Fix GetBooleani_v validation and params length for WebGL OES_draw_buffers_indexed

src/libANGLE/ErrorStrings.h

@@ -85,6 +85,7 @@ MSG kDestinationTextureTooSmall = "Destination texture too small.";
 MSG kDimensionsMustBePow2 = "Texture dimensions must be power-of-two.";
 MSG kDispatchIndirectBufferNotBound = "Dispatch indirect buffer must be bound.";
 MSG kDrawBufferMaskMismatch = "Active draw buffers with missing fragment shader outputs.";
+MSG kES31OrDrawBuffersIndexedExtensionNotAvailable = "EXT/OES_draw_buffers_indexed or ES 3.1 are required but not available.";
 MSG kDrawBufferTypeMismatch = "Fragment shader output type does not match the bound framebuffer attachment type.";
 MSG kDrawFramebufferIncomplete = "Draw framebuffer is incomplete";
 MSG kDrawIndirectBufferNotBound = "Draw indirect buffer must be bound.";

src/libANGLE/validationES3.cpp

@@ -2808,7 +2808,14 @@ bool ValidateIndexedStateQuery(const Context *context, GLenum pname, GLuint inde
 
     if (length)
     {
-        *length = 1;
+        if (pname == GL_COLOR_WRITEMASK)
+        {
+            *length = 4;
+        }
+        else
+        {
+            *length = 1;
+        }
     }
 
     return true;

src/libANGLE/validationES31.cpp

@@ -370,9 +370,10 @@ bool ValidateGetBooleani_v(const Context *context,
                            GLuint index,
                            const GLboolean *data)
 {
-    if (context->getClientVersion() < ES_3_1)
+    if (context->getClientVersion() < ES_3_1 && !context->getExtensions().drawBuffersIndexedAny())
     {
-        context->validationError(GL_INVALID_OPERATION, kES31Required);
+        context->validationError(GL_INVALID_OPERATION,
+                                 kES31OrDrawBuffersIndexedExtensionNotAvailable);
         return false;
     }
 
@@ -391,9 +392,10 @@ bool ValidateGetBooleani_vRobustANGLE(const Context *context,
                                       const GLsizei *length,
                                       const GLboolean *data)
 {
-    if (context->getClientVersion() < ES_3_1)
+    if (context->getClientVersion() < ES_3_1 && !context->getExtensions().drawBuffersIndexedAny())
     {
-        context->validationError(GL_INVALID_OPERATION, kES31Required);
+        context->validationError(GL_INVALID_OPERATION,
+                                 kES31OrDrawBuffersIndexedExtensionNotAvailable);
         return false;
     }