First pass

libraries/gpu/src/gpu/GLBackend.h

@@ -153,7 +153,7 @@ public:
 
     class GLInputFormat : public GPUObject {
     public:
-        
+        std::string key;
 
         GLInputFormat();
         ~GLInputFormat();
@@ -358,6 +358,7 @@ protected:
     struct InputStageState {
         bool _invalidFormat = true;
         Stream::FormatPointer _format;
+        std::string _formatKey;
 
         typedef std::bitset<MAX_NUM_ATTRIBUTES> ActivationCache;
         ActivationCache _attributeActivation;
@@ -385,6 +386,7 @@ protected:
         InputStageState() :
             _invalidFormat(true),
             _format(0),
+            _formatKey(),
             _attributeActivation(0),
             _invalidBuffers(0),
             _buffers(_invalidBuffers.size(), BufferPointer(0)),

libraries/gpu/src/gpu/GLBackendInput.cpp

@@ -28,6 +28,7 @@ GLBackend::GLInputFormat* GLBackend::syncGPUObject(const Stream::Format& inputFo
     }
 
     object = new GLInputFormat();
+    object->key = inputFormat.getKey();
     Backend::setGPUObject(inputFormat, object);
 }
 
@@ -37,7 +38,15 @@ void GLBackend::do_setInputFormat(Batch& batch, size_t paramOffset) {
     if (ifo) {
         if (format != _input._format) {
             _input._format = format;
-            _input._invalidFormat = true;
+            if (format) {
+                if (_input._formatKey != format->getKey()) {
+                    _input._formatKey = format->getKey();
+                    _input._invalidFormat = true;
+                }
+            } else {
+                _input._invalidFormat = true;
+                _input._formatKey.clear();
+            }
         }
     }
 }
@@ -295,6 +304,7 @@ void GLBackend::resetInputStage() {
 
     // Reset vertex buffer and format
     _input._format.reset();
+    _input._formatKey.clear();
     _input._invalidFormat = false;
     _input._attributeActivation.reset();
 

libraries/gpu/src/gpu/Stream.cpp

@@ -12,6 +12,8 @@
 #include "Stream.h"
 
 #include <algorithm> //min max and more
+#include <sstream>
+#include <iomanip>
 
 using namespace gpu;
 
@@ -39,7 +41,18 @@ const ElementArray& getDefaultElements() {
     return defaultElements;
 }
 
+std::string Stream::Attribute::getKey() const {
+    std::stringstream skey;
+
+    skey << std::hex;
+    skey << std::setw(8) << std::setfill('0') << (uint32)((((uint32)_slot) << 24) | (((uint32)_channel) << 16) | ((uint32)_element.getRaw()));
+    skey << _offset;
+    skey << _frequency;
+    return skey.str();
+}
+
 void Stream::Format::evaluateCache() {
+    _key.clear();
     _channels.clear();
     _elementTotalSize = 0;
     for(AttributeMap::iterator it = _attributes.begin(); it != _attributes.end(); it++) {
@@ -49,6 +62,8 @@ void Stream::Format::evaluateCache() {
         channel._stride = std::max(channel._stride, attrib.getSize() + attrib._offset);
         channel._netSize += attrib.getSize();
         _elementTotalSize += attrib.getSize();
+
+        _key += attrib.getKey();
     }
 }
 

libraries/gpu/src/gpu/Stream.h

@@ -73,6 +73,9 @@ public:
 
         // Size of the 
         uint32 getSize() const { return _element.getSize(); }
+
+        // Generate a string key describing the attribute uniquely
+        std::string getKey() const;
     };
 
     // Stream Format is describing how to feed a list of attributes from a bunch of stream buffer channels
@@ -106,6 +109,8 @@ public:
 
         bool hasAttribute(Slot slot) const { return (_attributes.find(slot) != _attributes.end()); }
 
+        const std::string& getKey() const { return _key; }
+
         const GPUObjectPointer gpuObject{};
     protected:
         AttributeMap _attributes;
@@ -113,6 +118,8 @@ public:
         uint32 _elementTotalSize { 0 };
 
         void evaluateCache();
+
+        std::string _key;
     };
 
     typedef std::shared_ptr<Format> FormatPointer;