Draw cube with ofMesh and ofVbo?

beginners
#1

Hi,

I’m trying to draw a cube with ofMesh and ofVbo. Although the cube is drawn I get a little weird results. From different points of view it seems some sides of the cube aren’t drawn and/or some sides are somehow transparent and sides that shouldn’t be visible are seen trough them from a the specific perspective.

I thought maybe culling was a problem so I turned it off but that doesn’t seem to make any difference though.

This screenshot shows an example of the cube. All blue and pink colors are the same, so that darker blue area doesn’t make sense.

the code:

  
  
//--------------------------------------------------------------  
void testApp::setup(){  
	ofBackground(255);  
	ofSetFrameRate(24);  
	ofSetVerticalSync(true);  
  
	truck = 0;  
	  
	mesh_fill_cube();  
}  
  
//--------------------------------------------------------------  
void testApp::update(){  
  
	cbe_vbo.setMesh(cbe_mesh, GL_DYNAMIC_DRAW);  
}  
  
//--------------------------------------------------------------  
void testApp::draw(){  
	easycam.begin();  
  
	glDisable(GL_CULL_FACE);  
	  
	cbe_vbo.draw(GL_QUADS, 0, 24);  
  
	easycam.end();  
}  
  
void testApp::mesh_fill_cube() {  
	for (int i=0; i<1; i++) { // amount of cubes  
		for (int j=0; j<1; j++) {  
			  
			vector<ofVec3f> vec;  
			  
			// front face coordinates  
			vec.push_back(ofVec3f(-50,50,50));  
			vec.push_back(ofVec3f(50,50,50));  
			vec.push_back(ofVec3f(50,-50,50));  
			vec.push_back(ofVec3f(-50,-50,50));  
			  
			// back face coordinates  
			vec.push_back(ofVec3f(-50,50,-50));  
			vec.push_back(ofVec3f(50,50,-50));  
			vec.push_back(ofVec3f(50,-50,-50));  
			vec.push_back(ofVec3f(-50,-50,-50));  
			  
			// back plane  
			for (int i=0, idx[4] = {4,5,6,7}; i<4; i++) {  
				cbe_mesh.addVertex(vec[idx[i]]);  
				  
				cbe_mesh.addColor(ofFloatColor(1,0.2,1,1));  
			}  
			  
			// front plane  
			for (int i=0, idx[4] = {0,1,2,3}; i<4; i++) {  
				cbe_mesh.addVertex(vec[idx[i]]);  
				  
				cbe_mesh.addColor(ofFloatColor(0.1,0.1,1,1));  
			}  
			  
			// bottom plane  
			for (int i=0, idx[4] = {2,3,7,6}; i<4; i++) {  
				cbe_mesh.addVertex(vec[idx[i]]);  
				  
				cbe_mesh.addColor(ofFloatColor(1,0.4,1));  
			}  
			  
			  
			// top plane  
			for (int i=0, idx[4] = {0,1,5,4}; i<4; i++) {  
				cbe_mesh.addVertex(vec[idx[i]]);  
				  
				cbe_mesh.addColor(ofFloatColor(0.3,0.3,1));  
			}  
			  
			// left plane  
			for (int i=0, idx[4] = {0,4,7,3}; i<4; i++) {  
				cbe_mesh.addVertex(vec[idx[i]]);  
				  
				cbe_mesh.addColor(ofFloatColor(1,0.4,1));  
			}  
			  
			// right plane  
			for (int i=0, idx[4] = {1,5,6,2}; i<4; i++) {  
				cbe_mesh.addVertex(vec[idx[i]]);  
				  
				cbe_mesh.addColor(ofFloatColor(0.3,0.3,1));  
			}  
		}  
	}  
}
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#2

put in setup()

  
glEnable(GL_DEPTH_TEST);
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