[Fix] (Espryt): re-arm the packed16 probe on the allocation-scoped mirror the device actually has and let any mirrored level trigger the widening

This commit is contained in:
2026-08-28 00:22:15 -04:00
parent bf376b230f
commit 5d140a41ce
9 changed files with 239 additions and 150 deletions
+117 -68
View File
@@ -1929,17 +1929,22 @@ namespace MobileGL::MG_Util::SelfTest {
constexpr const char* kPacked16CopyProbeName = "packed16 copy-image field order";
// The shape the KHR-GL4x.copy_image failures pin, verbatim: on the affected Mali only a
// 2D array whose base level is 30x30x12 showed the divergence at LEVEL 1 (the same
// suite's level-0 copies and a 14x14 base's level 1 round-trip clean), so the probe
// reproduces those dimensions rather than a minimal shape that might sit on the clean
// side of whatever allocation threshold picks the driver's layout. VERBATIM INCLUDES
// THE LEVEL COUNT: the CTS allocates THREE-level chains on BOTH endpoints
// (FUNCTIONAL_TEST_N_LEVELS = 3, makeTextureComplete(0, 2): 30/15/7 x12 for the array,
// 7/3/1 for the plain image), and every device data point above came from those
// allocations - a chain one level shorter has never been measured on the affected
// driver, and a probe miss here is not a red anything, it is the widening silently
// staying inert with all 18 bodies red.
// The shape the KHR-GL4x.copy_image failures pin: a 30x30x12 GL_RGB5_A1 2D array with
// the CTS's three-level chain (FUNCTIONAL_TEST_N_LEVELS = 3, makeTextureComplete(0, 2):
// 30/15/7 x12; the plain endpoints are 7/3/1), against plain-2D endpoints.
//
// WHAT THE DEVICE MEASUREMENTS ACTUALLY SHOWED (round 2): the mirrored field order is a
// property of the WHOLE ALLOCATION, not of a mip level. In MobileGL's live context this
// array shape lands in the *_REV layout at EVERY level - the first deployment's control
// copy out of LEVEL 0 delivered the mirror too, which is what vetoed its own verdict -
// while the small arrays the CTS's passing iterations used (7- and 15-texel bases; its
// src/dst dim loop is {7, 15}, so a base-30 array only ever appears at level 1) land in
// the plain layout. A raw standalone context on the same driver additionally showed one-
// and two-level 30x30x12 arrays mirrored where a fresh three-level one is not, so the
// driver's layout choice depends on allocation shape AND context history. The probe
// therefore measures IN SITU - this very context is the one the application's copies run
// in - and treats a mirror delivered from ANY level as the finding, with the machinery
// controls below instead of a per-level "clean" assumption that does not exist.
constexpr GLsizei kPacked16BaseSize = 30;
constexpr GLsizei kPacked16Layers = 12;
constexpr GLsizei kPacked16DstSize = 7;
@@ -1990,7 +1995,11 @@ namespace MobileGL::MG_Util::SelfTest {
// The plain-2D destination, three levels (7/3/1) like the CTS's, every level filled
// with 0xFFFF - the CTS's own (1,1,1,1) destination fill - so a copy that silently
// did nothing reads as "no verdict" rather than as either prediction.
GLuint MakePacked16DstTexture(const GLESFunctionsTable& gl) {
// A plain-2D endpoint with the CTS's three-level 7/3/1 chain, every texel of every
// level holding `fill`: 0xFFFF (the CTS's own (1,1,1,1) destination fill, so a copy
// that silently did nothing reads as "no verdict" rather than as either prediction),
// or kPacked16Word for the machinery control's source.
GLuint MakePacked16FlatTexture(const GLESFunctionsTable& gl, Uint16 fill) {
GLuint texture = 0;
gl.glGenTextures(1, &texture);
if (texture == 0) return 0;
@@ -2000,22 +2009,28 @@ namespace MobileGL::MG_Util::SelfTest {
gl.glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_LEVEL, kPacked16Levels - 1);
for (GLint level = 0; level < kPacked16Levels; ++level) {
const GLsizei size = std::max<GLsizei>(kPacked16DstSize >> level, 1);
const Vector<Uint16> fill(static_cast<SizeT>(size) * size, Uint16{0xFFFF});
const Vector<Uint16> texels(static_cast<SizeT>(size) * size, fill);
gl.glTexImage2D(GL_TEXTURE_2D, level, GL_RGB5_A1, size, size, 0, GL_RGBA,
GL_UNSIGNED_SHORT_5_5_5_1, fill.data());
GL_UNSIGNED_SHORT_5_5_5_1, texels.data());
}
gl.glBindTexture(GL_TEXTURE_2D, 0);
return texture;
}
// The destination's texel (0, 0), through a framebuffer of its own. False when the
// attachment is incomplete or the read errors - both are declines, not verdicts.
Bool ReadPacked16DstTexel(const GLESFunctionsTable& gl, GLuint texture, GLubyte out[4]) {
// Texel (0, 0) of a 2D level 0, or of layer 0 of an array's `level`, through a
// framebuffer of its own. False when the attachment is incomplete or the read errors -
// both are declines, not verdicts.
Bool ReadPacked16Texel(const GLESFunctionsTable& gl, GLuint texture, Bool isArray, GLint level,
GLubyte out[4]) {
GLuint framebuffer = 0;
gl.glGenFramebuffers(1, &framebuffer);
if (framebuffer == 0) return false;
gl.glBindFramebuffer(GL_FRAMEBUFFER, framebuffer);
gl.glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, texture, 0);
if (isArray) {
gl.glFramebufferTextureLayer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, texture, level, 0);
} else {
gl.glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, texture, level);
}
Bool read = false;
if (gl.glCheckFramebufferStatus(GL_FRAMEBUFFER) == GL_FRAMEBUFFER_COMPLETE) {
gl.glReadBuffer(GL_COLOR_ATTACHMENT0);
@@ -2029,18 +2044,18 @@ namespace MobileGL::MG_Util::SelfTest {
return read;
}
// Copies a kPacked16DstSize-square region out of layer 0 of the array's `sourceLevel`
// onto a freshly filled 2D destination and hands back the destination's texel (0, 0).
// False when the copy raised an error or the readback could not run.
Bool Packed16CopyLandsTexel(const GLESFunctionsTable& gl, GLuint array, GLint sourceLevel,
GLubyte out[4]) {
const GLuint destination = MakePacked16DstTexture(gl);
// Copies a kPacked16DstSize-square region out of (source, sourceTarget, sourceLevel)
// layer 0 onto a freshly 0xFFFF-filled 2D destination and hands back the destination's
// texel (0, 0). False when the copy raised an error or the readback could not run.
Bool Packed16CopyLandsTexel(const GLESFunctionsTable& gl, GLuint source, GLenum sourceTarget,
GLint sourceLevel, GLubyte out[4]) {
const GLuint destination = MakePacked16FlatTexture(gl, Uint16{0xFFFF});
if (destination == 0) return false;
Drain(gl);
gl.glCopyImageSubData(array, GL_TEXTURE_2D_ARRAY, sourceLevel, 0, 0, 0, destination,
gl.glCopyImageSubData(source, sourceTarget, sourceLevel, 0, 0, 0, destination,
GL_TEXTURE_2D, 0, 0, 0, 0, kPacked16DstSize, kPacked16DstSize, 1);
const Bool copied = gl.glGetError() == GL_NO_ERROR;
const Bool read = copied && ReadPacked16DstTexel(gl, destination, out);
const Bool read = copied && ReadPacked16Texel(gl, destination, false, 0, out);
gl.glDeleteTextures(1, &destination);
Drain(gl);
return read;
@@ -2058,9 +2073,9 @@ namespace MobileGL::MG_Util::SelfTest {
Bool ProbeCopyImageMirrorsPacked16FieldOrder(const GLESFunctionsTable& gl) {
if (!gl.glGenTextures || !gl.glBindTexture || !gl.glTexParameteri || !gl.glTexImage2D ||
!gl.glTexImage3D || !gl.glDeleteTextures || !gl.glCopyImageSubData || !gl.glGenFramebuffers ||
!gl.glBindFramebuffer || !gl.glFramebufferTexture2D || !gl.glCheckFramebufferStatus ||
!gl.glDeleteFramebuffers || !gl.glReadBuffer || !gl.glReadPixels || !gl.glPixelStorei ||
!gl.glGetError) {
!gl.glBindFramebuffer || !gl.glFramebufferTexture2D || !gl.glFramebufferTextureLayer ||
!gl.glCheckFramebufferStatus || !gl.glDeleteFramebuffers || !gl.glReadBuffer ||
!gl.glReadPixels || !gl.glPixelStorei || !gl.glGetError) {
return false;
}
@@ -2087,42 +2102,74 @@ namespace MobileGL::MG_Util::SelfTest {
Bool detected = false;
const GLuint array = MakePacked16ArrayTexture(gl);
GLubyte control[4] = {0, 0, 0, 0};
GLubyte subject[4] = {0, 0, 0, 0};
// THE CONTROL: the identical copy out of the array's LEVEL 0, which is clean on the
// affected driver too. It proves glCopyImageSubData works between a 5551 array and a
// 5551 2D image at all, that the upload and the FBO readback round-trip the word, and
// that only the mip level moves the answer - so a driver with no copy_image, or none
// for these formats, reaches no verdict instead of being reported as this.
if (array == 0 || !Packed16CopyLandsTexel(gl, array, 0, control)) {
MGLOG_I("[driver-bug] %s probe reached no verdict (the level-0 control copy could not run)",
const GLuint flatSource = MakePacked16FlatTexture(gl, kPacked16Word);
GLubyte machinery[4] = {0, 0, 0, 0};
GLubyte direct[4] = {0, 0, 0, 0};
GLubyte level0[4] = {0, 0, 0, 0};
GLubyte level1[4] = {0, 0, 0, 0};
// CONTROL ONE, the machinery: the same copy between two 2D images of the same
// three-level shape. Two identical allocations share the driver's layout whatever it
// is, so this must deliver the word on ANY driver that can run copy_image on these
// formats at all - a driver that cannot reaches no verdict instead of being reported
// as this.
if (array == 0 || flatSource == 0 ||
!Packed16CopyLandsTexel(gl, flatSource, GL_TEXTURE_2D, 0, machinery)) {
MGLOG_I("[driver-bug] %s probe reached no verdict (the 2D-to-2D machinery control "
"could not run)",
kPacked16CopyProbeName);
} else if (!Packed16TexelNear(control, kPacked16Expected)) {
MGLOG_I("[driver-bug] %s probe reached no verdict (the level-0 control read back "
"(%d, %d, %d, %d) instead of the uploaded word's (%d, %d, %d, %d))",
kPacked16CopyProbeName, control[0], control[1], control[2], control[3],
} else if (!Packed16TexelNear(machinery, kPacked16Expected)) {
MGLOG_I("[driver-bug] %s probe reached no verdict (the 2D-to-2D machinery control "
"read back (%d, %d, %d, %d) instead of the word's (%d, %d, %d, %d))",
kPacked16CopyProbeName, machinery[0], machinery[1], machinery[2], machinery[3],
kPacked16Expected[0], kPacked16Expected[1], kPacked16Expected[2], kPacked16Expected[3]);
} else if (!Packed16CopyLandsTexel(gl, array, 1, subject)) {
MGLOG_I("[driver-bug] %s probe reached no verdict (the level-1 subject copy could not run)",
} else if (!ReadPacked16Texel(gl, array, true, 1, direct) ||
!Packed16TexelNear(direct, kPacked16Expected)) {
// CONTROL TWO, the array's own round trip: reading the level DIRECTLY decodes the
// driver's own storage and must deliver the word whatever layout it picked. A wrong
// answer here means the UPLOAD is what corrupts - a different defect, and one the
// widening's raw-copy reasoning says nothing about.
MGLOG_I("[driver-bug] %s probe reached no verdict (the array's own level-1 readback "
"answered (%d, %d, %d, %d) instead of the word - the upload, not the copy, "
"is what diverges here)",
kPacked16CopyProbeName, direct[0], direct[1], direct[2], direct[3]);
} else if (!Packed16CopyLandsTexel(gl, array, GL_TEXTURE_2D_ARRAY, 0, level0) ||
!Packed16CopyLandsTexel(gl, array, GL_TEXTURE_2D_ARRAY, 1, level1)) {
MGLOG_I("[driver-bug] %s probe reached no verdict (an array-source subject copy "
"could not run)",
kPacked16CopyProbeName);
} else if (Packed16TexelNear(subject, kPacked16Mirrored)) {
detected = true;
MGLOG_I("[driver-bug] %s probe: a copy out of the array's level 1 delivered "
"(%d, %d, %d, %d), the 1_5_5_5_REV re-encoding of the word - THE FIELD ORDER "
"OF A NON-ZERO ARRAY MIP LEVEL IS MIRRORED",
kPacked16CopyProbeName, subject[0], subject[1], subject[2], subject[3]);
} else if (!Packed16TexelNear(subject, kPacked16Expected)) {
MGLOG_I("[driver-bug] %s probe reached no verdict (the level-1 copy read back "
"(%d, %d, %d, %d), which is neither the word nor its mirror)",
kPacked16CopyProbeName, subject[0], subject[1], subject[2], subject[3]);
} else {
// The clean verdict is logged too: on a device run the FIRST question is whether
// this probe executed at all, and a silent clean path is indistinguishable from a
// probe that never ran.
MGLOG_I("[driver-bug] %s probe: a copy out of the array's level 1 delivered the word "
"intact - the field order is consistent",
kPacked16CopyProbeName);
// THE SUBJECTS: the same copy out of the array's levels 0 and 1. The mirror is an
// allocation property, not a level property - the affected device delivers it from
// BOTH levels of this array in MobileGL's context - so a mirror from EITHER level
// is the finding, and each must match the mirror PREDICTION, not merely differ
// from the word: anything else is a different defect and reaches no verdict.
const Bool level0Mirrored = Packed16TexelNear(level0, kPacked16Mirrored);
const Bool level1Mirrored = Packed16TexelNear(level1, kPacked16Mirrored);
const Bool level0Clean = Packed16TexelNear(level0, kPacked16Expected);
const Bool level1Clean = Packed16TexelNear(level1, kPacked16Expected);
if (level0Mirrored || level1Mirrored) {
detected = true;
MGLOG_I("[driver-bug] %s probe: copies out of the array delivered level 0 "
"(%d, %d, %d, %d) and level 1 (%d, %d, %d, %d) - the 1_5_5_5_REV "
"re-encoding of the word - THE ALLOCATION'S FIELD ORDER IS MIRRORED",
kPacked16CopyProbeName, level0[0], level0[1], level0[2], level0[3],
level1[0], level1[1], level1[2], level1[3]);
} else if (!level0Clean || !level1Clean) {
MGLOG_I("[driver-bug] %s probe reached no verdict (array copies read back level 0 "
"(%d, %d, %d, %d) and level 1 (%d, %d, %d, %d), neither the word nor its "
"mirror)",
kPacked16CopyProbeName, level0[0], level0[1], level0[2], level0[3],
level1[0], level1[1], level1[2], level1[3]);
} else {
// The clean verdict is logged too: on a device run the FIRST question is
// whether this probe executed at all, and a silent clean path is
// indistinguishable from a probe that never ran.
MGLOG_I("[driver-bug] %s probe: copies out of both array levels delivered the "
"word intact - the field order is consistent",
kPacked16CopyProbeName);
}
}
if (flatSource != 0) gl.glDeleteTextures(1, &flatSource);
if (array != 0) gl.glDeleteTextures(1, &array);
Restore(gl, saved);
return detected;
@@ -2314,13 +2361,15 @@ namespace MobileGL::MG_Util::SelfTest {
const Bool widened = MG_Config::Features.EsprytWidenPacked16Storage !=
MG_Config::QuirkOverride::ForceOff;
String detail =
"the driver's physical field order for a 16-bit packed texel (RGB565 / RGB5_A1 / "
"RGBA4) at a non-zero mip level of a GL_TEXTURE_2D_ARRAY is the *_REV mirror of "
"the order every other image uses, so a glCopyImageSubData - a raw texel-block "
"move - between such a level and any other image lands the R/G/B/A fields "
"the driver stores SOME 16-bit packed images (RGB565 / RGB5_A1 / RGBA4) with the "
"R/G/B/A fields packed from the other end of the word - which allocations get the "
"*_REV layout depends on shape and context history (measured here on a 30x30x12 "
"three-level 2D array, every level of it) - so a glCopyImageSubData, a raw "
"texel-block move, between a mirrored allocation and a plain one lands the fields "
"reversed (a 5551 word 0x0047 arrives as 0x8C20). Uploads and readbacks of the "
"same level are clean - the driver decodes its own layout consistently, which is "
"this probe's control - so only the raw-copy path ever crosses the two layouts. ";
"same image are clean - the driver decodes its own layout consistently, which is "
"this probe's second control - so only the raw-copy path ever crosses the two "
"layouts. ";
if (widened) {
detail +=
"MobileGL stores these three formats as 8-bit-per-channel ES storage on this "
@@ -2330,13 +2379,13 @@ namespace MobileGL::MG_Util::SelfTest {
"memory for images of those formats; override with "
"MOBILEGL_WIDEN_PACKED16_STORAGE";
return DriverBugFinding{
"glCopyImageSubData mirrors 16-bit packed texels at a non-zero array mip level",
"glCopyImageSubData mirrors 16-bit packed texels between differently-laid-out images",
DriverBugVerdict::Fixed, detail};
}
detail += "MOBILEGL_WIDEN_PACKED16_STORAGE=0 keeps the native narrow storage, so such "
"copies are left exactly as the driver delivers them, mirrored words included";
return DriverBugFinding{
"glCopyImageSubData mirrors 16-bit packed texels at a non-zero array mip level",
"glCopyImageSubData mirrors 16-bit packed texels between differently-laid-out images",
DriverBugVerdict::Unfixable, detail};
}
+26 -23
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@@ -299,31 +299,34 @@ namespace MobileGL::MG_Util::SelfTest {
const ImageCoherencyResidualMeasurement& ImageWriteReadCoherencyResidual(
const MG_External::GLESFunctionsTable& gl);
// Copies one known GL_UNSIGNED_SHORT_5_5_5_1 word out of a GL_RGB5_A1 2D array's mip
// level 1 into a plain 2D image with glCopyImageSubData and reads the landed texel back.
// Returns true only when the level-1 copy delivers the word's 5_5_5_1 <-> 1_5_5_5_REV
// field-order mirror while the identical level-0 copy delivers the word itself.
// Copies one known GL_UNSIGNED_SHORT_5_5_5_1 word out of BOTH mip levels of a GL_RGB5_A1
// 2D array into plain 2D images with glCopyImageSubData and reads the landed texels back.
// Returns true only when a copy from EITHER level delivers the word's 5_5_5_1 <->
// 1_5_5_5_REV field-order mirror while both controls below hold.
//
// The affected Mali stores 16-bit packed texels (RGB565 / RGB5_A1 / RGBA4) at a non-zero
// mip level of a 2D array in the *_REV field order every other image does NOT use.
// Uploads and readbacks decode that layout consistently, so nothing but a raw texel-block
// move can see it - which is exactly what glCopyImageSubData is defined to be, and why
// the whole KHR-GL4x.copy_image rgb5/rgb5_a1/rgba4 x *2d_array* matrix fails there while
// every other suite touching these formats passes. The textures reproduce the failing
// shape verbatim - THREE-level chains on both endpoints (30/15/7 x12 for the array,
// 7/3/1 for the plain 2D image), exactly the CTS's FUNCTIONAL_TEST_N_LEVELS = 3
// allocation - because a 14x14 base's level 1 measured clean on the same driver, so
// every deviation from the measured shape risks landing on the clean side of whatever
// allocation threshold picks the driver's layout, and a probe miss here is not a red
// test: it is the widening silently staying inert with all 18 bodies still failing.
// The affected Mali stores SOME 16-bit packed allocations (RGB565 / RGB5_A1 / RGBA4) with
// their fields packed from the other end of the word, and the mirrored layout is an
// ALLOCATION property, not a mip-level one: on the failing device this probe's 30x30x12
// three-level array delivers the mirror from level 0 and level 1 alike, which is what
// vetoed the first deployment's "level 0 is the clean control" design. Which allocations
// mirror depends on shape AND context history (a raw standalone context mirrors one- and
// two-level 30x30x12 arrays but not a fresh three-level one; MobileGL's live context
// mirrors the three-level one too), so the probe measures IN SITU - this context is the
// one the application's copies run in - on the CTS's own failing shape (three-level
// chains both endpoints: 30/15/7 x12 array, 7/3/1 plain, FUNCTIONAL_TEST_N_LEVELS = 3).
// Uploads and readbacks decode each image's own layout consistently, so nothing but a raw
// texel-block move can see the divergence - which is exactly what glCopyImageSubData is
// defined to be, and why the whole KHR-GL4x.copy_image rgb5/rgb5_a1/rgba4 x *2d_array*
// matrix fails there while every other suite touching these formats passes.
//
// THE CONTROL is the identical copy out of mip level 0, which is clean on the affected
// driver too: it proves copy_image works between these images at all and that the
// upload/readback round trip is exact, so a driver that cannot host the shape reaches no
// verdict instead of being reported as this. The subject must also match the mirror
// PREDICTION, not merely differ from the expectation - a copy that delivered anything
// else is a different defect and reaches no verdict either. Restores every piece of GL
// state it touches.
// TWO CONTROLS. The machinery: an identical copy between two SAME-shape plain-2D images,
// which share a layout whatever it is, so it must deliver the word on any driver that can
// run copy_image on these formats - a driver that cannot reaches no verdict instead of
// being reported as this. And the array's own round trip: a direct FBO readback of its
// level 1 must answer the word, or the UPLOAD is what corrupts - a different defect. The
// subjects must also match the mirror PREDICTION, not merely differ from the word - a
// copy that delivered anything else is a different defect and reaches no verdict either.
// Restores every piece of GL state it touches.
Bool ProbeCopyImageMirrorsPacked16FieldOrder(const MG_External::GLESFunctionsTable& gl);
// ProbeCopyImageMirrorsPacked16FieldOrder(), evaluated at most once per process. The
@@ -344,11 +344,12 @@ namespace MobileGL::MG_Util::TextureFormatProcessor {
// GL_RGB565 are ES formats an application can legitimately ask for - the same
// normalization picks the storage for glRenderbufferStorage - so widening them
// used to be declined as "a memory decision, not a correctness one". The 18
// KHR-GL4x.copy_image.functional bodies on Mali falsified that: the driver's own
// 16-bit packed storage keeps a MIRRORED field order at a non-zero mip level of a
// 2D array, so a raw glCopyImageSubData between such a level and any other image
// delivers the channels reversed (0x0007 -> 0x3800 for a 5551 word: the 1_5_5_5_REV
// re-encoding of the same fields). Where that is measured -
// KHR-GL4x.copy_image.functional bodies on Mali falsified that: the driver
// stores SOME packed16 allocations with a MIRRORED field order (allocation-scoped,
// shape- and context-dependent; the failing 30x30x12 arrays are mirrored at every
// level), so a raw glCopyImageSubData between a mirrored allocation and a plain
// one delivers the channels reversed (0x0007 -> 0x3800 for a 5551 word: the
// 1_5_5_5_REV re-encoding of the same fields). Where that is measured -
// WidenPacked16Norm, set from the POST probe or its ForceOn override - the three
// formats take the same 8-bit widening; everywhere else they stay narrow and the
// memory argument stands. Nothing about the REPORTED precision moves either way:
@@ -47,9 +47,11 @@ namespace MobileGL {
// Store the three 16-bit packed normalized formats (GL_RGB565, GL_RGB5_A1, GL_RGBA4)
// as 8-bit-per-channel ES storage (GL_RGB8 / GL_RGBA8), the way the desktop-only
// narrow formats already are. Set by DirectGLES when the driver's 16-bit packed
// storage cannot be trusted as a raw-copy endpoint: some Mali drivers keep a
// MIRRORED field order for these texels at a non-zero mip level of a 2D array, so
// glCopyImageSubData (a raw texel-block move) delivers the channels reversed. The
// storage cannot be trusted as a raw-copy endpoint: some Mali drivers store SOME
// packed16 allocations with a MIRRORED field order (which ones depends on shape and
// context history - measured on a three-level 30x30x12 2D array, every level of it),
// so glCopyImageSubData (a raw texel-block move) between a mirrored allocation and a
// plain one delivers the channels reversed. The
// (format, type) transfer pair does not move with the bit - it is already the
// UNorm8 component layout the canonical shadow holds for all three formats.
// Reported precision does not move either: GL_TEXTURE_*_SIZE and