reactphysics3d/examples/common/ConvexMesh.cpp

/********************************************************************************
* ReactPhysics3D physics library, http://code.google.com/p/reactphysics3d/      *
* Copyright (c) 2010-2013 Daniel Chappuis                                       *
*********************************************************************************
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* This software is provided 'as-is', without any express or implied warranty.   *
* In no event will the authors be held liable for any damages arising from the  *
* use of this software.                                                         *
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* including commercial applications, and to alter it and redistribute it        *
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* 1. The origin of this software must not be misrepresented; you must not claim *
*    that you wrote the original software. If you use this software in a        *
*    product, an acknowledgment in the product documentation would be           *
*    appreciated but is not required.                                           *
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* 2. Altered source versions must be plainly marked as such, and must not be    *
*    misrepresented as being the original software.                             *
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* 3. This notice may not be removed or altered from any source distribution.    *
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********************************************************************************/

// Libraries
#include "ConvexMesh.h"


// Constructor
ConvexMesh::ConvexMesh(const openglframework::Vector3 &position, float mass,
                       reactphysics3d::DynamicsWorld* dynamicsWorld)
           : openglframework::Mesh() {

    // Load the mesh from a file
    openglframework::MeshReaderWriter::loadMeshFromFile("meshes/convexmesh.obj", *this);

    // Calculate the normals of the mesh
    calculateNormals();

    // Initialize the position where the sphere will be rendered
    translateWorld(position);

    // Create the collision shape for the rigid body (convex mesh shape)
    // ReactPhysics3D will clone this object to create an internal one. Therefore,
    // it is OK if this object is destroyed right after calling Dynamics::createRigidBody()
    rp3d::decimal* verticesArray = (rp3d::decimal*) getVerticesPointer();
    rp3d::ConvexMeshShape collisionShape(verticesArray, mVertices.size(),
                                         sizeof(openglframework::Vector3));

    // Add the edges information of the mesh into the convex mesh collision shape.
    // This is optional but it really speed up the convex mesh collision detection at the
    // cost of some additional memory to store the edges inside the collision shape.
    for (unsigned int i=0; i<getNbFaces(); i++) { // For each triangle face of the mesh

        // Get the three vertex IDs of the vertices of the face
        unsigned int v1 = getVertexIndexInFace(i, 0);
        unsigned int v2 = getVertexIndexInFace(i, 1);
        unsigned int v3 = getVertexIndexInFace(i, 2);

        // Add the three edges into the collision shape
        collisionShape.addEdge(v1, v2);
        collisionShape.addEdge(v1, v3);
        collisionShape.addEdge(v2, v3);
    }
    collisionShape.setIsEdgesInformationUsed(true);// Enable the fast collision detection with edges

    // Initial position and orientation of the rigid body
    rp3d::Vector3 initPosition(position.x, position.y, position.z);
    rp3d::Quaternion initOrientation = rp3d::Quaternion::identity();
    rp3d::Transform transform(initPosition, initOrientation);

    // Create a rigid body corresponding to the sphere in the dynamics world
    mRigidBody = dynamicsWorld->createRigidBody(transform, mass, collisionShape);
}

// Destructor
ConvexMesh::~ConvexMesh() {

    // Destroy the mesh
    destroy();
}

// Render the sphere at the correct position and with the correct orientation
void ConvexMesh::render(openglframework::Shader& shader,
                    const openglframework::Matrix4& worldToCameraMatrix) {

    // Bind the shader
    shader.bind();

    // Set the model to camera matrix
    const openglframework::Matrix4 localToCameraMatrix = worldToCameraMatrix * mTransformMatrix;
    shader.setMatrix4x4Uniform("localToCameraMatrix", localToCameraMatrix);

    // Set the normal matrix (inverse transpose of the 3x3 upper-left sub matrix of the
    // model-view matrix)
    const openglframework::Matrix3 normalMatrix =
                       localToCameraMatrix.getUpperLeft3x3Matrix().getInverse().getTranspose();
    shader.setMatrix3x3Uniform("normalMatrix", normalMatrix);

    glEnableClientState(GL_VERTEX_ARRAY);
    glEnableClientState(GL_NORMAL_ARRAY);
    if (hasTexture()) {
        glEnableClientState(GL_TEXTURE_COORD_ARRAY);
    }

    glVertexPointer(3, GL_FLOAT, 0, getVerticesPointer());
    glNormalPointer(GL_FLOAT, 0, getNormalsPointer());
    if(hasTexture()) {
        glTexCoordPointer(2, GL_FLOAT, 0, getUVTextureCoordinatesPointer());
    }

    // For each part of the mesh
    for (unsigned int i=0; i<getNbParts(); i++) {
        glDrawElements(GL_TRIANGLES, getNbFaces(i) * 3,
                       GL_UNSIGNED_INT, getIndicesPointer());
    }

    glDisableClientState(GL_NORMAL_ARRAY);
    glDisableClientState(GL_VERTEX_ARRAY);
    if (hasTexture()) {
        glDisableClientState(GL_TEXTURE_COORD_ARRAY);
    }

    // Unbind the shader
    shader.unbind();
}

// Update the transform matrix of the sphere
void ConvexMesh::updateTransform() {

    // Get the interpolated transform of the rigid body
    rp3d::Transform transform = mRigidBody->getInterpolatedTransform();

    // Compute the transform used for rendering the sphere
    float matrix[16];
    transform.getOpenGLMatrix(matrix);
    openglframework::Matrix4 newMatrix(matrix[0], matrix[4], matrix[8], matrix[12],
                                       matrix[1], matrix[5], matrix[9], matrix[13],
                                       matrix[2], matrix[6], matrix[10], matrix[14],
                                       matrix[3], matrix[7], matrix[11], matrix[15]);

    // Apply the scaling matrix to have the correct sphere dimensions
    mTransformMatrix = newMatrix;
}