DMM API Tutorial #1: Creating a simple scene

[dmmNOW]

Creating a simple scene

[attachment=0:1j4s4xjc]DMM_API_Tutorial#1.mov[/attachment:1j4s4xjc]

#include <DMM.h>
#include <Scene.h>
#include <Object.h>
#include <Node.h>
#include <Material.h>

// This is a primitive cube as created by the DMM Plugin
// It has 12 tets, each of them using a triangle of the cube
// shape as its base and the center of the cube as its top

// List of nodes (vertices)
const size_t numNodes = 9;
Pixelux::real cubeNodes[numNodes][3] = {
	{ -0.5, -0.5, 0.5 },    // Corner #0
	{ 0.5, -0.5, 0.5 },     // ...
	{ 0.5, 0.5, 0.5 },      // ...
	{ -0.5, 0.5, 0.5 },     // ...
	{ 0.5, 0.5, -0.5 },     // ...
	{ -0.5, 0.5, -0.5 },    // ...
	{ 0.5, -0.5, -0.5 },    // ...
	{ -0.5, -0.5, -0.5 },   // Corner #7
	{ 0.0, 0.0, 0.0 } };    // Center

// List of indices making the tets
const size_t numTets = 12;
size_t cubeTets[numTets][4] = {
	{ 1, 0, 8, 3 },         // Tet #0
	{ 7, 0, 8, 1 },         // ...
	{ 5, 0, 3, 8 },         // ...
	{ 5, 0, 8, 7 },         // ...
	{ 2, 1, 8, 3 },         // ...
	{ 6, 1, 8, 2 },         // ...
	{ 1, 8, 7, 6 },         // ...
	{ 2, 3, 8, 5 },         // ...
	{ 2, 4, 5, 8 },         // ...
	{ 4, 8, 2, 6 },         // ...
	{ 4, 8, 6, 5 },         // ...
	{ 6, 5, 8, 7 } };       // Tet #11

// List of tet nodes making the tet's triangles
size_t tetFaceNode[4][3] = {
	{ 0, 1, 2 },            // Triangle #0
	{ 2, 3, 0 },            // ...
	{ 2, 1, 3 },            // ...
	{ 3, 1, 0 } };          // Triangle #3

// Storage space for the simulated node's positions
Pixelux::Vec3 nodePositions[4 * numTets];

// The DMM singleton
Pixelux::DMM* pDMM = NULL;

// The DMM scene
Pixelux::Scene* pDMMScene = NULL;

// Initialize DMM and create the Scene
bool InitDMM()
{
	bool success = false;

	// Get DMM
	pDMM = Pixelux::GetDMM(PXX_DMM_VERSION);
	if (pDMM == NULL)
	{
		// Couldn't get DMM - probably wrong version number
	}
	else
	{
		// Create the scene
		pDMMScene = pDMM->CreateScene();
		success = true;
	}

	return success;
}

// Deletes the DMM scene
void DeleteDMMScene()
{
	if ((pDMM != NULL) && (pDMMScene != NULL))
	{
		pDMM->DeleteScene(pDMMScene);
		pDMMScene = NULL;
	}
}

// Add a DMM cube primitive to the scene, with a scale and a translation
Pixelux::Object* CreateDMMCube(const Pixelux::Vec3& scale, const Pixelux::Vec3& trans)
{
	// Create the object
	Pixelux::Object* pObject = pDMMScene->CreateObject(4 * numTets, numTets);
	if (pObject != NULL)
	{
		// Create the nodes (vertices)
		for (size_t i = 0; i < numNodes; ++i)
		{
			// Initialize a Vec3 with the node position
			Pixelux::Vec3 v;
			v.x = cubeNodes[i][0];
			v.y = cubeNodes[i][1];
			v.z = cubeNodes[i][2];

			// Scale and translate
			v.mult(scale);
			v.add(trans);

			// Create node
			pObject->CreateNode(v);
		}

		// Create the tets
		Pixelux::Node** beginNodes = pObject->BeginNodes();
		for (size_t i = 0; i < numTets; ++i)
		{
			// Get the 4 nodes forming the tet
			size_t n0 = cubeTets[i][0];
			size_t n1 = cubeTets[i][1];
			size_t n2 = cubeTets[i][2];
			size_t n3 = cubeTets[i][3];
			Pixelux::Node* nodes[] = {
				beginNodes[n0], beginNodes[n1], beginNodes[n2], beginNodes[n3] };

			// Create the tet
			pObject->CreateTet(nodes);
		}
	}

	return pObject;
}

bool CreateDMMObjects()
{
	if (pDMMScene == NULL)
	{
		return false;
	}

	// Create a new material
	Pixelux::Material* pMaterial = pDMMScene->CreateMaterial();

	if (pMaterial == NULL)
	{
		return false;
	}

	// Make it quite heavy and mushy
	pMaterial->SetName("myMaterial");
	pMaterial->Set(Pixelux::MATERIAL_DENSITY, 1e4);
	pMaterial->Set(Pixelux::MATERIAL_YOUNGS_MODULUS, 1e6);

	// Set it as the default material
	// (every newly created tet will use that material)
	pDMMScene->SetDefaultMaterial(pMaterial);

	// Create a cube that's translated it upwards,
	Pixelux::Vec3 scale(1);
	Pixelux::Vec3 trans(0);
	trans.y = 4;
	Pixelux::Object* pObject = CreateDMMCube(scale, trans);

	if (pObject == NULL)
	{
		return false;
	}

	// Create another cube, flattened and translated downward
	scale.x *= 10;
	scale.y *= 0.2;
	scale.z *= 10;
	trans.y = -2;
	pObject = CreateDMMCube(scale, trans);

	if (pObject == NULL)
	{
		return false;
	}

	// Let the first cube fall down on the second cube
	// => drive the node's positions of the second cube so it won't move
	//    (it would be a passive object in the DMM Plugin)
	// To do that, iterate each node of the second cube
	for (Pixelux::Node** it = pObject->BeginNodes(), ** end = pObject->EndNodes()
		; it != end; ++it)
	{
		// And set the node as "driven"
		Pixelux::Node* pNode = *it;
		pNode->SetNodeState(Pixelux::NODE_DRIVEN_BIT);
	}

	return true;
}

void StepDMMSim()
{
	if (pDMMScene != NULL)
	{
		// Mode 10 ms forward in the DMM simulation
		pDMMScene->Step(0.01);

		// Wait for 5 ms before returning
		// This is very innacurate, it's just to emulate
		// other computations that would be done in a game engine
		Sleep(5);
	}
}

void DrawDMMObjects()
{
	// Reset the model-view matrix
	glLoadIdentity();

	// And translate and rotate the objects so to better see them
	glTranslatef(0.0f,0.0f,-7.0f);
	glRotatef(30,0.0f,1.0f,0.0f);

	// Iterate the DMM objects
	for (Pixelux::Object** it = pDMMScene->BeginObjects(), ** end = pDMMScene->EndObjects()
		; it != end; ++it)
	{
		// Get the node positions for this DMM object
		Pixelux::Object* pObject = *it;
		pObject->GetTetsNodesPos(pObject->BeginTets(), pObject->EndTets(), &nodePositions[0]);

		// Start drawing triangles
		glBegin(GL_TRIANGLES);

		// Iterate the tets
		for (size_t i = 0; i < numTets; ++i)
		{
			// Iterate the tet's triangles
			for (size_t j = 0; j < 4; ++j)
			{
				// Get the node's positions for this triangle
				Pixelux::Vec3& v0 = nodePositions[4 * i + tetFaceNode[j][0]];
				Pixelux::Vec3& v1 = nodePositions[4 * i + tetFaceNode[j][1]];
				Pixelux::Vec3& v2 = nodePositions[4 * i + tetFaceNode[j][2]];

				// Draw one face (triangle) of the tet

				// 1st vertex, green
				glColor3f(0, 1, 0);
				glVertex3f(v0.x, v0.y, v0.z);

				// 2nd vertex, red
				glColor3f(1, 0, 0);
				glVertex3f(v1.x, v1.y, v1.z);

				// 3rd vertex, blue
				glColor3f(0, 0, 1);
				glVertex3f(v2.x, v2.y, v2.z);
			}
		}

		// Done with drawing the tets
		glEnd();
	}
}

[Friktion]

Great seems simple enough.
And the only way of getting this api is to send that message ?

[dmmNOW]

We will soon release a free version of the API, see this thread.