Open GL Rendering not proper in iOS when using glDrawArrays(GL_TRIANGLES,0,numVert); - ios

Question

I am using the following code to render a .h file for Open GL.
However, The eventual result comes in triangles and not the whole thing. Please see the attached image. Can anyone please guide me why this is happening. As I am new to Open GL.
I want to develop an app like - https://itunes.apple.com/us/app/mclaren-p1/id562173543?mt=8
- (void)renderFrameQCAR
{
[self setFramebuffer];
// Clear colour and depth buffers
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
// Render video background and retrieve tracking state
QCAR::State state = QCAR::Renderer::getInstance().begin();
QCAR::Renderer::getInstance().drawVideoBackground();
//NSLog(#"active trackables: %d", state.getNumActiveTrackables());
if (QCAR::GL_11 & qUtils.QCARFlags) {
glEnable(GL_TEXTURE_2D);
glEnable(GL_LIGHTING);
glEnableClientState(GL_VERTEX_ARRAY);
glEnableClientState(GL_NORMAL_ARRAY);
glEnableClientState(GL_TEXTURE_COORD_ARRAY);
}
glEnable(GL_DEPTH_TEST);
// We must detect if background reflection is active and adjust the culling direction.
// If the reflection is active, this means the pose matrix has been reflected as well,
// therefore standard counter clockwise face culling will result in "inside out" models.
glEnable(GL_CULL_FACE);
glCullFace(GL_BACK);
if(QCAR::Renderer::getInstance().getVideoBackgroundConfig().mReflection == QCAR::VIDEO_BACKGROUND_REFLECTION_ON)
glFrontFace(GL_CW); //Front camera
else
glFrontFace(GL_CCW); //Back camera
for (int i = 0; i < state.getNumTrackableResults(); ++i) {
// Get the trackable
const QCAR::TrackableResult* result = state.getTrackableResult(i);
const QCAR::Trackable& trackable = result->getTrackable();
QCAR::Matrix44F modelViewMatrix = QCAR::Tool::convertPose2GLMatrix(result->getPose());
// Choose the texture based on the target name
int targetIndex = 0; // "stones"
if (!strcmp(trackable.getName(), "chips"))
targetIndex = 1;
else if (!strcmp(trackable.getName(), "tarmac"))
targetIndex = 2;
Object3D *obj3D = [objects3D objectAtIndex:targetIndex];
// Render using the appropriate version of OpenGL
if (QCAR::GL_11 & qUtils.QCARFlags) {
// Load the projection matrix
glMatrixMode(GL_PROJECTION);
glLoadMatrixf(qUtils.projectionMatrix.data);
// Load the model-view matrix
glMatrixMode(GL_MODELVIEW);
glLoadMatrixf(modelViewMatrix.data);
glTranslatef(0.0f, 0.0f, -kObjectScale);
glScalef(kObjectScale, kObjectScale, kObjectScale);
// Draw object
glBindTexture(GL_TEXTURE_2D, [obj3D.texture textureID]);
glTexCoordPointer(2, GL_FLOAT, 0, (const GLvoid*)obj3D.texCoords);
glVertexPointer(3, GL_FLOAT, 0, (const GLvoid*)obj3D.vertices);
glVertexPointer(3, GL_FLOAT, 0, MclarenInfoVerts);
glNormalPointer(GL_FLOAT, 0, MclarenInfoNormals);
glTexCoordPointer(2, GL_FLOAT, 0, MclarenInfoTexCoords);
// draw data
glDrawArrays(GL_TRIANGLES, 0, MclarenInfoNumVerts);
}
#ifndef USE_OPENGL1
else {
// OpenGL 2
QCAR::Matrix44F modelViewProjection;
ShaderUtils::translatePoseMatrix(0.0f, 0.0f, kObjectScale, &modelViewMatrix.data[0]);
ShaderUtils::scalePoseMatrix(kObjectScale, kObjectScale, kObjectScale, &modelViewMatrix.data[0]);
ShaderUtils::multiplyMatrix(&qUtils.projectionMatrix.data[0], &modelViewMatrix.data[0], &modelViewProjection.data[0]);
glUseProgram(shaderProgramID);
glVertexAttribPointer(vertexHandle, 3, GL_FLOAT, GL_FALSE, 0, (const GLvoid*)obj3D.vertices);
glVertexAttribPointer(normalHandle, 3, GL_FLOAT, GL_FALSE, 0, (const GLvoid*)obj3D.normals);
glVertexAttribPointer(textureCoordHandle, 2, GL_FLOAT, GL_FALSE, 0, (const GLvoid*)obj3D.texCoords);
glEnableVertexAttribArray(vertexHandle);
glEnableVertexAttribArray(normalHandle);
glEnableVertexAttribArray(textureCoordHandle);
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, [obj3D.texture textureID]);
glUniformMatrix4fv(mvpMatrixHandle, 1, GL_FALSE, (const GLfloat*)&modelViewProjection.data[0]);
glUniform1i(texSampler2DHandle, 0 /*GL_TEXTURE0*/);
glVertexPointer(3, GL_FLOAT, 0, MclarenInfoVerts);
glNormalPointer(GL_FLOAT, 0, MclarenInfoNormals);
glTexCoordPointer(2, GL_FLOAT, 0, MclarenInfoTexCoords);
// draw data
glDrawArrays(GL_TRIANGLES, 0, MclarenInfoNumVerts);
ShaderUtils::checkGlError("EAGLView renderFrameQCAR");
}
#endif
}
glDisable(GL_DEPTH_TEST);
glDisable(GL_CULL_FACE);
if (QCAR::GL_11 & qUtils.QCARFlags) {
glDisable(GL_TEXTURE_2D);
glDisableClientState(GL_VERTEX_ARRAY);
glDisableClientState(GL_NORMAL_ARRAY);
glDisableClientState(GL_TEXTURE_COORD_ARRAY);
}
#ifndef USE_OPENGL1
else {
glDisableVertexAttribArray(vertexHandle);
glDisableVertexAttribArray(normalHandle);
glDisableVertexAttribArray(textureCoordHandle);
}
#endif
QCAR::Renderer::getInstance().end();
[self presentFramebuffer];
}

Answer 1

Ok. I found the issue. It so happened that my designer was giving me a file with quadilateral rendering, where as Vuforia-Qualcomm-Unity etc recognizes just triangulated .obj. For anyone who gets stuck here :) Just let your designer know to render in triangulation and not Quad.