max dimension limit of 1024 to avoid vtflib crash

Make max dimension 1024x1024 to avoid vtflib crash in Create function. Convert to linear and then back to SRGB when calculating average last pixel color

sln/vs2017/cubemaker/cubemaker.cpp

@@ -84,6 +84,7 @@ struct RGBA8
 
 // needed to convert to HDR
 // TODO: make a table for 0 to 255?
+// DIVIDE by 255
 float SRGBToLinear(float u)
 {
     if (u <= 0.04045)
@@ -259,6 +260,13 @@ int main(int argc, char* argv[])
         base_nopath[len - 2] = 0;
     }
 
+    /*
+    char base[MAX_PATH];
+    char base_nopath[MAX_PATH];
+    strcpy_s(base, R"(C:\Users\d\Documents\GitHub\Cubemaker\sln\vs2017\Debug\sky_skylab_01)");
+    strcpy_s(base_nopath, R"(sky_skylab_01)");
+    */
+
     VTFLib::CVTFFile* faces[6]{};
 
     vlUInt width = 0;
@@ -292,6 +300,12 @@ int main(int argc, char* argv[])
     }
 
     printf("assuming dimensions of %i x %i based on largest square VTF \n", width, height);
+    if (width > 1024)
+    {
+        printf("downsizing to 1024 to avoid vtflib crash\n");
+        width = 1024;
+        height = 1024;
+    }
     auto cubemap = VTFLib::CVTFFile();
 
     vlByte* main_buffer[6];
@@ -351,22 +365,23 @@ int main(int argc, char* argv[])
         float r = 0.0, g = 0.0, b = 0.0, a = 0.0;
         for (int i = 0; i <= 3; i++)
         {
-            r += lastPixel[i].r;
-            g += lastPixel[i].g;
-            b += lastPixel[i].b;
+            r += SRGBToLinear(lastPixel[i].r / 255.0);
+            g += SRGBToLinear(lastPixel[i].g / 255.0);
+            b += SRGBToLinear(lastPixel[i].b / 255.0);
             a += lastPixel[i].a;
         }
 
-        lastPixelAverage.r = (vlByte)round(r / 4.0);
-        lastPixelAverage.g = (vlByte)round(g / 4.0);
-        lastPixelAverage.b = (vlByte)round(b / 4.0);
+        lastPixelAverage.r = LinearToSRGB(r / 4.0);
+        lastPixelAverage.g = LinearToSRGB(g / 4.0);
+        lastPixelAverage.b = LinearToSRGB(b / 4.0);
         lastPixelAverage.a = (vlByte)round(a / 4.0);
     }
 
     for(int i = 0; i < 6; i++)
     {
         auto face_width = faces[i]->GetWidth();
         auto face_height = faces[i]->GetHeight();
+
         if (face_width != width || face_height != height)
         {
             printf("%s%s.vtf has a different dimension %i x %i. attempting to resize.\n", base_nopath, g_faceorder[i], face_width, face_height);
@@ -536,11 +551,11 @@ int main(int argc, char* argv[])
 
     snprintf(output_name, sizeof(output_name), "%s_cubemap.vmt", base);
     FILE* f;
-    errnum = fopen_s(&f, output_name, "w");
-    if (errnum || f == NULL)
+    auto errnum2 = fopen_s(&f, output_name, "w");
+    if (errnum2 || f == NULL)
     {
         char err[64];
-        strerror_s(err, errnum);
+        strerror_s(err, errnum2);
         printf("Error opening %s to write: %s\n", output_name, err);
         PressKeyToContinue();
         std::terminate();