GLSL Versions

Intro

You can use the #version command as the first line of your shader to specify GLSL version:

#version 120

void main() {
    gl_FragColor = vec4(1.0);
}

GLSL versions are released alongside GL versions. See the following charts to decide which version you would like to target.

GLSL Versions

OpenGL Version	GLSL Version
2.0	110
2.1	120
3.0	130
3.1	140
3.2	150
3.3	330
4.0	400
4.1	410
4.2	420
4.3	430

GLSL ES Versions (Android, iOS, WebGL)

OpenGL ES has its own Shading Language, and the versioning starts fresh. It is based on OpenGL Shading Language version 1.10.

OpenGL ES Version	GLSL ES Version
2.0	100
3.0	300

So, for example, if a feature is available in GLSL 120, it probably won't be available in GLSL ES 100 unless the ES compiler specifically allows it.

Changes

GLSL 110 vs. 120

Some major additions to GLSL 120. Note that most of these will not work on GLSL ES.

• You can initialize arrays within a shader, like so:

float a[5] = float[5](3.4, 4.2, 5.0, 5.2, 1.1);
float b[5] = float[](3.4, 4.2, 5.0, 5.2, 1.1);

However, the above is not supported on Mac OSX Snow Leopard, even with GLSL 120. (1)

• You can initialize uniforms in a shader, and the value will be set at link time:

uniform float val = 1.0;

• You can use built-ins like sin() when setting a const value
• Integers are implicitly converted to floats when necessary, for example:

float f = 1.0; <-- valid
float g = 1; <-- only supported in GLSL 120
vec2 v = vec2(1, 2.0); <-- only supported in GLSL 120

• You can use f to define a float: float f = 2.5f;

GLSL 120 vs. 130

• int and uint support (and bitwise operations with them)
• switch statement support
• New built-ins: trunc(), round(), roundEven(), isnan(), isinf(), modf()
• Fragment output can be user-defined
• Input and output is declared with in and out syntax instead of attribute and varying

GLSL 330

• Layout qualifiers can declare the location of vertex shader inputs and fragment shader outputs, eg: layout(location = 2) in vec3 values[4]; Formally this was only possible with ARB_explicit_attrib_location extension