Fragment Shaders

Common GLSL Variables and Functions:

These functions could be specific to Shadertoy or OpenGL ES 

• fragCoord.xy: Current pixel coordinates (in pixels).
• iResolution.xy: Screen resolution, used for normalization.
• iTime: Time since shader started, useful for animation.
• iMouse: Mouse position, used for interaction.
• iChannel0, iChannel1, etc.: Texture samplers for loading images or videos.
• gl_FragCoord: Built-in pixel coordinates in GLSL.
• dot, cross, normalize: Vector math functions for lighting and geometric operations.
• Transformations: Rotation, scaling, and translation toanipulate coordinates.
• mod, fract: Useful for creating repeating or tiled patterns.