WebGL EXT_conservative_depth Extension Specification

Name

EXT_conservative_depth

Contact

WebGL working group (public_webgl 'at' khronos.org)

Contributors

Members of the WebGL working group

Version

Last modified date: January 11, 2024
Revision: 2

Number

WebGL extension #54

Dependencies

Written against the WebGL API 2.0 specification.

Overview

This extension exposes the EXT_conservative_depth functionality to WebGL.

The following WebGL-specific behavioral changes apply:

• The depth_unchanged layout qualifier is not supported.
• If the final value of gl_FragDepth is inconsistent with its layout qualifier, implementations may enforce consistency by clamping it to the value of gl_FragCoord.z.

Consult the above extension for documentation, issues and new functions and enumerants.

When this extension is enabled:

• When a fragment shader enables, requires, or warns GL_EXT_conservative_depth with an #extension directive:
  • The gl_FragDepth built-in output variable may be redeclared with a depth layout qualifier.
• The GLSL macro GL_EXT_conservative_depth is defined as 1.

IDL

[Exposed=(Window,Worker), LegacyNoInterfaceObject]
interface EXT_conservative_depth {
};
  

Sample Code

#extension GL_EXT_conservative_depth : enable

// Ensure that the shader compiles when the extension is not supported
#ifdef GL_EXT_conservative_depth
    layout (depth_greater) out highp float gl_FragDepth;
#endif

void main() {
    // Assign to gl_FragDepth as usual
}
    

Revision History

Revision 1, 2023/06/01

• Initial Draft.

Revision 2, 2024/01/11

• Promoted to Community Approved.