145 lines
2.8 KiB
C++
145 lines
2.8 KiB
C++
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#include <lib-opengl-test.hpp>
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#include <GL/freeglut.h>
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#include <GL/gl.h>
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#include <GL/glu.h>
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#include <cstdio>
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//Screen constants
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const int SCREEN_WIDTH = 640;
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const int SCREEN_HEIGHT = 480;
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const int SCREEN_FPS = 60;
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//Color modes
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const int COLOR_MODE_CYAN = 0;
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const int COLOR_MODE_MULTI = 1;
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//The current color rendering mode
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int gColorMode = 0;
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//The projection scale
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GLfloat gProjectionScale = 1.f;
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void runMainLoop( int val )
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{
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//Frame logic
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update();
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render();
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//Run frame one more time
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glutTimerFunc( 1000 / SCREEN_FPS, runMainLoop, val );
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}
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bool initGL()
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{
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//Initialize Projection Matrix
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glMatrixMode( GL_PROJECTION );
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glLoadIdentity();
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glOrtho( 0.0, SCREEN_WIDTH, SCREEN_HEIGHT, 0.0, 1.0, -1.0 );
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//Initialize Modelview Matrix
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glMatrixMode( GL_MODELVIEW );
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glLoadIdentity();
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//Initialize clear color
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glClearColor( 0.f, 0.f, 0.f, 1.f );
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//Check for error
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GLenum error = glGetError();
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if( error != GL_NO_ERROR )
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{
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printf( "Error initializing OpenGL! %s\n", gluErrorString( error ) );
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return false;
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}
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return true;
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}
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void update()
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{
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}
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void render()
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{
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//Clear color buffer
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glClear( GL_COLOR_BUFFER_BIT );
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//Reset modelview matrix
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glMatrixMode( GL_MODELVIEW );
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glLoadIdentity();
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//Move to center of the screen
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glTranslatef( SCREEN_WIDTH / 2.f, SCREEN_HEIGHT / 2.f, 0.f );
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//Render quad
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if( gColorMode == COLOR_MODE_CYAN )
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{
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//Solid Cyan
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glBegin( GL_QUADS );
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glColor3f( 0.f, 1.f, 1.f );
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glVertex2f( -50.f, -50.f );
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glVertex2f( 50.f, -50.f );
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glVertex2f( 50.f, 50.f );
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glVertex2f( -50.f, 50.f );
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glEnd();
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}
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else
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{
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//RYGB Mix
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glBegin( GL_QUADS );
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glColor3f( 1.f, 0.f, 0.f ); glVertex2f( -50.f, -50.f );
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glColor3f( 1.f, 1.f, 0.f ); glVertex2f( 50.f, -50.f );
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glColor3f( 0.f, 1.f, 0.f ); glVertex2f( 50.f, 50.f );
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glColor3f( 0.f, 0.f, 1.f ); glVertex2f( -50.f, 50.f );
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glEnd();
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}
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//Update screen
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glutSwapBuffers();
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}
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void handleKeys( unsigned char key, int x, int y )
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{
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//If the user presses q
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if( key == 'q' )
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{
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//Toggle color mode
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if( gColorMode == COLOR_MODE_CYAN )
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{
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gColorMode = COLOR_MODE_MULTI;
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}
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else
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{
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gColorMode = COLOR_MODE_CYAN;
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}
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}
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else if( key == 'e' )
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{
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//Cycle through projection scales
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if( gProjectionScale == 1.f )
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{
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//Zoom out
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gProjectionScale = 2.f;
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}
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else if( gProjectionScale == 2.f )
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{
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//Zoom in
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gProjectionScale = 0.5f;
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}
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else if( gProjectionScale == 0.5f )
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{
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//Regular zoom
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gProjectionScale = 1.f;
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}
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//Update projection matrix
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glMatrixMode( GL_PROJECTION );
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glLoadIdentity();
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glOrtho( 0.0, SCREEN_WIDTH * gProjectionScale, SCREEN_HEIGHT * gProjectionScale, 0.0, 1.0, -1.0 );
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}
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}
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