diff --git a/src/osgVolume/Shaders/volume_accumulateSamples_iso_frag.cpp b/src/osgVolume/Shaders/volume_accumulateSamples_iso_frag.cpp
index 75907aee1..f78efd819 100644
--- a/src/osgVolume/Shaders/volume_accumulateSamples_iso_frag.cpp
+++ b/src/osgVolume/Shaders/volume_accumulateSamples_iso_frag.cpp
@@ -3,7 +3,7 @@ char volume_accumulateSamples_iso_frag[] = "#version 110\n"
                                            "uniform sampler3D volumeTexture;\n"
                                            "\n"
                                            "uniform float IsoSurfaceValue;\n"
-                                           "\n"
+                                           "uniform float TransparencyValue;\n"
                                            "varying vec3 lightDirection;\n"
                                            "\n"
                                            "vec4 accumulateSamples(vec4 fragColor, vec3 ts, vec3 te, vec3 dt, float scale, float cutoff, int num_iterations)\n"
@@ -29,7 +29,7 @@ char volume_accumulateSamples_iso_frag[] = "#version 110\n"
                                            "            float r = (targetValue-color.a)/(previousColor.a-color.a);\n"
                                            "            texcoord = texcoord - r*dt;\n"
                                            "\n"
-                                           "            color.r = vec4(1.0, 1.0, 1.0, 1.0);\n"
+                                           "            color.rgba = vec4(1.0, 1.0, 1.0, 1.0);\n"
                                            "\n"
                                            "            float px = texture3D( volumeTexture, texcoord + deltaX).a;\n"
                                            "            float py = texture3D( volumeTexture, texcoord + deltaY).a;\n"
diff --git a/src/osgVolume/Shaders/volume_accumulateSamples_mip_frag.cpp b/src/osgVolume/Shaders/volume_accumulateSamples_mip_frag.cpp
index 0511e1e99..ff2322d68 100644
--- a/src/osgVolume/Shaders/volume_accumulateSamples_mip_frag.cpp
+++ b/src/osgVolume/Shaders/volume_accumulateSamples_mip_frag.cpp
@@ -1,6 +1,8 @@
 char volume_accumulateSamples_mip_frag[] = "#version 110\n"
                                            "\n"
                                            "uniform sampler3D volumeTexture;\n"
+                                           "uniform float TransparencyValue;\n"
+                                           "uniform float AlphaFuncValue;\n"
                                            "\n"
                                            "vec4 accumulateSamples(vec4 fragColor, vec3 ts, vec3 te, vec3 dt, float scale, float cutoff, int num_iterations)\n"
                                            "{\n"
@@ -10,7 +12,7 @@ char volume_accumulateSamples_mip_frag[] = "#version 110\n"
                                            "    {\n"
                                            "        vec4 color = texture3D( volumeTexture, texcoord);\n"
                                            "\n"
-                                           "        if (colorcolor.a>AlphaFuncValue &&  color.a>fragColor.a)\n"
+                                           "        if (color.a>AlphaFuncValue &&  color.a>fragColor.a)\n"
                                            "        {\n"
                                            "            fragColor = color;\n"
                                            "        }\n"
@@ -20,6 +22,8 @@ char volume_accumulateSamples_mip_frag[] = "#version 110\n"
                                            "        --num_iterations;\n"
                                            "    }\n"
                                            "\n"
+                                           "    fragColor.a *= TransparencyValue;\n"
+                                           "\n"
                                            "    return fragColor;\n"
                                            "}\n"
                                            "\n";