Name AMD_gpu_shader_int64 Name Strings GL_AMD_gpu_shader_int64 Contact Daniel Rakos, AMD (daniel.rakos 'at' amd.com) Contributors Daniel Rakos, AMD Graham Sellers, AMD Status Shipping Version Last Modified Date: 07/07/2014 Author Revision: 3 Number OpenGL Extension #451 Dependencies This extension is written against the OpenGL 4.4 (Core Profile) Specification. This extension is written against version 4.40 of the OpenGL Shading Language Specification. OpenGL 4.0 and GLSL 4.00 are required. This extension interacts with NV_gpu_shader5. This extension interacts with NV_shader_buffer_load. This extension interacts with EXT_direct_state_access. This extension interacts with NV_vertex_attrib_integer_64bit. This extension interacts with EXT_shader_integer_mix. Overview This extension was developed based on the NV_gpu_shader5 extension to allow implementations supporting 64-bit integers to expose the feature without the additional requirements that are present in NV_gpu_shader5. The extension introduces the following features for all shader types: * support for 64-bit scalar and vector integer data types, including uniform API, uniform buffer object, transform feedback, and shader input and output support; * new built-in functions to pack and unpack 64-bit integer types into a two-component 32-bit integer vector; * new built-in functions to convert double-precision floating-point values to or from their 64-bit integer bit encodings; * vector relational functions supporting comparisons of vectors of 64-bit integer types; and * common functions abs, sign, min, max, clamp, and mix supporting arguments of 64-bit integer types. This extension is designed to be a functional superset of the 64-bit integer support introduced by NV_gpu_shader5 and to be source code compatible with that, thus the new procedures, functions, and tokens are identical to those found in that extension. New Procedures and Functions (The functions are identical to those defined in NV_gpu_shader5.) void Uniform1i64NV(int location, int64EXT x); void Uniform2i64NV(int location, int64EXT x, int64EXT y); void Uniform3i64NV(int location, int64EXT x, int64EXT y, int64EXT z); void Uniform4i64NV(int location, int64EXT x, int64EXT y, int64EXT z, int64EXT w); void Uniform1i64vNV(int location, sizei count, const int64EXT *value); void Uniform2i64vNV(int location, sizei count, const int64EXT *value); void Uniform3i64vNV(int location, sizei count, const int64EXT *value); void Uniform4i64vNV(int location, sizei count, const int64EXT *value); void Uniform1ui64NV(int location, uint64EXT x); void Uniform2ui64NV(int location, uint64EXT x, uint64EXT y); void Uniform3ui64NV(int location, uint64EXT x, uint64EXT y, uint64EXT z); void Uniform4ui64NV(int location, uint64EXT x, uint64EXT y, uint64EXT z, uint64EXT w); void Uniform1ui64vNV(int location, sizei count, const uint64EXT *value); void Uniform2ui64vNV(int location, sizei count, const uint64EXT *value); void Uniform3ui64vNV(int location, sizei count, const uint64EXT *value); void Uniform4ui64vNV(int location, sizei count, const uint64EXT *value); void GetUniformi64vNV(uint program, int location, int64EXT *params); (The following function is also provided by NV_shader_buffer_load.) void GetUniformui64vNV(uint program, int location, uint64EXT *params); (All of the following ProgramUniform* functions are supported if and only if EXT_direct_state_access is supported.) void ProgramUniform1i64NV(uint program, int location, int64EXT x); void ProgramUniform2i64NV(uint program, int location, int64EXT x, int64EXT y); void ProgramUniform3i64NV(uint program, int location, int64EXT x, int64EXT y, int64EXT z); void ProgramUniform4i64NV(uint program, int location, int64EXT x, int64EXT y, int64EXT z, int64EXT w); void ProgramUniform1i64vNV(uint program, int location, sizei count, const int64EXT *value); void ProgramUniform2i64vNV(uint program, int location, sizei count, const int64EXT *value); void ProgramUniform3i64vNV(uint program, int location, sizei count, const int64EXT *value); void ProgramUniform4i64vNV(uint program, int location, sizei count, const int64EXT *value); void ProgramUniform1ui64NV(uint program, int location, uint64EXT x); void ProgramUniform2ui64NV(uint program, int location, uint64EXT x, uint64EXT y); void ProgramUniform3ui64NV(uint program, int location, uint64EXT x, uint64EXT y, uint64EXT z); void ProgramUniform4ui64NV(uint program, int location, uint64EXT x, uint64EXT y, uint64EXT z, uint64EXT w); void ProgramUniform1ui64vNV(uint program, int location, sizei count, const uint64EXT *value); void ProgramUniform2ui64vNV(uint program, int location, sizei count, const uint64EXT *value); void ProgramUniform3ui64vNV(uint program, int location, sizei count, const uint64EXT *value); void ProgramUniform4ui64vNV(uint program, int location, sizei count, const uint64EXT *value); New Tokens Returned by the parameter of GetActiveAttrib, GetActiveUniform, and GetTransformFeedbackVarying: (The tokens are identical to those defined in NV_gpu_shader5.) INT64_NV 0x140E UNSIGNED_INT64_NV 0x140F INT8_NV 0x8FE0 INT8_VEC2_NV 0x8FE1 INT8_VEC3_NV 0x8FE2 INT8_VEC4_NV 0x8FE3 INT16_NV 0x8FE4 INT16_VEC2_NV 0x8FE5 INT16_VEC3_NV 0x8FE6 INT16_VEC4_NV 0x8FE7 INT64_VEC2_NV 0x8FE9 INT64_VEC3_NV 0x8FEA INT64_VEC4_NV 0x8FEB UNSIGNED_INT8_NV 0x8FEC UNSIGNED_INT8_VEC2_NV 0x8FED UNSIGNED_INT8_VEC3_NV 0x8FEE UNSIGNED_INT8_VEC4_NV 0x8FEF UNSIGNED_INT16_NV 0x8FF0 UNSIGNED_INT16_VEC2_NV 0x8FF1 UNSIGNED_INT16_VEC3_NV 0x8FF2 UNSIGNED_INT16_VEC4_NV 0x8FF3 UNSIGNED_INT64_VEC2_NV 0x8FF5 UNSIGNED_INT64_VEC3_NV 0x8FF6 UNSIGNED_INT64_VEC4_NV 0x8FF7 FLOAT16_NV 0x8FF8 FLOAT16_VEC2_NV 0x8FF9 FLOAT16_VEC3_NV 0x8FFA FLOAT16_VEC4_NV 0x8FFB Additions to Chapter 7 of the OpenGL 4.4 (Core Profile) Specification (Program Objects) Modify Section 7.3.1, Program Interfaces (add to Table 7.3, OpenGL Shading Language type tokens, p. 107) +----------------------------+--------------+--------+--------+--------+ | Type Name Token | Keyword | Attrib | Xfb | Buffer | +----------------------------+--------------+--------+--------+--------+ | INT64_NV | int64_t | * | * | * | | INT64_VEC2_NV | i64vec2 | * | * | * | | INT64_VEC3_NV | i64vec3 | * | * | * | | INT64_VEC4_NV | i64vec4 | * | * | * | | UNSIGNED_INT64_NV | uint64_t | * | * | * | | UNSIGNED_INT64_VEC2_NV | u64vec2 | * | * | * | | UNSIGNED_INT64_VEC3_NV | u64vec3 | * | * | * | | UNSIGNED_INT64_VEC4_NV | u64vec4 | * | * | * | +----------------------------+--------------+--------+--------+--------+ Modify Section 7.6, Uniform Variables (modify second paragraph on p. 120) Scalar, vector, and matrix uniforms with double-precision components, and scalar and vector uniforms with 64-bit integer components will consume no more than twice the number of components of equivalent uniforms with single-precision components. Modify Section 7.6.1, Loading Uniform Variables (add to the list of commands in first paragraph on p. 125) void Uniform{1,2,3,4}{i64,ui64}NV(int location, T value); void Uniform{1,2,3,4}{i64,ui64}vNV(int location, T value); (insert after third paragraph on p. 127) The Uniform*i64{v}NV and Uniform*ui{v}NV commands will load count sets of one to four 64-bit signed or unsigned integer values into a uniform location defined as a 64-bit signed or unsigned integer scalar or vector types. Modify Section 7.6.2.1, Uniform Buffer Object Storage (modify the first two bullets of the first paragraph on p. 130) * Members of type bool int, uint, float, double, int64_t, and uint64_t are respectively extracted from a buffer object by reading a single uint, int, uint, float, double, int64_t, or uint64_t value at the specified offset. * Vectors with N elements with basic data types of bool, int, uint, float, double, int64_t, or uint64_t are extracted as N values in consecutive memory locations beginning at the specified offset, with components stored in order with the first (X) component at the lowest offset. The GL data type used for component extraction is derived according to the rules for scalar members above. Modify Section 7.13, Shader, Program, and Program Pipeline Queries (add to the list of commands in last paragraph on p. 155) void GetUniformi64vNV(uint program, int location, int64* params) void GetUniformui64vNV(uint program, int location, uint64* params) Additions to Chapter 11 of the OpenGL 4.4 (Core Profile) Specification (Programmable Vertex Processing) Modify Section 11.1.1, Vertex Attributes (modify third sentence of second paragraph on p. 344) ... hardware resources. For the purposes of this test, attribute variables of the type dvec3, dvec4, dmat2x3, dmat2x3, dmat3, dmat3x4, dmat4x3, dmat4, i64vec3, i64vec4, u64vec3, and u64vec4 may count as consuming twice as many attributes as equivalent single-precision types. While these types use the same number of generic attributes as their single-precision vectors of internal storage for each three- or four-component double-precision or 64-bit integer vector. Modify Section 11.1.2.1, Output Variables (modify last sentence of fourth paragraph on p. 345) ... multiple components. Each component of variables declared as double- precision floating point scalars, vectors, or matrices, or declared as 64-bit integer scalars or vectors may be counted as consuming two components. (modify third bullet of the first paragraph on p. 349) * any variable containing double-precision floating-point or 64-bit integer components - has an xfb_offset layout qualifier that is not a multiple of eight; or - is associated with a binding point with an xfb_stride layout qualifier that is not a multiple of eight; (modify second paragraph on p. 349) For transform feedback purposes, each component of outputs declared as double-precision floating-point scalars, vectors, or matrices, or 64-bit integer scalars or vectors are considered to consume eight basic machine units, and each component of any other type is considered to consume four basic machine units. Modifications to the OpenGL Shading Language Specification, Version 4.40 Including the following line in a shader can be used to control the language features described in this extension: #extension GL_AMD_gpu_shader_int64 : where is as specified in section 3.3. New preprocessor #defines are added to the OpenGL Shading Language: #define GL_AMD_gpu_shader_int64 1 Additions to Chapter 3 of the OpenGL Shading Language Specification (Basics) Modify Section 3.6, Keywords (add the following to the list of reserved keywords at p. 15) int64_t i64vec2 i64vec3 i64vec4 uint64_t u64vec2 u64vec3 u64vec4 Additions to Chapter 4 of the OpenGL Shading Language Specification (Variables and Types) Modify Section 4.1, Basic Types (add to the basic "Transparent Types" table, p. 19) +-----------+------------------------------------------------------------+ | Type | Meaning | +-----------+------------------------------------------------------------+ | int64_t | a 64-bit signed integer | | uint64_t | a 64-bit unsigned integer | | i64vec2 | a two-component 64-bit signed integer vector | | i64vec3 | a three-component 64-bit signed integer vector | | i64vec4 | a four-component 64-bit signed integer vector | | u64vec2 | a two-component 64-bit unsigned integer vector | | u64vec3 | a three-component 64-bit unsigned integer vector | | u64vec4 | a four-component 64-bit unsigned integer vector | +-----------+------------------------------------------------------------+ Modify Section 4.1.3, Integers (replace first paragraph of the section, p. 23) Signed and unsigned integer variables are fully supported. In this document, the term integer is meant to generally include both signed and unsigned integers, including both 32-bit and 64-bit integers. Unsigned integers of type uint, uvec2, uvec3, and uvec4 have exactly 32 bits of precision, while unsigned integers of type uint64_t, u64vec2, u64vec3, and u64vec4 have exactly 64 bits of precision. Signed integers of type int, ivec2, ivec3, and ivec4 have exactly 32 bits of precision, while signed integers of type int64_t, i64vec2, i64vec3, and i64vec4 have exactly 64 bits of precision. Addition, subtraction, and shift operations resulting in overflow or underflow will not cause any exceptions, nor will they saturate, rather they will "wrap" to yield the low-order bits of the result. Divison and multiplication operations resulting in overflow or underflow will not cause any exception but will result in an undefined value. (add after the first paragraph of the section, p. 23) Variables with the types "int64_t" and "uint64_t" represent signed and unsigned integer values, respectively, with exactly 64 bits of precision. (modify grammar rule for "integer-suffix", p. 24) integer-suffix: one of u U l L ul UL (modify first sentence of second paragraph on p. 24) No white space is allowed between the digits of an integer constant, including after the leading 0 or after the leading 0x or 0X of a constant, or before the suffix u, U, l, L, ul, or UL. (modify third sentence of second paragraph on p. 24) When the suffix u or U is present, the literal has type uint. When the suffix l or L is present, the literal has type int64_t. When the suffix ul or UL is present, the literal has type uint64_t. Otherwise, the type is int. Modify Section 4.1.10, Implicit Conversions (modify table of implicit conversions on p. 33) +----------------------+-------------------------------------------------+ | Type of expression | Can be implicitly converted to | +----------------------+-------------------------------------------------+ | int | uint, int64_t, uint64_t, float, double | | uint | uint64_t, float, double | | int64_t | uint64_t, double | | uint64_t | double | | ivec2 | uvec2, i64vec2, u64vec2, vec2, dvec2 | | ivec3 | uvec3, i64vec3, u64vec3, vec3, dvec3 | | ivec4 | uvec4, i64vec4, u64vec4, vec4, dvec4 | | uvec2 | u64vec2, vec2, dvec2 | | uvec3 | u64vec3, vec3, dvec3 | | uvec4 | u64vec4, vec4, dvec4 | | i64vec2 | u64vec2, dvec2 | | i64vec3 | u64vec3, dvec3 | | i64vec4 | u64vec4, dvec4 | | u64vec2 | dvec2 | | u64vec3 | dvec3 | | u64vec4 | dvec4 | +----------------------+-------------------------------------------------+ Modify Section 4.3.6, Output Variables (modify third and fourth sentence of second paragraph on p. 46) ... in a fragment shader. Fragment outputs can only be float, single- precision floating-point vectors, signed or unsigned 32-bit integer vectors, or arrays of any these. It is a compile-time error to declare any double-precision type, 64-bit integer type, matrix, or structure as an output. Additions to Chapter 5 of the OpenGL Shading Language Specification (Operators and Expressions) Modify Section 5.4.1, Conversion and Scalar Constructors (add after first list of constructor examples on p. 91) int64_t(double) // converts a double value to a 64-bit signed integer uint64_t(bool) // converts a Boolean value to a 64-bit unsigned integer (modify second sentence of first paragraph on p. 92) ... is dropped. It is undefined to convert a negative floating-point value to an uint or uint64_t. (replace third paragraph on p. 92) The constructors int(uint) and int64_t(uint64_t) preserve the bit pattern in the argument, which will change the argument's value if its sign bit is set. The constructor uint(int) and uint64_t(int64_t) preserve the bit pattern in the argument, which will change its value if it is negative. Additions to Chapter 6 of the OpenGL Shading Language Specification (Statements and Structure) Modify Section 6.1, Function Defintions (replace second rule in third paragraph on p. 106) 2. A match involving a conversion from a signed integer, unsigned integer, or floating-point type to a similar type having a larger number of bits is better than a match involving any other implicit conversion. Additions to Chapter 8 of the OpenGL Shading Language Specification (Built-in Functions) (insert after third sentence of last paragraph on p. 132) ... genUType is used as the argument. Where the input arguments (and corresponding output) can be int64_t, i64vec2, i64vec3, i64vec4, genI64Type is used as the argument. Where the input arguments (and corresponding output) can be uint64_t, u64vec2, u64vec3, u64vec4, genU64Type is used as the argument. Modify Section 8.3, Common Functions (add to the table of common functions on p. 136) +------------------------------------------------+----------------------------------------------------+ | Syntax | Desciption | +------------------------------------------------+----------------------------------------------------+ | genI64Type abs(genI64Type x) | Returns x if x >= 0; otherwise it returns -x. | +------------------------------------------------+----------------------------------------------------+ | genI64Type sign(genI64Type x) | Returns 1 if x > 0, 0 if x = 0, or -1 if x < 0. | +------------------------------------------------+----------------------------------------------------+ | genI64Type min(genI64Type x, | Returns y if y < x; otherwise it returns x. | | genI64Type y) | | | genI64Type min(genI64Type x, | | | int64_t y) | | | genU64Type min(genU64Type x, | | | genU64Type y) | | | genU64Type min(genU64Type x, | | | uint64_t y) | | +------------------------------------------------+----------------------------------------------------+ | genI64Type max(genI64Type x, | Returns y if x < y; otherwise it returns x. | | genI64Type y) | | | genI64Type max(genI64Type x, | | | int64_t y) | | | genU64Type max(genU64Type x, | | | genU64Type y) | | | genU64Type max(genU64Type x, | | | uint64_t y) | | +------------------------------------------------+----------------------------------------------------+ | genI64Type clamp(genI64Type x, | Returns min(max(x, minVal), maxVal). | | genI64Type minVal, | | | genI64Type maxVal) | Results are undefined if minVal > maxVal. | | genI64Type clamp(genI64Type x, | | | int64_t minVal, | | | int64_t maxVal) | | | genU64Type clamp(genU64Type x, | | | genU64Type minVal, | | | genU64Type maxVal) | | | genU64Type clamp(genU64Type x, | | | uint64_t minVal, | | | uint64_t maxVal) | | +------------------------------------------------+----------------------------------------------------+ | genI64Type mix(genI64Type x, | Selects which vector each returned component comes | | genI64Type y, | from. For a component of a that is false, the | | genBType a) | corresponding component of x is returned. For a | | genU64Type mix(genU64Type x, | component of a that is true, the corresponding | | genU64Type y, | component of y is returned. | | genBType a) | | +------------------------------------------------+----------------------------------------------------+ | genI64Type doubleBitsToInt64(genDType value) | Returns a signed or unsigned 64-bit integer value | | genU64Type doubleBitsToUint64(genDType value) | representing the encoding of a double. The double | | | value's bit-level representation is preserved | +------------------------------------------------+----------------------------------------------------+ | genDType int64BitsToDouble(genI64Type value) | Returns a double value corresponding to a signed | | genDType uint64BitsToDouble(genU64Type value) | or unsigned integer encoding of a double. If a NaN | | | is passed in, it will not signal, and the | | | resulting value is unspecified. If an Inf is | | | passed in, the resulting value is the | | | corresponding Inf. | +------------------------------------------------+----------------------------------------------------+ Rename Section 8.4, Floating-Point Pack and Unpack Functions to 8.4, Floating-Point and Integer Pack and Unpack Functions Modify Section 8.4, Floating-Point and Integer Pack and Unpack Functions (add to the table of pack and unpack functions on p. 141) +-----------------------------------+------------------------------------------------------+ | Syntax | Desciption | +-----------------------------------+------------------------------------------------------+ | int64_t packInt2x32(ivec2 v) | Returns a signed or unsigned 64-bit integer obtained | | uint64_t packUint2x32(uvec2 v) | by packing the components of a two-component signed | | | or unsigned integer vector, respectively. The first | | | vector component specifies the 32 least significant | | | bits; the second component specifies the 32 most | | | significant bits. | +-----------------------------------+------------------------------------------------------+ | ivec2 unpackInt2x32(int64_t v) | Returns a signed or unsigned integer vector built | | uvec2 unpackUint2x32(uint64_t v) | from a 64-bit signed or unsigned integer scalar, | | | respectively. The first component of the vector | | | contains the 32 least significant bits of the input; | | | the second component contains the 32 most | | | significant bits. | +-----------------------------------+------------------------------------------------------+ Modify Section, 8.7, Vector Relational Functions (add to the table of placeholders at the top of p. 147) +-------------+-----------------------------+ | Placeholder | Specific Types Allowed | +-------------+-----------------------------+ | i64vec | i64vec2, i64vec3, i64vec4 | | u64vec | u64vec2, u64vec3, u64vec4 | +-------------+-----------------------------+ (add to the table of vector relational functions at the bottom of p. 147) +-------------------------------------------+-----------------------------------------------+ | Syntax | Desciption | +-------------------------------------------+-----------------------------------------------+ | bvec lessThan(i64vec x, i64vec y) | Returns the component-wise compare of x < y. | | bvec lessThan(u64vec x, u64vec y) | | +-------------------------------------------+-----------------------------------------------+ | bvec lessThanEqual(i64vec x, i64vec y) | Returns the component-wise compare of x <= y. | | bvec lessThanEqual(u64vec x, u64vec y) | | +-------------------------------------------+-----------------------------------------------+ | bvec greaterThan(i64vec x, i64vec y) | Returns the component-wise compare of x > y. | | bvec greaterThan(u64vec x, u64vec y) | | +-------------------------------------------+-----------------------------------------------+ | bvec greaterThanEqual(i64vec x, i64vec y) | Returns the component-wise compare of x >= y. | | bvec greaterThanEqual(u64vec x, u64vec y) | | +-------------------------------------------+-----------------------------------------------+ | bvec equal(i64vec x, i64vec y) | Returns the component-wise compare of x == y. | | bvec equal(u64vec x, u64vec y) | | +-------------------------------------------+-----------------------------------------------+ | bvec notEqual(i64vec x, i64vec y) | Returns the component-wise compare of x != y. | | bvec notEqual(u64vec x, u64vec y) | | +-------------------------------------------+-----------------------------------------------+ Modify Section 9, Shading Language Grammar for Core Profile (add to the list of tokens on p. 180) ... INT64 UINT64 I64VEC2 I64VEC3 I64VEC4 U64VEC2 U64VEC3 U64VEC4 ... INT64CONSTANT UINT64CONSTANT (add to the rule of "primary_expression" on p. 181) primary_expression: ... INT64CONSTANT UINT64CONSTANT ... (add to the rule of "type_specifier_nonarray" on p. 188) type_specifier_nonarray: ... INT64 UINT64 ... I64VEC2 I64VEC3 I64VEC4 U64VEC2 U64VEC3 U64VEC4 ... Dependencies on NV_gpu_shader5 If the shader enables only NV_gpu_shader5, but not AMD_gpu_shader_int64 then implicit conversions from int and uint types to int64_t and uint64_t types are not allowed. Also, the overloaded built-in functions abs, sign, min, max, clamp, and mix are not available. Dependencies on NV_shader_buffer_load If NV_shader_buffer_load is supported, that specification should be edited as follows, to allow pointers to dereference the new data types added by this extension. Modify "Section 2.20.X, Shader Memory Access" from NV_shader_buffer_load. (add rules for loads of variables having the new data types from this extension to the list of bullets following "When a shader dereferences a pointer variable") - Data of type int64_t and uint64_t are read from or written to memory as a signel 64-bit signed and unsigned integer value, respectively, at the specified GPU address. Dependencies on EXT_direct_state_access If EXT_direct_state_access is supported, that specification should be edited as follows to include new ProgramUniform* functions. (add to the list of ProgramUniform* commands) void ProgramUniform{1,2,3,4}{i64,ui64}NV (uint program int location, T value); void ProgramUniform{1,2,3,4}{i64,ui64}vNV (uint program, int location, const T *value); Dependencies on NV_vertex_attrib_integer_64bit This extension only provides the ability to specify 64-bit integer input variables in a GLSL vertex shader, but does not provide a way to specify the values of the corresponding vertex attributes via the OpenGL API. The NV_vertex_attrib_integer_64bit extension exactly provides that functionality. Dependencies on EXT_shader_integer_mix If EXT_shader_integer_mix is not supported remove all references to the new overloaded built-in functions of mix. Errors None. New State None. New Implementation Dependent State None. Issues (1) How the functionality in this extension different than the 64-bit integer support introduced by NV_gpu_shader5? RESOLVED: This extension is designed to be source code compatible with the 64-bit integer support in NV_gpu_shader5. However, it is a functional superset of that, as it adds the following additional features: * support for overloaded versions of the functions abs, sign, min, max, clamp, and mix that accept 64-bit integers as parameters. (2) How do the implicit conversions impact binary operators? RESOLVED: For binary operators, we prefer converting to a common type that is as close as possible in size and type to the original expression. (3) How do the implicit conversions impact function overloading rules? RESOLVED: We extend the preference rules in core OpenGL to account for the new data types, adding a rule to favor conversion from 32-bit integers to 64-bit integers over coversions to floating-point values. (4) What should be done to distinguish between 32- and 64-bit integer constants? RESOLVED: We will use "L" and "UL" to identify signed and unsigned 64-bit integer constants; the use of "L" matches a similar ("long") suffix in the C programming language. C leaves the size of integer types implementation-dependent, and many implementations require an "LL" suffix to declare 64-bit integer constants. With our size definitions, "L" will be considered sufficient to make an integer constant 64-bit. (5) Should provide support for vertex attributes with 64-bit components, and if so, how should the support be provided in the OpenGL API? RESOLVED: Yes, but in order to specify 64-bit vertex attribute values in the OpenGL API support for NV_vertex_attrib_integer_64bit or a similar extension is also required. (6) Should we support 64-bit integer uniforms in the default uniform block? DISCUSSION: There isn't much value in extending the standalone uniform API, as uniform buffers provide a way more efficient way to feed uniforms to the shaders, but in order to achieve feature parity with the 64-bit integer support in NV_gpu_shader5 it might be favorable to add support for it. RESOLVED: Yes, for compatibility with NV_gpu_shader5. (7) Should we support 64-bit integer types as members of uniform blocks, shader storage buffer blocks, or as transform feedback varyings? RESOLVED: Yes, support all of them. 64-bit integers will consume eight basic machine units just like double-precision floating-point variables. (8) How do the uniform loading commands introduced by this extension interact similar commands added by NV_shader_buffer_load? RESOLVED: NV_shader_buffer_load provided the command Uniformui64NV to load pointer uniforms with a single 64-bit unsigned integer. This extension provides vectors of 64-bit unsigned integers, so we needed Uniform{2,3,4}ui64NV commands. We chose to provide a Uniform1ui64NV command, which will be functionally equivalent to Uniformui64NV. (9) Should we provide distinct sized types for 32-bit integers, floats, and doubles? RESOLVED: No. While NV_gpu_shader5 does add such types, it seems there isn't much value in adding those in this extension, especially because this extension strictly focuses on supporting 64-bit integers. (10) Can the 64-bit uniform APIs be used to load values for uniforms of type "bool", "bvec2", "bvec3", or "bvec4"? RESOLVED: No. OpenGL 2.0 and beyond did allow "bool" variable to be set with Uniform*i* and Uniform*f APIs, and OpenGL 3.0 extended that support to Uniform*ui* for orthogonality. But it seems pointless to extended this capability forward to 64-bit Uniform APIs as well. (11) There exists both an UNSIGNED_INT64_AMD and UNSIGNED_INT64_NV token with different values (the former existed earlier) so which one this extension should use? DISCUSSION: No functions in this extension accept these values as inputs, they only should return one of these in various scenarios. RESOLVED: This extension will return the value of UNSIGNED_INT64_NV to stay source code compatible with NV_gpu_shader5. However, future extensions that should accept any of these tokens as inputs should accept both of them. Revision History Rev. Date Author Changes ---- -------- -------- ------------------------------------------------- 3 07/07/14 drakos Fixed inconsistency in implicit conversion rules. 2 31/04/14 gsellers Ready to post. 1 10/09/13 drakos Initial revision.