Fix #106945: IES file parsing failures

There were two issues here preventing the proper display of the IES
files in question.

The primary one was that these lights are actually vertical. Their
profiles actually point upwards from 90deg to 180deg but our parser was
trying hard to adjust it to start at 0deg incorrectly.

Lastly, the files in question ended with the parser in the `eof`
state - they are "missing" the final carriage return that other IES
files tend to have but other viewers don't seem to mind. Change the
`eof` check instead for a better one that will indicate if any parsing
errors occurred along the way.

Pull Request: https://projects.blender.org/blender/blender/pulls/107320

intern/cycles/kernel/svm/ies.h

@@ -43,10 +43,10 @@ ccl_device_inline float kernel_ies_interp(KernelGlobals kg, int slot, float h_an
 #define IES_LOOKUP_ANGLE_V(v) kernel_data_fetch(ies, ofs + h_num + (v))
 
   /* Check whether the angle is within the bounds of the IES texture. */
-  if (v_angle >= IES_LOOKUP_ANGLE_V(v_num - 1)) {
+  if (v_angle < IES_LOOKUP_ANGLE_V(0) || v_angle >= IES_LOOKUP_ANGLE_V(v_num - 1)) {
     return 0.0f;
   }
-  kernel_assert(v_angle >= IES_LOOKUP_ANGLE_V(0));
+
   kernel_assert(h_angle >= IES_LOOKUP_ANGLE_H(0));
   kernel_assert(h_angle <= IES_LOOKUP_ANGLE_H(h_num - 1));
 

intern/cycles/util/ies.cpp

@@ -64,8 +64,9 @@ class IESTextParser {
  public:
   vector<char> text;
   char *data;
+  bool error;
 
-  IESTextParser(const string &str) : text(str.begin(), str.end())
+  IESTextParser(const string &str) : text(str.begin(), str.end()), error(false)
   {
     std::replace(text.begin(), text.end(), ',', ' ');
     data = strstr(&text[0], "\nTILT=");
@@ -76,15 +77,22 @@ class IESTextParser {
     return (data == NULL) || (data[0] == '\0');
   }
 
+  bool has_error()
+  {
+    return error;
+  }
+
   double get_double()
   {
     if (eof()) {
+      error = true;
       return 0.0;
     }
     char *old_data = data;
     double val = strtod(data, &data);
     if (data == old_data) {
       data = NULL;
+      error = true;
       return 0.0;
     }
     return val;
@@ -93,12 +101,14 @@ class IESTextParser {
   long get_long()
   {
     if (eof()) {
+      error = true;
       return 0;
     }
     char *old_data = data;
     long val = strtol(data, &data, 10);
     if (data == old_data) {
       data = NULL;
+      error = true;
       return 0;
     }
     return val;
@@ -191,7 +201,7 @@ bool IESFile::parse(const string &ies)
     }
   }
 
-  return !parser.eof();
+  return !parser.has_error();
 }
 
 bool IESFile::process_type_b()
@@ -340,13 +350,7 @@ bool IESFile::process_type_c()
 
   float v_first = v_angles[0], v_last = v_angles[v_angles.size() - 1];
   if (v_first == 90.0f) {
-    if (v_last == 180.0f) {
-      /* Flip to ensure that vertical angles always start at 0°. */
-      for (int i = 0; i < v_angles.size(); i++) {
-        v_angles[i] = 180.0f - v_angles[i];
-      }
-    }
-    else {
+    if (v_last != 180.0f) {
       return false;
     }
   }
@@ -375,7 +379,7 @@ bool IESFile::process()
     }
   }
 
-  assert(v_angles[0] == 0.0f);
+  assert(v_angles[0] == 0.0f || v_angles[0] == 90.0f);
   assert(h_angles[0] == 0.0f);
   assert(h_angles[h_angles.size() - 1] == 360.0f);