{line-strip-adjacency:}}
270* {{lines-adjacency:}}
271* {{triangle-strip:}}
272* {{triangle-fan:}}
273* {{triangles:}}
274* {{triangle-strip-adjacency:}}
275* {{triangles-adjacency:}}
276* {{patches:}}
277
278
279==== gl-utils-ply
280<procedure> (load-ply FILE BUFFER-SPEC)</procedure>
281
282Loads a [[http://paulbourke.net/dataformats/ply/|PLY]] file. {{FILE}} is a path that may be pointing either to a gziped PLY file or a regular PLY file. {{BUFFER-SPEC}} is a list in the form {{((NAME VARS) ...)}} where {{NAME}} is the name of an element in the PLY file and {{VARS}} is either a list of property names or, in the case of a property list, a single name. Two values are returned: a list of bytevectors which correspond to the buffers named in {{BUFFER-SPEC}} and a list of the elements that are in the PLY file in the form of:
283
284    (element-name n-elements (property-name property-type))
285
286Or, when an element is a property list:
287
288    (element-name n-elements (property-name (list: list-length-type element-type)))
289
290The buffers returned are packed with the contents of the properties named in the {{BUFFER-SPEC}}. Thus, for a PLY file that has element {{vertex}} with properties {{float x}}, {{float y}}, {{float z}}, {{float confidence}}, {{uchar r}}, {{uchar g}}, and {{uchar b}}, as well as an element {{face}} with a property list {{uchar ushort vertex_index}}, the following {{BUFFER-SPEC}} could be used:
291
292    (load-ply "example.ply.gz" '((vertex: (x y z r g b)) (face: vertex_index)))
293
294This buffer spec would result in a list of two u8vectors being returned: one with the packed elements corresponding to properties {{x}}, {{y}}, {{z}}, {{r}}, {{g}}, and {{b}} (with the corresponding property types), and the second containing the vertex indices.
295
296<procedure> (load-ply-mesh FILE vertex: VERTEX face: FACE)</procedure>
297
298Similar to load-ply, but returns a mesh. {{FILE}} is a PLY file (which may be gziped). The PLY file must contain at least the elements {{vertex}} and {{face}} (other elements will be ignored). {{VERTEX}} is a list of {{(ATTRIBUTE-NAME PROPERTY-NAME ...)}} elements, which specifies which PLY properties are associate with which attribute, in which order. Attributes are all normalized. All properties named by each element of {{VERTEX}} must be of the same type. {{FACE}} is the name of the face property list.
299
300Again, for a PLY file that has element {{vertex}} with properties {{float x}}, {{float y}}, {{float z}}, {{float confidence}}, {{uchar r}}, {{uchar g}}, and {{uchar b}}, as well as a element {{face}} with a property list {{uchar ushort vertex_index}}, the following could be used:
301
302    (load-ply-mesh "example.ply" vertex: `((position x y z)
303                                          (color r g b))
304                                face: vertex_index)
305
306This would create a mesh with vertex attributes {{(position #:float 3)}} and {{(color #:unsigned-byte 3 normalized: #t)}} and the {{#:unsigned-short}} indices given by {{vertex_index}}.
307
308
309==== gl-utils-srfi4
310gl-utils-srfi4 reexports a version of [[http://api.call-cc.org/doc/srfi-4|srfi-4]] that gives preference to vectors being created in non-garbage collected memory. This is useful for use with OpenGL, since it is often desirable to pass vectors to OpenGL that will remain in one place. All srfi-4 functions not mentioned below are reexported without changes.
311
312The {{NNNvector}} and {{list->NNNvector}} constructors have been modified so that they return vectors in non-garbage collected memory. They will still be freed when no longer used.
313
314The {{make-NNNvector}} constructors act as their srfi-4 counterparts, except they return vectors in non-garbage collected memory by default. They will still be freed when non longer used.
315
316
317=== Examples
318This example depends on the [[http://wiki.call-cc.org/eggref/4/opengl-glew|opengl-glew]] egg, the [[http://wiki.call-cc.org/eggref/4/glfw3|glfw3]] egg for window and context creation, and the [[http://wiki.call-cc.org/eggref/4/gl-math|gl-math]] egg for matrix math.
319
320For more examples, check out the [[https://github.com/AlexCharlton/gl-utils/tree/master/examples|examples directory]].
321
322<enscript highlight="scheme">    
323(import chicken scheme)
324(use (prefix glfw3 glfw:) (prefix opengl-glew gl:) gl-math gl-utils)
325
326(define *vertex*
327#<<END
328#version 330
329in vec2 position;
330in vec3 color;
331out vec3 c;
332uniform mat4 MVP;
333
334void main(){
335   gl_Position = MVP * vec4(position, 0.0, 1.0);
336   c = color;
337}
338END
339)
340
341(define *fragment*
342#<<END
343#version 330
344in vec3 c;
345out vec4 fragColor;
346void main(){
347  fragColor = vec4(c, 1.0);
348}
349END
350)
351
352(define rect (make-mesh
353              vertices: '(attributes: ((position #:float 2)
354                                       (color #:unsigned-byte 3
355                                              normalized: #t))
356                          initial-elements: ((position . (-1 -1
357                                                           1 -1
358                                                           1  1
359                                                           -1  1))
360                                             (color . (255 0   0
361                                                       0   255 0
362                                                       0   0   255
363                                                       255 0   255))))
364              indices: '(type: #:ushort
365                         initial-elements: (0 1 2
366                                            0 2 3))))
367
368(define program (make-parameter #f))
369
370(define projection-matrix
371  (perspective 640 480 0.1 100 70))
372
373(define view-matrix
374  (look-at (make-point 1 0 3)
375           (make-point 0 0 0)
376           (make-point 0 1 0)))
377
378(define model-matrix (mat4-identity))
379
380(define (render)
381  (gl:use-program (program))
382  (gl:uniform-matrix4fv (gl:get-uniform-location (program) "MVP")
383                        1 #f
384                        (m* projection-matrix
385                            (m* view-matrix model-matrix)))
386  (gl:bind-vertex-array (mesh-vao rect))
387  (gl:draw-elements-base-vertex (mode->gl (mesh-mode rect))
388                                (mesh-n-indices rect)
389                                (type->gl (mesh-index-type rect))
390                                #f 0)
391
392  (check-error)
393  (gl:bind-vertex-array 0))
394
395(glfw:with-window (640 480 "Example" resizable: #f
396                       context-version-major: 3
397                       context-version-minor: 3)
398  (gl:init)
399
400  (print (gl:supported? "GL_ARB_framebuffer_object"))
401
402  (set! *vertex* (make-shader gl:+vertex-shader+ *vertex*))
403  (set! *fragment* (make-shader gl:+fragment-shader+ *fragment*))
404  (program (make-program (list *vertex* *fragment*)))
405
406  (mesh-attribute-locations-set! rect `((position . ,(gl:get-attrib-location
407                                                      (program) "position"))
408                                        (color . ,(gl:get-attrib-location
409                                                   (program) "color"))))
410  (mesh-make-vao! rect)
411  (let loop ()
412    (glfw:swap-buffers (glfw:window))
413    (gl:clear (bitwise-ior gl:+color-buffer-bit+ gl:+depth-buffer-bit+))
414    (render)
415    (glfw:poll-events) ; Because of the context version, initializing GLEW results in a harmless invalid enum
416    (unless (glfw:window-should-close (glfw:window))
417      (loop))))
418</enscript>
419
420
421=== Version history
422
423==== Version 0.2.0
42410 September 2014
425
426* Add gl-utils-bytevector module
427* Add gl-utils-mesh module
428* Remove now-unneeded (and broken) {{make-vao}}, {{make-ply-vao}}
429
430
431==== Version 0.1.2
4322 September 2014
433
434* Update example for gl-math 0.5
435
436'''Version 0.1.1'''
437* Initial release
438
439
440=== Source repository
441Source available on [[https://github.com/AlexCharlton/gl-utils|GitHub]].
442
443Bug reports and patches welcome! Bugs can be reported via GitHub or to alex.n.charlton at gmail.
444
445
446=== Author
447Alex Charlton
448
449
450=== License
451BSD
452
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