diff --git a/src/float_colorbuffer.cpp b/src/float_colorbuffer.cpp
deleted file mode 100644
index 6d0415b..0000000
--- a/src/float_colorbuffer.cpp
+++ /dev/null
@@ -1,115 +0,0 @@
-#include <assert.h>
-#include <errno.h>
-#include <stdbool.h>
-#include <stdint.h>
-#include <stdio.h>
-#include <unistd.h>
-#include <string.h>
-#include <stdlib.h>
-#include <math.h>
-
-#include <fcntl.h>
-#include <sys/mman.h>
-
-#include "r500/3d_registers.h"
-#include "r500/3d_registers_undocumented.h"
-#include "r500/3d_registers_bits.h"
-#include "r500/indirect_buffer.h"
-#include "r500/shader.h"
-#include "r500/display_controller.h"
-
-#include "drm/buffer.h"
-#include "drm/drm.h"
-
-#include "math/float_types.hpp"
-#include "math/transform.hpp"
-#include "math/constants.hpp"
-
-#include "../model/model2.h"
-#include "../model/plane.h"
-
-#define CLEAR_SHADER 0
-#define PLANE_SHADER 1
-#define PARTICLE_SHADER 2
-#define TEXTURE_TILE_SHADER 3
-
-const char * vertex_shader_paths[] = {
-  "clear.vs.bin",
-};
-const int vertex_shader_paths_length = (sizeof (vertex_shader_paths)) / (sizeof (vertex_shader_paths[0]));
-const char * fragment_shader_paths[] = {
-  "clear.fs.bin",
-};
-const int fragment_shader_paths_length = (sizeof (fragment_shader_paths)) / (sizeof (fragment_shader_paths[0]));
-
-#define PARTICLE_TEXTURE 0
-
-const char * textures[] = {
-  "../texture/particle_32x32_rgba8888.data",
-};
-const int textures_length = (sizeof (textures)) / (sizeof (textures[0]));
-
-struct shaders {
-  struct shader_offset * vertex;
-  struct shader_offset * fragment;
-  int vertex_length;
-  int fragment_length;
-};
-
-int main()
-{
-  struct shaders shaders = {
-    .vertex = load_shaders(vertex_shader_paths, vertex_shader_paths_length),
-    .fragment = load_shaders(fragment_shader_paths, fragment_shader_paths_length),
-    .vertex_length = vertex_shader_paths_length,
-    .fragment_length = fragment_shader_paths_length,
-  };
-
-  void * rmmio = map_pci_resource2();
-
-  int fd = open("/dev/dri/card0", O_RDWR | O_CLOEXEC);
-  assert(fd != -1);
-
-  const int colorbuffer_size = 1600 * 1200 * 4;
-  int colorbuffer_handle[2];
-  int zbuffer_handle;
-  int * texturebuffer_handle;
-  int flush_handle;
-
-  void * colorbuffer_ptr[2];
-  void * zbuffer_ptr;
-
-  // colorbuffer
-  colorbuffer_handle[0] = create_buffer(fd, colorbuffer_size, &colorbuffer_ptr[0]);
-  colorbuffer_handle[1] = create_buffer(fd, colorbuffer_size, &colorbuffer_ptr[1]);
-  zbuffer_handle = create_buffer(fd, colorbuffer_size, &zbuffer_ptr);
-  flush_handle = create_flush_buffer(fd);
-  texturebuffer_handle = load_textures(fd, textures, textures_length);
-
-  fprintf(stderr, "colorbuffer handle[0] %d\n", colorbuffer_handle[0]);
-  fprintf(stderr, "colorbuffer handle[1] %d\n", colorbuffer_handle[1]);
-  fprintf(stderr, "zbuffer handle %d\n", zbuffer_handle);
-
-  int colorbuffer_ix = 0;
-  float theta = PI * 0.5;
-
-  while (true) {
-    int ib_dwords = indirect_buffer(shaders, theta);
-
-    drm_radeon_cs(fd,
-                  colorbuffer_handle[colorbuffer_ix],
-                  zbuffer_handle,
-                  flush_handle,
-                  texturebuffer_handle,
-                  textures_length,
-                  ib_dwords);
-
-    primary_surface_address(rmmio, colorbuffer_ix);
-
-    // next state
-    theta += 0.01f;
-    colorbuffer_ix = (colorbuffer_ix + 1) & 1;
-  }
-
-  close(fd);
-}
diff --git a/src/matrix_cubesphere_tiled.cpp b/src/matrix_cubesphere_tiled.cpp
index 79ec7c6..321dc75 100644
--- a/src/matrix_cubesphere_tiled.cpp
+++ b/src/matrix_cubesphere_tiled.cpp
@@ -687,8 +687,8 @@ int _tile_texture(const shaders& shaders,
   //////////////////////////////////////////////////////////////////////////////
 
   T0V(GA_POINT_SIZE
-      , GA_POINT_SIZE__HEIGHT((int)(x * 12.0f))
-      | GA_POINT_SIZE__WIDTH((int)(y * 12.0f))
+      , GA_POINT_SIZE__HEIGHT((int)(y * 12.0f))
+      | GA_POINT_SIZE__WIDTH((int)(x * 12.0f))
       );
 
   //////////////////////////////////////////////////////////////////////////////
@@ -788,15 +788,17 @@ int main()
   while (true) {
     int ib_dwords = indirect_buffer(shaders, theta);
 
-    drm_radeon_cs(fd,
-                  colorbuffer_handle[colorbuffer_ix],
-                  zbuffer_handle,
-                  flush_handle,
-                  //texturebuffer_handle,
-                  //textures_length,
-                  &test_handle,
-                  1,
-                  ib_dwords);
+    int ret = drm_radeon_cs(fd,
+                            colorbuffer_handle[colorbuffer_ix],
+                            zbuffer_handle,
+                            flush_handle,
+                            //texturebuffer_handle,
+                            //textures_length,
+                            &test_handle,
+                            1,
+                            ib_dwords);
+    if (ret == -1)
+      break;
 
     primary_surface_address(rmmio, colorbuffer_ix);
 
diff --git a/src/tx_rt.cpp b/src/tx_rt.cpp
new file mode 100644
index 0000000..32f141e
--- /dev/null
+++ b/src/tx_rt.cpp
@@ -0,0 +1,293 @@
+#include <assert.h>
+#include <errno.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <string.h>
+#include <stdlib.h>
+#include <math.h>
+
+#include <fcntl.h>
+#include <sys/mman.h>
+
+#include "r500/3d_registers.h"
+#include "r500/3d_registers_undocumented.h"
+#include "r500/3d_registers_bits.h"
+#include "r500/indirect_buffer.h"
+#include "r500/shader.h"
+#include "r500/display_controller.h"
+
+#include "drm/buffer.h"
+#include "drm/drm.h"
+
+#include "math/float_types.hpp"
+#include "math/transform.hpp"
+#include "math/constants.hpp"
+
+#include "../model/model2.h"
+#include "../model/plane.h"
+
+#define TEXTURE_TILE_SHADER 0
+
+const char * vertex_shader_paths[] = {
+  "tx_rt.vs.bin",
+};
+const int vertex_shader_paths_length = (sizeof (vertex_shader_paths)) / (sizeof (vertex_shader_paths[0]));
+const char * fragment_shader_paths[] = {
+  "tx_rt.fs.bin",
+};
+const int fragment_shader_paths_length = (sizeof (fragment_shader_paths)) / (sizeof (fragment_shader_paths[0]));
+
+#define PARTICLE_TEXTURE 0
+
+const char * textures[] = {
+  "../texture/butterfly_1024x1024_rgba8888.data",
+};
+const int textures_length = (sizeof (textures)) / (sizeof (textures[0]));
+
+struct shaders {
+  struct shader_offset * vertex;
+  struct shader_offset * fragment;
+  int vertex_length;
+  int fragment_length;
+};
+
+int _tile_texture(const shaders& shaders,
+                  int input_reloc_index,
+                  int output_reloc_index)
+{
+  int viewport_width = 1600;
+  int viewport_height = 1200;
+  int texture_width = 1024;
+  int texture_height = 1024;
+  float vx = ((float)viewport_width) * 0.5f;
+  float vy = ((float)viewport_height) * 0.5f;
+  float tx = 0.5f / ((float)texture_width);
+  float ty = 0.5f / ((float)texture_height);
+
+  ib_ix = 0;
+
+  ib_generic_initialization();
+
+  T0V(SC_SCISSOR0
+      , SC_SCISSOR0__XS0(0)
+      | SC_SCISSOR0__YS0(0)
+      );
+  T0V(SC_SCISSOR1
+      , SC_SCISSOR1__XS1(viewport_width - 1)
+      | SC_SCISSOR1__YS1(viewport_height - 1)
+      );
+  T0Vf(VAP_VPORT_XSCALE, (float)viewport_width);
+  T0Vf(VAP_VPORT_YSCALE, (float)viewport_height);
+
+  ib_colorbuffer(output_reloc_index, viewport_width, 0, 0); // macrotile, microtile
+
+  T0V(US_OUT_FMT_0
+      , US_OUT_FMT__OUT_FMT(0)  // C4_8
+      | US_OUT_FMT__C0_SEL__BLUE
+      | US_OUT_FMT__C1_SEL__GREEN
+      | US_OUT_FMT__C2_SEL__RED
+      | US_OUT_FMT__C3_SEL__ALPHA
+      | US_OUT_FMT__OUT_SIGN(0)
+      );
+  T0V(US_OUT_FMT_1
+      , US_OUT_FMT__OUT_FMT(15) // render target is not used
+      );
+  T0V(US_OUT_FMT_2
+      , US_OUT_FMT__OUT_FMT(15) // render target is not used
+      );
+  T0V(US_OUT_FMT_3
+      , US_OUT_FMT__OUT_FMT(15) // render target is not used
+      );
+
+  // shaders
+  load_pvs_shaders(shaders.vertex, shaders.vertex_length);
+  load_us_shaders(shaders.fragment, shaders.fragment_length);
+
+  // GA
+
+  T0V(GB_ENABLE
+      , 0
+    );
+
+  //////////////////////////////////////////////////////////////////////////////
+  // RS
+  //////////////////////////////////////////////////////////////////////////////
+
+  ib_rs_instructions(1);
+
+  //////////////////////////////////////////////////////////////////////////////
+  // VAP OUT
+  //////////////////////////////////////////////////////////////////////////////
+
+  T0V(VAP_OUT_VTX_FMT_0
+      , VAP_OUT_VTX_FMT_0__VTX_POS_PRESENT(1)
+      );
+  T0V(VAP_OUT_VTX_FMT_1
+      , VAP_OUT_VTX_FMT_1__TEX_0_COMP_CNT(4)
+      );
+
+  //
+
+  T0V(ZB_CNTL, 0);
+  T0V(ZB_ZSTENCILCNTL, 0);
+
+  //
+
+  int macrotile = 0;
+  int microtile = 0;
+  int clamp = 2; // clamp to [0.0, 1.0]
+  ib_texture__1(input_reloc_index,
+                texture_width, texture_height,
+                macrotile, microtile,
+                clamp);
+
+  ib_vap_stream_cntl__2();
+
+  T0V(US_PIXSIZE
+      , US_PIXSIZE__PIX_SIZE(1)
+      );
+
+  ib_ga_us(&shaders.fragment[TEXTURE_TILE_SHADER]);
+  ib_vap_pvs(&shaders.vertex[TEXTURE_TILE_SHADER]);
+
+  // fragment constants
+  const float fragment_consts[] = {
+    tx, ty, 0, 0,
+  };
+  int fragment_consts_length = (sizeof (fragment_consts)) / (sizeof (fragment_consts[0]));
+
+  T0V(GA_US_VECTOR_INDEX
+      , GA_US_VECTOR_INDEX__INDEX(0)
+      | GA_US_VECTOR_INDEX__TYPE(1)
+      );
+  T0_ONE_REG(GA_US_VECTOR_DATA, (fragment_consts_length - 1));
+  for (int i = 0; i < fragment_consts_length; i++)
+    TF(fragment_consts[i]);
+
+  //////////////////////////////////////////////////////////////////////////////
+  // VAP
+  //////////////////////////////////////////////////////////////////////////////
+
+  T0V(VAP_CLIP_CNTL
+      , VAP_CLIP_CNTL__CLIP_DISABLE(1)
+      );
+
+  T0V(VAP_VTE_CNTL
+      , VAP_VTE_CNTL__VPORT_X_SCALE_ENA(1)
+      | VAP_VTE_CNTL__VPORT_Y_SCALE_ENA(1)
+      | VAP_VTE_CNTL__VTX_XY_FMT(1) // disable W division
+      | VAP_VTE_CNTL__VTX_Z_FMT(1)  // disable W division
+      );
+
+  T0V(VAP_CNTL_STATUS
+      , VAP_CNTL_STATUS__PVS_BYPASS(0)
+      );
+
+  //////////////////////////////////////////////////////////////////////////////
+  // GA POINT SIZE
+  //////////////////////////////////////////////////////////////////////////////
+
+  T0V(GA_POINT_SIZE
+      , GA_POINT_SIZE__HEIGHT((int)(vy * 12.0f))
+      | GA_POINT_SIZE__WIDTH((int)(vx * 12.0f))
+      );
+
+  //////////////////////////////////////////////////////////////////////////////
+  // 3D_DRAW
+  //////////////////////////////////////////////////////////////////////////////
+
+  const int dwords_per_vtx = 2;
+
+  T0V(VAP_VTX_SIZE
+      , VAP_VTX_SIZE__DWORDS_PER_VTX(dwords_per_vtx)
+      );
+
+  const float vertices[] = {
+    0.0f, 0.0f,
+    1.0f, 0.0f,
+    1.0f, 1.0f,
+    0.0f, 1.0f,
+  };
+  const int vertex_count = 4;
+  T3(_3D_DRAW_IMMD_2, (1 + vertex_count * dwords_per_vtx) - 1);
+  TU( VAP_VF_CNTL__PRIM_TYPE(5) // triangle fan
+    | VAP_VF_CNTL__PRIM_WALK(3)
+    | VAP_VF_CNTL__INDEX_SIZE(0)
+    | VAP_VF_CNTL__VTX_REUSE_DIS(0)
+    | VAP_VF_CNTL__DUAL_INDEX_MODE(0)
+    | VAP_VF_CNTL__USE_ALT_NUM_VERTS(0)
+    | VAP_VF_CNTL__NUM_VERTICES(vertex_count)
+    );
+  for (int i = 0; i < vertex_count * 2; i++) {
+    TF(vertices[i]);
+  }
+
+  return ib_ix;
+}
+
+int main()
+{
+  struct shaders shaders = {
+    .vertex = load_shaders(vertex_shader_paths, vertex_shader_paths_length),
+    .fragment = load_shaders(fragment_shader_paths, fragment_shader_paths_length),
+    .vertex_length = vertex_shader_paths_length,
+    .fragment_length = fragment_shader_paths_length,
+  };
+
+  void * rmmio = map_pci_resource2();
+
+  int fd = open("/dev/dri/card0", O_RDWR | O_CLOEXEC);
+  assert(fd != -1);
+
+  const int colorbuffer_size = 1600 * 1200 * 4;
+  int colorbuffer_handle[2];
+  int zbuffer_handle;
+  int * texturebuffer_handle;
+  int flush_handle;
+
+  void * colorbuffer_ptr[2];
+  void * zbuffer_ptr;
+
+  // colorbuffer
+  colorbuffer_handle[0] = create_buffer(fd, colorbuffer_size, &colorbuffer_ptr[0]);
+  colorbuffer_handle[1] = create_buffer(fd, colorbuffer_size, &colorbuffer_ptr[1]);
+  zbuffer_handle = create_buffer(fd, colorbuffer_size, &zbuffer_ptr);
+  flush_handle = create_flush_buffer(fd);
+  texturebuffer_handle = load_textures(fd, textures, textures_length);
+
+  fprintf(stderr, "colorbuffer handle[0] %d\n", colorbuffer_handle[0]);
+  fprintf(stderr, "colorbuffer handle[1] %d\n", colorbuffer_handle[1]);
+  fprintf(stderr, "zbuffer handle %d\n", zbuffer_handle);
+
+  int colorbuffer_ix = 0;
+  float theta = PI * 0.5;
+
+  while (true) {
+    //int ib_dwords = indirect_buffer(shaders, theta);
+    int ib_dwords = _tile_texture(shaders,
+                                  TEXTUREBUFFER_RELOC_INDEX, // input
+                                  COLORBUFFER_RELOC_INDEX);  // output
+
+    int ret = drm_radeon_cs(fd,
+                            colorbuffer_handle[colorbuffer_ix],
+                            zbuffer_handle,
+                            flush_handle,
+                            texturebuffer_handle,
+                            textures_length,
+                            ib_dwords);
+    if (ret == -1)
+      break;
+
+    primary_surface_address(rmmio, colorbuffer_ix);
+
+    // next state
+    theta += 0.01f;
+    colorbuffer_ix = (colorbuffer_ix + 1) & 1;
+
+    break;
+  }
+
+  close(fd);
+}
diff --git a/src/tx_rt.fs.asm b/src/tx_rt.fs.asm
new file mode 100644
index 0000000..3e534e8
--- /dev/null
+++ b/src/tx_rt.fs.asm
@@ -0,0 +1,8 @@
+TEX TEX_SEM_WAIT TEX_SEM_ACQUIRE
+  temp[0].rgba = LD tex[0].rgba temp[0].rgaa ;
+
+OUT TEX_SEM_WAIT
+src0.a = temp[0],
+src0.rgb = temp[0] :
+  out[0].a    = MAX src0.a src0.a ,
+  out[0].rgb  = MAX src0.rgb src0.rgb ;
diff --git a/src/tx_rt.fs.bin b/src/tx_rt.fs.bin
new file mode 100644
index 0000000..bbfaa90
Binary files /dev/null and b/src/tx_rt.fs.bin differ
diff --git a/src/tx_rt.vs.asm b/src/tx_rt.vs.asm
new file mode 100644
index 0000000..a19ad5a
--- /dev/null
+++ b/src/tx_rt.vs.asm
@@ -0,0 +1,2 @@
+out[0].xyzw = VE_ADD  input[0].xyzw  input[0].0000 ;
+out[1].xyzw = VE_ADD  input[0].xyzw  input[0].0000 ;
diff --git a/src/tx_rt.vs.bin b/src/tx_rt.vs.bin
new file mode 100644
index 0000000..11c172b
Binary files /dev/null and b/src/tx_rt.vs.bin differ