Name
MESA_shader_debug
Name Strings
GL_MESA_shader_debug
Contact
Brian Paul (brian.paul 'at' tungstengraphics.com)
Michal Krol (mjkrol 'at' gmail.com)
Status
Obsolete.
Version
Last Modified Date: July 30, 2006
Author Revision: 0.2
Number
TBD
Dependencies
OpenGL 1.0 is required.
The ARB_shader_objects extension is required.
The ARB_shading_language_100 extension is required.
The extension is written against the OpenGL 1.5 specification.
The extension is written against the OpenGL Shading Language 1.10
Specification.
Overview
This extension introduces a debug object that can be attached to
a program object to enable debugging. Vertex and/or fragment shader,
during execution, issue diagnostic function calls that are logged
to the debug object's log. A separate debug log for each shader type
is maintained. A debug object can be attached, detached and queried
at any time outside the Begin/End pair. Multiple debug objects can
be attached to a single program object.
IP Status
None
Issues
None
New Procedures and Functions
handleARB CreateDebugObjectMESA(void)
void ClearDebugLogMESA(handleARB obj, enum logType, enum shaderType)
void GetDebugLogMESA(handleARB obj, enum logType, enum shaderType,
sizei maxLength, sizei *length,
charARB *debugLog)
sizei GetDebugLogLengthMESA(handleARB obj, enum logType,
enum shaderType)
New Types
None
New Tokens
Returned by the <params> parameter of GetObjectParameter{fi}vARB:
DEBUG_OBJECT_MESA 0x8759
Accepted by the <logType> argument of ClearDebugLogMESA,
GetDebugLogLengthMESA and GetDebugLogMESA:
DEBUG_PRINT_MESA 0x875A
DEBUG_ASSERT_MESA 0x875B
Additions to Chapter 2 of the OpenGL 1.5 Specification
(OpenGL Operation)
None
Additions to Chapter 3 of the OpenGL 1.5 Specification (Rasterization)
None
Additions to Chapter 4 of the OpenGL 1.5 Specification (Per-Fragment
Operations and the Frame Buffer)
None
Additions to Chapter 5 of the OpenGL 1.5 Specification
(Special Functions)
None
Additions to Chapter 6 of the OpenGL 1.5 Specification (State and State
Requests)
None
Additions to Appendix A of the OpenGL 1.5 Specification (Invariance)
None
Additions to Chapter 1 of the OpenGL Shading Language 1.10 Specification
(Introduction)
None
Additions to Chapter 2 of the OpenGL Shading Language 1.10 Specification
(Overview of OpenGL Shading)
None
Additions to Chapter 3 of the OpenGL Shading Language 1.10 Specification
(Basics)
None
Additions to Chapter 4 of the OpenGL Shading Language 1.10 Specification
(Variables and Types)
None
Additions to Chapter 5 of the OpenGL Shading Language 1.10 Specification
(Operators and Expressions)
None
Additions to Chapter 6 of the OpenGL Shading Language 1.10 Specification
(Statements and Structure)
None
Additions to Chapter 7 of the OpenGL Shading Language 1.10 Specification
(Built-in Variables)
None
Additions to Chapter 8 of the OpenGL Shading Language 1.10 Specification
(Built-in Functions)
Add a new section 8.10 "Debug Functions":
Debug functions are available to both fragment and vertex shaders.
They are used to track the execution of a shader by logging
passed-in arguments to the debug object's log. Those values can be
retrieved by the application for inspection after shader execution
is complete.
The text, if any, produced by any of these functions is appended
to each debug object that is attached to the program object.
There are different debug log types
Add a new section 8.10.1 "Print Function":
The following printMESA prototypes are available.
void printMESA(const float value)
void printMESA(const int value)
void printMESA(const bool value)
void printMESA(const vec2 value)
void printMESA(const vec3 value)
void printMESA(const vec4 value)
void printMESA(const ivec2 value)
void printMESA(const ivec3 value)
void printMESA(const ivec4 value)
void printMESA(const bvec2 value)
void printMESA(const bvec3 value)
void printMESA(const bvec4 value)
void printMESA(const mat2 value)
void printMESA(const mat3 value)
void printMESA(const mat4 value)
void printMESA(const sampler1D value)
void printMESA(const sampler2D value)
void printMESA(const sampler3D value)
void printMESA(const samplerCube value)
void printMESA(const sampler1DShadow value)
void printMESA(const sampler2DShadow value)
The printMESA function writes the argument <value> to the "debug
print log" (XXX DEBUG_PRINT_MESA?). Each component is written in
text format (XXX format!) and is delimited by a white space (XXX 1
or more?).
Add a new section 8.10.2 "Assert Function":
The following assertMESA prototypes are available.
void assertMESA(const bool condition)
void assertMESA(const bool condition, const int cookie)
void assertMESA(const bool condition, const int cookie,
const int file, const int line)
The assertMESA function checks if the argument <condition> is
true or false. If it is true, nothing happens. If it is false,
a diagnostic message is written to the "debug assert log".
The message contains the argument <file>, <line>, <cookie> and
implementation dependent double-quoted string, each of this
delimited by a white space. If the argument <cookie> is not present,
it is meant as if it was of value 0. If the arguments <file> and
<line> are not present, they are meant as if they were of values
__FILE__ and __LINE__, respectively. The following three calls
produce the same output, assuming they were issued from the same
file and line.
assertMESA (false);
assertMESA (false, 0);
assertMESA (false, 0, __FILE__, __LINE__);
The diagnostic message examples follow.
1 89 0 ""
1 45 333 "all (lessThanEqual (fragColor, vec4 (1.0)))"
1 66 1 "assertion failed in file 1, line 66, cookie 1"
Additions to Chapter 9 of the OpenGL Shading Language 1.10 Specification
(Shading Language Grammar)
None
Additions to Chapter 10 of the OpenGL Shading Language 1.10
Specification (Issues)
None
Additions to the AGL/EGL/GLX/WGL Specifications
None
GLX Protocol
None
Errors
TBD
New State
TBD
New Implementation Dependent State
TBD
Sample Code
TBD
Revision History
29 May 2006
Initial draft. (Michal Krol)
30 July 2006
Add Overview, New Procedures and Functions, New Tokens sections.
Add sections 8.10.1, 8.10.2 to GLSL spec.