// // Display a rotating cube with lighting // // Light and material properties are sent to the shader as uniform // variables. Vertex positions and normals are sent after each // rotation. #include "Angel.h" typedef Angel::vec4 color4; typedef Angel::vec4 point4; const int NumVertices = 36; //(6 faces)(2 triangles/face)(3 vertices/triangle) point4 points[NumVertices]; vec3 normals[NumVertices]; // Vertices of a unit cube centered at origin, sides aligned with axes point4 vertices[8] = { point4( -0.5, -0.5, 0.5, 1.0 ), point4( -0.5, 0.5, 0.5, 1.0 ), point4( 0.5, 0.5, 0.5, 1.0 ), point4( 0.5, -0.5, 0.5, 1.0 ), point4( -0.5, -0.5, -0.5, 1.0 ), point4( -0.5, 0.5, -0.5, 1.0 ), point4( 0.5, 0.5, -0.5, 1.0 ), point4( 0.5, -0.5, -0.5, 1.0 ) }; // Array of rotation angles (in degrees) for each coordinate axis enum { Xaxis = 0, Yaxis = 1, Zaxis = 2, NumAxes = 3 }; int Axis = Xaxis; GLfloat Theta[NumAxes] = { 0.0, 0.0, 0.0 }; // Model-view and projection matrices uniform location GLuint ModelView, Projection; //---------------------------------------------------------------------------- // quad generates two triangles for each face and assigns colors // to the vertices int Index = 0; void quad( int a, int b, int c, int d ) { // Initialize temporary vectors along the quad's edge to // compute its face normal vec4 u = vertices[b] - vertices[a]; vec4 v = vertices[c] - vertices[b]; vec3 normal = normalize( cross(u, v) ); normals[Index] = normal; points[Index] = vertices[a]; Index++; normals[Index] = normal; points[Index] = vertices[b]; Index++; normals[Index] = normal; points[Index] = vertices[c]; Index++; normals[Index] = normal; points[Index] = vertices[a]; Index++; normals[Index] = normal; points[Index] = vertices[c]; Index++; normals[Index] = normal; points[Index] = vertices[d]; Index++; } //---------------------------------------------------------------------------- // generate 12 triangles: 36 vertices and 36 colors void colorcube() { quad( 1, 0, 3, 2 ); quad( 2, 3, 7, 6 ); quad( 3, 0, 4, 7 ); quad( 6, 5, 1, 2 ); quad( 4, 5, 6, 7 ); quad( 5, 4, 0, 1 ); } //---------------------------------------------------------------------------- // OpenGL initialization void init() { colorcube(); // Create a vertex array object GLuint vao; glGenVertexArraysAPPLE( 1, &vao ); glBindVertexArrayAPPLE( vao ); // Create and initialize a buffer object GLuint buffer; glGenBuffers( 1, &buffer ); glBindBuffer( GL_ARRAY_BUFFER, buffer ); glBufferData( GL_ARRAY_BUFFER, sizeof(points) + sizeof(normals), NULL, GL_STATIC_DRAW ); glBufferSubData( GL_ARRAY_BUFFER, 0, sizeof(points), points ); glBufferSubData( GL_ARRAY_BUFFER, sizeof(points), sizeof(normals), normals ); // Load shaders and use the resulting shader program GLuint program = InitShader( "vshader53.glsl", "fshader53.glsl" ); glUseProgram( program ); // set up vertex arrays GLuint vPosition = glGetAttribLocation( program, "vPosition" ); glEnableVertexAttribArray( vPosition ); glVertexAttribPointer( vPosition, 4, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0) ); GLuint vNormal = glGetAttribLocation( program, "vNormal" ); glEnableVertexAttribArray( vNormal ); glVertexAttribPointer( vNormal, 3, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(sizeof(points)) ); // Initialize shader lighting parameters point4 light_position( 0.0, 0.0, -1.0, 0.0 ); color4 light_ambient( 0.2, 0.2, 0.2, 1.0 ); color4 light_diffuse( 1.0, 1.0, 1.0, 1.0 ); color4 light_specular( 1.0, 1.0, 1.0, 1.0 ); color4 material_ambient( 1.0, 0.0, 1.0, 1.0 ); color4 material_diffuse( 1.0, 0.8, 0.0, 1.0 ); color4 material_specular( 1.0, 0.8, 0.0, 1.0 ); float material_shininess = 100.0; color4 ambient_product = light_ambient * material_ambient; color4 diffuse_product = light_diffuse * material_diffuse; color4 specular_product = light_specular * material_specular; glUniform4fv( glGetUniformLocation(program, "AmbientProduct"), 1, ambient_product ); glUniform4fv( glGetUniformLocation(program, "DiffuseProduct"), 1, diffuse_product ); glUniform4fv( glGetUniformLocation(program, "SpecularProduct"), 1, specular_product ); glUniform4fv( glGetUniformLocation(program, "LightPosition"), 1, light_position ); glUniform1f( glGetUniformLocation(program, "Shininess"), material_shininess ); // Retrieve transformation uniform variable locations ModelView = glGetUniformLocation( program, "ModelView" ); Projection = glGetUniformLocation( program, "Projection" ); glEnable( GL_DEPTH_TEST ); glShadeModel(GL_FLAT); glClearColor( 1.0, 1.0, 1.0, 1.0 ); } //---------------------------------------------------------------------------- void display( void ) { glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); // Generate tha model-view matrixn const vec3 viewer_pos( 0.0, 0.0, 2.0 ); mat4 model_view = ( Translate( -viewer_pos ) * RotateX( Theta[Xaxis] ) * RotateY( Theta[Yaxis] ) * RotateZ( Theta[Zaxis] ) ); glUniformMatrix4fv( ModelView, 1, GL_TRUE, model_view ); glDrawArrays( GL_TRIANGLES, 0, NumVertices ); glutSwapBuffers(); } //---------------------------------------------------------------------------- void mouse( int button, int state, int x, int y ) { if ( state == GLUT_DOWN ) { switch( button ) { case GLUT_LEFT_BUTTON: Axis = Xaxis; break; case GLUT_MIDDLE_BUTTON: Axis = Yaxis; break; case GLUT_RIGHT_BUTTON: Axis = Zaxis; break; } } } //---------------------------------------------------------------------------- void idle( void ) { Theta[Axis] += 0.01; if ( Theta[Axis] > 360.0 ) { Theta[Axis] -= 360.0; } glutPostRedisplay(); } //---------------------------------------------------------------------------- void keyboard( unsigned char key, int x, int y ) { switch( key ) { case 033: // Escape Key case 'q': case 'Q': exit( EXIT_SUCCESS ); break; } } //---------------------------------------------------------------------------- void reshape( int width, int height ) { glViewport( 0, 0, width, height ); GLfloat aspect = GLfloat(width)/height; mat4 projection = Perspective( 45.0, aspect, 0.5, 3.0 ); glUniformMatrix4fv( Projection, 1, GL_TRUE, projection ); } //---------------------------------------------------------------------------- int main( int argc, char **argv ) { glutInit( &argc, argv ); glutInitDisplayMode( GLUT_RGBA | GLUT_DOUBLE | GLUT_DEPTH ); glutInitWindowSize( 512, 512 ); glutCreateWindow( "Color Cube" ); init(); glutDisplayFunc( display ); glutKeyboardFunc( keyboard ); glutReshapeFunc( reshape ); glutMouseFunc( mouse ); glutIdleFunc( idle ); glutMainLoop(); return 0; }