YES PLEASE

4J.Input/4J_Input.cpp

@@ -140,9 +140,9 @@ void C_4JInput::Initialise(int /*iInputStateC*/, unsigned char /*ucMapC*/,
     if (w) {
         glfwSetCursorPosCallback(w, onCursorPos);
         glfwSetScrollCallback(w, onScroll);
-        if (glfwRawMouseMotionSupported()) {
-            glfwSetInputMode(w, GLFW_RAW_MOUSE_MOTION, GLFW_TRUE);
-        }
+        // NOTE: GLFW_RAW_MOUSE_MOTION must only be set when cursor mode is
+        // GLFW_CURSOR_DISABLED (Wayland zwp_relative_pointer_v1 requirement).
+        // It is activated at the cursor-lock call sites below in Tick().
     }
 
     printf("[4J_Input] GLFW input initialised\n");
@@ -181,6 +181,8 @@ void C_4JInput::Tick(void) {
     if (menuNow && s_mouseLocked) {
         // Re-entered a menu → release mouse cursor
         s_mouseLocked = false;
+        if (glfwRawMouseMotionSupported())
+            glfwSetInputMode(w, GLFW_RAW_MOUSE_MOTION, GLFW_FALSE);
         glfwSetInputMode(w, GLFW_CURSOR, GLFW_CURSOR_NORMAL);
         // Discard stale delta so the view doesn't jerk on re-lock
         s_mouseAccumX = s_mouseAccumY = 0.0f;
@@ -190,6 +192,11 @@ void C_4JInput::Tick(void) {
         // Left the menu → lock mouse for look control
         s_mouseLocked = true;
         glfwSetInputMode(w, GLFW_CURSOR, GLFW_CURSOR_DISABLED);
+        // Enable raw (un-accelerated) relative motion now that cursor is disabled.
+        // On Wayland this activates zwp_relative_pointer_v1 for sub-pixel precise
+        // mouse deltas; on X11 it bypasses the compositor acceleration curve.
+        if (glfwRawMouseMotionSupported())
+            glfwSetInputMode(w, GLFW_RAW_MOUSE_MOTION, GLFW_TRUE);
         s_mouseAccumX = s_mouseAccumY = 0.0f;
         s_cursorInitialized = false;
     }
@@ -210,6 +217,8 @@ void C_4JInput::Tick(void) {
         if (!menuNow && lclick) {
             s_mouseLocked = true;
             glfwSetInputMode(w, GLFW_CURSOR, GLFW_CURSOR_DISABLED);
+            if (glfwRawMouseMotionSupported())
+                glfwSetInputMode(w, GLFW_RAW_MOUSE_MOTION, GLFW_TRUE);
             s_mouseAccumX = s_mouseAccumY = 0.0f;
             s_cursorInitialized = false;
         }

4J.Render/4J_Render.cpp

@@ -1,5 +1,6 @@
 #include "4J_Render.h"
 #include <cstring>
+#include <cstdlib>  // getenv
 
 #define GL_GLEXT_PROTOTYPES
 #include <GL/gl.h>
@@ -37,6 +38,17 @@ static bool s_mainThreadSet = false;
 
 void C4JRender::Initialise()
 {
+#if defined(__linux__) && (GLFW_VERSION_MAJOR > 3 || (GLFW_VERSION_MAJOR == 3 && GLFW_VERSION_MINOR >= 4))
+    // If the session is a native Wayland session, tell GLFW to use the Wayland
+    // backend instead of falling back to XWayland.  This enables proper cursor
+    // confine-and-hide (zwp_confined_pointer_v1 + zwp_relative_pointer_v1) which
+    // is required for correct first-person mouse input on Wayland compositors.
+    if (getenv("WAYLAND_DISPLAY")) {
+        glfwInitHint(GLFW_PLATFORM, GLFW_PLATFORM_WAYLAND);
+        fprintf(stderr, "[4J_Render] Wayland session detected — requesting native Wayland backend\n");
+    }
+#endif
+
     if (!glfwInit()) {
         fprintf(stderr, "[4J_Render] Failed to initialise GLFW\n");
         return;
@@ -408,16 +420,17 @@ void C4JRender::TextureData(int width, int height, void *data, int level,
                    width, height, 0,
                    GL_RGBA, GL_UNSIGNED_BYTE, data);
 
-    // Do NOT set filter params here — the game calls glTexParameteri with the correct
-    // filter settings (GL_NEAREST_MIPMAP_LINEAR etc.) BEFORE calling TextureData.
-    // Setting params here would override those mipmap settings.
-    // Only guarantee the texture is always complete by generating mipmaps as a safety net.
+    // For the base level (0), force the texture to be non-mipmapped and pixel-crisp.
+    // glGenerateMipmap() was previously called here as a "safety net", but on Mesa/Nvidia
+    // drivers it silently resets GL_TEXTURE_MIN_FILTER to the OpenGL spec default
+    // (GL_NEAREST_MIPMAP_LINEAR), overriding the GL_NEAREST set before this call.
+    // Fix: set GL_TEXTURE_MAX_LEVEL=0 (only sample level 0) and re-enforce GL_NEAREST.
+    // The game manually uploads explicit mip levels 1..N-1 after this call anyway,
+    // so we don't need glGenerateMipmap() as a completeness safety net.
     if (level == 0) {
-        GLint maxLevel = 0;
-        ::glGetTexParameteriv(GL_TEXTURE_2D, GL_TEXTURE_MAX_LEVEL, &maxLevel);
-        if (maxLevel > 0) {
-            ::glGenerateMipmap(GL_TEXTURE_2D);
-        }
+        ::glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_LEVEL, 0);
+        ::glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+        ::glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
     }
 }
 

Minecraft.Client/Rendering/GameRenderer.cpp

@@ -838,11 +838,16 @@ void GameRenderer::turnOnLightLayer(double alpha)
         glActiveTexture(GL_TEXTURE0);
     }
 #endif
+	// Linux/PC: TextureBindVertex is a no-op (no vertex texture unit on desktop GL2.1).
+	// The glTexParameteri calls below MUST NOT execute — they would corrupt the currently
+	// bound terrain atlas on GL_TEXTURE0, replacing GL_NEAREST with GL_LINEAR every frame.
 	RenderManager.TextureBindVertex(getLightTexture(mc->player->GetXboxPad(), mc->level));
+#if 0
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
 	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP);
     glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP);
+#endif
 }
 
 // 4J - change brought forward from 1.8.2

Minecraft.Client/Textures/Textures.cpp

@@ -17,7 +17,12 @@
 #include "../../Minecraft.World/Headers/net.minecraft.world.level.h"
 #include "../../Minecraft.World/Util/StringHelpers.h"
 
-bool Textures::MIPMAP = true;
+// Linux/PC port: disable mipmapping globally so textures are always sampled from
+// the full-resolution level 0 with GL_NEAREST, giving pixel-crisp Minecraft blocks
+// at all distances. Mipmapping causes glGenerateMipmap() to fire (which resets the
+// min-filter to GL_NEAREST_MIPMAP_LINEAR on many Mesa/Nvidia drivers) and the
+// per-level crispBlend loop is both wasteful and still causes visible blurring.
+bool Textures::MIPMAP = false;
 C4JRender::eTextureFormat Textures::TEXTURE_FORMAT = C4JRender::TEXTURE_FORMAT_RxGyBzAw;
 
 int Textures::preLoadedIdx[TN_COUNT];