GLSL ES 300

[mattdesl]

Changes at a glance:
http://www.shaderific.com/blog/2014/3/13/tutorial-how-to-update-a-shader-for-opengl-es-30

• #version 300 es appears at top
• texture2D -> texture
• attribute -> in
• gl_FragCoord - custom out
• varying -> in / out
• some more constants:
  • gl_VertexID, gl_InstanceID, 'gl_MaxVertexAttribs', 'gl_MaxVertexUniformVectors', 'gl_MaxVertexOutputVectors', 'gl_MaxFragmentInputVectors', 'gl_MaxVertexTextureImageUnits', 'gl_MaxCombinedTextureImageUnits', 'gl_MaxTextureImageUnits', 'gl_MaxFragmentUniformVectors', 'gl_MaxDrawBuffers', 'gl_MinProgramTexelOffset', 'gl_MaxProgramTexelOffset',
• new functions like textureSize, inversesqrt, transpose, inverse, textureProj
• new literals like sampler2DArray

Reference:
https://www.khronos.org/registry/gles/specs/3.0/GLSL_ES_Specification_3.00.3.pdf