shared/OpenglCodecCommon/glUtils.cpp

   1 /*
   2 * Copyright (C) 2011 The Android Open Source Project
   3 *
   4 * Licensed under the Apache License, Version 2.0 (the "License");
   5 * you may not use this file except in compliance with the License.
   6 * You may obtain a copy of the License at
   7 *
   8 * http://www.apache.org/licenses/LICENSE-2.0
   9 *
  10 * Unless required by applicable law or agreed to in writing, software
  11 * distributed under the License is distributed on an "AS IS" BASIS,
  12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13 * See the License for the specific language governing permissions and
  14 * limitations under the License.
  15 */
  16 #include "glUtils.h"
  17 #include <string.h>
  18 #include "ErrorLog.h"
  19 #include <IOStream.h>
  20
  21 #include <GLES3/gl31.h>
  22
  23 size_t glSizeof(GLenum type)
  24 {
  25     size_t retval = 0;
  26     switch(type) {
  27     case GL_BYTE:
  28     case GL_UNSIGNED_BYTE:
  29         retval = 1;
  30         break;
  31     case GL_SHORT:
  32     case GL_UNSIGNED_SHORT:
  33     case GL_HALF_FLOAT:
  34     case GL_HALF_FLOAT_OES:
  35         retval = 2;
  36         break;
  37     case GL_IMAGE_2D:
  38     case GL_IMAGE_3D:
  39     case GL_UNSIGNED_INT:
  40     case GL_INT:
  41     case GL_FLOAT:
  42     case GL_FIXED:
  43     case GL_BOOL:
  44         retval =  4;
  45         break;
  46 #ifdef GL_DOUBLE
  47     case GL_DOUBLE:
  48         retval = 8;
  49         break;
  50 #endif
  51     case GL_FLOAT_VEC2:
  52     case GL_INT_VEC2:
  53     case GL_UNSIGNED_INT_VEC2:
  54     case GL_BOOL_VEC2:
  55         retval = 8;
  56         break;
  57     case GL_INT_VEC3:
  58     case GL_UNSIGNED_INT_VEC3:
  59     case GL_BOOL_VEC3:
  60     case GL_FLOAT_VEC3:
  61         retval = 12;
  62         break;
  63     case GL_FLOAT_VEC4:
  64     case GL_BOOL_VEC4:
  65     case GL_INT_VEC4:
  66     case GL_UNSIGNED_INT_VEC4:
  67     case GL_FLOAT_MAT2:
  68         retval = 16;
  69         break;
  70     case GL_FLOAT_MAT3:
  71         retval = 36;
  72         break;
  73     case GL_FLOAT_MAT4:
  74         retval = 64;
  75         break;
  76     case GL_FLOAT_MAT2x3:
  77     case GL_FLOAT_MAT3x2:
  78         retval = 4 * 6;
  79         break;
  80     case GL_FLOAT_MAT2x4:
  81     case GL_FLOAT_MAT4x2:
  82         retval = 4 * 8;
  83         break;
  84     case GL_FLOAT_MAT3x4:
  85     case GL_FLOAT_MAT4x3:
  86         retval = 4 * 12;
  87         break;
  88     case GL_SAMPLER_2D:
  89     case GL_SAMPLER_3D:
  90     case GL_SAMPLER_CUBE:
  91         retval = 4;
  92         break;
  93     case GL_UNSIGNED_SHORT_4_4_4_4:
  94         case GL_UNSIGNED_SHORT_5_5_5_1:
  95         case GL_UNSIGNED_SHORT_5_6_5:
  96         case GL_UNSIGNED_SHORT_4_4_4_4_REV_EXT:
  97         case GL_UNSIGNED_SHORT_1_5_5_5_REV_EXT:
  98         retval = 2;
  99         break;
 100         case GL_INT_2_10_10_10_REV:
 101         case GL_UNSIGNED_INT_10F_11F_11F_REV:
 102         case GL_UNSIGNED_INT_5_9_9_9_REV:
 103         case GL_UNSIGNED_INT_2_10_10_10_REV:
 104         case GL_UNSIGNED_INT_24_8_OES:;
 105         retval = 4;
 106         break;
 107         case GL_FLOAT_32_UNSIGNED_INT_24_8_REV:
 108                 retval = 4 + 4;
 109         break;
 110     default:
 111         ALOGE("**** ERROR unknown type 0x%x (%s,%d)\n", type, __FUNCTION__,__LINE__);
 112         retval = 4;
 113     }
 114     return retval;
 115
 116 }
 117
 118 size_t glUtilsParamSize(GLenum param)
 119 {
 120     size_t s = 0;
 121
 122     switch(param)
 123     {
 124     case GL_DEPTH_TEST:
 125     case GL_DEPTH_FUNC:
 126     case GL_DEPTH_BITS:
 127     case GL_MAX_CLIP_PLANES:
 128     case GL_GREEN_BITS:
 129     case GL_MAX_MODELVIEW_STACK_DEPTH:
 130     case GL_MAX_PROJECTION_STACK_DEPTH:
 131     case GL_MAX_TEXTURE_STACK_DEPTH:
 132     case GL_IMPLEMENTATION_COLOR_READ_FORMAT_OES:
 133     case GL_IMPLEMENTATION_COLOR_READ_TYPE_OES:
 134     case GL_NUM_COMPRESSED_TEXTURE_FORMATS:
 135     case GL_MAX_TEXTURE_SIZE:
 136     case GL_TEXTURE_GEN_MODE_OES:
 137     case GL_TEXTURE_ENV_MODE:
 138     case GL_FOG_MODE:
 139     case GL_FOG_DENSITY:
 140     case GL_FOG_START:
 141     case GL_FOG_END:
 142     case GL_SPOT_EXPONENT:
 143     case GL_CONSTANT_ATTENUATION:
 144     case GL_LINEAR_ATTENUATION:
 145     case GL_QUADRATIC_ATTENUATION:
 146     case GL_SHININESS:
 147     case GL_LIGHT_MODEL_TWO_SIDE:
 148     case GL_POINT_SIZE:
 149     case GL_POINT_SIZE_MIN:
 150     case GL_POINT_SIZE_MAX:
 151     case GL_POINT_FADE_THRESHOLD_SIZE:
 152     case GL_CULL_FACE:
 153     case GL_CULL_FACE_MODE:
 154     case GL_FRONT_FACE:
 155     case GL_SHADE_MODEL:
 156     case GL_DEPTH_WRITEMASK:
 157     case GL_DEPTH_CLEAR_VALUE:
 158     case GL_STENCIL_FAIL:
 159     case GL_STENCIL_PASS_DEPTH_FAIL:
 160     case GL_STENCIL_PASS_DEPTH_PASS:
 161     case GL_STENCIL_REF:
 162     case GL_STENCIL_WRITEMASK:
 163     case GL_MATRIX_MODE:
 164     case GL_MODELVIEW_STACK_DEPTH:
 165     case GL_PROJECTION_STACK_DEPTH:
 166     case GL_TEXTURE_STACK_DEPTH:
 167     case GL_ALPHA_TEST_FUNC:
 168     case GL_ALPHA_TEST_REF:
 169     case GL_ALPHA_TEST:
 170     case GL_DITHER:
 171     case GL_BLEND_DST:
 172     case GL_BLEND_SRC:
 173     case GL_BLEND:
 174     case GL_LOGIC_OP_MODE:
 175     case GL_SCISSOR_TEST:
 176     case GL_MAX_TEXTURE_UNITS:
 177     case GL_ACTIVE_TEXTURE:
 178     case GL_ALPHA_BITS:
 179     case GL_ARRAY_BUFFER_BINDING:
 180     case GL_BLUE_BITS:
 181     case GL_CLIENT_ACTIVE_TEXTURE:
 182     case GL_CLIP_PLANE0:
 183     case GL_CLIP_PLANE1:
 184     case GL_CLIP_PLANE2:
 185     case GL_CLIP_PLANE3:
 186     case GL_CLIP_PLANE4:
 187     case GL_CLIP_PLANE5:
 188     case GL_COLOR_ARRAY:
 189     case GL_COLOR_ARRAY_BUFFER_BINDING:
 190     case GL_COLOR_ARRAY_SIZE:
 191     case GL_COLOR_ARRAY_STRIDE:
 192     case GL_COLOR_ARRAY_TYPE:
 193     case GL_COLOR_LOGIC_OP:
 194     case GL_COLOR_MATERIAL:
 195     case GL_PACK_ALIGNMENT:
 196     case GL_PERSPECTIVE_CORRECTION_HINT:
 197     case GL_POINT_SIZE_ARRAY_BUFFER_BINDING_OES:
 198     case GL_POINT_SIZE_ARRAY_STRIDE_OES:
 199     case GL_POINT_SIZE_ARRAY_TYPE_OES:
 200     case GL_POINT_SMOOTH:
 201     case GL_POINT_SMOOTH_HINT:
 202     case GL_POINT_SPRITE_OES:
 203     case GL_COORD_REPLACE_OES:
 204     case GL_COMBINE_ALPHA:
 205     case GL_SRC0_RGB:
 206     case GL_SRC1_RGB:
 207     case GL_SRC2_RGB:
 208     case GL_OPERAND0_RGB:
 209     case GL_OPERAND1_RGB:
 210     case GL_OPERAND2_RGB:
 211     case GL_SRC0_ALPHA:
 212     case GL_SRC1_ALPHA:
 213     case GL_SRC2_ALPHA:
 214     case GL_OPERAND0_ALPHA:
 215     case GL_OPERAND1_ALPHA:
 216     case GL_OPERAND2_ALPHA:
 217     case GL_RGB_SCALE:
 218     case GL_ALPHA_SCALE:
 219     case GL_COMBINE_RGB:
 220     case GL_POLYGON_OFFSET_FACTOR:
 221     case GL_POLYGON_OFFSET_FILL:
 222     case GL_POLYGON_OFFSET_UNITS:
 223     case GL_RED_BITS:
 224     case GL_RESCALE_NORMAL:
 225     case GL_SAMPLE_ALPHA_TO_COVERAGE:
 226     case GL_SAMPLE_ALPHA_TO_ONE:
 227     case GL_SAMPLE_BUFFERS:
 228     case GL_SAMPLE_COVERAGE:
 229     case GL_SAMPLE_COVERAGE_INVERT:
 230     case GL_SAMPLE_COVERAGE_VALUE:
 231     case GL_SAMPLES:
 232     case GL_MAX_SAMPLES_EXT:
 233     case GL_STENCIL_BITS:
 234     case GL_STENCIL_CLEAR_VALUE:
 235     case GL_STENCIL_FUNC:
 236     case GL_STENCIL_TEST:
 237     case GL_STENCIL_VALUE_MASK:
 238     case GL_STENCIL_BACK_FUNC:
 239     case GL_STENCIL_BACK_VALUE_MASK:
 240     case GL_STENCIL_BACK_REF:
 241     case GL_STENCIL_BACK_FAIL:
 242     case GL_STENCIL_BACK_PASS_DEPTH_FAIL:
 243     case GL_STENCIL_BACK_PASS_DEPTH_PASS:
 244     case GL_STENCIL_BACK_WRITEMASK:
 245     case GL_TEXTURE_2D:
 246     case GL_TEXTURE_BINDING_2D:
 247     case GL_TEXTURE_BINDING_CUBE_MAP:
 248     case GL_TEXTURE_BINDING_EXTERNAL_OES:
 249     case GL_TEXTURE_COORD_ARRAY:
 250     case GL_TEXTURE_COORD_ARRAY_BUFFER_BINDING:
 251     case GL_TEXTURE_COORD_ARRAY_SIZE:
 252     case GL_TEXTURE_COORD_ARRAY_STRIDE:
 253     case GL_TEXTURE_COORD_ARRAY_TYPE:
 254     case GL_UNPACK_ALIGNMENT:
 255     case GL_VERTEX_ARRAY:
 256     case GL_VERTEX_ARRAY_BUFFER_BINDING:
 257     case GL_VERTEX_ARRAY_SIZE:
 258     case GL_VERTEX_ARRAY_STRIDE:
 259     case GL_VERTEX_ARRAY_TYPE:
 260     case GL_SPOT_CUTOFF:
 261     case GL_TEXTURE_MIN_FILTER:
 262     case GL_TEXTURE_MAG_FILTER:
 263     case GL_TEXTURE_WRAP_S:
 264     case GL_TEXTURE_WRAP_T:
 265     case GL_GENERATE_MIPMAP:
 266     case GL_GENERATE_MIPMAP_HINT:
 267     case GL_RENDERBUFFER_WIDTH_OES:
 268     case GL_RENDERBUFFER_HEIGHT_OES:
 269     case GL_RENDERBUFFER_INTERNAL_FORMAT_OES:
 270     case GL_RENDERBUFFER_RED_SIZE_OES:
 271     case GL_RENDERBUFFER_GREEN_SIZE_OES:
 272     case GL_RENDERBUFFER_BLUE_SIZE_OES:
 273     case GL_RENDERBUFFER_ALPHA_SIZE_OES:
 274     case GL_RENDERBUFFER_DEPTH_SIZE_OES:
 275     case GL_RENDERBUFFER_STENCIL_SIZE_OES:
 276     case GL_RENDERBUFFER_BINDING:
 277     case GL_FRAMEBUFFER_BINDING:
 278     case GL_FRAMEBUFFER_ATTACHMENT_OBJECT_TYPE_OES:
 279     case GL_FRAMEBUFFER_ATTACHMENT_OBJECT_NAME_OES:
 280     case GL_FRAMEBUFFER_ATTACHMENT_TEXTURE_LEVEL_OES:
 281     case GL_FRAMEBUFFER_ATTACHMENT_TEXTURE_CUBE_MAP_FACE_OES:
 282     case GL_FENCE_STATUS_NV:
 283     case GL_FENCE_CONDITION_NV:
 284     case GL_TEXTURE_WIDTH_QCOM:
 285     case GL_TEXTURE_HEIGHT_QCOM:
 286     case GL_TEXTURE_DEPTH_QCOM:
 287     case GL_TEXTURE_INTERNAL_FORMAT_QCOM:
 288     case GL_TEXTURE_FORMAT_QCOM:
 289     case GL_TEXTURE_TYPE_QCOM:
 290     case GL_TEXTURE_IMAGE_VALID_QCOM:
 291     case GL_TEXTURE_NUM_LEVELS_QCOM:
 292     case GL_TEXTURE_TARGET_QCOM:
 293     case GL_TEXTURE_OBJECT_VALID_QCOM:
 294     case GL_BLEND_EQUATION_RGB_OES:
 295     case GL_BLEND_EQUATION_ALPHA_OES:
 296     case GL_BLEND_DST_RGB_OES:
 297     case GL_BLEND_SRC_RGB_OES:
 298     case GL_BLEND_DST_ALPHA_OES:
 299     case GL_BLEND_SRC_ALPHA_OES:
 300     case GL_MAX_LIGHTS:
 301     case GL_SHADER_TYPE:
 302     case GL_COMPILE_STATUS:
 303     case GL_SHADER_SOURCE_LENGTH:
 304     case GL_CURRENT_PROGRAM:
 305     case GL_SUBPIXEL_BITS:
 306     case GL_MAX_CUBE_MAP_TEXTURE_SIZE:
 307     case GL_NUM_SHADER_BINARY_FORMATS:
 308     case GL_SHADER_COMPILER:
 309     case GL_MAX_VERTEX_ATTRIBS:
 310     case GL_MAX_VERTEX_UNIFORM_VECTORS:
 311     case GL_MAX_VARYING_VECTORS:
 312     case GL_MAX_COMBINED_TEXTURE_IMAGE_UNITS:
 313     case GL_MAX_VERTEX_TEXTURE_IMAGE_UNITS:
 314     case GL_MAX_FRAGMENT_UNIFORM_VECTORS:
 315     case GL_MAX_RENDERBUFFER_SIZE:
 316     case GL_MAX_TEXTURE_IMAGE_UNITS:
 317     case GL_REQUIRED_TEXTURE_IMAGE_UNITS_OES:
 318     case GL_FRAGMENT_SHADER_DERIVATIVE_HINT_OES:
 319     case GL_LINE_WIDTH:
 320     case GL_MAX_TRANSFORM_FEEDBACK_SEPARATE_ATTRIBS:
 321     case GL_MAX_UNIFORM_BUFFER_BINDINGS:
 322     case GL_MAX_ATOMIC_COUNTER_BUFFER_BINDINGS:
 323     case GL_MAX_SHADER_STORAGE_BUFFER_BINDINGS:
 324     case GL_UNIFORM_BLOCK_BINDING:
 325     case GL_UNIFORM_BLOCK_DATA_SIZE:
 326     case GL_UNIFORM_BLOCK_NAME_LENGTH:
 327     case GL_UNIFORM_BLOCK_ACTIVE_UNIFORMS:
 328     case GL_UNIFORM_BLOCK_REFERENCED_BY_VERTEX_SHADER:
 329     case GL_UNIFORM_BLOCK_REFERENCED_BY_FRAGMENT_SHADER:
 330     case GL_CURRENT_QUERY:
 331     case GL_QUERY_RESULT:
 332     case GL_QUERY_RESULT_AVAILABLE:
 333     case GL_READ_BUFFER:
 334
 335     case GL_ACTIVE_ATOMIC_COUNTER_BUFFERS:
 336     case GL_ACTIVE_ATTRIBUTES:
 337     case GL_ACTIVE_ATTRIBUTE_MAX_LENGTH:
 338     case GL_ACTIVE_UNIFORM_BLOCKS:
 339     case GL_ACTIVE_UNIFORM_BLOCK_MAX_NAME_LENGTH:
 340     case GL_ACTIVE_UNIFORMS:
 341     case GL_ACTIVE_UNIFORM_MAX_LENGTH:
 342     case GL_ATTACHED_SHADERS:
 343     case GL_DELETE_STATUS:
 344     case GL_INFO_LOG_LENGTH:
 345     case GL_LINK_STATUS:
 346     case GL_PROGRAM_BINARY_RETRIEVABLE_HINT:
 347     case GL_PROGRAM_SEPARABLE:
 348     case GL_TRANSFORM_FEEDBACK_BUFFER_MODE:
 349     case GL_TRANSFORM_FEEDBACK_VARYINGS:
 350     case GL_TRANSFORM_FEEDBACK_VARYING_MAX_LENGTH:
 351     case GL_VALIDATE_STATUS:
 352         s = 1;
 353         break;
 354     case GL_ALIASED_LINE_WIDTH_RANGE:
 355     case GL_ALIASED_POINT_SIZE_RANGE:
 356     case GL_DEPTH_RANGE:
 357     case GL_MAX_VIEWPORT_DIMS:
 358     case GL_SMOOTH_POINT_SIZE_RANGE:
 359     case GL_SMOOTH_LINE_WIDTH_RANGE:
 360     case GL_SAMPLE_POSITION:
 361         s= 2;
 362         break;
 363     case GL_SPOT_DIRECTION:
 364     case GL_POINT_DISTANCE_ATTENUATION:
 365     case GL_CURRENT_NORMAL:
 366     case GL_COMPUTE_WORK_GROUP_SIZE:
 367         s =  3;
 368         break;
 369     case GL_CURRENT_VERTEX_ATTRIB:
 370     case GL_CURRENT_TEXTURE_COORDS:
 371     case GL_CURRENT_COLOR:
 372     case GL_FOG_COLOR:
 373     case GL_AMBIENT:
 374     case GL_DIFFUSE:
 375     case GL_SPECULAR:
 376     case GL_EMISSION:
 377     case GL_POSITION:
 378     case GL_LIGHT_MODEL_AMBIENT:
 379     case GL_TEXTURE_ENV_COLOR:
 380     case GL_SCISSOR_BOX:
 381     case GL_VIEWPORT:
 382     case GL_TEXTURE_CROP_RECT_OES:
 383     case GL_COLOR_CLEAR_VALUE:
 384     case GL_COLOR_WRITEMASK:
 385     case GL_AMBIENT_AND_DIFFUSE:
 386     case GL_BLEND_COLOR:
 387         s =  4;
 388         break;
 389     case GL_MODELVIEW_MATRIX:
 390     case GL_PROJECTION_MATRIX:
 391     case GL_TEXTURE_MATRIX:
 392         s = 16;
 393     break;
 394     default:
 395         ERR("glUtilsParamSize: unknow param 0x%08x\n", param);
 396         s = 1; // assume 1
 397     }
 398     return s;
 399 }
 400
 401 void glUtilsPackPointerData(unsigned char *dst, unsigned char *src,
 402                      int size, GLenum type, unsigned int stride,
 403                      unsigned int datalen)
 404 {
 405     unsigned int  vsize = size * glSizeof(type);
 406     switch (type) {
 407     case GL_INT_2_10_10_10_REV:
 408     case GL_UNSIGNED_INT_2_10_10_10_REV:
 409         vsize = vsize / 4;
 410         break;
 411     default:
 412         break;
 413     }
 414
 415     if (stride == 0) stride = vsize;
 416
 417     if (stride == vsize) {
 418         memcpy(dst, src, datalen);
 419     } else {
 420         for (unsigned int i = 0; i < datalen; i += vsize) {
 421             memcpy(dst, src, vsize);
 422             dst += vsize;
 423             src += stride;
 424         }
 425     }
 426 }
 427
 428 void glUtilsWritePackPointerData(void* _stream, unsigned char *src,
 429                                  int size, GLenum type, unsigned int stride,
 430                                  unsigned int datalen)
 431 {
 432     IOStream* stream = reinterpret_cast<IOStream*>(_stream);
 433
 434     unsigned int  vsize = size * glSizeof(type);
 435     if (stride == 0) stride = vsize;
 436
 437     if (stride == vsize) {
 438         stream->writeFully(src, datalen);
 439     } else {
 440         for (unsigned int i = 0; i < datalen; i += vsize) {
 441             stream->writeFully(src, (size_t)vsize);
 442             src += stride;
 443         }
 444     }
 445 }
 446
 447 int glUtilsPixelBitSize(GLenum format, GLenum type)
 448 {
 449     int components = 0;
 450     int componentsize = 0;
 451     int pixelsize = 0;
 452     switch(type) {
 453     case GL_BYTE:
 454     case GL_UNSIGNED_BYTE:
 455         componentsize = 8;
 456         break;
 457     case GL_SHORT:
 458     case GL_UNSIGNED_SHORT:
 459     case GL_UNSIGNED_SHORT_5_6_5:
 460     case GL_UNSIGNED_SHORT_4_4_4_4:
 461     case GL_UNSIGNED_SHORT_5_5_5_1:
 462     case GL_RGB565_OES:
 463     case GL_RGB5_A1_OES:
 464     case GL_RGBA4_OES:
 465         pixelsize = 16;
 466         break;
 467     case GL_INT:
 468     case GL_UNSIGNED_INT:
 469     case GL_FLOAT:
 470     case GL_FIXED:
 471     case GL_UNSIGNED_INT_24_8_OES:
 472         pixelsize = 32;
 473         break;
 474     default:
 475         ERR("glUtilsPixelBitSize: unknown pixel type - assuming pixel data 0\n");
 476         componentsize = 0;
 477     }
 478
 479     if (pixelsize == 0) {
 480         switch(format) {
 481 #if 0
 482         case GL_RED:
 483         case GL_GREEN:
 484         case GL_BLUE:
 485 #endif
 486         case GL_ALPHA:
 487         case GL_LUMINANCE:
 488         case GL_DEPTH_COMPONENT:
 489         case GL_DEPTH_STENCIL_OES:
 490             components = 1;
 491             break;
 492         case GL_LUMINANCE_ALPHA:
 493             components = 2;
 494             break;
 495         case GL_RGB:
 496 #if 0
 497         case GL_BGR:
 498 #endif
 499             components = 3;
 500             break;
 501         case GL_RGBA:
 502         case GL_BGRA_EXT:
 503             components = 4;
 504             break;
 505         default:
 506             ERR("glUtilsPixelBitSize: unknown pixel format...\n");
 507             components = 0;
 508         }
 509         pixelsize = components * componentsize;
 510     }
 511
 512     return pixelsize;
 513 }
 514
 515 // pack a list of strings into one.
 516 void glUtilsPackStrings(char *ptr,  char **strings,  GLint *length, GLsizei count)
 517 {
 518     char *p = ptr;
 519     *p = '\0';
 520     for (int i = 0; i < count; i++) {
 521         int l=0;
 522         if (strings[i]!=NULL) {
 523             if (length == NULL || length[i] < 0) {
 524                 l = strlen(strings[i]);
 525                 strcat(p, strings[i]);
 526             } else {
 527                 l = length[i];
 528                 strncat(p, strings[i], l);
 529             }
 530         }
 531         p += l;
 532     }
 533 }
 534
 535 // claculate the length of a list of strings
 536 int glUtilsCalcShaderSourceLen( char **strings,  GLint *length, GLsizei count)
 537 {
 538     int len = 0;
 539     for (int i = 0; i < count; i++) {
 540         int l;
 541         if (length == NULL || length[i] < 0) {
 542             l = strings[i]!=NULL ? strlen(strings[i]) : 0;
 543         } else {
 544             l = length[i];
 545         }
 546         len += l;
 547     }
 548     return len;
 549
 550 }
 551
 552 // helper to get GL_COLOR_ATTACHMENTn names
 553 GLenum glUtilsColorAttachmentName(int i) {
 554 #undef COLOR_ATTACHMENT_CASE
 555 #define COLOR_ATTACHMENT_CASE(i) \
 556     case i: \
 557         return GL_COLOR_ATTACHMENT##i; \
 558
 559     switch (i) {
 560         COLOR_ATTACHMENT_CASE(0)
 561         COLOR_ATTACHMENT_CASE(1)
 562         COLOR_ATTACHMENT_CASE(2)
 563         COLOR_ATTACHMENT_CASE(3)
 564         COLOR_ATTACHMENT_CASE(4)
 565         COLOR_ATTACHMENT_CASE(5)
 566         COLOR_ATTACHMENT_CASE(6)
 567         COLOR_ATTACHMENT_CASE(7)
 568         COLOR_ATTACHMENT_CASE(8)
 569         COLOR_ATTACHMENT_CASE(9)
 570         COLOR_ATTACHMENT_CASE(10)
 571         COLOR_ATTACHMENT_CASE(11)
 572         COLOR_ATTACHMENT_CASE(12)
 573         COLOR_ATTACHMENT_CASE(13)
 574         COLOR_ATTACHMENT_CASE(14)
 575         COLOR_ATTACHMENT_CASE(15)
 576     }
 577     return GL_NONE;
 578 #undef COLOR_ATTACHMENT_CASE
 579 }
 580
 581 int glUtilsColorAttachmentIndex(GLenum attachment) {
 582 #undef COLOR_ATTACHMENT_CASE
 583 #define COLOR_ATTACHMENT_CASE(i) \
 584     case GL_COLOR_ATTACHMENT##i: \
 585         return i; \
 586
 587     switch (attachment) {
 588         COLOR_ATTACHMENT_CASE(0)
 589         COLOR_ATTACHMENT_CASE(1)
 590         COLOR_ATTACHMENT_CASE(2)
 591         COLOR_ATTACHMENT_CASE(3)
 592         COLOR_ATTACHMENT_CASE(4)
 593         COLOR_ATTACHMENT_CASE(5)
 594         COLOR_ATTACHMENT_CASE(6)
 595         COLOR_ATTACHMENT_CASE(7)
 596         COLOR_ATTACHMENT_CASE(8)
 597         COLOR_ATTACHMENT_CASE(9)
 598         COLOR_ATTACHMENT_CASE(10)
 599         COLOR_ATTACHMENT_CASE(11)
 600         COLOR_ATTACHMENT_CASE(12)
 601         COLOR_ATTACHMENT_CASE(13)
 602         COLOR_ATTACHMENT_CASE(14)
 603         COLOR_ATTACHMENT_CASE(15)
 604     }
 605     return -1;
 606 #undef COLOR_ATTACHMENT_CASE
 607 }
 608
 609 struct glUtilsDrawArraysIndirectCommand {
 610     GLuint count;
 611     GLuint primCount;
 612     GLuint first;
 613     GLuint reserved;
 614 };
 615
 616 struct glUtilsDrawElementsIndirectCommand {
 617     GLuint count;
 618     GLuint primCount;
 619     GLuint first;
 620     GLint baseVertex;
 621     GLuint reserved;
 622 };
 623
 624 GLuint glUtilsIndirectStructSize(IndirectCommandType cmdType) {
 625     switch (cmdType) {
 626     case INDIRECT_COMMAND_DRAWARRAYS:
 627         return sizeof(glUtilsDrawArraysIndirectCommand);
 628     case INDIRECT_COMMAND_DRAWELEMENTS:
 629         return sizeof(glUtilsDrawElementsIndirectCommand);
 630     }
 631     return 4;
 632 }