void
WebGLTexture::GenerateMipmap(TexTarget texTarget)
{
// GLES 3.0.4 p160:
// "Mipmap generation replaces texel array levels level base + 1 through q with arrays
// derived from the level base array, regardless of their previous contents. All
// other mipmap arrays, including the level base array, are left unchanged by this
// computation."
const ImageInfo& baseImageInfo = BaseImageInfo();
if (!baseImageInfo.IsDefined()) {
mContext->ErrorInvalidOperation("generateMipmap: The base level of the texture is"
" not defined.");
return;
}
if (IsCubeMap() && !IsCubeComplete()) {
mContext->ErrorInvalidOperation("generateMipmap: Cube maps must be \"cube"
" complete\".");
return;
}
if (!mContext->IsWebGL2() && !baseImageInfo.IsPowerOfTwo()) {
mContext->ErrorInvalidOperation("generateMipmap: The base level of the texture"
" does not have power-of-two dimensions.");
return;
}
auto format = baseImageInfo.mFormat->format;
if (format->compression) {
mContext->ErrorInvalidOperation("generateMipmap: Texture data at base level is"
" compressed.");
return;
}
if (format->hasDepth) {
mContext->ErrorInvalidOperation("generateMipmap: Depth textures are not"
" supported.");
return;
}
// OpenGL ES 3.0.4 p160:
// If the level base array was not specified with an unsized internal format from
// table 3.3 or a sized internal format that is both color-renderable and
// texture-filterable according to table 3.13, an INVALID_OPERATION error
// is generated.
const auto usage = baseImageInfo.mFormat;
bool canGenerateMipmap = (usage->isRenderable && usage->isFilterable);
switch (usage->format->effectiveFormat) {
case webgl::EffectiveFormat::Luminance8:
case webgl::EffectiveFormat::Alpha8:
case webgl::EffectiveFormat::Luminance8Alpha8:
// Non-color-renderable formats from Table 3.3.
canGenerateMipmap = true;
break;
default:
break;
}
if (!canGenerateMipmap) {
mContext->ErrorInvalidOperation("generateMipmap: Texture at base level is not unsized"
" internal format or is not"
" color-renderable or texture-filterable.");
return;
}
// Done with validation. Do the operation.
mContext->MakeContextCurrent();
gl::GLContext* gl = mContext->gl;
if (gl->WorkAroundDriverBugs()) {
// bug 696495 - to work around failures in the texture-mips.html test on various drivers, we
// set the minification filter before calling glGenerateMipmap. This should not carry a significant performance
// overhead so we do it unconditionally.
//
// note that the choice of GL_NEAREST_MIPMAP_NEAREST really matters. See Chromium bug 101105.
gl->fTexParameteri(texTarget.get(), LOCAL_GL_TEXTURE_MIN_FILTER,
LOCAL_GL_NEAREST_MIPMAP_NEAREST);
gl->fGenerateMipmap(texTarget.get());
gl->fTexParameteri(texTarget.get(), LOCAL_GL_TEXTURE_MIN_FILTER,
mMinFilter.get());
} else {
gl->fGenerateMipmap(texTarget.get());
}
// Record the results.
// Note that we don't use MaxEffectiveMipmapLevel() here, since that returns
// mBaseMipmapLevel if the min filter doesn't require mipmaps.
const uint32_t lastLevel = mBaseMipmapLevel + baseImageInfo.MaxMipmapLevels() - 1;
PopulateMipChain(mBaseMipmapLevel, lastLevel);
}
void WebGLTexture::GenerateMipmap() {
// GLES 3.0.4 p160:
// "Mipmap generation replaces texel array levels level base + 1 through q
// with arrrays derived from the level base array, regardless of their
// previous contents. All other mipmap arrays, including the level base
// array, are left unchanged by this computation."
// But only check and init the base level.
const bool ensureInit = true;
const bool skipMips = true;
const auto completeness = CalcCompletenessInfo(ensureInit, skipMips);
if (!completeness || !completeness->levels) {
mContext->ErrorInvalidOperation(
"The texture's base level must be complete.");
return;
}
const auto& usage = completeness->usage;
const auto& format = usage->format;
if (!mContext->IsWebGL2()) {
if (!completeness->powerOfTwo) {
mContext->ErrorInvalidOperation(
"The base level of the texture does not"
" have power-of-two dimensions.");
return;
}
if (format->isSRGB) {
mContext->ErrorInvalidOperation(
"EXT_sRGB forbids GenerateMipmap with"
" sRGB.");
return;
}
}
if (format->compression) {
mContext->ErrorInvalidOperation(
"Texture data at base level is compressed.");
return;
}
if (format->d) {
mContext->ErrorInvalidOperation("Depth textures are not supported.");
return;
}
// OpenGL ES 3.0.4 p160:
// If the level base array was not specified with an unsized internal format
// from table 3.3 or a sized internal format that is both color-renderable and
// texture-filterable according to table 3.13, an INVALID_OPERATION error
// is generated.
bool canGenerateMipmap = (usage->IsRenderable() && usage->isFilterable);
switch (usage->format->effectiveFormat) {
case webgl::EffectiveFormat::Luminance8:
case webgl::EffectiveFormat::Alpha8:
case webgl::EffectiveFormat::Luminance8Alpha8:
// Non-color-renderable formats from Table 3.3.
canGenerateMipmap = true;
break;
default:
break;
}
if (!canGenerateMipmap) {
mContext->ErrorInvalidOperation(
"Texture at base level is not unsized"
" internal format or is not"
" color-renderable or texture-filterable.");
return;
}
// Done with validation. Do the operation.
gl::GLContext* gl = mContext->gl;
if (gl->WorkAroundDriverBugs()) {
// bug 696495 - to work around failures in the texture-mips.html test on
// various drivers, we set the minification filter before calling
// glGenerateMipmap. This should not carry a significant performance
// overhead so we do it unconditionally.
//
// note that the choice of GL_NEAREST_MIPMAP_NEAREST really matters. See
// Chromium bug 101105.
gl->fTexParameteri(mTarget.get(), LOCAL_GL_TEXTURE_MIN_FILTER,
LOCAL_GL_NEAREST_MIPMAP_NEAREST);
gl->fGenerateMipmap(mTarget.get());
gl->fTexParameteri(mTarget.get(), LOCAL_GL_TEXTURE_MIN_FILTER,
mSamplingState.minFilter.get());
} else {
gl->fGenerateMipmap(mTarget.get());
}
// Record the results.
const auto maxLevel = EffectiveMaxLevel();
PopulateMipChain(maxLevel);
}
