gl_unix.go raw

   1  // SPDX-License-Identifier: Unlicense OR MIT
   2  
   3  // +build darwin linux freebsd openbsd
   4  
   5  package gl
   6  
   7  import (
   8  	"runtime"
   9  	"strings"
  10  	"unsafe"
  11  )
  12  
  13  /*
  14  #cgo CFLAGS: -Werror
  15  #cgo linux,!android pkg-config: glesv2
  16  #cgo linux freebsd LDFLAGS: -ldl
  17  #cgo freebsd openbsd android LDFLAGS: -lGLESv2
  18  #cgo freebsd CFLAGS: -I/usr/local/include
  19  #cgo freebsd LDFLAGS: -L/usr/local/lib
  20  #cgo openbsd CFLAGS: -I/usr/X11R6/include
  21  #cgo openbsd LDFLAGS: -L/usr/X11R6/lib
  22  #cgo darwin,!ios CFLAGS: -DGL_SILENCE_DEPRECATION
  23  #cgo darwin,!ios LDFLAGS: -framework OpenGL
  24  #cgo darwin,ios CFLAGS: -DGLES_SILENCE_DEPRECATION
  25  #cgo darwin,ios LDFLAGS: -framework OpenGLES
  26  
  27  #include <stdlib.h>
  28  #define __USE_GNU
  29  #include <dlfcn.h>
  30  
  31  #ifdef __APPLE__
  32  	#include "TargetConditionals.h"
  33  	#if TARGET_OS_IPHONE
  34  	#include <OpenGLES/ES3/gl.h>
  35  	#else
  36  	#include <OpenGL/gl3.h>
  37  	#endif
  38  #else
  39  #include <GLES2/gl2.h>
  40  #include <GLES3/gl3.h>
  41  #endif
  42  
  43  static void (*_glBindBufferBase)(GLenum target, GLuint index, GLuint buffer);
  44  static GLuint (*_glGetUniformBlockIndex)(GLuint program, const GLchar *uniformBlockName);
  45  static void (*_glUniformBlockBinding)(GLuint program, GLuint uniformBlockIndex, GLuint uniformBlockBinding);
  46  static void (*_glInvalidateFramebuffer)(GLenum target, GLsizei numAttachments, const GLenum *attachments);
  47  
  48  static void (*_glBeginQuery)(GLenum target, GLuint id);
  49  static void (*_glDeleteQueries)(GLsizei n, const GLuint *ids);
  50  static void (*_glEndQuery)(GLenum target);
  51  static void (*_glGenQueries)(GLsizei n, GLuint *ids);
  52  static void (*_glGetProgramBinary)(GLuint program, GLsizei bufsize, GLsizei *length, GLenum *binaryFormat, void *binary);
  53  static void (*_glGetQueryObjectuiv)(GLuint id, GLenum pname, GLuint *params);
  54  static const GLubyte* (*_glGetStringi)(GLenum name, GLuint index);
  55  static void (*_glMemoryBarrier)(GLbitfield barriers);
  56  static void (*_glDispatchCompute)(GLuint x, GLuint y, GLuint z);
  57  static void* (*_glMapBufferRange)(GLenum target, GLintptr offset, GLsizeiptr length, GLbitfield access);
  58  static GLboolean (*_glUnmapBuffer)(GLenum target);
  59  static void (*_glBindImageTexture)(GLuint unit, GLuint texture, GLint level, GLboolean layered, GLint layer, GLenum access, GLenum format);
  60  static void (*_glTexStorage2D)(GLenum target, GLsizei levels, GLenum internalformat, GLsizei width, GLsizei height);
  61  static void (*_glBlitFramebuffer)(GLint srcX0, GLint srcY0, GLint srcX1, GLint srcY1, GLint dstX0, GLint dstY0, GLint dstX1, GLint dstY1, GLbitfield mask, GLenum filter);
  62  
  63  // The pointer-free version of glVertexAttribPointer, to avoid the Cgo pointer checks.
  64  __attribute__ ((visibility ("hidden"))) void gio_glVertexAttribPointer(GLuint index, GLint size, GLenum type, GLboolean normalized, GLsizei stride, uintptr_t offset) {
  65  	glVertexAttribPointer(index, size, type, normalized, stride, (const GLvoid *)offset);
  66  }
  67  
  68  // The pointer-free version of glDrawElements, to avoid the Cgo pointer checks.
  69  __attribute__ ((visibility ("hidden"))) void gio_glDrawElements(GLenum mode, GLsizei count, GLenum type, const uintptr_t offset) {
  70  	glDrawElements(mode, count, type, (const GLvoid *)offset);
  71  }
  72  
  73  __attribute__ ((visibility ("hidden"))) void gio_glBindBufferBase(GLenum target, GLuint index, GLuint buffer) {
  74  	_glBindBufferBase(target, index, buffer);
  75  }
  76  
  77  __attribute__ ((visibility ("hidden"))) void gio_glUniformBlockBinding(GLuint program, GLuint uniformBlockIndex, GLuint uniformBlockBinding) {
  78  	_glUniformBlockBinding(program, uniformBlockIndex, uniformBlockBinding);
  79  }
  80  
  81  __attribute__ ((visibility ("hidden"))) GLuint gio_glGetUniformBlockIndex(GLuint program, const GLchar *uniformBlockName) {
  82  	return _glGetUniformBlockIndex(program, uniformBlockName);
  83  }
  84  
  85  __attribute__ ((visibility ("hidden"))) void gio_glInvalidateFramebuffer(GLenum target, GLenum attachment) {
  86  	// Framebuffer invalidation is just a hint and can safely be ignored.
  87  	if (_glInvalidateFramebuffer != NULL) {
  88  		_glInvalidateFramebuffer(target, 1, &attachment);
  89  	}
  90  }
  91  
  92  __attribute__ ((visibility ("hidden"))) void gio_glBeginQuery(GLenum target, GLenum attachment) {
  93  	_glBeginQuery(target, attachment);
  94  }
  95  
  96  __attribute__ ((visibility ("hidden"))) void gio_glDeleteQueries(GLsizei n, const GLuint *ids) {
  97  	_glDeleteQueries(n, ids);
  98  }
  99  
 100  __attribute__ ((visibility ("hidden"))) void gio_glEndQuery(GLenum target) {
 101  	_glEndQuery(target);
 102  }
 103  
 104  __attribute__ ((visibility ("hidden"))) const GLubyte* gio_glGetStringi(GLenum name, GLuint index) {
 105  	if (_glGetStringi == NULL) {
 106  		return NULL;
 107  	}
 108  	return _glGetStringi(name, index);
 109  }
 110  
 111  __attribute__ ((visibility ("hidden"))) void gio_glGenQueries(GLsizei n, GLuint *ids) {
 112  	_glGenQueries(n, ids);
 113  }
 114  
 115  __attribute__ ((visibility ("hidden"))) void gio_glGetProgramBinary(GLuint program, GLsizei bufsize, GLsizei *length, GLenum *binaryFormat, void *binary) {
 116  	_glGetProgramBinary(program, bufsize, length, binaryFormat, binary);
 117  }
 118  
 119  __attribute__ ((visibility ("hidden"))) void gio_glGetQueryObjectuiv(GLuint id, GLenum pname, GLuint *params) {
 120  	_glGetQueryObjectuiv(id, pname, params);
 121  }
 122  
 123  __attribute__ ((visibility ("hidden"))) void gio_glMemoryBarrier(GLbitfield barriers) {
 124  	_glMemoryBarrier(barriers);
 125  }
 126  
 127  __attribute__ ((visibility ("hidden"))) void gio_glDispatchCompute(GLuint x, GLuint y, GLuint z) {
 128  	_glDispatchCompute(x, y, z);
 129  }
 130  
 131  __attribute__ ((visibility ("hidden"))) void *gio_glMapBufferRange(GLenum target, GLintptr offset, GLsizeiptr length, GLbitfield access) {
 132  	return _glMapBufferRange(target, offset, length, access);
 133  }
 134  
 135  __attribute__ ((visibility ("hidden"))) GLboolean gio_glUnmapBuffer(GLenum target) {
 136  	return _glUnmapBuffer(target);
 137  }
 138  
 139  __attribute__ ((visibility ("hidden"))) void gio_glBindImageTexture(GLuint unit, GLuint texture, GLint level, GLboolean layered, GLint layer, GLenum access, GLenum format) {
 140  	_glBindImageTexture(unit, texture, level, layered, layer, access, format);
 141  }
 142  
 143  __attribute__ ((visibility ("hidden"))) void gio_glTexStorage2D(GLenum target, GLsizei levels, GLenum internalFormat, GLsizei width, GLsizei height) {
 144  	_glTexStorage2D(target, levels, internalFormat, width, height);
 145  }
 146  
 147  __attribute__ ((visibility ("hidden"))) void gio_glBlitFramebuffer(GLint srcX0, GLint srcY0, GLint srcX1, GLint srcY1, GLint dstX0, GLint dstY0, GLint dstX1, GLint dstY1, GLbitfield mask, GLenum filter) {
 148  	_glBlitFramebuffer(srcX0, srcY0, srcX1, srcY1, dstX0, dstY0, dstX1, dstY1, mask, filter);
 149  }
 150  
 151  __attribute__((constructor)) static void gio_loadGLFunctions() {
 152  	// Load libGLESv3 if available.
 153  	dlopen("libGLESv3.so", RTLD_NOW | RTLD_GLOBAL);
 154  
 155  	_glBindBufferBase = dlsym(RTLD_DEFAULT, "glBindBufferBase");
 156  	_glGetUniformBlockIndex = dlsym(RTLD_DEFAULT, "glGetUniformBlockIndex");
 157  	_glUniformBlockBinding = dlsym(RTLD_DEFAULT, "glUniformBlockBinding");
 158  	_glInvalidateFramebuffer = dlsym(RTLD_DEFAULT, "glInvalidateFramebuffer");
 159  	_glGetStringi = dlsym(RTLD_DEFAULT, "glGetStringi");
 160  	// Fall back to EXT_invalidate_framebuffer if available.
 161  	if (_glInvalidateFramebuffer == NULL) {
 162  		_glInvalidateFramebuffer = dlsym(RTLD_DEFAULT, "glDiscardFramebufferEXT");
 163  	}
 164  
 165  	_glBeginQuery = dlsym(RTLD_DEFAULT, "glBeginQuery");
 166  	if (_glBeginQuery == NULL)
 167  		_glBeginQuery = dlsym(RTLD_DEFAULT, "glBeginQueryEXT");
 168  	_glDeleteQueries = dlsym(RTLD_DEFAULT, "glDeleteQueries");
 169  	if (_glDeleteQueries == NULL)
 170  		_glDeleteQueries = dlsym(RTLD_DEFAULT, "glDeleteQueriesEXT");
 171  	_glEndQuery = dlsym(RTLD_DEFAULT, "glEndQuery");
 172  	if (_glEndQuery == NULL)
 173  		_glEndQuery = dlsym(RTLD_DEFAULT, "glEndQueryEXT");
 174  	_glGenQueries = dlsym(RTLD_DEFAULT, "glGenQueries");
 175  	if (_glGenQueries == NULL)
 176  		_glGenQueries = dlsym(RTLD_DEFAULT, "glGenQueriesEXT");
 177  	_glGetQueryObjectuiv = dlsym(RTLD_DEFAULT, "glGetQueryObjectuiv");
 178  	if (_glGetQueryObjectuiv == NULL)
 179  		_glGetQueryObjectuiv = dlsym(RTLD_DEFAULT, "glGetQueryObjectuivEXT");
 180  
 181  	_glMemoryBarrier = dlsym(RTLD_DEFAULT, "glMemoryBarrier");
 182  	_glDispatchCompute = dlsym(RTLD_DEFAULT, "glDispatchCompute");
 183  	_glMapBufferRange = dlsym(RTLD_DEFAULT, "glMapBufferRange");
 184  	_glUnmapBuffer = dlsym(RTLD_DEFAULT, "glUnmapBuffer");
 185  	_glBindImageTexture = dlsym(RTLD_DEFAULT, "glBindImageTexture");
 186  	_glTexStorage2D = dlsym(RTLD_DEFAULT, "glTexStorage2D");
 187  	_glBlitFramebuffer = dlsym(RTLD_DEFAULT, "glBlitFramebuffer");
 188  	_glGetProgramBinary = dlsym(RTLD_DEFAULT, "glGetProgramBinary");
 189  }
 190  */
 191  import "C"
 192  
 193  type Context interface{}
 194  
 195  type Functions struct {
 196  	// Query caches.
 197  	uints [100]C.GLuint
 198  	ints  [100]C.GLint
 199  }
 200  
 201  func NewFunctions(ctx Context) (*Functions, error) {
 202  	if ctx != nil {
 203  		panic("non-nil context")
 204  	}
 205  	return new(Functions), nil
 206  }
 207  
 208  func (f *Functions) ActiveTexture(texture Enum) {
 209  	C.glActiveTexture(C.GLenum(texture))
 210  }
 211  
 212  func (f *Functions) AttachShader(p Program, s Shader) {
 213  	C.glAttachShader(C.GLuint(p.V), C.GLuint(s.V))
 214  }
 215  
 216  func (f *Functions) BeginQuery(target Enum, query Query) {
 217  	C.gio_glBeginQuery(C.GLenum(target), C.GLenum(query.V))
 218  }
 219  
 220  func (f *Functions) BindAttribLocation(p Program, a Attrib, name string) {
 221  	cname := C.CString(name)
 222  	defer C.free(unsafe.Pointer(cname))
 223  	C.glBindAttribLocation(C.GLuint(p.V), C.GLuint(a), cname)
 224  }
 225  
 226  func (f *Functions) BindBufferBase(target Enum, index int, b Buffer) {
 227  	C.gio_glBindBufferBase(C.GLenum(target), C.GLuint(index), C.GLuint(b.V))
 228  }
 229  
 230  func (f *Functions) BindBuffer(target Enum, b Buffer) {
 231  	C.glBindBuffer(C.GLenum(target), C.GLuint(b.V))
 232  }
 233  
 234  func (f *Functions) BindFramebuffer(target Enum, fb Framebuffer) {
 235  	C.glBindFramebuffer(C.GLenum(target), C.GLuint(fb.V))
 236  }
 237  
 238  func (f *Functions) BindRenderbuffer(target Enum, fb Renderbuffer) {
 239  	C.glBindRenderbuffer(C.GLenum(target), C.GLuint(fb.V))
 240  }
 241  
 242  func (f *Functions) BindImageTexture(unit int, t Texture, level int, layered bool, layer int, access, format Enum) {
 243  	l := C.GLboolean(C.GL_FALSE)
 244  	if layered {
 245  		l = C.GL_TRUE
 246  	}
 247  	C.gio_glBindImageTexture(C.GLuint(unit), C.GLuint(t.V), C.GLint(level), l, C.GLint(layer), C.GLenum(access), C.GLenum(format))
 248  }
 249  
 250  func (f *Functions) BindTexture(target Enum, t Texture) {
 251  	C.glBindTexture(C.GLenum(target), C.GLuint(t.V))
 252  }
 253  
 254  func (f *Functions) BlendEquation(mode Enum) {
 255  	C.glBlendEquation(C.GLenum(mode))
 256  }
 257  
 258  func (f *Functions) BlendFunc(sfactor, dfactor Enum) {
 259  	C.glBlendFunc(C.GLenum(sfactor), C.GLenum(dfactor))
 260  }
 261  
 262  func (f *Functions) BlitFramebuffer(sx0, sy0, sx1, sy1, dx0, dy0, dx1, dy1 int, mask Enum, filter Enum) {
 263  	C.gio_glBlitFramebuffer(
 264  		C.GLint(sx0), C.GLint(sy0), C.GLint(sx1), C.GLint(sy1),
 265  		C.GLint(dx0), C.GLint(dy0), C.GLint(dx1), C.GLint(dy1),
 266  		C.GLenum(mask), C.GLenum(filter),
 267  	)
 268  }
 269  
 270  func (f *Functions) BufferData(target Enum, size int, usage Enum) {
 271  	C.glBufferData(C.GLenum(target), C.GLsizeiptr(size), nil, C.GLenum(usage))
 272  }
 273  
 274  func (f *Functions) BufferSubData(target Enum, offset int, src []byte) {
 275  	var p unsafe.Pointer
 276  	if len(src) > 0 {
 277  		p = unsafe.Pointer(&src[0])
 278  	}
 279  	C.glBufferSubData(C.GLenum(target), C.GLintptr(offset), C.GLsizeiptr(len(src)), p)
 280  }
 281  
 282  func (f *Functions) CheckFramebufferStatus(target Enum) Enum {
 283  	return Enum(C.glCheckFramebufferStatus(C.GLenum(target)))
 284  }
 285  
 286  func (f *Functions) Clear(mask Enum) {
 287  	C.glClear(C.GLbitfield(mask))
 288  }
 289  
 290  func (f *Functions) ClearColor(red float32, green float32, blue float32, alpha float32) {
 291  	C.glClearColor(C.GLfloat(red), C.GLfloat(green), C.GLfloat(blue), C.GLfloat(alpha))
 292  }
 293  
 294  func (f *Functions) ClearDepthf(d float32) {
 295  	C.glClearDepthf(C.GLfloat(d))
 296  }
 297  
 298  func (f *Functions) CompileShader(s Shader) {
 299  	C.glCompileShader(C.GLuint(s.V))
 300  }
 301  
 302  func (f *Functions) CreateBuffer() Buffer {
 303  	C.glGenBuffers(1, &f.uints[0])
 304  	return Buffer{uint(f.uints[0])}
 305  }
 306  
 307  func (f *Functions) CreateFramebuffer() Framebuffer {
 308  	C.glGenFramebuffers(1, &f.uints[0])
 309  	return Framebuffer{uint(f.uints[0])}
 310  }
 311  
 312  func (f *Functions) CreateProgram() Program {
 313  	return Program{uint(C.glCreateProgram())}
 314  }
 315  
 316  func (f *Functions) CreateQuery() Query {
 317  	C.gio_glGenQueries(1, &f.uints[0])
 318  	return Query{uint(f.uints[0])}
 319  }
 320  
 321  func (f *Functions) CreateRenderbuffer() Renderbuffer {
 322  	C.glGenRenderbuffers(1, &f.uints[0])
 323  	return Renderbuffer{uint(f.uints[0])}
 324  }
 325  
 326  func (f *Functions) CreateShader(ty Enum) Shader {
 327  	return Shader{uint(C.glCreateShader(C.GLenum(ty)))}
 328  }
 329  
 330  func (f *Functions) CreateTexture() Texture {
 331  	C.glGenTextures(1, &f.uints[0])
 332  	return Texture{uint(f.uints[0])}
 333  }
 334  
 335  func (f *Functions) DeleteBuffer(v Buffer) {
 336  	f.uints[0] = C.GLuint(v.V)
 337  	C.glDeleteBuffers(1, &f.uints[0])
 338  }
 339  
 340  func (f *Functions) DeleteFramebuffer(v Framebuffer) {
 341  	f.uints[0] = C.GLuint(v.V)
 342  	C.glDeleteFramebuffers(1, &f.uints[0])
 343  }
 344  
 345  func (f *Functions) DeleteProgram(p Program) {
 346  	C.glDeleteProgram(C.GLuint(p.V))
 347  }
 348  
 349  func (f *Functions) DeleteQuery(query Query) {
 350  	f.uints[0] = C.GLuint(query.V)
 351  	C.gio_glDeleteQueries(1, &f.uints[0])
 352  }
 353  
 354  func (f *Functions) DeleteRenderbuffer(v Renderbuffer) {
 355  	f.uints[0] = C.GLuint(v.V)
 356  	C.glDeleteRenderbuffers(1, &f.uints[0])
 357  }
 358  
 359  func (f *Functions) DeleteShader(s Shader) {
 360  	C.glDeleteShader(C.GLuint(s.V))
 361  }
 362  
 363  func (f *Functions) DeleteTexture(v Texture) {
 364  	f.uints[0] = C.GLuint(v.V)
 365  	C.glDeleteTextures(1, &f.uints[0])
 366  }
 367  
 368  func (f *Functions) DepthFunc(v Enum) {
 369  	C.glDepthFunc(C.GLenum(v))
 370  }
 371  
 372  func (f *Functions) DepthMask(mask bool) {
 373  	m := C.GLboolean(C.GL_FALSE)
 374  	if mask {
 375  		m = C.GLboolean(C.GL_TRUE)
 376  	}
 377  	C.glDepthMask(m)
 378  }
 379  
 380  func (f *Functions) DisableVertexAttribArray(a Attrib) {
 381  	C.glDisableVertexAttribArray(C.GLuint(a))
 382  }
 383  
 384  func (f *Functions) Disable(cap Enum) {
 385  	C.glDisable(C.GLenum(cap))
 386  }
 387  
 388  func (f *Functions) DrawArrays(mode Enum, first int, count int) {
 389  	C.glDrawArrays(C.GLenum(mode), C.GLint(first), C.GLsizei(count))
 390  }
 391  
 392  func (f *Functions) DrawElements(mode Enum, count int, ty Enum, offset int) {
 393  	C.gio_glDrawElements(C.GLenum(mode), C.GLsizei(count), C.GLenum(ty), C.uintptr_t(offset))
 394  }
 395  
 396  func (f *Functions) DispatchCompute(x, y, z int) {
 397  	C.gio_glDispatchCompute(C.GLuint(x), C.GLuint(y), C.GLuint(z))
 398  }
 399  
 400  func (f *Functions) Enable(cap Enum) {
 401  	C.glEnable(C.GLenum(cap))
 402  }
 403  
 404  func (f *Functions) EndQuery(target Enum) {
 405  	C.gio_glEndQuery(C.GLenum(target))
 406  }
 407  
 408  func (f *Functions) EnableVertexAttribArray(a Attrib) {
 409  	C.glEnableVertexAttribArray(C.GLuint(a))
 410  }
 411  
 412  func (f *Functions) Finish() {
 413  	C.glFinish()
 414  }
 415  
 416  func (f *Functions) FramebufferRenderbuffer(target, attachment, renderbuffertarget Enum, renderbuffer Renderbuffer) {
 417  	C.glFramebufferRenderbuffer(C.GLenum(target), C.GLenum(attachment), C.GLenum(renderbuffertarget), C.GLuint(renderbuffer.V))
 418  }
 419  
 420  func (f *Functions) FramebufferTexture2D(target, attachment, texTarget Enum, t Texture, level int) {
 421  	C.glFramebufferTexture2D(C.GLenum(target), C.GLenum(attachment), C.GLenum(texTarget), C.GLuint(t.V), C.GLint(level))
 422  }
 423  
 424  func (c *Functions) GetBinding(pname Enum) Object {
 425  	return Object{uint(c.GetInteger(pname))}
 426  }
 427  
 428  func (f *Functions) GetError() Enum {
 429  	return Enum(C.glGetError())
 430  }
 431  
 432  func (f *Functions) GetRenderbufferParameteri(target, pname Enum) int {
 433  	C.glGetRenderbufferParameteriv(C.GLenum(target), C.GLenum(pname), &f.ints[0])
 434  	return int(f.ints[0])
 435  }
 436  
 437  func (f *Functions) GetFramebufferAttachmentParameteri(target, attachment, pname Enum) int {
 438  	C.glGetFramebufferAttachmentParameteriv(C.GLenum(target), C.GLenum(attachment), C.GLenum(pname), &f.ints[0])
 439  	return int(f.ints[0])
 440  }
 441  
 442  func (f *Functions) GetInteger(pname Enum) int {
 443  	C.glGetIntegerv(C.GLenum(pname), &f.ints[0])
 444  	return int(f.ints[0])
 445  }
 446  
 447  func (f *Functions) GetProgrami(p Program, pname Enum) int {
 448  	C.glGetProgramiv(C.GLuint(p.V), C.GLenum(pname), &f.ints[0])
 449  	return int(f.ints[0])
 450  }
 451  
 452  func (f *Functions) GetProgramBinary(p Program) []byte {
 453  	sz := f.GetProgrami(p, PROGRAM_BINARY_LENGTH)
 454  	if sz == 0 {
 455  		return nil
 456  	}
 457  	buf := make([]byte, sz)
 458  	var format C.GLenum
 459  	C.gio_glGetProgramBinary(C.GLuint(p.V), C.GLsizei(sz), nil, &format, unsafe.Pointer(&buf[0]))
 460  	return buf
 461  }
 462  
 463  func (f *Functions) GetProgramInfoLog(p Program) string {
 464  	n := f.GetProgrami(p, INFO_LOG_LENGTH)
 465  	buf := make([]byte, n)
 466  	C.glGetProgramInfoLog(C.GLuint(p.V), C.GLsizei(len(buf)), nil, (*C.GLchar)(unsafe.Pointer(&buf[0])))
 467  	return string(buf)
 468  }
 469  
 470  func (f *Functions) GetQueryObjectuiv(query Query, pname Enum) uint {
 471  	C.gio_glGetQueryObjectuiv(C.GLuint(query.V), C.GLenum(pname), &f.uints[0])
 472  	return uint(f.uints[0])
 473  }
 474  
 475  func (f *Functions) GetShaderi(s Shader, pname Enum) int {
 476  	C.glGetShaderiv(C.GLuint(s.V), C.GLenum(pname), &f.ints[0])
 477  	return int(f.ints[0])
 478  }
 479  
 480  func (f *Functions) GetShaderInfoLog(s Shader) string {
 481  	n := f.GetShaderi(s, INFO_LOG_LENGTH)
 482  	buf := make([]byte, n)
 483  	C.glGetShaderInfoLog(C.GLuint(s.V), C.GLsizei(len(buf)), nil, (*C.GLchar)(unsafe.Pointer(&buf[0])))
 484  	return string(buf)
 485  }
 486  
 487  func (f *Functions) GetStringi(pname Enum, index int) string {
 488  	str := C.gio_glGetStringi(C.GLenum(pname), C.GLuint(index))
 489  	if str == nil {
 490  		return ""
 491  	}
 492  	return C.GoString((*C.char)(unsafe.Pointer(str)))
 493  }
 494  
 495  func (f *Functions) GetString(pname Enum) string {
 496  	switch {
 497  	case runtime.GOOS == "darwin" && pname == EXTENSIONS:
 498  		// macOS OpenGL 3 core profile doesn't support glGetString(GL_EXTENSIONS).
 499  		// Use glGetStringi(GL_EXTENSIONS, <index>).
 500  		var exts []string
 501  		nexts := f.GetInteger(NUM_EXTENSIONS)
 502  		for i := 0; i < nexts; i++ {
 503  			ext := f.GetStringi(EXTENSIONS, i)
 504  			exts = append(exts, ext)
 505  		}
 506  		return strings.Join(exts, " ")
 507  	default:
 508  		str := C.glGetString(C.GLenum(pname))
 509  		return C.GoString((*C.char)(unsafe.Pointer(str)))
 510  	}
 511  }
 512  
 513  func (f *Functions) GetUniformBlockIndex(p Program, name string) uint {
 514  	cname := C.CString(name)
 515  	defer C.free(unsafe.Pointer(cname))
 516  	return uint(C.gio_glGetUniformBlockIndex(C.GLuint(p.V), cname))
 517  }
 518  
 519  func (f *Functions) GetUniformLocation(p Program, name string) Uniform {
 520  	cname := C.CString(name)
 521  	defer C.free(unsafe.Pointer(cname))
 522  	return Uniform{int(C.glGetUniformLocation(C.GLuint(p.V), cname))}
 523  }
 524  
 525  func (f *Functions) InvalidateFramebuffer(target, attachment Enum) {
 526  	C.gio_glInvalidateFramebuffer(C.GLenum(target), C.GLenum(attachment))
 527  }
 528  
 529  func (f *Functions) LinkProgram(p Program) {
 530  	C.glLinkProgram(C.GLuint(p.V))
 531  }
 532  
 533  func (f *Functions) PixelStorei(pname Enum, param int32) {
 534  	C.glPixelStorei(C.GLenum(pname), C.GLint(param))
 535  }
 536  
 537  func (f *Functions) MemoryBarrier(barriers Enum) {
 538  	C.gio_glMemoryBarrier(C.GLbitfield(barriers))
 539  }
 540  
 541  func (f *Functions) MapBufferRange(target Enum, offset, length int, access Enum) []byte {
 542  	p := C.gio_glMapBufferRange(C.GLenum(target), C.GLintptr(offset), C.GLsizeiptr(length), C.GLbitfield(access))
 543  	if p == nil {
 544  		return nil
 545  	}
 546  	return (*[1 << 30]byte)(p)[:length:length]
 547  }
 548  
 549  func (f *Functions) Scissor(x, y, width, height int32) {
 550  	C.glScissor(C.GLint(x), C.GLint(y), C.GLsizei(width), C.GLsizei(height))
 551  }
 552  
 553  func (f *Functions) ReadPixels(x, y, width, height int, format, ty Enum, data []byte) {
 554  	var p unsafe.Pointer
 555  	if len(data) > 0 {
 556  		p = unsafe.Pointer(&data[0])
 557  	}
 558  	C.glReadPixels(C.GLint(x), C.GLint(y), C.GLsizei(width), C.GLsizei(height), C.GLenum(format), C.GLenum(ty), p)
 559  }
 560  
 561  func (f *Functions) RenderbufferStorage(target, internalformat Enum, width, height int) {
 562  	C.glRenderbufferStorage(C.GLenum(target), C.GLenum(internalformat), C.GLsizei(width), C.GLsizei(height))
 563  }
 564  
 565  func (f *Functions) ShaderSource(s Shader, src string) {
 566  	csrc := C.CString(src)
 567  	defer C.free(unsafe.Pointer(csrc))
 568  	strlen := C.GLint(len(src))
 569  	C.glShaderSource(C.GLuint(s.V), 1, &csrc, &strlen)
 570  }
 571  
 572  func (f *Functions) TexImage2D(target Enum, level int, internalFormat Enum, width int, height int, format Enum, ty Enum) {
 573  	C.glTexImage2D(C.GLenum(target), C.GLint(level), C.GLint(internalFormat), C.GLsizei(width), C.GLsizei(height), 0, C.GLenum(format), C.GLenum(ty), nil)
 574  }
 575  
 576  func (f *Functions) TexStorage2D(target Enum, levels int, internalFormat Enum, width, height int) {
 577  	C.gio_glTexStorage2D(C.GLenum(target), C.GLsizei(levels), C.GLenum(internalFormat), C.GLsizei(width), C.GLsizei(height))
 578  }
 579  
 580  func (f *Functions) TexSubImage2D(target Enum, level int, x int, y int, width int, height int, format Enum, ty Enum, data []byte) {
 581  	var p unsafe.Pointer
 582  	if len(data) > 0 {
 583  		p = unsafe.Pointer(&data[0])
 584  	}
 585  	C.glTexSubImage2D(C.GLenum(target), C.GLint(level), C.GLint(x), C.GLint(y), C.GLsizei(width), C.GLsizei(height), C.GLenum(format), C.GLenum(ty), p)
 586  }
 587  
 588  func (f *Functions) TexParameteri(target, pname Enum, param int) {
 589  	C.glTexParameteri(C.GLenum(target), C.GLenum(pname), C.GLint(param))
 590  }
 591  
 592  func (f *Functions) UniformBlockBinding(p Program, uniformBlockIndex uint, uniformBlockBinding uint) {
 593  	C.gio_glUniformBlockBinding(C.GLuint(p.V), C.GLuint(uniformBlockIndex), C.GLuint(uniformBlockBinding))
 594  }
 595  
 596  func (f *Functions) Uniform1f(dst Uniform, v float32) {
 597  	C.glUniform1f(C.GLint(dst.V), C.GLfloat(v))
 598  }
 599  
 600  func (f *Functions) Uniform1i(dst Uniform, v int) {
 601  	C.glUniform1i(C.GLint(dst.V), C.GLint(v))
 602  }
 603  
 604  func (f *Functions) Uniform2f(dst Uniform, v0 float32, v1 float32) {
 605  	C.glUniform2f(C.GLint(dst.V), C.GLfloat(v0), C.GLfloat(v1))
 606  }
 607  
 608  func (f *Functions) Uniform3f(dst Uniform, v0 float32, v1 float32, v2 float32) {
 609  	C.glUniform3f(C.GLint(dst.V), C.GLfloat(v0), C.GLfloat(v1), C.GLfloat(v2))
 610  }
 611  
 612  func (f *Functions) Uniform4f(dst Uniform, v0 float32, v1 float32, v2 float32, v3 float32) {
 613  	C.glUniform4f(C.GLint(dst.V), C.GLfloat(v0), C.GLfloat(v1), C.GLfloat(v2), C.GLfloat(v3))
 614  }
 615  
 616  func (f *Functions) UseProgram(p Program) {
 617  	C.glUseProgram(C.GLuint(p.V))
 618  }
 619  
 620  func (f *Functions) UnmapBuffer(target Enum) bool {
 621  	r := C.gio_glUnmapBuffer(C.GLenum(target))
 622  	return r == C.GL_TRUE
 623  }
 624  
 625  func (f *Functions) VertexAttribPointer(dst Attrib, size int, ty Enum, normalized bool, stride int, offset int) {
 626  	var n C.GLboolean = C.GL_FALSE
 627  	if normalized {
 628  		n = C.GL_TRUE
 629  	}
 630  	C.gio_glVertexAttribPointer(C.GLuint(dst), C.GLint(size), C.GLenum(ty), n, C.GLsizei(stride), C.uintptr_t(offset))
 631  }
 632  
 633  func (f *Functions) Viewport(x int, y int, width int, height int) {
 634  	C.glViewport(C.GLint(x), C.GLint(y), C.GLsizei(width), C.GLsizei(height))
 635  }
 636