diff --git a/drm/shadertoy.c b/drm/shadertoy.c
index bebf4b5..a4fa851 100644
--- a/drm/shadertoy.c
+++ b/drm/shadertoy.c
@@ -251,7 +251,6 @@ int indirect_buffer()
 
   T0V(FG_DEPTH_SRC, 0x00000000);
   T0V(US_W_FMT, 0x00000000);
-  T0V(VAP_PVS_CONST_CNTL, 0x00000000);
   T0V(TX_INVALTAGS, 0x00000000);
   T0V(TX_ENABLE, 0x00000000);
   T0V(VAP_INDEX_OFFSET, 0x00000000);
@@ -361,6 +360,23 @@ int indirect_buffer()
   // VAP_PVS
   //////////////////////////////////////////////////////////////////////////////
 
+  T0V(VAP_PVS_CONST_CNTL
+      , VAP_PVS_CONST_CNTL__PVS_CONST_BASE_OFFSET(0)
+      | VAP_PVS_CONST_CNTL__PVS_MAX_CONST_ADDR(1)
+      );
+
+  T0V(VAP_PVS_VECTOR_INDX_REG
+      , VAP_PVS_VECTOR_INDX_REG__OCTWORD_OFFSET(1024)
+      );
+
+  const float consts[] = {
+    4.0f / 3.0f, 0.0f, 0.0f, 0.0f,
+  };
+  int consts_length = (sizeof (consts)) / (sizeof (consts[0]));
+  T0_ONE_REG(VAP_PVS_VECTOR_DATA_REG_128, (consts_length - 1));
+  for (int i = 0; i < consts_length; i++)
+    ib[ix++].f32 = consts[i];
+
   T0V(VAP_PVS_CODE_CNTL_0
       , VAP_PVS_CODE_CNTL_0__PVS_FIRST_INST(0)
       | VAP_PVS_CODE_CNTL_0__PVS_XYZW_VALID_INST(1)
diff --git a/drm/shadertoy.vs.asm b/drm/shadertoy.vs.asm
index f5380d0..745be4e 100644
--- a/drm/shadertoy.vs.asm
+++ b/drm/shadertoy.vs.asm
@@ -1,2 +1,3 @@
-out[1].xy    = VE_ADD       input[0].xy__     input[0].0000     input[0].0000    
-out[0].xyzw  = VE_ADD       input[0].xyz1     input[0].0000     input[0].0000    
+; CONST[0] = { 1.3333 , _, _, _ }
+out[1].xy    = VE_MUL       input[0].xy__     const[0].x1__
+out[0].xyzw  = VE_ADD       input[0].xyz1     input[0].0000
diff --git a/drm/texture_cube_clear_zwrite_vertex_shader.c b/drm/texture_cube_clear_zwrite_vertex_shader.c
index 896abda..286f79a 100644
--- a/drm/texture_cube_clear_zwrite_vertex_shader.c
+++ b/drm/texture_cube_clear_zwrite_vertex_shader.c
@@ -436,7 +436,7 @@ int _3d_cube(int ix, float theta)
   float theta1 = theta;
   //float theta2 = 3.14f * theta;
   float theta2 = theta;
-  float consts[] = {
+  const float consts[] = {
     I_PI_2, 0.5f, PI_2, -PI,
     theta1, theta2, 0.2f, 0.5f,
   };