mirror of
https://github.com/mozilla/gecko-dev.git
synced 2024-11-08 12:37:37 +00:00
403 lines
16 KiB
Plaintext
403 lines
16 KiB
Plaintext
Name
|
|
|
|
ANGLE_depth_texture
|
|
|
|
Name Strings
|
|
|
|
GL_ANGLE_depth_texture
|
|
|
|
Contributors
|
|
|
|
Nicolas Capens, TransGaming
|
|
Daniel Koch, TransGaming
|
|
Shannon Woods, TransGaming
|
|
Kenneth Russell, Google
|
|
Vangelis Kokkevis, Google
|
|
Gregg Tavares, Google
|
|
Contributors to OES_depth_texture
|
|
Contributors to OES_packed_depth_stencil
|
|
|
|
Contact
|
|
|
|
Shannon Woods, TransGaming (shannon 'dot' woods 'at' transgaming.com)
|
|
|
|
Status
|
|
|
|
Implemented in ANGLE.
|
|
|
|
Version
|
|
|
|
Last Modified Date: February 25, 2013
|
|
Revision: #4
|
|
|
|
Number
|
|
|
|
TBD
|
|
|
|
Dependencies
|
|
|
|
OpenGL ES 2.0 is required.
|
|
This extension is written against the OpenGL ES 2.0.25 specification
|
|
|
|
OES_packed_depth_stencil affects the definition of this extension.
|
|
|
|
EXT_texture_storage affects the definition of this extension.
|
|
|
|
Overview
|
|
|
|
This extension defines support for 2D depth and depth-stencil
|
|
textures in an OpenGL ES implementation.
|
|
|
|
This extension incorporates the depth texturing functionality of
|
|
OES_depth_texture and OES_packed_depth_stencil, but does not
|
|
provide the ability to load existing data via TexImage2D or
|
|
TexSubImage2D. This extension also allows implementation
|
|
variability in which components from a sampled depth texture
|
|
contain the depth data. Depth textures created with this
|
|
extension only support 1 level.
|
|
|
|
New Procedures and Functions
|
|
|
|
None
|
|
|
|
New Tokens
|
|
|
|
Accepted by the <format> parameter of TexImage2D and TexSubImage2D and
|
|
<internalformat> parameter of TexImage2D:
|
|
|
|
DEPTH_COMPONENT 0x1902
|
|
DEPTH_STENCIL_OES 0x84F9
|
|
|
|
Accepted by the <type> parameter of TexImage2D, TexSubImage2D:
|
|
|
|
UNSIGNED_SHORT 0x1403
|
|
UNSIGNED_INT 0x1405
|
|
UNSIGNED_INT_24_8_OES 0x84FA
|
|
|
|
Accepted by the <internalformat> parameter of TexStorage2DEXT:
|
|
|
|
DEPTH_COMPONENT16 0x81A5
|
|
DEPTH_COMPONENT32_OES 0x81A7
|
|
DEPTH24_STENCIL8_OES 0x88F0
|
|
|
|
Additions to Chapter 2 of the OpenGL ES 2.0 Specification (OpenGL Operation)
|
|
|
|
Update Section 2.10.5 "Shader Execution" in the subsection titled
|
|
"Texture Access" add a new paragraph before the last paragraph add
|
|
this line:
|
|
|
|
"The stencil index texture internal component is ignored if the base
|
|
internal format is DEPTH_STENCIL_OES.
|
|
|
|
If a vertex shader uses..."
|
|
|
|
Additions to Chapter 3 of the OpenGL ES 2.0 specification (Rasterization)
|
|
|
|
Add the following rows to Table 3.2 (page 62):
|
|
|
|
type Parameter GL Data Type Special
|
|
------------------------------------------------
|
|
... ... ...
|
|
UNSIGNED_SHORT ushort No
|
|
UNSIGNED_INT uint No
|
|
UNSIGNED_INT_24_8_OES uint Yes
|
|
|
|
Add the following rows to Table 3.3 (page 62):
|
|
|
|
Format Name Element Meaning and Order Target Buffer
|
|
------------------------------------------------------------------
|
|
... ... ...
|
|
DEPTH_COMPONENT Depth Depth
|
|
DEPTH_STENCIL_OES Depth and Stencil Index Depth and Stencil
|
|
... ... ...
|
|
|
|
Add a row to Table 3.5 "Packed pixel formats" (page 64):
|
|
|
|
type Parameter GL Type Components Pixel Formats
|
|
------------------------------------------------------------------
|
|
... ... ... ...
|
|
UNSIGNED_INT_24_8_OES uint 2 DEPTH_STENCIL_OES
|
|
|
|
Add a new table after Table 3.6 (page 64):
|
|
|
|
UNSIGNED_INT_24_8_OES
|
|
|
|
31 30 29 28 27 26 ... 12 11 10 9 8 7 6 5 4 3 2 1 0
|
|
+----------------------------------+---------------+
|
|
| 1st Component | 2nd Component |
|
|
+----------------------------------+---------------+
|
|
|
|
Table 3.6.B: UNSIGNED_INT formats
|
|
|
|
Add a row to Table 3.7 "Packed pixel field assignments" (page 65):
|
|
|
|
Format | 1st 2nd 3rd 4th
|
|
------------------+-------------------------------
|
|
... | ... ... ... ...
|
|
DEPTH_STENCIL_OES | depth stencil N/A N/A
|
|
|
|
Add the following paragraph to the end of the section "Conversion to
|
|
floating-point" (page 65):
|
|
|
|
"For groups of components that contain both standard components and index
|
|
elements, such as DEPTH_STENCIL_OES, the index elements are not converted."
|
|
|
|
In section 3.7.1 "Texture Image Specification", update page 67 to
|
|
say:
|
|
|
|
"The selected groups are processed as described in section 3.6.2, stopping
|
|
just before final conversion. Each R, G, B, A, or depth value so generated
|
|
is clamped to [0, 1], while the stencil index values are masked by 2^n-1,
|
|
where n is the number of stencil bits in the internal format resolution
|
|
(see below).
|
|
|
|
Components are then selected from the resulting R, G, B, A, depth, or
|
|
stencil index values to obtain a texture with the base internal format
|
|
specified by <internalformat>. Table 3.8 summarizes the mapping of R, G,
|
|
B, A, depth, or stencil values to texture components, as a function of the
|
|
base internal format of the texture image. <internalformat> may be
|
|
specified as one of the internal format symbolic constants listed in
|
|
table 3.8. Specifying a value for <internalformat> that is not one of the
|
|
above values generates the error INVALID_VALUE. If <internalformat> does
|
|
not match <format>, the error INVALID_OPERATION is generated.
|
|
|
|
Textures with a base internal format of DEPTH_COMPONENT or
|
|
DEPTH_STENCIL_OES are supported by texture image specification commands
|
|
only if <target> is TEXTURE_2D. Using these formats in conjunction with
|
|
any other <target> will result in an INVALID_OPERATION error.
|
|
|
|
Textures with a base internal format of DEPTH_COMPONENT or
|
|
DEPTH_STENCIL_OES only support one level of image data. Specifying a
|
|
non-zero value for <level> will result in an INVALID_OPERATION error.
|
|
|
|
Textures with a base internal format of DEPTH_COMPONENT or DEPTH_STENCIL_OES
|
|
require either depth component data or depth/stencil component data.
|
|
Textures with other base internal formats require RGBA component data. The
|
|
error INVALID_OPERATION is generated if the base internal format is
|
|
DEPTH_COMPONENT or DEPTH_STENCIL_OES and <format> is not DEPTH_COMPONENT or
|
|
DEPTH_STENCIL_OES, or if the base internal format is not DEPTH_COMPONENT or
|
|
DEPTH_STENCIL_OES and <format> is DEPTH_COMPONENT or DEPTH_STENCIL_OES.
|
|
|
|
Textures with a base internal format of DEPTH_COMPONENT or
|
|
DEPTH_STENCIL_OES do not support loading image data via the TexImage
|
|
commands. They can only have their contents specified by rendering
|
|
to them. The INVALID_OPERATION error is generated by the TexImage2D
|
|
command if <data> is not NULL for such textures."
|
|
|
|
Add a row to table 3.8 (page 68), and update the title of the
|
|
second column:
|
|
|
|
Base Internal Format RGBA, Depth and Stencil Values Internal Components
|
|
-------------------------------------------------------------------------
|
|
... ... ...
|
|
DEPTH_COMPONENT Depth D
|
|
DEPTH_STENCIL_OES Depth,Stencil D,S
|
|
... ... ...
|
|
|
|
Update the caption for table 3.8 (page 68)
|
|
|
|
"Table 3.8: Conversion from RGBA, depth, and stencil pixel components to
|
|
internal texture components. Texture components R, G, B, A, and L are
|
|
converted back to RGBA colors during filtering as shown in table 3.12.
|
|
Texture components D are converted to RGBA colors as described in
|
|
section 3.7.8-1/2."
|
|
|
|
Add the following to section 3.7.2 "Alternate Texture Image Specification
|
|
Commands":
|
|
|
|
"CopyTexImage2D and CopyTexSubImage2D generate the INVALID_OPERATION
|
|
error if the base internal format of the destination texture is
|
|
DEPTH_COMPONENT or DEPTH_STENCIL_OES.
|
|
|
|
TexSubImage2D generates the INVALID_OPERATION error if the base internal
|
|
format of the texture is DEPTH_COMPONENT or DEPTH_STENCIL_OES."
|
|
|
|
Add a new section between sections 3.7.8 and 3.7.9:
|
|
|
|
"3.7.8-1/2 Depth/Stencil Textures
|
|
|
|
If the currently bound texture's base internal format is DEPTH_COMPONENT or
|
|
DEPTH_STENCIL_OES, then the output of the texture unit is as described
|
|
below. Otherwise, the texture unit operates in the normal manner.
|
|
|
|
Let <D_t> be the depth texture value, provided by the shader's texture lookup
|
|
function. Then the effective texture value is computed as follows:
|
|
<Tau> = <D_t>
|
|
|
|
If the texture image has a base internal format of DEPTH_STENCIL_OES, then
|
|
the stencil index texture component is ignored. The texture value <Tau> does
|
|
not include a stencil index component, but includes only the depth
|
|
component.
|
|
|
|
The resulting <Tau> is assigned to <R_t>. In some implementations, <Tau> is
|
|
also assigned to <G_t>, <B_t>, or <A_t>. Thus in table 3.12, textures with
|
|
depth component data behave as if their base internal format is RGBA, with
|
|
values in <G_t>, <B_t>, and <A_t> being implementation dependent."
|
|
|
|
Add the following to section 3.7.11 "Mipmap Generation":
|
|
|
|
"If the level zero array contains depth or depth-stencil data, the
|
|
error INVALID_OPERATION is generated."
|
|
|
|
Insert a new paragraph after the first paragraph of the "Texture Access"
|
|
subsection of section 3.8.2 on page 87, which says:
|
|
|
|
"Texture lookups involving textures with depth component data generate
|
|
a texture source color by using depth data directly, as described in
|
|
section 3.7.8-1/2. The stencil texture internal component is ignored
|
|
if the base internal format is DEPTH_STENCIL_OES."
|
|
|
|
Additions to Chapter 4 of the OpenGL ES 2.0 specification (Per-Fragment
|
|
Operations and the Framebuffer)
|
|
|
|
In section 4.4.5 "Framebuffer Completeness", replace the the 3rd
|
|
paragraph with the following text:
|
|
|
|
"* An internal format is color-renderable if it is one of the formats
|
|
from table 4.5 noted as color-renderable or if it is unsized format
|
|
RGBA or RGB. No other formats, including compressed internal formats,
|
|
are color-renderable.
|
|
|
|
* An internal format is depth-renderable if it is one of the sized
|
|
internal formats from table 4.5 noted as depth-renderable, if it
|
|
is the unsized format DEPTH_COMPONENT or if it is the internal
|
|
format value of DEPTH24_STENCIL8_OES. No other formats are
|
|
depth-renderable.
|
|
|
|
* An internal format is stencil-renderable if it is one of the sized
|
|
internal formats from table 4.5 noted as stencil-renderable or if it
|
|
is DEPTH24_STENCIL8_OES. No other formats are stencil-renderable."
|
|
|
|
Additions to Chapter 5 of the OpenGL ES 2.0 Specification (Special
|
|
Functions)
|
|
|
|
None.
|
|
|
|
Additions to Chapter 6 of the OpenGL ES 2.0 Specification (State and State
|
|
Requests)
|
|
|
|
None.
|
|
|
|
Interactions with OES_packed_depth_stencil
|
|
|
|
If OES_packed_depth_stencil is not supported, mentions of
|
|
DEPTH_STENCIL_OES and UNSIGNED_INT_24_8_OES as a format/type combinations
|
|
for TexImage2D and TexSubImage2D are omitted. Mentions of
|
|
the internal format DEPTH24_STENCIL8_OES are also omitted.
|
|
|
|
Interactions with EXT_texture_storage
|
|
|
|
If EXT_texture_storage is supported the following internalformat
|
|
to format/type mappings are used:
|
|
|
|
<internalformat> <format> <type>
|
|
---------------- -------- ------
|
|
DEPTH_COMPONENT16 DEPTH_COMPONENT UNSIGNED_SHORT
|
|
DEPTH_COMPONENT32_OES DEPTH_COMPONENT UNSIGNED_INT
|
|
DEPTH24_STENCIL8_OES DEPTH_STENCIL_OES UNSIGNED_INT
|
|
|
|
Textures with the above <internalformats> only support one level of
|
|
image data. Specifying a value other than one for the <levels> parameter
|
|
to TexStorage2DEXT will result in an INVALID_OPERATION error.
|
|
|
|
If EXT_texture_storage is not supported, ignore any references
|
|
to TexStorage2DEXT.
|
|
|
|
Errors
|
|
|
|
The error INVALID_OPERATION is generated by TexImage2D if <format> and
|
|
<internalformat> are DEPTH_COMPONENT and <type> is not UNSIGNED_SHORT,
|
|
or UNSIGNED_INT.
|
|
|
|
The error INVALID_OPERATION is generated by TexSubImage2D if <format> is
|
|
DEPTH_COMPONENT and <type> is not UNSIGNED_SHORT, or UNSIGNED_INT.
|
|
|
|
The error INVALID_OPERATION is generated by TexImage2D if <format> and
|
|
<internalformat> are not DEPTH_COMPONENT and <type> is UNSIGNED_SHORT,
|
|
or UNSIGNED_INT.
|
|
|
|
The error INVALID_OPERATION is generated by TexSubImage2D if <format> is
|
|
not DEPTH_COMPONENT and <type> is UNSIGNED_SHORT, or UNSIGNED_INT.
|
|
|
|
The error INVALID_OPERATION is generated by TexImage2D if <format> and
|
|
<internalformat> are DEPTH_STENCIL_OES and <type> is not
|
|
UNSIGNED_INT_24_8_OES.
|
|
|
|
The error INVALID_OPERATION is generated by TexSubImage2D if <format>
|
|
is DEPTH_STENCIL_OES and <type> is not UNSIGNED_INT_24_8_OES.
|
|
|
|
The error INVALID_OPERATION is generated by TexImage2D if <format> and
|
|
<internalformat> is not DEPTH_STENCIL_OES and <type> is
|
|
UNSIGNED_INT_24_8_OES.
|
|
|
|
The error INVALID_OPERATION is generated by TexSubImage2D if <format>
|
|
is not DEPTH_STENCIL_OES and <type> is UNSIGNED_INT_24_8_OES.
|
|
|
|
The error INVALID_OPERATION is generated in the following situations:
|
|
- TexImage2D is called with <format> and <internalformat> of
|
|
DEPTH_COMPONENT or DEPTH_STENCIL_OES and
|
|
- <target> is not TEXTURE_2D,
|
|
- <data> is not NULL, or
|
|
- <level> is not zero.
|
|
- TexSubImage2D is called with <format> of DEPTH_COMPONENT or
|
|
DEPTH_STENCIL_OES.
|
|
- TexStorage2DEXT is called with <internalformat> of DEPTH_COMPONENT16,
|
|
DEPTH_COMPONENT32_OES, or DEPTH24_STENCIL8_OES, and
|
|
- <target> is not TEXTURE_2D, or
|
|
- <levels> is not one.
|
|
- CopyTexImage2D is called with an <internalformat> that has a base
|
|
internal format of DEPTH_COMPONENT or DEPTH_STENCIL_OES.
|
|
- CopyTexSubImage2D is called with a target texture that has a base
|
|
internal format of DEPTH_COMPONENT or DEPTH_STENCIL_OES.
|
|
- GenerateMipmap is called on a texture that has a base internal format
|
|
of DEPTH_COMPONENT or DEPTH_STENCIL_OES.
|
|
|
|
New State
|
|
|
|
None.
|
|
|
|
Issues
|
|
|
|
1) What are the differences between this extension and OES_depth_texture
|
|
and OES_packed_depth_stencil?
|
|
|
|
RESOLVED: This extension:
|
|
- does not support loading pre-baked depth stencil data via
|
|
TexImage2D or TexSubImage2D.
|
|
- allows variability in the y-, z-, and w-components of the sample
|
|
results from depth textures.
|
|
- only supports one level textures.
|
|
- explicitly lists the errors for unsupported functionality.
|
|
Since these were not clearly specified in the OES_depth_texture
|
|
extension there may be differences in error values between
|
|
implementations of OES_depth_texture and ANGLE_depth_texture.
|
|
This specification was also rebased to apply against the OpenGL ES 2.0
|
|
specification instead of the OpenGL specification, making it more
|
|
obvious what all the functionality changes are.
|
|
|
|
2) Why does TexSubImage2D accept the new format/type combinations even
|
|
though it does not actually support loading data?
|
|
|
|
RESOLVED: This was done to be more consistent with the OES_depth_texture
|
|
extension and to make it easier to add support for loading texture
|
|
data if it is possible to support in the future.
|
|
|
|
3) Why are only 1-level depth textures supported?
|
|
|
|
RESOLVED: The only use for multiple levels of depth textures would
|
|
be for fitlered texturing. However since it is not possible to
|
|
render to non-zero-level texture levels in OpenGL ES 2.0, and since
|
|
this extension forbids loading existing data and GenerateMipmap on
|
|
depth textures, it is impossible to initialize or specify contents
|
|
for non-zero levels of depth textures.
|
|
|
|
Revision History
|
|
|
|
02/25/2013 swoods revise to allow texture lookup to guarantee depth values
|
|
only in red channel of sample result.
|
|
06/04/2012 dgkoch fix errors, disallow multi-level depth textures.
|
|
05/30/2012 dgkoch minor updates and add issues.
|
|
05/23/2012 dgkoch intial revision based on OES_depth_texture and
|
|
OES_packed_depth_stencil and rebased against the ES 2.0 spec
|
|
|