diff --git a/src/fixed/common.h b/src/fixed/common.h
index 0b330c2..dca937b 100644
--- a/src/fixed/common.h
+++ b/src/fixed/common.h
@@ -435,7 +435,7 @@ extern int32 fps;
 #define FOG_SHIFT       1
 #define FOG_MAX         VIEW_DIST
 #define FOG_MIN         (FOG_MAX - (8192 >> FOG_SHIFT))
-#define VIEW_MIN_F      (256 << FIXED_SHIFT)
+#define VIEW_MIN_F      (64 << FIXED_SHIFT)
 #define VIEW_MAX_F      (VIEW_DIST << FIXED_SHIFT)
 
 #define FRUSTUM_FAR_X   (5 << 10)
@@ -2249,6 +2249,7 @@ void drawFree();
 void drawModel(const ItemObj* item);
 void drawItem(const ItemObj* item);
 void drawRooms(Camera* camera);
+void drawBox(const AABBi &box);
 
 void checkTrigger(const FloorData* fd, ItemObj* lara);
 void readLevel(const uint8 *data);
diff --git a/src/fixed/draw.h b/src/fixed/draw.h
index d7e72a4..4fd24c3 100644
--- a/src/fixed/draw.h
+++ b/src/fixed/draw.h
@@ -935,4 +935,42 @@ void drawRooms(Camera* camera)
     setViewport(camera->view.room->clip);
 }
 
+
+#define MESH_FACE(flags, i0, i1, i2, i3) { flags, (i0 | (i1 << 8) | (i2 << 16) | (i3 << 24)) }
+
+const MeshQuad gBoxFaces[6] = {
+    MESH_FACE(15, 0, 4, 5, 1),
+    MESH_FACE(15, 1, 5, 6, 2),
+    MESH_FACE(15, 2, 6, 7, 3),
+    MESH_FACE(15, 3, 7, 4, 0),
+    MESH_FACE(15, 0, 1, 2, 3),
+    MESH_FACE(15, 7, 6, 5, 4)
+};
+
+MeshVertex boxVertices[8];
+
+void drawBox(const AABBi &box)
+{
+    lightAmbient = 4096;
+    int32 minX = box.minX << 2;
+    int32 minY = box.minY << 2;
+    int32 minZ = box.minZ << 2;
+    int32 maxX = box.maxX << 2;
+    int32 maxY = box.maxY << 2;
+    int32 maxZ = box.maxZ << 2;
+
+    boxVertices[0].x = minX; boxVertices[0].y = minY; boxVertices[0].z = minZ;
+    boxVertices[1].x = maxX; boxVertices[1].y = minY; boxVertices[1].z = minZ;
+    boxVertices[2].x = maxX; boxVertices[2].y = minY; boxVertices[2].z = maxZ;
+    boxVertices[3].x = minX; boxVertices[3].y = minY; boxVertices[3].z = maxZ;
+    boxVertices[4].x = minX; boxVertices[4].y = maxY; boxVertices[4].z = minZ;
+    boxVertices[5].x = maxX; boxVertices[5].y = maxY; boxVertices[5].z = minZ;
+    boxVertices[6].x = maxX; boxVertices[6].y = maxY; boxVertices[6].z = maxZ;
+    boxVertices[7].x = minX; boxVertices[7].y = maxY; boxVertices[7].z = maxZ;
+
+    transformMesh(boxVertices, 8, NULL, NULL);
+    faceAddMesh(NULL, gBoxFaces, NULL, NULL, 0, 6, 0, 0);
+}
+
+
 #endif
diff --git a/src/platform/3do/boxIsVisible.s b/src/platform/3do/boxIsVisible.s
index 1966af0..dbcfa68 100644
--- a/src/platform/3do/boxIsVisible.s
+++ b/src/platform/3do/boxIsVisible.s
@@ -92,8 +92,8 @@ boxIsVisible_asm
         ldr m, =matrixPtr
         ldr m, [m]
         ldr bz, [m, #(11 * 4)]
-        sub bz, bz, #VIEW_MIN_F
-        cmp bz, #(VIEW_MAX_F - VIEW_MIN_F)
+        add bz, bz, #VIEW_OFF_F
+        cmp bz, #(VIEW_OFF_F + VIEW_MAX_F)
         movhi r0, #0
         movhi pc, lr
 
diff --git a/src/platform/3do/common_asm.inc b/src/platform/3do/common_asm.inc
index e80fc5d..6e6ee50 100644
--- a/src/platform/3do/common_asm.inc
+++ b/src/platform/3do/common_asm.inc
@@ -52,8 +52,9 @@ VIEW_DIST       EQU (1024 * 10)     ; max = DIV_TABLE_END << PROJ_SHIFT
 FOG_SHIFT       EQU 1
 FOG_MAX         EQU VIEW_DIST
 FOG_MIN         EQU (FOG_MAX - (8192 >> FOG_SHIFT))
-VIEW_MIN_F      EQU (256 << FIXED_SHIFT)
+VIEW_MIN_F      EQU (64 << FIXED_SHIFT)
 VIEW_MAX_F      EQU (VIEW_DIST << FIXED_SHIFT)
+VIEW_OFF_F      EQU (1024 << FIXED_SHIFT)
 OT_SHIFT        EQU 4
 OT_SIZE         EQU ((VIEW_MAX_F >> (FIXED_SHIFT + OT_SHIFT)) + 1)
 
@@ -64,4 +65,68 @@ VIEW_MAX        EQU (VIEW_DIST << CLIP_SHIFT)
 MIN_INT32       EQU 0x80000000
 MAX_INT32       EQU 0x7FFFFFFF
 
-MulManyVec3Mat33_F16 EQU (0x50000 + 2)
\ No newline at end of file
+MulManyVec3Mat33_F16 EQU (0x50000 + 2)
+
+
+; max depth = max(z0, z1, z2, z3) >> (CLIP_SHIFT + OT_SHIFT)
+    MACRO
+        MAX_Z4 $depth, $z0, $z1, $z2, $z3
+        mov $depth, $z0, asr #(CLIP_SHIFT + OT_SHIFT)
+        cmp $depth, $z1, asr #(CLIP_SHIFT + OT_SHIFT)
+        movlt $depth, $z1, asr #(CLIP_SHIFT + OT_SHIFT)
+        cmp $depth, $z2, asr #(CLIP_SHIFT + OT_SHIFT)
+        movlt $depth, $z2, asr #(CLIP_SHIFT + OT_SHIFT)
+        cmp $depth, $z3, asr #(CLIP_SHIFT + OT_SHIFT)
+        movlt $depth, $z3, asr #(CLIP_SHIFT + OT_SHIFT)
+    MEND
+
+
+; max depth = max(z0, z1, z2) >> (CLIP_SHIFT + OT_SHIFT)
+    MACRO
+        MAX_Z3 $depth, $z0, $z1, $z2, $z3
+        mov $depth, $z0, asr #(CLIP_SHIFT + OT_SHIFT)
+        cmp $depth, $z1, asr #(CLIP_SHIFT + OT_SHIFT)
+        movlt $depth, $z1, asr #(CLIP_SHIFT + OT_SHIFT)
+        cmp $depth, $z2, asr #(CLIP_SHIFT + OT_SHIFT)
+        movlt $depth, $z2, asr #(CLIP_SHIFT + OT_SHIFT)
+    MEND
+
+
+; average depth = (z0 + z1 + z2 + z2) / 4 >> (CLIP_SHIFT + OT_SHIFT)
+    MACRO
+        AVG_Z4 $depth, $z0, $z1, $z2, $z3
+        add $depth, $z0, $z1
+        add $depth, $depth, $z2
+        add $depth, $depth, $z3
+        mov $depth, $depth, asr #(2 + CLIP_SHIFT + OT_SHIFT)
+    MEND
+
+
+; average depth = (z0 + z1 + z2 + z2) / 4 >> (CLIP_SHIFT + OT_SHIFT)
+    MACRO
+        AVG_Z3 $depth, $z0, $z1, $z2
+        add $depth, $z0, $z1
+        add $depth, $depth, $z2, lsl #1
+        mov $depth, $depth, asr #(2 + CLIP_SHIFT + OT_SHIFT)
+    MEND
+
+
+; back facing check
+    MACRO
+        CCW $cross, $dx0, $dy0, $dx1, $dy1, $skip
+        mul $cross, $dy0, $dx1
+        rsb $cross, cross, #0
+        mlas $cross, $dx0, $dy1, $cross
+        ble skip
+    MEND
+
+
+; back/front facing check depending on sign
+    MACRO
+        CCW_SIGN $cross, $sign, $dx0, $dy0, $dx1, $dy1, $skip
+        mul $cross, $dy0, $dx1
+        rsb $cross, cross, #0
+        mla $cross, $dx0, $dy1, $cross
+        teq $cross, $sign
+        bmi skip
+    MEND
diff --git a/src/platform/3do/faceAddMeshQuads.s b/src/platform/3do/faceAddMeshQuads.s
index 99a1535..7fd3607 100644
--- a/src/platform/3do/faceAddMeshQuads.s
+++ b/src/platform/3do/faceAddMeshQuads.s
@@ -119,12 +119,11 @@ skip    cmp fPolys, fLast
         ldmia fPolys!, {flags, indices}
 
         ; get vertex pointers
-        and vp0, indices, #0xFF
-        mov vp1, indices, lsr #8
-        and vp1, vp1, #0xFF
-        mov vp2, indices, lsr #16
-        and vp2, vp2, #0xFF
-        mov vp3, indices, lsr #24
+        mov mask, #0xFF
+        and vp0, mask, indices
+        and vp1, mask, indices, lsr #8
+        and vp2, mask, indices, lsr #16
+        and vp3, mask, indices, lsr #24
 
         add vp0, vp0, vp0, lsl #1
         add vp1, vp1, vp1, lsl #1
@@ -149,10 +148,7 @@ skip    cmp fPolys, fLast
         tst mask, #CLIP_MASK
         bne skip
 
-        ; depth = (vz0 + vz1 + vz2 + vz3) (DEPTH_Q_AVG)
-        add depth, vz0, vz1
-        add depth, depth, vz2
-        add depth, depth, vz3
+        AVG_Z4 depth, vz0, vz1, vz2, vz3
 
         ; (vx1 - vx0) * (vy3 - vy0) <= (vy1 - vy0) * (vx3 - vx0)
         ldmia vp0, {vx0, vy0}
@@ -162,25 +158,16 @@ skip    cmp fPolys, fLast
         sub hdy0, vy1, vy0
         sub vdx0, vx3, vx0
         sub vdy0, vy3, vy0
-        mul cross, hdy0, vdx0
-        rsb cross, cross, #0
-        mla cross, hdx0, vdy0, cross
-        teq cross, flags
-        bmi skip
+
+        CCW_SIGN cross, flags, hdx0, hdy0, vdx0, vdy0, skip
 
         ; poly is visible, store fPolys on the stack to reuse the reg
         str fPolys, [sp, #SP_POLYS]
 
-        ; depth = max(0, (depth / 4) >> (CLIP_SHIFT + OT_SHIFT))
-        movs depth, depth, lsr #(2 + CLIP_SHIFT + OT_SHIFT)
-        movmi depth, #0
-
         add tmp, sp, #SP_OT
         ldmia tmp, {ot, faceBase, tex}
 
         ; faceAdd
-        cmp depth, #(OT_SIZE - 1)
-        movgt depth, #(OT_SIZE - 1)
         add ot, ot, depth, lsl #3   ; mul by size of OT element
 
         ldr face, [faceBase]
diff --git a/src/platform/3do/faceAddMeshQuadsFlat.s b/src/platform/3do/faceAddMeshQuadsFlat.s
index 6e9007e..3ea85cf 100644
--- a/src/platform/3do/faceAddMeshQuadsFlat.s
+++ b/src/platform/3do/faceAddMeshQuadsFlat.s
@@ -116,12 +116,11 @@ skip    cmp fPolys, fLast
         ldmia fPolys!, {flags, indices}
 
         ; get vertex pointers
-        and vp0, indices, #0xFF
-        mov vp1, indices, lsr #8
-        and vp1, vp1, #0xFF
-        mov vp2, indices, lsr #16
-        and vp2, vp2, #0xFF
-        mov vp3, indices, lsr #24
+        mov mask, #0xFF
+        and vp0, mask, indices
+        and vp1, mask, indices, lsr #8
+        and vp2, mask, indices, lsr #16
+        and vp3, mask, indices, lsr #24
 
         add vp0, vp0, vp0, lsl #1
         add vp1, vp1, vp1, lsl #1
@@ -146,10 +145,7 @@ skip    cmp fPolys, fLast
         tst mask, #CLIP_MASK
         bne skip
 
-        ; depth = (vz0 + vz1 + vz2 + vz3) (DEPTH_Q_AVG)
-        add depth, vz0, vz1
-        add depth, depth, vz2
-        add depth, depth, vz3
+        AVG_Z4 depth, vz0, vz1, vz2, vz3
 
         ; (vx1 - vx0) * (vy3 - vy0) <= (vy1 - vy0) * (vx3 - vx0)
         ldmia vp0, {vx0, vy0}
@@ -159,18 +155,12 @@ skip    cmp fPolys, fLast
         sub hdy0, vy1, vy0
         sub vdx0, vx3, vx0
         sub vdy0, vy3, vy0
-        mul cross, hdy0, vdx0
-        rsb cross, cross, #0
-        mlas cross, hdx0, vdy0, cross
-        ble skip
+
+        CCW cross, hdx0, hdy0, vdx0, vdy0, skip
 
         ; poly is visible, store fPolys on the stack to reuse the reg
         str fPolys, [sp, #SP_POLYS]
 
-        ; depth = max(0, (depth / 4) >> (CLIP_SHIFT + OT_SHIFT))
-        movs depth, depth, lsr #(2 + CLIP_SHIFT + OT_SHIFT)
-        movmi depth, #0
-
         ; get color index from flags
         and colorIndex, flags, #0xFF
 
@@ -181,8 +171,6 @@ skip    cmp fPolys, fLast
         add dataPtr, plutOffset, colorIndex, lsl #1
 
         ; faceAdd
-        cmp depth, #(OT_SIZE - 1)
-        movgt depth, #(OT_SIZE - 1)
         add ot, ot, depth, lsl #3   ; mul by size of OT element
 
         ldr face, [faceBase]
diff --git a/src/platform/3do/faceAddMeshTriangles.s b/src/platform/3do/faceAddMeshTriangles.s
index 9d4b6f5..8b5d6f7 100644
--- a/src/platform/3do/faceAddMeshTriangles.s
+++ b/src/platform/3do/faceAddMeshTriangles.s
@@ -115,10 +115,10 @@ skip    cmp fPolys, fLast
         ldmia fPolys!, {flags, indices}
 
         ; get vertex pointers
-        and vp0, indices, #0xFF
-        mov vp1, indices, lsr #8
-        and vp1, vp1, #0xFF
-        mov vp2, indices, lsr #16
+        mov mask, #0xFF
+        and vp0, mask, indices
+        and vp1, mask, indices, lsr #8
+        and vp2, mask, indices, lsr #16
 
         add vp0, vp0, vp0, lsl #1
         add vp1, vp1, vp1, lsl #1
@@ -139,9 +139,7 @@ skip    cmp fPolys, fLast
         tst mask, #CLIP_MASK
         bne skip
 
-        ; depth = (vz0 + vz1 + vz2 + vz2) (DEPTH_T_AVG)
-        add depth, vz0, vz1
-        add depth, depth, vz2, lsl #1
+        AVG_Z3 depth, vz0, vz1, vz2
 
         ; (vx1 - vx0) * (vy2 - vy0) - (vy1 - vy0) * (vx2 - vx0) <= 0
         ldmia vp0, {vx0, vy0}
@@ -151,24 +149,16 @@ skip    cmp fPolys, fLast
         sub hdy0, vy1, vy0
         sub vdx0, vx2, vx0
         sub vdy0, vy2, vy0
-        mul cross, hdy0, vdx0
-        rsb cross, cross, #0
-        mlas cross, hdx0, vdy0, cross
-        ble skip
+
+        CCW cross, hdx0, hdy0, vdx0, vdy0, skip
 
         ; poly is visible, store fPolys on the stack to reuse the reg
         str fPolys, [sp, #SP_POLYS]
 
-        ; depth = max(0, (depth / 4) >> (CLIP_SHIFT + OT_SHIFT))
-        movs depth, depth, lsr #(2 + CLIP_SHIFT + OT_SHIFT)
-        movmi depth, #0
-
         add tmp, sp, #SP_OT
         ldmia tmp, {ot, plutOffset, faceBase, tex}
 
         ; faceAdd
-        cmp depth, #(OT_SIZE - 1)
-        movgt depth, #(OT_SIZE - 1)
         add ot, ot, depth, lsl #3   ; mul by size of OT element
 
         ldr face, [faceBase]
diff --git a/src/platform/3do/faceAddMeshTrianglesFlat.s b/src/platform/3do/faceAddMeshTrianglesFlat.s
index 584f626..846f139 100644
--- a/src/platform/3do/faceAddMeshTrianglesFlat.s
+++ b/src/platform/3do/faceAddMeshTrianglesFlat.s
@@ -112,10 +112,10 @@ skip    cmp fPolys, fLast
         ldmia fPolys!, {flags, indices}
 
         ; get vertex pointers
-        and vp0, indices, #0xFF
-        mov vp1, indices, lsr #8
-        and vp1, vp1, #0xFF
-        mov vp2, indices, lsr #16
+        mov mask, #0xFF
+        and vp0, mask, indices
+        and vp1, mask, indices, lsr #8
+        and vp2, mask, indices, lsr #16
 
         add vp0, vp0, vp0, lsl #1
         add vp1, vp1, vp1, lsl #1
@@ -136,9 +136,7 @@ skip    cmp fPolys, fLast
         tst mask, #CLIP_MASK
         bne skip
 
-        ; depth = (vz0 + vz1 + vz2 + vz3) (DEPTH_T_AVG)
-        add depth, vz0, vz1
-        add depth, depth, vz2, lsl #1
+        AVG_Z3 depth, vz0, vz1, vz2
 
         ; (vx1 - vx0) * (vy2 - vy0) - (vy1 - vy0) * (vx2 - vx0) <= 0
         ldmia vp0, {vx0, vy0}
@@ -148,18 +146,12 @@ skip    cmp fPolys, fLast
         sub hdy0, vy1, vy0
         sub vdx0, vx2, vx0
         sub vdy0, vy2, vy0
-        mul cross, hdy0, vdx0
-        rsb cross, cross, #0
-        mlas cross, hdx0, vdy0, cross
-        ble skip
+
+        CCW cross, hdx0, hdy0, vdx0, vdy0, skip
 
         ; poly is visible, store fPolys on the stack to reuse the reg
         str fPolys, [sp, #SP_POLYS]
 
-        ; depth = max(0, (depth / 4) >> (CLIP_SHIFT + OT_SHIFT))
-        movs depth, depth, lsr #(2 + CLIP_SHIFT + OT_SHIFT)
-        movmi depth, #0
-
         ; get color index from flags
         and colorIndex, flags, #0xFF
 
@@ -170,8 +162,6 @@ skip    cmp fPolys, fLast
         add dataPtr, plutOffset, colorIndex, lsl #1
 
         ; faceAdd
-        cmp depth, #(OT_SIZE - 1)
-        movgt depth, #(OT_SIZE - 1)
         add ot, ot, depth, lsl #3   ; mul by size of OT element
 
         ldr face, [faceBase]
diff --git a/src/platform/3do/faceAddRoomQuads.s b/src/platform/3do/faceAddRoomQuads.s
index e1accd6..907934a 100644
--- a/src/platform/3do/faceAddRoomQuads.s
+++ b/src/platform/3do/faceAddRoomQuads.s
@@ -122,7 +122,7 @@ skip    cmp fPolys, fLast
 
         ldmia fPolys!, {flags, i0, i1}
 
-        ; get vertex pointers
+        ; get vertex pointers (indices are pre-multiplied by 12)
         add vp0, fVertices, i0, lsr #16
         mov i0, i0, lsl #16
         add vp1, fVertices, i0, lsr #16
@@ -144,14 +144,7 @@ skip    cmp fPolys, fLast
         tst mask, #CLIP_MASK
         bne skip
 
-        ; depth = max(vz0, vz1, vz2, vz3) (DEPTH_Q_MAX)
-        mov depth, vz0
-        cmp depth, vz1
-        movlt depth, vz1
-        cmp depth, vz2
-        movlt depth, vz2
-        cmp depth, vz3
-        movlt depth, vz3
+        MAX_Z4 depth, vz0, vz1, vz2, vz3
 
         ; (vx1 - vx0) * (vy3 - vy0) <= (vy1 - vy0) * (vx3 - vx0)
         ldmia vp0, {vx0, vy0}
@@ -161,18 +154,12 @@ skip    cmp fPolys, fLast
         sub hdy0, vy1, vy0
         sub vdx0, vx3, vx0
         sub vdy0, vy3, vy0
-        mul cross, hdy0, vdx0
-        rsb cross, cross, #0
-        mlas cross, hdx0, vdy0, cross
-        ble skip
+
+        CCW cross, hdx0, hdy0, vdx0, vdy0, skip
 
         ; poly is visible, store fPolys on the stack to reuse the reg
         str fPolys, [sp, #SP_POLYS]
 
-        ; depth = max(0, depth >> (CLIP_SHIFT + OT_SHIFT))
-        movs depth, depth, lsr #(CLIP_SHIFT + OT_SHIFT)
-        movmi depth, #0
-
         ; fog = max(0, (depth - (FOG_MIN >> OT_SHIFT)) >> 1)
         sub fog, depth, #(FOG_MIN >> OT_SHIFT)
         movs fog, fog, asr #1
@@ -199,8 +186,6 @@ skip    cmp fPolys, fLast
         add tex, tex, texIndex, lsr #(32 - FACE_MIP_SHIFT - 3)  ; sizeof(Texture) = 2^3
 
         ; faceAdd
-        cmp depth, #(OT_SIZE - 1)
-        movgt depth, #(OT_SIZE - 1)
         add ot, ot, depth, lsl #3   ; mul by size of OT element
 
         mov depth, faceBase     ; use depth reg due face vs faceBase reg collision
diff --git a/src/platform/3do/faceAddRoomTriangles.s b/src/platform/3do/faceAddRoomTriangles.s
index 85ba2b1..352a7f2 100644
--- a/src/platform/3do/faceAddRoomTriangles.s
+++ b/src/platform/3do/faceAddRoomTriangles.s
@@ -118,7 +118,7 @@ skip    cmp fPolys, fLast
 
         ldmia fPolys!, {flags, i0, i1}
 
-        ; get vertex pointers
+        ; get vertex pointers (indices are pre-multiplied by 12)
         add vp0, fVertices, i0, lsr #16
         mov i0, i0, lsl #16
         add vp1, fVertices, i0, lsr #16
@@ -136,12 +136,7 @@ skip    cmp fPolys, fLast
         tst mask, #CLIP_MASK
         bne skip
 
-        ; depth = max(vz0, vz1, vz2) (DEPTH_T_MAX)
-        mov depth, vz0
-        cmp depth, vz1
-        movlt depth, vz1
-        cmp depth, vz2
-        movlt depth, vz2
+        MAX_Z3 depth, vz0, vz1, vz2
 
         ; (vx1 - vx0) * (vy2 - vy0) <= (vy1 - vy0) * (vx2 - vx0)
         ldmia vp0, {vx0, vy0}
@@ -151,18 +146,12 @@ skip    cmp fPolys, fLast
         sub hdy0, vy1, vy0
         sub vdx0, vx2, vx0
         sub vdy0, vy2, vy0
-        mul cross, hdy0, vdx0
-        rsb cross, cross, #0
-        mlas cross, hdx0, vdy0, cross
-        ble skip
+
+        CCW cross, hdx0, hdy0, vdx0, vdy0, skip
 
         ; poly is visible, store fPolys on the stack to reuse the reg
         str fPolys, [sp, #SP_POLYS]
 
-        ; depth = max(0, depth >> (CLIP_SHIFT + OT_SHIFT))
-        movs depth, depth, lsr #(CLIP_SHIFT + OT_SHIFT)
-        movmi depth, #0
-
         ; fog = max(0, (depth - (FOG_MIN >> OT_SHIFT)) >> 1)
         sub fog, depth, #(FOG_MIN >> OT_SHIFT)
         movs fog, fog, asr #1
@@ -189,8 +178,6 @@ skip    cmp fPolys, fLast
         add tex, tex, texIndex, lsr #(32 - FACE_MIP_SHIFT - 3)  ; sizeof(Texture) = 2^3
 
         ; faceAdd
-        cmp depth, #(OT_SIZE - 1)
-        movgt depth, #(OT_SIZE - 1)
         add ot, ot, depth, lsl #3   ; mul by size of OT element
 
         mov depth, faceBase     ; use depth reg due face vs faceBase reg collision
diff --git a/src/platform/3do/matrixTranslate.s b/src/platform/3do/matrixTranslate.s
index dc2f697..faf01ad 100644
--- a/src/platform/3do/matrixTranslate.s
+++ b/src/platform/3do/matrixTranslate.s
@@ -10,13 +10,10 @@
 x   RN r0
 y   RN r1
 z   RN r2
-
 m   RN r3
-
 e0  RN r4
 e1  RN r5
 e2  RN r6
-
 dx  RN r7
 dy  RN r12
 dz  RN lr
@@ -26,28 +23,27 @@ matrixTranslateRel_asm
 
         ldr m, =matrixPtr
         ldr m, [m]
+        add m, m, #(12 * 4)
 
-        ldmia m!, {e0, e1, e2}
-        mul dx, e0, x
-        mul dy, e1, x
-        mul dz, e2, x
+        ldmdb m!, {dx, dy, dz}
 
-        ldmia m!, {e0, e1, e2}
-        mla dx, e0, y, dx
-        mla dy, e1, y, dy
-        mla dz, e2, y, dz
-
-        ldmia m!, {e0, e1, e2}
+        ldmdb m!, {e0, e1, e2}
         mla dx, e0, z, dx
         mla dy, e1, z, dy
         mla dz, e2, z, dz
 
-        ldmia m, {e0, e1, e2}
-        add e0, e0, dx
-        add e1, e1, dy
-        add e2, e2, dz
+        ldmdb m!, {e0, e1, e2}
+        mla dx, e0, y, dx
+        mla dy, e1, y, dy
+        mla dz, e2, y, dz
 
-        stmia m!, {e0, e1, e2}
+        ldmdb m!, {e0, e1, e2}
+        mla dx, e0, x, dx
+        mla dy, e1, x, dy
+        mla dz, e2, x, dz
+
+        add m, m, #(9 * 4)
+        stmia m!, {dx, dy, dz}
 
         ldmfd sp!, {r4-r7, pc}
 
diff --git a/src/platform/3do/projectVertices.s b/src/platform/3do/projectVertices.s
index a2d4f8f..bb943be 100644
--- a/src/platform/3do/projectVertices.s
+++ b/src/platform/3do/projectVertices.s
@@ -61,9 +61,9 @@ loop    ldmia vertex, {x, y, z}     ; read transformed vertex
 
     ; check z clipping
         cmp z, minZ
-        orrlt z, minZ, #CLIP_NEAR
+        orrle z, minZ, #CLIP_NEAR
         cmp z, maxZ
-        orrgt z, maxZ, #CLIP_FAR
+        orrge z, maxZ, #CLIP_FAR
 
     ; projection
         mov dz, z, lsr #(PROJ_SHIFT + CLIP_SHIFT)   ; z is positive
diff --git a/src/platform/3do/render_cel.cpp b/src/platform/3do/render_cel.cpp
index 4671b87..da6bb4c 100644
--- a/src/platform/3do/render_cel.cpp
+++ b/src/platform/3do/render_cel.cpp
@@ -177,9 +177,6 @@ enum ClipFlags {
 
 X_INLINE Face* faceAdd(int32 depth)
 {
-    if (depth < 0) depth = 0;
-    if (depth > OT_SIZE - 1) depth = OT_SIZE - 1;
-
     Face* face = gFacesBase++;
 
     if (gOT[depth].head) {
@@ -343,10 +340,10 @@ void projectVertices_c(int32 vCount)
 
         int32 clip = 0;
 
-        if (z < (VIEW_MIN_F >> FIXED_SHIFT)) {
+        if (z <= (VIEW_MIN_F >> FIXED_SHIFT)) {
             z = (VIEW_MIN_F >> FIXED_SHIFT);
             clip = CLIP_NEAR;
-        } else if (z > (VIEW_MAX_F >> FIXED_SHIFT)) {
+        } else if (z >= (VIEW_MAX_F >> FIXED_SHIFT)) {
             z = (VIEW_MAX_F >> FIXED_SHIFT);
             clip = CLIP_FAR;
         }
@@ -608,11 +605,11 @@ void faceAddMeshTriangles_c(const MeshTriangle* polys, int32 count, uint32 shade
         if ((c0 & c1 & c2) & CLIP_MASK)
             continue;
 
+        int32 depth = DEPTH_T_AVG(v0->z, v1->z, v2->z);
+
         if (cross(v0, v1, v2) <= 0)
             continue;
 
-        int32 depth = DEPTH_T_AVG(v0->z, v1->z, v2->z);
-
         Face* f = faceAdd(depth);
         f->ccb_PIXC = shade;
 
@@ -648,11 +645,11 @@ void faceAddMeshQuadsFlat_c(const MeshQuad* polys, int32 count, uint32 shade)
         if ((c0 & c1 & c2 & c3) & CLIP_MASK)
             continue;
 
+        int32 depth = DEPTH_Q_AVG(v0->z, v1->z, v2->z, v3->z);
+
         if (cross(v0, v1, v3) <= 0)
             continue;
 
-        int32 depth = DEPTH_Q_AVG(v0->z, v1->z, v2->z, v3->z);
-
         Face* f = faceAdd(depth);
         f->ccb_PIXC = shade;
 
@@ -684,11 +681,11 @@ void faceAddMeshTrianglesFlat_c(const MeshTriangle* polys, int32 count, uint32 s
         if ((c0 & c1 & c2) & CLIP_MASK)
             continue;
 
+        int32 depth = DEPTH_T_AVG(v0->z, v1->z, v2->z);
+
         if (cross(v0, v1, v2) <= 0)
             continue;
 
-        int32 depth = DEPTH_T_AVG(v0->z, v1->z, v2->z);
-
         Face* f = faceAdd(depth);
         f->ccb_PIXC = shade;