The different names are aliases, they don't replace/remove GLSL's names. You can write "pure GLSL" in LÖVE natively, as long as you use the 'effect' entry point for pixel shaders (and the 'position' entry point for vertex shaders.)
For example, this function will compile in WebGL, GLSL 1.10, GLSL 1.20, GLSL ES 1.00, and LÖVE 0.8 - 0.10 (although if you use WebGL or raw OpenGL/OpenGL ES then you will need to call the function from 'main'):
Code: Select all
vec4 effect(vec4 vcolor, sampler2D tex, vec2 tex_coords, vec2 pixel_coords)
{
float alpha = texture2D(tex, tex_coords).a;
vcolor.a *= alpha;
return vcolor;
}
However I do recommend using the 'Texel' function instead of 'texture2D' for future portability to different versions of GLSL, since 'texture2D' doesn't exist in GLSL 1.40+ or GLSL ES 3.00+, whereas 'Texel' can always be aliased to the correct function automatically by LÖVE.
If you try to use third-party GLSL code which uses built in fixed-function compatibility variables from old versions of GLSL (for example gl_Vertex or gl_ModelViewProjectionMatrix) it may not work, because LÖVE doesn't necessarily use the deprecated OpenGL codepaths necessary for those things to work. They only existed to make it easier for programs transitioning from OpenGL 1 to OpenGL 2 to use shaders, and they don't exist at all in later versions of OpenGL / GLSL, or in any version of OpenGL ES.
