LWJGL Drawing a rectangle at a position

Newbie & Debugging Questions
#1

Alright, I’m a bit new to Game Development, but I had been messing around for awhile with it and was able to draw rectangles of a particular size at a position relative to pixels.

Like this:


public static void drawRect(float x, float y, float width, float height, float rot)
	{
		glPushMatrix();
		{
			glTranslatef(x, y, 0); // Shifts the position
			glRotatef(rot, 0, 0, 1);

			glBegin(GL_QUADS);
			{
				glVertex2f(0, 0);
				glVertex2f(0, height);
				glVertex2f(width, height);
				glVertex2f(width, 0);
			}
			glEnd();
		}
		glPopMatrix();
	}

There’s nothing really wrong with that, but I’ve been trying to get the hang of VBO’s which are a more modern technique for rendering. The problem I have is that it draws the rectangle relative to GL co-ordinates (-1 top left, 1 top right for x) etc. But I want it so that I can draw a rectangle at a particular position on the screen.

This is my rendering code:


public void addVertices(Vector2f[] vertices)
	{
		size = vertices.length;
		FloatBuffer bufferedVertices = Render.createFlippedBuffer(vertices);
		
		glBindBuffer(GL_ARRAY_BUFFER, vbo);
		glBufferData(GL_ARRAY_BUFFER, bufferedVertices, GL_STATIC_DRAW);
	}
	
	public void render()
	{
		glEnableVertexAttribArray(0);
		glVertexAttribPointer(0, 3, GL_FLOAT, false, Vector2f.SIZE * 4, 0);
		glDrawArrays(GL_QUADS, 0, size);
		glDisableVertexAttribArray(0);
	}

I just use a standard floatbuffer adding the x and y coordinates into it, and then call buffer.flip() so that OGL can read it.

And this is how I create my square object


public Square(int x, int y, int height, int width)
	{
		super(x, y);
		mesh = new Mesh();

		Vector2f[] vertices = new Vector2f[] { new Vector2f (0, 0),
												new Vector2f(0, height),
												new Vector2f(width, height),
												new Vector2f(width, 0) };
		mesh.addVertices(vertices);
	}

and then I just call mesh.render() when I’m rendering it…

It just draws on the top left quadrant…
Help please, I want to be able to draw it at a given size and position on the screen, not relative to the quadrant positions of ogl :frowning: