Shaderpack comparison

Prompt

Make me a shaderpack for 1.21.11, with a ultra optimization that runs even on integrated graphics card. Act as an expert GLSL graphics programmer specializing in low-spec driver optimization and the Iris shader pipeline for Minecraft (1.21.11 / Fabric). I need a customized, highly optimized shaderpack for an Intel HD Graphics 2500 GPU. The shader must add directional sun brightness and simple screen-space fake/directional shadows without dropping performance below 20-25 FPS. ### Technical Context & Constraints: - Target Environment: Minecraft 1.21.11 (Fabric) + Iris Shaders - Target Hardware: Intel HD Graphics 2500 (Legacy Ivy Bridge Integrated iGPU) - Performance Goal: 20-25+ FPS at 720p / 0.75x render scale. ### Required Shader Features: 1. Dynamic Sun Brightness: Adjust surface exposure based on normal vectors relative to the sun vector (`sunPosition`). Surfaces facing the sun should look significantly brighter and warmer; surfaces facing away should look cooler and shaded. 2. Lightweight Directional Shading (Fake Shadows): Apply a directional light multiplier to terrain (leaves, ground, structures) to mimic tree/block self-shadowing without creating a full shadow map pass. 3. Fast Color Grading: Subtle contrast boost, vibrant daylight tone mapping, and soft ambient night coloring. ### Optimization Rules (To Keep Frame Rates Playable): - DO NOT use full shadow mapping (`shadowtex0` / `shadow.vsh` / `shadow.fsh`). - DO NOT use raymarching, volumetric fog, SSAO, or bloom loops. - Use simple dot product light math (`max(dot(normal, sunVector), 0.0)`) in `gbuffers_terrain.fsh` for instant directional lighting without rendering cost. Please generate the code for `shaders/gbuffers_terrain.vsh`, `shaders/gbuffers_terrain.fsh`, `shaders/final.vsh`, and `shaders/final.fsh`.