Vertex Array Object crash fix

Vertex array objects are not allocated when generated,
but only when bound, so it's legal to have a null
vertex array object internally.

Change-Id: Ib28a388939e285425c09cfbc9f4efef3f4a8cead
Reviewed-on: https://swiftshader-review.googlesource.com/4700
Tested-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <capn@google.com>

src/OpenGL/libGLESv2/Context.cpp

diff --git a/src/OpenGL/libGLESv2/Context.cpp b/src/OpenGL/libGLESv2/Context.cpp
index 04ec7f8..237a8a6 100644
--- a/src/OpenGL/libGLESv2/Context.cpp
+++ b/src/OpenGL/libGLESv2/Context.cpp
@@ -1536,6 +1536,13 @@
 	return getVertexArray(mState.vertexArray);

 }

 

+bool Context::isVertexArray(GLuint array) const

+{

+	VertexArrayMap::const_iterator vertexArray = mVertexArrayMap.find(array);

+

+	return vertexArray != mVertexArrayMap.end();

+}

+

 bool Context::hasZeroDivisor() const

 {

 	// Verify there is at least one active attribute with a divisor of zero

@@ -3642,7 +3649,11 @@
 

 	for(auto vaoIt = mVertexArrayMap.begin(); vaoIt != mVertexArrayMap.end(); vaoIt++)

 	{

-		vaoIt->second->detachBuffer(buffer);

+		VertexArray* vertexArray = vaoIt->second;

+		if(vertexArray)

+		{

+			vertexArray->detachBuffer(buffer);

+		}

 	}

 

     for(int attribute = 0; attribute < MAX_VERTEX_ATTRIBS; attribute++)

src/OpenGL/libGLESv2/Context.h

diff --git a/src/OpenGL/libGLESv2/Context.h b/src/OpenGL/libGLESv2/Context.h
index cf06cfb..73f7358 100644
--- a/src/OpenGL/libGLESv2/Context.h
+++ b/src/OpenGL/libGLESv2/Context.h
@@ -601,6 +601,7 @@
 	Query *getQuery(GLuint handle) const;

 	VertexArray *getVertexArray(GLuint array) const;

 	VertexArray *getCurrentVertexArray() const;

+	bool isVertexArray(GLuint array) const;

 	TransformFeedback *getTransformFeedback(GLuint transformFeedback) const;

 	TransformFeedback *getTransformFeedback() const;

 	Sampler *getSampler(GLuint sampler) const;

src/OpenGL/libGLESv2/libGLESv3.cpp

diff --git a/src/OpenGL/libGLESv2/libGLESv3.cpp b/src/OpenGL/libGLESv2/libGLESv3.cpp
index 5e5dc4d..dcea67b 100644
--- a/src/OpenGL/libGLESv2/libGLESv3.cpp
+++ b/src/OpenGL/libGLESv2/libGLESv3.cpp
@@ -1743,7 +1743,7 @@
 

 	if(context)

 	{

-		if(!context->getVertexArray(array))

+		if(!context->isVertexArray(array))

 		{

 			return error(GL_INVALID_OPERATION);

 		}