Developing GLSL Shaders¶
Like Cg shaders, GLSL shaders represents a single pass, and requires a preset file to describe how multiple shaders are combined. The extension is .glsl.
As GLSL shaders are normally placed in two different files (vertex, fragment), making it impractical to select in a menu. This is worked around by using compiler defines in order to be equivalent to Cg shaders.
Example GLSL shader¶
Note
GLSL shaders must be modern style, and using ruby prefix is discouraged.
varying vec2 tex_coord;
#if defined(VERTEX)
attribute vec2 TexCoord;
attribute vec2 VertexCoord;
uniform mat4 MVPMatrix;
void main()
{
gl_Position = MVPMatrix * vec4(VertexCoord, 0.0, 1.0);
tex_coord = TexCoord;
}
#elif defined(FRAGMENT)
uniform sampler2D Texture;
void main()
{
gl_FragColor = texture2D(Texture, tex_coord);
}
#endif
GLSL presets¶
Like Cg shaders, there is a GLSL preset format. Instead of .cgp extension, .glslp extension is used. The format is exactly the same, just replace .cg shaders with .glsl. To convert a .cgp preset, rename to .glslp and replace all references to .cg shaders with .glsl.
Converting from Cg shaders¶
GLSL shaders are mostly considered a compatibility format. It is possible to compile Cg shaders into GLSL shaders automatically using our cg2glsl script. It can convert single shaders as well as batch conversion. Shader converstion relies on nVidia's cgc tool found in the nvidia-cg-toolkit package.