diff --git a/src/osgVolume/Shaders/volume_frag.cpp b/src/osgVolume/Shaders/volume_frag.cpp
index 6351da4f9..c2cf5fc10 100644
--- a/src/osgVolume/Shaders/volume_frag.cpp
+++ b/src/osgVolume/Shaders/volume_frag.cpp
@@ -61,16 +61,18 @@ char volume_frag[] = "uniform sampler3D baseTexture;\n"
                      "    t0 = t0 * texgen;\n"
                      "    te = te * texgen;\n"
                      "\n"
-                     "    const int max_iteratrions = 2048;\n"
-                     "    int num_iterations = ceil(length((te-t0).xyz)/SampleDensityValue);\n"
-                     "    if (num_iterations<2) num_iterations = 2;\n"
-                     "    if (num_iterations>max_iteratrions) num_iterations = max_iteratrions;\n"
+                     "    const float min_iterations = 2.0;\n"
+                     "    const float max_iterations = 2048.0;\n"
+                     "    float num_iterations = ceil(length((te-t0).xyz)/SampleDensityValue);\n"
+                     "    if (num_iterations<min_iterations) num_iterations = min_iterations;\n"
+                     "    else if (num_iterations>max_iterations) num_iterations = max_iterations;\n"
+                     "    else if (num_iterations!=num_iterations) num_iterations = max_iterations;\n"
                      "\n"
-                     "    vec3 deltaTexCoord=(te-t0).xyz/float(num_iterations-1);\n"
+                     "    vec3 deltaTexCoord=(te-t0).xyz/(num_iterations-1.0);\n"
                      "    vec3 texcoord = t0.xyz;\n"
                      "\n"
                      "    vec4 fragColor = vec4(0.0, 0.0, 0.0, 0.0);\n"
-                     "    while(num_iterations>0)\n"
+                     "    while(num_iterations>0.0)\n"
                      "    {\n"
                      "        vec4 color = texture3D( baseTexture, texcoord);\n"
                      "        float r = color[3]*TransparencyValue;\n"
diff --git a/src/osgVolume/Shaders/volume_iso_frag.cpp b/src/osgVolume/Shaders/volume_iso_frag.cpp
index 85542b7ac..dbef5ef20 100644
--- a/src/osgVolume/Shaders/volume_iso_frag.cpp
+++ b/src/osgVolume/Shaders/volume_iso_frag.cpp
@@ -62,13 +62,14 @@ char volume_iso_frag[] = "uniform sampler3D baseTexture;\n"
                          "    t0 = t0 * texgen;\n"
                          "    te = te * texgen;\n"
                          "\n"
-                         "    const int max_iteratrions = 2048;\n"
-                         "    int num_iterations = ceil(length((te-t0).xyz)/SampleDensityValue);\n"
-                         "    if (num_iterations<2) num_iterations = 2;\n"
-                         "    if (num_iterations>max_iteratrions) num_iterations = max_iteratrions;\n"
+                         "    const float min_iterations = 2.0;\n"
+                         "    const float max_iterations = 2048.0;\n"
+                         "    float num_iterations = ceil(length((te-t0).xyz)/SampleDensityValue);\n"
+                         "    if (num_iterations<min_iterations) num_iterations = min_iterations;\n"
+                         "    else if (num_iterations>max_iterations) num_iterations = max_iterations;\n"
+                         "    else if (num_iterations!=num_iterations) num_iterations = max_iterations;\n"
                          "\n"
-                         "\n"
-                         "    vec3 deltaTexCoord=(t0-te).xyz/float(num_iterations-1);\n"
+                         "    vec3 deltaTexCoord=(t0-te).xyz/(num_iterations-1.0);\n"
                          "    vec3 texcoord = te.xyz;\n"
                          "\n"
                          "    vec4 previousColor = texture3D( baseTexture, texcoord);\n"
@@ -78,7 +79,7 @@ char volume_iso_frag[] = "uniform sampler3D baseTexture;\n"
                          "    vec3 deltaY = vec3(0.0, normalSampleDistance, 0.0);\n"
                          "    vec3 deltaZ = vec3(0.0, 0.0, normalSampleDistance);\n"
                          "    \n"
-                         "    while(num_iterations>0)\n"
+                         "    while(num_iterations>0.0)\n"
                          "    {\n"
                          "        vec4 color = texture3D( baseTexture, texcoord);\n"
                          "\n"
diff --git a/src/osgVolume/Shaders/volume_lit_frag.cpp b/src/osgVolume/Shaders/volume_lit_frag.cpp
index 97b4ef05b..584fed6e3 100644
--- a/src/osgVolume/Shaders/volume_lit_frag.cpp
+++ b/src/osgVolume/Shaders/volume_lit_frag.cpp
@@ -62,12 +62,14 @@ char volume_lit_frag[] = "uniform sampler3D baseTexture;\n"
                          "    t0 = t0 * texgen;\n"
                          "    te = te * texgen;\n"
                          "\n"
-                         "    const int max_iteratrions = 2048;\n"
-                         "    int num_iterations = ceil(length((te-t0).xyz)/SampleDensityValue);\n"
-                         "    if (num_iterations<2) num_iterations = 2;\n"
-                         "    if (num_iterations>max_iteratrions) num_iterations = max_iteratrions;\n"
+                        "    const float min_iterations = 2.0;\n"
+                        "    const float max_iterations = 2048.0;\n"
+                        "    float num_iterations = ceil(length((te-t0).xyz)/SampleDensityValue);\n"
+                        "    if (num_iterations<min_iterations) num_iterations = min_iterations;\n"
+                        "    else if (num_iterations>max_iterations) num_iterations = max_iterations;\n"
+                        "    else if (num_iterations!=num_iterations) num_iterations = max_iterations;\n"
                          "\n"
-                         "    vec3 deltaTexCoord=(te-t0).xyz/float(num_iterations-1);\n"
+                         "    vec3 deltaTexCoord=(te-t0).xyz/(num_iterations-1.0);\n"
                          "    vec3 texcoord = t0.xyz;\n"
                          "\n"
                          "    float normalSampleDistance = 1.0/512.0;\n"
@@ -76,7 +78,7 @@ char volume_lit_frag[] = "uniform sampler3D baseTexture;\n"
                          "    vec3 deltaZ = vec3(0.0, 0.0, normalSampleDistance);\n"
                          "\n"
                          "    vec4 fragColor = vec4(0.0, 0.0, 0.0, 0.0); \n"
-                         "    while(num_iterations>0)\n"
+                         "    while(num_iterations>0.0)\n"
                          "    {\n"
                          "        vec4 color = texture3D( baseTexture, texcoord);\n"
                          "\n"
diff --git a/src/osgVolume/Shaders/volume_lit_tf_frag.cpp b/src/osgVolume/Shaders/volume_lit_tf_frag.cpp
index 63e02dc2e..08c74b4d5 100644
--- a/src/osgVolume/Shaders/volume_lit_tf_frag.cpp
+++ b/src/osgVolume/Shaders/volume_lit_tf_frag.cpp
@@ -69,12 +69,14 @@ char volume_lit_tf_frag[] = "uniform sampler3D baseTexture;\n"
                             "\n"
                             "    vec3 eyeDirection = normalize((te-t0).xyz);\n"
                             "\n"
-                            "    const int max_iteratrions = 2048;\n"
-                            "    int num_iterations = ceil(length((te-t0).xyz)/SampleDensityValue);\n"
-                            "    if (num_iterations<2) num_iterations = 2;\n"
-                            "    if (num_iterations>max_iteratrions) num_iterations = max_iteratrions;\n"
+                            "    const float min_iterations = 2.0;\n"
+                            "    const float max_iterations = 2048.0;\n"
+                            "    float num_iterations = ceil(length((te-t0).xyz)/SampleDensityValue);\n"
+                            "    if (num_iterations<min_iterations) num_iterations = min_iterations;\n"
+                            "    else if (num_iterations>max_iterations) num_iterations = max_iterations;\n"
+                            "    else if (num_iterations!=num_iterations) num_iterations = max_iterations;\n"
                             "\n"
-                            "    vec3 deltaTexCoord=(te-t0).xyz/float(num_iterations-1);\n"
+                            "    vec3 deltaTexCoord=(te-t0).xyz/(num_iterations-1.0);\n"
                             "    vec3 texcoord = t0.xyz;\n"
                             "\n"
                             "    float normalSampleDistance = 1.0/512.0;\n"
@@ -83,7 +85,7 @@ char volume_lit_tf_frag[] = "uniform sampler3D baseTexture;\n"
                             "    vec3 deltaZ = vec3(0.0, 0.0, normalSampleDistance);\n"
                             "\n"
                             "    vec4 fragColor = vec4(0.0, 0.0, 0.0, 0.0); \n"
-                            "    while(num_iterations>0)\n"
+                            "    while(num_iterations>0.0)\n"
                             "    {\n"
                             "        float v = texture3D( baseTexture, texcoord).a  * tfScale + tfOffset;\n"
                             "        vec4 color = texture1D( tfTexture, v);\n"
diff --git a/src/osgVolume/Shaders/volume_mip_frag.cpp b/src/osgVolume/Shaders/volume_mip_frag.cpp
index c399831c5..5299c6bbc 100644
--- a/src/osgVolume/Shaders/volume_mip_frag.cpp
+++ b/src/osgVolume/Shaders/volume_mip_frag.cpp
@@ -61,16 +61,18 @@ char volume_mip_frag[] = "uniform sampler3D baseTexture;\n"
                          "    t0 = t0 * texgen;\n"
                          "    te = te * texgen;\n"
                          "\n"
-                         "    const int max_iteratrions = 2048;\n"
-                         "    int num_iterations = ceil(length((te-t0).xyz)/SampleDensityValue);\n"
-                         "    if (num_iterations<2) num_iterations = 2;\n"
-                         "    if (num_iterations>max_iteratrions) num_iterations = max_iteratrions;\n"
+                         "    const float min_iterations = 2.0;\n"
+                         "    const float max_iterations = 2048.0;\n"
+                         "    float num_iterations = ceil(length((te-t0).xyz)/SampleDensityValue);\n"
+                         "    if (num_iterations<min_iterations) num_iterations = min_iterations;\n"
+                         "    else if (num_iterations>max_iterations) num_iterations = max_iterations;\n"
+                         "    else if (num_iterations!=num_iterations) num_iterations = max_iterations;\n"
                          "\n"
-                         "    vec3 deltaTexCoord=(te-t0).xyz/float(num_iterations-1);\n"
+                         "    vec3 deltaTexCoord=(te-t0).xyz/(num_iterations-1.0);\n"
                          "    vec3 texcoord = t0.xyz;\n"
                          "\n"
                          "    vec4 fragColor = vec4(0.0, 0.0, 0.0, 0.0);\n"
-                         "    while(num_iterations>0)\n"
+                         "    while(num_iterations>0.0)\n"
                          "    {\n"
                          "        vec4 color = texture3D( baseTexture, texcoord);\n"
                          "        if (fragColor.w<color.w)\n"
diff --git a/src/osgVolume/Shaders/volume_tf_frag.cpp b/src/osgVolume/Shaders/volume_tf_frag.cpp
index be6333721..95ec4c38c 100644
--- a/src/osgVolume/Shaders/volume_tf_frag.cpp
+++ b/src/osgVolume/Shaders/volume_tf_frag.cpp
@@ -66,16 +66,18 @@ char volume_tf_frag[] = "uniform sampler3D baseTexture;\n"
                         "    t0 = t0 * texgen;\n"
                         "    te = te * texgen;\n"
                         "\n"
-                        "    const int max_iteratrions = 2048;\n"
-                        "    int num_iterations = ceil(length((te-t0).xyz)/SampleDensityValue);\n"
-                        "    if (num_iterations<2) num_iterations = 2;\n"
-                        "    if (num_iterations>max_iteratrions) num_iterations = max_iteratrions;\n"
+                        "    const float min_iterations = 2.0;\n"
+                        "    const float max_iterations = 2048.0;\n"
+                        "    float num_iterations = ceil(length((te-t0).xyz)/SampleDensityValue);\n"
+                        "    if (num_iterations<min_iterations) num_iterations = min_iterations;\n"
+                        "    else if (num_iterations>max_iterations) num_iterations = max_iterations;\n"
+                        "    else if (num_iterations!=num_iterations) num_iterations = max_iterations;\n"
                         "\n"
-                        "    vec3 deltaTexCoord=(te-t0).xyz/float(num_iterations-1);\n"
+                        "    vec3 deltaTexCoord=(te-t0).xyz/(num_iterations-1.0);\n"
                         "    vec3 texcoord = t0.xyz;\n"
                         "\n"
                         "    vec4 fragColor = vec4(0.0, 0.0, 0.0, 0.0);\n"
-                        "    while(num_iterations>0)\n"
+                        "    while(num_iterations>0.0)\n"
                         "    {\n"
                         "        float v = texture3D( baseTexture, texcoord).a * tfScale + tfOffset;\n"
                         "        vec4 color = texture1D( tfTexture, v);\n"
diff --git a/src/osgVolume/Shaders/volume_tf_iso_frag.cpp b/src/osgVolume/Shaders/volume_tf_iso_frag.cpp
index e0df5217c..76f4b85e0 100644
--- a/src/osgVolume/Shaders/volume_tf_iso_frag.cpp
+++ b/src/osgVolume/Shaders/volume_tf_iso_frag.cpp
@@ -67,13 +67,15 @@ char volume_tf_iso_frag[] = "uniform sampler3D baseTexture;\n"
                             "    t0 = t0 * texgen;\n"
                             "    te = te * texgen;\n"
                             "\n"
-                            "    const int max_iteratrions = 2048;\n"
-                            "    int num_iterations = ceil(length((te-t0).xyz)/SampleDensityValue);\n"
-                            "    if (num_iterations<2) num_iterations = 2;\n"
-                            "    if (num_iterations>max_iteratrions) num_iterations = max_iteratrions;\n"
+                            "    const float min_iterations = 2.0;\n"
+                            "    const float max_iterations = 2048.0;\n"
+                            "    float num_iterations = ceil(length((te-t0).xyz)/SampleDensityValue);\n"
+                            "    if (num_iterations<min_iterations) num_iterations = min_iterations;\n"
+                            "    else if (num_iterations>max_iterations) num_iterations = max_iterations;\n"
+                            "    else if (num_iterations!=num_iterations) num_iterations = max_iterations;\n"
                             "\n"
                             "\n"
-                            "    vec3 deltaTexCoord=(t0-te).xyz/float(num_iterations-1);\n"
+                            "    vec3 deltaTexCoord=(t0-te).xyz/float(num_iterations-1.0);\n"
                             "    vec3 texcoord = te.xyz;\n"
                             "    float previousV = texture3D( baseTexture, texcoord).a;\n"
                             "\n"
@@ -82,7 +84,7 @@ char volume_tf_iso_frag[] = "uniform sampler3D baseTexture;\n"
                             "    vec3 deltaY = vec3(0.0, normalSampleDistance, 0.0);\n"
                             "    vec3 deltaZ = vec3(0.0, 0.0, normalSampleDistance);\n"
                             "    \n"
-                            "    while(num_iterations>0)\n"
+                            "    while(num_iterations>0.0)\n"
                             "    {\n"
                             "\n"
                             "        float v = texture3D( baseTexture, texcoord).a;\n"
diff --git a/src/osgVolume/Shaders/volume_tf_mip_frag.cpp b/src/osgVolume/Shaders/volume_tf_mip_frag.cpp
index fed843298..31f4b2545 100644
--- a/src/osgVolume/Shaders/volume_tf_mip_frag.cpp
+++ b/src/osgVolume/Shaders/volume_tf_mip_frag.cpp
@@ -66,16 +66,18 @@ char volume_tf_mip_frag[] = "uniform sampler3D baseTexture;\n"
                             "    t0 = t0 * texgen;\n"
                             "    te = te * texgen;\n"
                             "\n"
-                            "    const int max_iteratrions = 2048;\n"
-                            "    int num_iterations = ceil(length((te-t0).xyz)/SampleDensityValue);\n"
-                            "    if (num_iterations<2) num_iterations = 2;\n"
-                            "    if (num_iterations>max_iteratrions) num_iterations = max_iteratrions;\n"
+                            "    const float min_iterations = 2.0;\n"
+                            "    const float max_iterations = 2048.0;\n"
+                            "    float num_iterations = ceil(length((te-t0).xyz)/SampleDensityValue);\n"
+                            "    if (num_iterations<min_iterations) num_iterations = min_iterations;\n"
+                            "    else if (num_iterations>max_iterations) num_iterations = max_iterations;\n"
+                            "    else if (num_iterations!=num_iterations) num_iterations = max_iterations;\n"
                             "\n"
-                            "    vec3 deltaTexCoord=(te-t0).xyz/float(num_iterations-1);\n"
+                            "    vec3 deltaTexCoord=(te-t0).xyz/float(num_iterations-1.0);\n"
                             "    vec3 texcoord = t0.xyz;\n"
                             "\n"
                             "    vec4 fragColor = vec4(0.0, 0.0, 0.0, 0.0);\n"
-                            "    while(num_iterations>0)\n"
+                            "    while(num_iterations>0.0)\n"
                             "    {\n"
                             "        float v = texture3D( baseTexture, texcoord).s * tfScale + tfOffset;\n"
                             "        vec4 color = texture1D( tfTexture, v);\n"