b3dSetDefaultScreenShader

Sets default screen shader and reverts to normal rendering (identical to b3dClearScreenShader). Takes no parameters. Returns nothing. Sets g_activeScreenShader3D = 0 (clears active shader, reverts to default rendering). Use to reset to default state (explicit "set default" semantic, same behavior as clear), revert to normal rendering (after using custom shader), or match Blitz3D naming (SetDefaultScreenShader mirrors classic Blitz3D API naming convention). Default behavior: sets active shader to 0 (g_activeScreenShader3D = 0, default rendering), immediate next frame (no shader applied starting next b3dRenderWorld call), doesn't free shader (shader remains loaded in memory, can reapply later), identical to b3dClearScreenShader (exact same implementation, both call g_activeScreenShader3D = 0). Use cases: (1) Reset to default (b3dSetDefaultScreenShader() explicit "use default" semantics), (2) After custom shader (used shader for effect, now return to normal), (3) Init state (call at startup to ensure default, even though default anyway), (4) Blitz3D compatibility (matches classic Blitz3D function name, familiar to Blitz users), (5) Before scene change (reset to default before loading new scene with different shader setup). Common patterns: reset = b3dSetDefaultScreenShader() revert to normal; after effect = b3dApplyScreenShader(flashShader): Wait(frames): b3dSetDefaultScreenShader() temporary effect. Naming convention: "Set" prefix (matches Blitz3D naming, SetEntityShader/SetDefaultEntityShader pattern), "Default" emphasizes intent (explicitly setting to default, not just clearing), synonymous with Clear (b3dClearScreenShader same functionality, user preference which to use). Implementation: g_activeScreenShader3D = 0 (single line, flag set), identical to ClearScreenShader (exact same code, both functions do same thing), exists for API completeness (provides both "clear" and "set default" semantics, user choice). Difference from clear: semantic only (Clear implies removing, SetDefault implies setting, but behavior identical), no functional difference (both do exact same thing, g_activeScreenShader3D = 0), user preference (use whichever name makes more sense in context). Default rendering: no post-processing shader (scene rendered directly to back buffer, no custom effects), engine's built-in pipeline (standard 3D rendering, PBR lighting, no user shader), same as startup state (pristine default, never applied shader). Typical workflow: load shader (shader = b3dLoadScreenShader("effect.hlsl")), apply shader (b3dApplyScreenShader(shader) activate), use for frames (shader applies automatically), set default (this function, reverts to normal rendering), shader still loaded (can reapply or free with b3dFreeScreenShader). Performance: set default cost zero (flag set, trivial operation), next frame faster (no shader processing, default rendering cheaper ~0.1-5ms saved depending on shader complexity), safe to call anytime (always succeeds, harmless even if already default). Validation: no parameters (nothing to validate), always succeeds (flag set can't fail), safe to call multiple times (setting default when already default harmless, no-op). No return value: void function (doesn't indicate success/failure), assumes success (always works, flag set), silent operation (no error messages, no confirmation prints). Related: b3dClearScreenShader clears active shader (identical function, same behavior, alternative name), b3dApplyScreenShader applies shader (opposite of this function, activates shader instead of clearing), b3dFreeScreenShader frees shader (alternative for permanent removal, releases memory), b3dLoadScreenShader loads shader (creates shader reverted by this function).