title: Issues drawing a line in OpenGL
body: <p>I already have a program that can draw textured objects. I want to draw debug lines, so I tried to copy the same sort of drawing process I use for sprites to draw a line. I made a new fragment and vertex shader because lines aren't going to be textured and having a different debug shader could be useful. </p>
  
  <p>My system continues to work if I try to draw a line, but the line doesn't draw. I tried to write code similar to working code for my sprites, but clearly I've missed something or made a mistake.  </p>
  
  <p>Vertex Shader:</p>
  
  <pre><code>#version 330 core
  
  layout (location = 0) in vec2 position;
  
  uniform mat4 uniformView;
  uniform mat4 uniformProjection;
  
  void main()
  {
      gl_Position = uniformProjection * uniformView * vec4(position, 0.0f, 1.0f);
  }
  </code></pre>
  
  <p>Fragment Shader:</p>
  
  <pre><code>#version 330 core
  
  out vec4 color;
  uniform vec4 uniformColor;
  
  void main()
  {
      color = uniformColor;
  }
  </code></pre>
  
  <p>Drawing Code:</p>
  
  <pre><code>void debugDrawLine(glm::vec3 startPoint, glm::vec3 endPoint, glm::vec3 color, Shader debugShader)
  {
    GLint transformLocation, colorLocation;
    GLfloat lineCoordinates[] = { startPoint.x, startPoint.y,
                                 endPoint.x, endPoint.y};
    GLuint vertexArray, vertexBuffer;
  
    glLineWidth(5.0f);
  
    glGenVertexArrays(1, &amp;vertexArray);
    glGenBuffers(1, &amp;vertexBuffer);
  
    glBindVertexArray(vertexArray);
    glBindBuffer(GL_ARRAY_BUFFER, vertexBuffer);
  
    debugShader.Use();
  
    //Copies the Vertex data into the buffer
    glBufferData(GL_ARRAY_BUFFER, sizeof(lineCoordinates), lineCoordinates, GL_STATIC_DRAW);
  
    glVertexAttribPointer(
      0,                  // attribute 0. No particular reason for 0, but must match the layout in the shader.
      2,                  // size
      GL_FLOAT,           // type
      GL_FALSE,           // normalized?
      2*sizeof(GL_FLOAT), // stride
      (GLvoid*)0            // array buffer offset
      );
  
  
    //Sends the sprite's color information in the the shader 
    colorLocation = glGetUniformLocation(debugShader.Program, "uniformColor");
    glUniform4f(colorLocation, 1.0f, color.x, color.y, color.z);
  
    //Activates Vertex Position Information
    glEnableVertexAttribArray(0);
  
    // Draw the line
    glDrawArrays(GL_LINES, 0, 2);
  
    glBindBuffer(GL_ARRAY_BUFFER, 0);
    glBindVertexArray(0);
  }
  </code></pre>