Visual Studio：サブウィンドウに矩形を描画しません

Question

この3つのサブウィンドウを作成しましたが、そのうちの1つ（最初のウィンドウ）に四角形を描きたいと思います。クワッドは、アイデンティティ投影錐台の近くにどこにもないことを

#include "glut.h" 
#include <stdio.h> 

// ***** Main Window *****// 

#define GAP 10 // gap between subwindows 

// define the window position on screen 
float main_window_x; 
float main_window_y; 

// variables representing the window size 
float main_window_w = 256 + GAP * 2; 
float main_window_h = 256 + 64 + GAP * 3; 

// variable representing the window title 
char *window_title = "SubWindow Template"; 

// Represents the window id 
int main_window; 

// ***** Sub Window 1 *****// 

// define the window position on screen 
float subwindow1_x = GAP; 
float subwindow1_y = GAP; 

// variables representing the window size 
float subwindow1_w = 256; 
float subwindow1_h = 220; 

// Represents the subwindow id 
int subwindow_1; 

// ***** Sub Window 2 *****// 

// define the window position on screen 
float subwindow2_x = GAP; 
float subwindow2_y = GAP + 220 + GAP; 

// variables representing the window size 
float subwindow2_w = 123; 
float subwindow2_h = 100; 

// Represents the subwindow id 
int subwindow_2; 

// ***** Sub Window 3 *****// 

// define the window position on screen 
float subwindow3_x = GAP + 123 + GAP; 
float subwindow3_y = GAP + 220 + GAP; 

// variables representing the window size 
float subwindow3_w = 123; 
float subwindow3_h = 100; 

// Represents the subwindow id 
int subwindow_3; 

void main_display(void) 
{ 
// Set background color to black 
    glClearColor(0.0, 0.0, 0.0, 0.0); 
    glClear(GL_COLOR_BUFFER_BIT); 

// Swap front and back buffers 
    glutSwapBuffers(); 
} 

void subwindow1_display(void) 
{ 
// Set background color to white 
    glClearColor(1.0, 1.0, 1.0, 1.0); 
    glClear(GL_COLOR_BUFFER_BIT); 

// Set drawing color to gray 
    glColor3f(0.75, 0.75, 0.75); 

    glBegin(GL_QUADS); 
    glVertex2i(GAP + 20, GAP + 10); 
    glVertex2i(GAP + 40, GAP + 10); 
    glVertex2i(GAP + 40, GAP + 30); 
    glVertex2i(GAP + 20, GAP + 30); 

    glEnd(); 

    glFlush(); 

// Swap front and back buffers 
    glutSwapBuffers(); 
} 

void subwindow2_display(void) 
{ 
// Set background color to white 
    glClearColor(1.0, 1.0, 1.0, 1.0); 
    glClear(GL_COLOR_BUFFER_BIT); 

// Set drawing color to blue 
    glColor3f(0, 0, 1); 

// Swap front and back buffers 
    glutSwapBuffers(); 
} 

void subwindow3_display(void) 
{ 
// Set background color to white 
    glClearColor(1.0, 1.0, 1.0, 1.0); 
    glClear(GL_COLOR_BUFFER_BIT); 

// Set drawing color to blue 
    glColor3f(0, 0, 1); 

// Swap front and back buffers 
    glutSwapBuffers(); 
} 

// ***** General *****// 

// Tells whether to display the window full screen or not 
int full_screen = 0; 

void main_reshape(int width, int height) 
{ 

// Just take the case when the user tries 
// to make the size of the window very small... 
    if (width < GAP * 4 || height < GAP * 6) 
    { 
     glutSetWindow(main_window); 
     glutReshapeWindow(main_window_w, main_window_h); 
     return; 
    } 

// Change the subwindow 1 dimensions as window dimensions change 
// main_window_w   ---> subwindow1_w 
// main_window_w' (width) ---> ?? 
// ==> 
    subwindow1_w = (subwindow1_w * (width - GAP * 2.0))/(main_window_w - GAP * 2.0); 
    subwindow1_h = (subwindow1_h * (height - GAP * 3.0))/(main_window_h - GAP * 3.0); 

// Set subwindow 1 as current window and then reposition and resize it 
    glutSetWindow(subwindow_1); 
    glutPositionWindow(GAP, GAP); 
    glutReshapeWindow(subwindow1_w, subwindow1_h); 

// Change the subwindow 2 dimensions as window dimensions change 
    subwindow2_w = (subwindow2_w * (width - GAP * 2.0))/(main_window_w - GAP * 2.0); 
    subwindow2_h = (subwindow2_h * (height - GAP * 3.0))/(main_window_h - GAP * 3.0); 

// Set subwindow 2 as current window and then reposition and resize it 
    glutSetWindow(subwindow_2); 
    glutPositionWindow(GAP, GAP + subwindow1_h + GAP); 
    glutReshapeWindow(subwindow2_w, subwindow2_h); 

// Change the subwindow 3 dimensions as window dimensions change 
    subwindow3_w = (subwindow3_w * (width - GAP * 2.0))/(main_window_w - GAP * 2.0); 
    subwindow3_h = (subwindow3_h * (height - GAP * 3.0))/(main_window_h - GAP * 3.0); 

// Set subwindow 3 as current window and then reposition and resize it 
    glutSetWindow(subwindow_3); 
    glutPositionWindow(GAP * 2 + 123, GAP + subwindow1_h + GAP); 
    glutReshapeWindow(subwindow3_w, subwindow3_h); 

// Stay updated with the window width and height 
    main_window_w = width; 
    main_window_h = height; 

} 

//------------------------------------------------------------------------- 
// SubWindow 1 Reshape Function. 
// 
// Preserve aspect ratio of viewport when subwindow is resized. 
//------------------------------------------------------------------------- 
void subwindow1_reshape(int width, int height) 
{ 

// Represents a side of the viewport. A viewport is intended to 
// to take a square shape so that the aspect ratio is reserved 
    int viewport_side = 0; 

// Viewport x and y positions (Center viewport) 
    int viewport_x = 0, viewport_y = 0; 

// Calculate viewport side 
    viewport_side = (width > height) ? height : width; 

// Calculate viewport position 
    viewport_x = (width - viewport_side)/2; 
    viewport_y = (height - viewport_side)/2; 

// Preserve aspect ratio 
    glViewport(viewport_x, viewport_y, viewport_side, viewport_side); 

// Set subwindow width and height 
    subwindow1_w = width; 
    subwindow1_h = height; 
} 

//------------------------------------------------------------------------- 
// SubWindow 2 Reshape Function. 
// 
// Preserve aspect ratio of viewport when subwindow is resized. 
//------------------------------------------------------------------------- 
void subwindow2_reshape(int width, int height) 
{ 
// Represents a side of the viewport. A viewport is intended to 
// to take a square shape so that the aspect ratio is reserved 
    int viewport_side = 0; 

// Viewport x and y positions (Center viewport) 
    int viewport_x = 0, viewport_y = 0; 

// Calculate viewport side 
    viewport_side = (width > height) ? height : width; 

// Calculate viewport position 
    viewport_x = (width - viewport_side)/2; 
    viewport_y = (height - viewport_side)/2; 

// Preserve aspect ratio 
    glViewport(viewport_x, viewport_y, viewport_side, viewport_side); 

// Set subwindow width and height 
    subwindow2_w = width; 
    subwindow2_h = height; 
} 

//------------------------------------------------------------------------- 
// SubWindow 3 Reshape Function. 
// 
// Preserve aspect ratio of viewport when subwindow is resized. 
//------------------------------------------------------------------------- 
void subwindow3_reshape(int width, int height) 
{ 
// Represents a side of the viewport. A viewport is intended to 
// to take a square shape so that the aspect ratio is reserved 
    int viewport_side = 0; 

// Viewport x and y positions (Center viewport) 
    int viewport_x = 0, viewport_y = 0; 

// Calculate viewport side 
    viewport_side = (width > height) ? height : width; 

// Calculate viewport position 
    viewport_x = (width - viewport_side)/2; 
    viewport_y = (height - viewport_side)/2; 

// Preserve aspect ratio 
    glViewport(viewport_x, viewport_y, viewport_side, viewport_side); 

// Set subwindow width and height 
    subwindow3_w = width; 
    subwindow3_h = height; 
} 

//------------------------------------------------------------------------- 
// Redisplay contents of subwindow 1 and subwindow 2 and subwindow3. 
//------------------------------------------------------------------------- 
void redisplay_all(void) 
{ 
    glutSetWindow(subwindow_1); 
    glutPostRedisplay(); 
    glutSetWindow(subwindow_2); 
    glutPostRedisplay(); 
    glutSetWindow(subwindow_3); 
    glutPostRedisplay(); 
} 

//------------------------------------------------------------------------- 
// This function sets the window x and y coordinates 
// such that the window becomes centered 
//------------------------------------------------------------------------- 
void centerOnScreen() 
{ 
    main_window_x = (glutGet(GLUT_SCREEN_WIDTH) - main_window_w)/2; 
    main_window_y = (glutGet(GLUT_SCREEN_HEIGHT) - main_window_h)/2; 
} 

//------------------------------------------------------------------------- 
// Program Main method. 
//------------------------------------------------------------------------- 
int main(int argc, char **argv) 
{ 
/**** Main Window **** */ 
    glutInit(&argc, argv); 
// Set the main window x and y coordinates such that the 
// window becomes centered 
    centerOnScreen(); 

    glutInitWindowSize(main_window_w, main_window_h); 
    glutInitWindowPosition(main_window_x, main_window_y); 
    glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE); 

    main_window = glutCreateWindow(window_title); 

    glutDisplayFunc(main_display); 
    glutReshapeFunc(main_reshape); 

/**** Subwindow 1 **** */ 
    subwindow_1 = glutCreateSubWindow(main_window, subwindow1_x, subwindow1_y, subwindow1_w, subwindow1_h); 

    glutDisplayFunc(subwindow1_display); 
    glutReshapeFunc(subwindow1_reshape); 

/**** Subwindow 2 **** */ 
    subwindow_2 = glutCreateSubWindow(main_window, subwindow2_x, subwindow2_y, subwindow2_w, subwindow2_h); 

    glutDisplayFunc(subwindow2_display); 
    glutReshapeFunc(subwindow2_reshape); 

/**** Subwindow 3 **** */ 
    subwindow_3 = glutCreateSubWindow(main_window, subwindow3_x, subwindow3_y, subwindow3_w, subwindow3_h); 

    glutDisplayFunc(subwindow3_display); 
    glutReshapeFunc(subwindow3_reshape); 

// View in full screen if the full_screen flag is on 
    if (full_screen) 
     glutFullScreen(); 

// Start GLUT event processing loop 
    glutMainLoop(); 

    return 0; 
} 

Answer 1

：ここ

はCのコードである...私はエラーを持っていないが、それは何も（わずか3空のサブウィンドウ）が表示されません。それが動作

void subwindow1_display(void) 
{ 
    // Set background color to white 
    glClearColor(0.0, 1.0, 1.0, 1.0); 
    glClear(GL_COLOR_BUFFER_BIT); 

    // Set drawing color to gray 
    glColor3f(0.75, 0.75, 0.75); 

    glMatrixMode(GL_PROJECTION); 
    glLoadIdentity(); 
    glOrtho(-50, 50, -50, 50, -1 , 1); 

    glMatrixMode(GL_MODELVIEW); 
    glLoadIdentity(); 

    glBegin(GL_QUADS); 
    glVertex2i(GAP + 20, GAP + 10); 
    glVertex2i(GAP + 40, GAP + 10); 
    glVertex2i(GAP + 40, GAP + 30); 
    glVertex2i(GAP + 20, GAP + 30); 

    glEnd(); 

    glFlush(); 

    // Swap front and back buffers 
    glutSwapBuffers(); 
}