tersun.frag rasterised every terrain patch a second time into a screen buffer, because on OpenGL the cascade read inside terrain.frag fell off a driver cliff (about 6 ms a frame). Vulkan has no such cliff: its terrain programs are the SUN_INLINE variant, which evaluates the same two tiers with the same normal and cross-fade in the ground's own shader, and terrain_draw skips the pass - in the frame and in the water reflection. OpenGL keeps the pass. R3D_SUN_PASS=1 keeps it on Vulkan, for comparing. Mac Vulkan town 1759 -> 1692 draws; frames within 2/255 of the pass (15331 px, float rounding). PC camp 1984 -> 1882 draws, 3.9 s for 400 frames either way, self-tests 59/59, validation 0. OpenGL frames byte-identical. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
7.8 KiB
7.8 KiB