glslLangValidator is GLSL tool for Windows / Linux released by the Khronos Group. glslLangValidator is the official reference compiler front end for both OpenGL ES and OpenGL shading languages. It implements a strict interpretation of the specifications for these languages. It is open and free for anyone to use, either from a command line or programmatically.

More information about can be found here: OpenGL / OpenGL ES Reference Compiler. You can download the command line version from HERE.

I quickly tested glslLangValidator with the following GLSL 1.40 (OpenGL 3.1) vertex shader took from GLSL Hacker code sample pack.

#version 140 in vec4 gxl3d_Position; in vec4 gxl3d_Color; in vec4 gxl3d_Normal; uniform mat4 gxl3d_ModelViewProjectionMatrix; uniform mat4 gxl3d_ModelViewMatrix; out vec4 Vertex_Color; void main() { gl_Position = gxl3d_ModelViewProjectionMatrix * gxl3d_Position; vec4 eye = gxl3d_ModelViewMatrix * gxl3d_Position; float d = length(eye); gl_PointSize = 30.0 * 1.0/(0.0 + 0.04*d + 0.0001*d*d); Vertex_Color = gxl3d_Color; }

To validate this vertex shader (file vs.vert), just use type this command:

glslangValidator.exe vs.vert

Here is the output:

Warning, version 140 is not yet complete; most features are present, but a few are missing.

I guess it means there’s no error.

Now if I remove the ; at the line 11, here is the output:

Warning, version 140 is not yet complete; most features are present, but a few are missing. ERROR: 0:11: '' : syntax error ERROR: 1 compilation errors. No code generated.

The current version of glslangValidator can be checked with

glslangValidator -v

The associated output is:

ESSL Version: OpenGL ES GLSL 3.00 glslang LunarG Khronos.24740 2014/01/11 12:29:55 GLSL Version: 4.20 glslang LunarG Khronos.24740 2014/01/11 12:29:55

According to the documentation, the current version of glslangValidator supports GLSL shaders up to GLSL #version 1.40 / OpenGL 3.1 (so why it tells that version 140 is not yet complete? Is it related to the machine I currently use to write this new?).

Using the -i option, you can generate the intermediate tree (glslang AST, AST is the not structured flow control representation of the GLSL shader). The tree of our vertex shader is:

0:? Sequence 0:8 Function Definition: main( (void) 0:8 Function Parameters: 0:10 Sequence 0:10 move second child to first child (4-component vector of float) 0:10 'gl_Position' (gl_Position 4-component vector of float) 0:10 matrix-times-vector (4-component vector of float) 0:10 'gxl3d_ModelViewProjectionMatrix' (uniform 4X4 matrix of float) 0:10 'gxl3d_Position' (in 4-component vector of float) 0:11 Sequence 0:11 move second child to first child (4-component vector of float) 0:11 'eye' (4-component vector of float) 0:11 matrix-times-vector (4-component vector of float) 0:11 'gxl3d_ModelViewMatrix' (uniform 4X4 matrix of float) 0:11 'gxl3d_Position' (in 4-component vector of float) 0:12 Sequence 0:12 move second child to first child (float) 0:12 'd' (float) 0:12 length (float) 0:12 'eye' (4-component vector of float) 0:13 move second child to first child (float) 0:13 'gl_PointSize' (gl_PointSize float) 0:13 divide (float) 0:13 Constant: 0:13 30.000000 0:13 add (float) 0:13 add (float) 0:13 Constant: 0:13 0.000000 0:13 component-wise multiply (float) 0:13 Constant: 0:13 0.040000 0:13 'd' (float) 0:13 component-wise multiply (float) 0:13 component-wise multiply (float) 0:13 Constant: 0:13 0.000100 0:13 'd' (float) 0:13 'd' (float) 0:14 move second child to first child (4-component vector of float) 0:14 'Vertex_Color' (smooth out 4-component vector of float) 0:14 'gxl3d_Color' (in 4-component vector of float) 0:? Linker Objects 0:? 'gxl3d_Position' (in 4-component vector of float) 0:? 'gxl3d_Color' (in 4-component vector of float) 0:? 'gxl3d_Normal' (in 4-component vector of float) 0:? 'gxl3d_ModelViewProjectionMatrix' (uniform 4X4 matrix of float) 0:? 'gxl3d_ModelViewMatrix' (uniform 4X4 matrix of float) 0:? 'Vertex_Color' (smooth out 4-component vector of float) 0:? 'gl_VertexID' (gl_VertexId int) 0:? 'gl_InstanceID' (gl_InstanceId int)

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