openGL draw circle triangle and square in different display mode - c++

Question

I am using Xcode to write openGL. What I am doing is to draw a circle, a triangle, and a square.
However, I found that my circle only can display on
glutInitDisplayMode(GLUT_RGBA | GLUT_SINGLE);
the triangle and square can only display on glutInitDisplayMode(GLUT_3_2_CORE_PROFILE|GLUT_RGBA | GLUT_SINGLE);
How can i make them display together?
Here is part of my entire code:
#include "Angel.h" //includes gl.h, glut.h and other stuff...
void m_glewInitAndVersion(void); //pre-implementation declaration (could do in header file)
void close(void);
//Mesh 0
GLuint buffer[3];
GLuint VAO[3];
GLuint color_loc;
GLuint program;
const int NumVertices = 4;
// Vertices of a unit cube centered at origin, sides aligned with axes
vec2 points[4] = {
vec2( 0.25, 0.25),
vec2( 0.75, 0.25),
vec2( 0.75, 0.75),
vec2( 0.25, 0.75)
};
vec2 points2[3]={
vec2(-1,-1),
vec2(0,-1),
vec2(0,-0.7)};
// RGBA colors
vec4 blue_opaque = vec4( 0.0, 0.0, 1.0, 1.0 );
vec4 red_opaque = vec4(1.0, 0.0, 0.0, 1.0);
//----------------------------------------------------------------------------
// OpenGL initialization
void
init()
{
glClearColor( 1.0, 1.0, 1.0, 1.0 );
// glColor3f(1.0, 0.0, 0.0);
// glMatrixMode(GL_PROJECTION);
// glLoadIdentity();
// gluOrtho2D(-3.5, 3.5, -3.5, 3.5);
// Create and initialize a buffer object
glGenBuffers( 2, buffer );
glBindBuffer( GL_ARRAY_BUFFER, buffer[0] );
glBufferData( GL_ARRAY_BUFFER, sizeof(points), points, GL_STATIC_DRAW );
// Load shaders and use the resulting shader program
program = InitShader( "vshader00_v150.glsl", "fshader00_v150.glsl" );
glUseProgram( program );
// set up vertex arrays
GLuint vPosition = glGetAttribLocation( program, "vPosition" );
//Set up VAO
glGenVertexArrays(2,VAO);
glBindVertexArray(VAO[0]);
glBindBuffer(GL_ARRAY_BUFFER,buffer[0]);
glEnableVertexAttribArray( vPosition );
glVertexAttribPointer( vPosition, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0) );
color_loc = glGetUniformLocation(program, "color");
//triangle
// glBindVertexArray(VAO[1]);
// glBindBuffer(GL_ARRAY_BUFFER, buffer[1]);
// glBufferData(GL_ARRAY_BUFFER, sizeof(points2), points2, GL_STATIC_DRAW);
// glUseProgram(program);
// glEnableVertexAttribArray(vPosition);
// glVertexAttribPointer(vPosition, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0) );
}
//----------------------------------------------------------------------------
void
display( void )
{
glClear( GL_COLOR_BUFFER_BIT );
// const float PI=3.14159;
// glBegin(GL_TRIANGLE_FAN);
// All triangles fan out starting with this point
// glVertex2f (0.0,0.0);
// for (int i = 0; i <=361; i++)
// {
// glColor3f(float(rand())/float(RAND_MAX),
// float(rand())/float(RAND_MAX),
// float(rand())/float(RAND_MAX));
// glVertex2f(2.0*cos(i*PI/180), 2.0*sin(i*PI/180));
// }
// glEnd();
glBindVertexArray(VAO[0]);
glDrawArrays( GL_TRIANGLE_FAN, 0, NumVertices );
glUseProgram(program);
glUniform4fv(color_loc, 1, blue_opaque);
// glBindVertexArray(VAO[1]);
// glDrawArrays( GL_TRIANGLE_FAN, 0, 3);
// glUseProgram(program);
// glUniform4fv(color_loc, 1, red_opaque);
glFlush();
}
int main( int argc, char **argv )
{
glutInit( &argc, argv );
#ifdef __APPLE__
glutInitDisplayMode(GLUT_3_2_CORE_PROFILE|GLUT_RGBA | GLUT_SINGLE);
#else
glutInitDisplayMode( GLUT_RGBA | GLUT_SINGLE);
#endif
glutInitWindowSize( 500, 500 );
glutCreateWindow( "CS 432 Hello World" );
m_glewInitAndVersion();
init();
glutDisplayFunc( display );
glutKeyboardFunc( keyboard );
glutWMCloseFunc(close);
glutMainLoop();
return 0;
}

Answer 1

Your circle code doesn't work with GLUT_3_2_CORE_PROFILE because glBegin, glColor3f, glVertex2f and glEnd were removed in OpenGL 3, so OpenGL 3.2 (or later) doesn't have them.
I'm not sure exactly why your triangle and square code doesn't work without GLUT_3_2_CORE_PROFILE, but consider that VAOs were added in OpenGL 3, and when you don't specify GLUT_3_2_CORE_PROFILE, you get a version before 3.
Pick a version and stick with it.