Each mesh now has it's own transform matrix applied, so that our example framework can support breaking a volume into regions.

examples/Basic/OpenGLWidget.cpp

@@ -127,17 +127,14 @@ void OpenGLWidget::paintGL()
 	//Clear the screen
 	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 
-	QMatrix4x4 modelToWorldMatrix{};
-	//modelToWorldMatrix.rotate(m_xRotation, 0, 1, 0); //rotate around y-axis
-	//modelToWorldMatrix.rotate(m_yRotation, 1, 0, 0); //rotate around x-axis
-	//modelToWorldMatrix.translate(-32, -32, -32); //centre the model on the origin
-
 	shader.bind();
 
-	shader.setUniformValue("modelToWorldMatrix", modelToWorldMatrix); //Update to the latest camera matrix
-
 	for (OpenGLMeshData meshData : mMeshData)
 	{
+		QMatrix4x4 modelToWorldMatrix{};
+		modelToWorldMatrix.translate(meshData.translation.getX(), meshData.translation.getY(), meshData.translation.getZ()); // Centre the model on the origin
+		shader.setUniformValue("modelToWorldMatrix", modelToWorldMatrix); // Update to the latest camera matrix
+
 		glBindVertexArray(meshData.vertexArrayObject);
 
 		glDrawElements(GL_TRIANGLES, meshData.noOfIndices, GL_UNSIGNED_INT, 0);

examples/Basic/OpenGLWidget.h

@@ -37,6 +37,7 @@ struct OpenGLMeshData
 	GLuint indexBuffer;
 	GLuint vertexBuffer;
 	GLuint vertexArrayObject;
+	PolyVox::Vector3DInt32 translation;
 };
 
 class OpenGLWidget : public QGLWidget
@@ -49,13 +50,48 @@ public:
 	void mouseMoveEvent(QMouseEvent* event);
 	void mousePressEvent(QMouseEvent* event);
 
-	// Convert a SurfaceMesh to OpenGL index/vertex buffers
-	template <typename MeshType>
-	void addMesh(const MeshType& surfaceMesh);
-
 	// The viewable region can be adjusted so that this example framework can be use for different volume sizes.
 	void setViewableRegion(PolyVox::Region viewableRegion);
 
+	// Convert a SurfaceMesh to OpenGL index/vertex buffers. Inlined because it's templatised.
+	template <typename MeshType>
+	void addMesh(const MeshType& surfaceMesh)
+	{
+		//Convienient access to the vertices and indices
+		const auto& vecIndices = surfaceMesh.getIndices();
+		const auto& vecVertices = surfaceMesh.getVertices();
+
+		// This struct holds the OpenGL properties (buffer handles, etc) which will be used
+		// to render our mesh. We copy the data from the PolyVox mesh into this structure.
+		OpenGLMeshData meshData;
+
+		//Create the VAO for the mesh
+		glGenVertexArrays(1, &(meshData.vertexArrayObject));
+		glBindVertexArray(meshData.vertexArrayObject);
+
+		//The GL_ARRAY_BUFFER will contain the list of vertex positions
+		glGenBuffers(1, &(meshData.vertexBuffer));
+		glBindBuffer(GL_ARRAY_BUFFER, meshData.vertexBuffer);
+		glBufferData(GL_ARRAY_BUFFER, vecVertices.size() * sizeof(CubicVertex<uint8_t>), vecVertices.data(), GL_STATIC_DRAW);
+
+		//and GL_ELEMENT_ARRAY_BUFFER will contain the indices
+		glGenBuffers(1, &(meshData.indexBuffer));
+		glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, meshData.indexBuffer);
+		glBufferData(GL_ELEMENT_ARRAY_BUFFER, vecIndices.size() * sizeof(uint32_t), vecIndices.data(), GL_STATIC_DRAW);
+
+		//We need to tell OpenGL how to understand the format of the vertex data
+		glEnableVertexAttribArray(0); //We're talking about shader attribute '0' 
+		glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, sizeof(CubicVertex<uint8_t>), 0); //take the first 3 floats from every sizeof(decltype(vecVertices)::value_type)
+
+		glBindVertexArray(0);
+
+		meshData.noOfIndices = vecIndices.size(); //Save this for the call to glDrawElements later
+
+		meshData.translation = surfaceMesh.m_Region.getLowerCorner();
+
+		mMeshData.push_back(meshData);
+	}
+
 protected:
 	
 
@@ -83,40 +119,4 @@ private:
 	int m_yRotation;
 };
 
-template <typename MeshType>
-void OpenGLWidget::addMesh(const MeshType& surfaceMesh)
-{
-	//Convienient access to the vertices and indices
-	const auto& vecIndices = surfaceMesh.getIndices();
-	const auto& vecVertices = surfaceMesh.getVertices();
-
-	// This struct holds the OpenGL properties (buffer handles, etc) which will be used
-	// to render our mesh. We copy the data from the PolyVox mesh into this structure.
-	OpenGLMeshData meshData;
-
-	//Create the VAO for the mesh
-	glGenVertexArrays(1, &(meshData.vertexArrayObject));
-	glBindVertexArray(meshData.vertexArrayObject);
-
-	//The GL_ARRAY_BUFFER will contain the list of vertex positions
-	glGenBuffers(1, &(meshData.vertexBuffer));
-	glBindBuffer(GL_ARRAY_BUFFER, meshData.vertexBuffer);
-	glBufferData(GL_ARRAY_BUFFER, vecVertices.size() * sizeof(CubicVertex<uint8_t>), vecVertices.data(), GL_STATIC_DRAW);
-
-	//and GL_ELEMENT_ARRAY_BUFFER will contain the indices
-	glGenBuffers(1, &(meshData.indexBuffer));
-	glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, meshData.indexBuffer);
-	glBufferData(GL_ELEMENT_ARRAY_BUFFER, vecIndices.size() * sizeof(uint32_t), vecIndices.data(), GL_STATIC_DRAW);
-
-	//We need to tell OpenGL how to understand the format of the vertex data
-	glEnableVertexAttribArray(0); //We're talking about shader attribute '0' 
-	glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, sizeof(CubicVertex<uint8_t>), 0); //take the first 3 floats from every sizeof(decltype(vecVertices)::value_type)
-
-	glBindVertexArray(0);
-
-	meshData.noOfIndices = vecIndices.size(); //Save this for the call to glDrawElements later
-
-	mMeshData.push_back(meshData);
-}
-
 #endif //__BasicExample_OpenGLWidget_H__

examples/Basic/main.cpp

@@ -78,16 +78,16 @@ int main(int argc, char *argv[])
 	createSphereInVolume(volData, 30);
 
 	// Extract the surface for the specified region of the volume. Uncomment the line for the kind of surface extraction you want to see.
-	auto mesh = extractCubicMesh(&volData, volData.getEnclosingRegion());
+	//auto mesh = extractCubicMesh(&volData, volData.getEnclosingRegion());
 	//auto mesh = extractMarchingCubesMesh(&volData, volData.getEnclosingRegion());
 
-	//auto mesh = extractCubicMesh(&volData, PolyVox::Region(Vector3DInt32(0, 0, 0), Vector3DInt32(31, 31, 31)));
+	auto mesh = extractCubicMesh(&volData, PolyVox::Region(Vector3DInt32(0, 0, 0), Vector3DInt32(31, 31, 31)));
-	//auto mesh2 = extractCubicMesh(&volData, PolyVox::Region(Vector3DInt32(32, 32, 32), Vector3DInt32(63, 63, 63)));
+	auto mesh2 = extractCubicMesh(&volData, PolyVox::Region(Vector3DInt32(32, 32, 32), Vector3DInt32(63, 63, 63)));
 
 	//Pass the surface to the OpenGL window
 	openGLWidget.addMesh(mesh);
+	openGLWidget.addMesh(mesh2);
 	openGLWidget.setViewableRegion(volData.getEnclosingRegion());
-	//openGLWidget.addMesh(mesh2);
 
 	//Run the message pump.
 	return app.exec();