diff --git a/GL/platforms/sh4.c b/GL/platforms/sh4.c
index 29b9f62..e12535c 100644
--- a/GL/platforms/sh4.c
+++ b/GL/platforms/sh4.c
@@ -74,7 +74,6 @@ GL_FORCE_INLINE void _glSubmitHeaderOrVertex(const Vertex* v) {
 #ifndef NDEBUG
     assert(!isnan(v->xyz[2]));
     assert(!isnan(v->w));
-    assert(v->xyz[2] > 0.0f);
 #endif
 
     uint32_t *s = (uint32_t*) v;
@@ -118,15 +117,20 @@ GL_FORCE_INLINE void _glClipEdge(const Vertex* v1, const Vertex* v2, Vertex* vou
     const float d0 = v1->w + v1->xyz[2];
     const float d1 = v2->w + v2->xyz[2];
 
-    float t = MATH_Fast_Divide(d0, (d0 - d1));
+    const float epsilon = (d0 < d1) ? -0.00001f : 0.00001f;
 
-    vout->xyz[0] = MATH_fmac(v2->xyz[0] - v1->xyz[0], t, v1->xyz[0]);
-    vout->xyz[1] = MATH_fmac(v2->xyz[1] - v1->xyz[1], t, v1->xyz[1]);
-    vout->xyz[2] = MATH_fmac(v2->xyz[2] - v1->xyz[2], t, v1->xyz[2]);
-    vout->w = MATH_fmac(v2->w - v1->w, t, v1->w);
+    float t = MATH_Fast_Divide(d0, (d0 - d1)) + epsilon;
 
-    vout->uv[0] = MATH_fmac(v2->uv[0] - v1->uv[0], t, v1->uv[0]);
-    vout->uv[1] = MATH_fmac(v2->uv[1] - v1->uv[1], t, v1->uv[1]);
+    t = (t > 1.0f) ? 1.0f : t;
+    t = (t < 0.0f) ? 0.0f : t;
+
+    vout->xyz[0] = __builtin_fmaf(v2->xyz[0] - v1->xyz[0], t, v1->xyz[0]);
+    vout->xyz[1] = __builtin_fmaf(v2->xyz[1] - v1->xyz[1], t, v1->xyz[1]);
+    vout->xyz[2] = __builtin_fmaf(v2->xyz[2] - v1->xyz[2], t, v1->xyz[2]);
+    vout->w = __builtin_fmaf(v2->w - v1->w, t, v1->w);
+
+    vout->uv[0] = __builtin_fmaf(v2->uv[0] - v1->uv[0], t, v1->uv[0]);
+    vout->uv[1] = __builtin_fmaf(v2->uv[1] - v1->uv[1], t, v1->uv[1]);
 
     interpolateColour(v1->bgra, v2->bgra, t, vout->bgra);
 }
@@ -176,7 +180,7 @@ void SceneListSubmit(void* src, int n) {
         if(tri_count < 3) {
             if(likely(glIsVertex(vertex->flags))) {
                 triangle[tri_count].v = vertex;
-                triangle[tri_count].visible = vertex->w > 0 && vertex->xyz[2] > -vertex->w;
+                triangle[tri_count].visible = vertex->xyz[2] > -vertex->w;
                 tri_count++;
                 strip_count++;
             } else {