Merge pull request #1835 from juj/gl_get_null

glGetXXX fixes.

2 files changed, 28 insertions, 13 deletions

diff --git a/src/library_gl.js b/src/library_gl.js
index cc39b048..29f78c8a 100644
--- a/src/library_gl.js
+++ b/src/library_gl.js
@@ -210,21 +210,30 @@ var LibraryGL = {
     },
 
     get: function(name_, p, type) {
+      // Guard against user passing a null pointer.
+      // Note that GLES2 spec does not say anything about how passing a null pointer should be treated.
+      // Testing on desktop core GL 3, the application crashes on glGetIntegerv to a null pointer, but
+      // better to report an error instead of doing anything random.
+      if (!p) {
+#if GL_ASSERTIONS
+        Module.printErr('GL_INVALID_VALUE in glGet' + type + 'v(name=' + name_ + ': Function called with null out pointer!');
+#endif
+        GL.recordError(0x0501 /* GL_INVALID_VALUE */);
+        return;
+      }
       var ret = undefined;
       switch(name_) { // Handle a few trivial GLES values
         case 0x8DFA: // GL_SHADER_COMPILER
           ret = 1;
           break;
         case 0x8DF8: // GL_SHADER_BINARY_FORMATS
-          if (type === 'Integer') {
-            // fall through, see gles2_conformance.cpp
-          } else {
+          if (type !== 'Integer') {
             GL.recordError(0x0500); // GL_INVALID_ENUM
 #if GL_ASSERTIONS
             Module.printErr('GL_INVALID_ENUM in glGet' + type + 'v(GL_SHADER_BINARY_FORMATS): Invalid parameter type!');
 #endif
-            return;
           }
+          return; // Do not write anything to the out pointer, since no binary formats are supported.
         case 0x8DF9: // GL_NUM_SHADER_BINARY_FORMATS
           ret = 0;
           break;
diff --git a/tests/gles2_conformance.cpp b/tests/gles2_conformance.cpp
index 80539f7f..77681bf4 100644
--- a/tests/gles2_conformance.cpp
+++ b/tests/gles2_conformance.cpp
@@ -30,6 +30,16 @@ int main(int argc, char *argv[])
     glShaderBinary(1, &vs, 0, 0, 0);
     assert(glGetError() != GL_NO_ERROR);
 
+    // Calling any of glGet() with null pointer should be detected and not crash.
+    // Note that native code can crash when passed a null pointer, and the GL spec does not say anything
+    // about this, so we spec that Emscripten GLES2 code should generate GL_INVALID_VALUE.
+    glGetBooleanv(GL_ACTIVE_TEXTURE, 0);
+    assert(glGetError() == GL_INVALID_VALUE);
+    glGetIntegerv(GL_ACTIVE_TEXTURE, 0);
+    assert(glGetError() == GL_INVALID_VALUE);
+    glGetFloatv(GL_ACTIVE_TEXTURE, 0);
+    assert(glGetError() == GL_INVALID_VALUE);
+
     GLboolean b = GL_TRUE;
     GLint i = -1;
     GLfloat f = -1.f;
@@ -44,18 +54,14 @@ int main(int argc, char *argv[])
     assert(f == 0.f);
 
     // Currently testing that glGetIntegerv(GL_SHADER_BINARY_FORMATS) should be a no-op.
-    // The spec is somewhat vague here, equally as good could be to return GL_INVALID_ENUM here.
-    i = 123;
-    glGetIntegerv(GL_SHADER_BINARY_FORMATS, &i);
+    int formats[10] = { 123 };
+    glGetIntegerv(GL_SHADER_BINARY_FORMATS, formats);
     assert(glGetError() == GL_NO_ERROR);
-    assert(i == 0);
+    assert(formats[0] == 123);
 
-    // Spec does not say what to report on the following, but since GL_SHADER_BINARY_FORMATS is supposed
-    // to return a a pointer to an array representing a list, the pointer can't be converted to bool or float,
-    // so report a GL_INVALID_ENUM.
+    // Converting enums to booleans or floats would be odd, so test that the following report a GL_INVALID_ENUM.
     glGetBooleanv(GL_SHADER_BINARY_FORMATS, &b);
-    assert(glGetError() == GL_INVALID_ENUM);
-    
+    assert(glGetError() == GL_INVALID_ENUM);    
     glGetFloatv(GL_SHADER_BINARY_FORMATS, &f);
     assert(glGetError() == GL_INVALID_ENUM);