Introduction
Hello I will start out by explaining my setup, showing samples as I go along explaining
the situation.
I'm using these tools:
OpenGL 3.3
GLSL 330
C++
Problem
The problem is when I render
the wavefront obj 3d model it gives a very weird visual glitch
the model was supposed to be a square but instead its a triangluated mess with parts of
the vertexes pointing in a stretched direction in massive amounts towards
the bottom left side of
the frustum....
Explanation:
I'm using std::vectors to store my wavefront .obj model data using sscanf to get
the floating point values into
the structure members x,y,z and store them into
the Points structure variable p;
int index = IndexAssigner(1, 1);
ifstream file (list[index].c_str() );
points.push_back(Point());
Point p;
int face[4];
while (!file.eof() ) {
char modelbuffer[10000];
file.getline(modelbuffer, 10000);
switch(modelbuffer[0]) {
case 'v' :
sscanf(modelbuffer, "v %f %f %f", &p.x, &p.y, &p.z);
points.push_back(p);
break;
case 'f':
sscanf(modelbuffer, "f %d %d %d %d", face, face+1, face+2, face+3 );
faces.push_back(face[0]);
faces.push_back(face[1]);
faces.push_back(face[2]);
faces.push_back(face[3]);
}
//Turn on FileReader aka "RENDER CODE"
FileReader = true;
}
then I render
the Points vector using
the .data() member of std::vectors to
the frustum.
Other declarations:
int numfloats = 4;
float* point=reinterpret_cast<float*>(&points[0]);
int num_bytes=numfloats*sizeof(float);
Vector declarations:
struct Point {float x, y , z; };
std::vector<int>faces;
std::vector<Point>points;
Render code:
glGenBuffers(1, &vertexbuffer);
glGenTextures(1, &ModelTexture);
glBindBuffer(GL_ARRAY_BUFFER, vertexbuffer);
glBindTexture(GL_TEXTURE_3D, ModelTexture);
glTexImage2D(GL_TEXTURE_2D, 0,GL_RGBA, ModelSurface->w, ModelSurface->h, 0, GL_BGR, GL_UNSIGNED_BYTE, ModelSurface->pixels);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glBufferData(GL_ARRAY_BUFFER, sizeof(points), points.data(), GL_STATIC_DRAW);
glVertexAttribPointer(3, 3, GL_FLOAT, GL_FALSE,num_bytes ,points.data());
glEnableVertexAttribArray(3);
//Translation Process
GLfloat TranslationMatrix[] = {
1.0, 0.0, 0.0, 0.0,
0.0, 1.0, 0.0, 0.0,
0.0, 0.0, 1.0, 1.0,
0.0, 0.0, 0.0, 1.0
};
//Send Translation Matrix up to
the vertex shader
glUniformMatrix4fv(translation, 1, TRUE, TranslationMatrix);
glDrawElements( GL_QUADS, faces.size(), GL_UNSIGNED_INT, faces.data());
I tried looking at what was causing this and went through every function every parameter ,etc looked at
the man pages.
Then found out that it could be my glVertexAttribPointer.
Here are
the man pages for glVertexAttribPointer
http://www.opengl.org/sdk/docs/man/xhtml/glVertexAttribPointer.xml
The last 2 parameters is my problem
How do I write those 2 last parameters do I try putting
the data from Points into it?.
glVertexAttribPointer(3, 3, GL_FLOAT, GL_FALSE,num_bytes ,points.data());
How does it work with vectors?
Is it fast?*
if you can not be bothered too look at
the man pages here is
the scripts coming from
the man pages directly.
Stride
Specifies
the byte offset between consecutive generic vertex attributes. If stride is 0,
the generic vertex attributes are understood to be tightly packed in
the array.
The initial value is 0.
Pointer
Specifies a pointer to
the first component of
the first generic vertex attribute in
the array.
The initial value is 0.
If you want my full source - http://ideone.com/fPfkg
Thanks Again if you do read this.
