Glut Reshape 기능이 작동하지 않습니다.

Question

glut 창 크기를 조정하려고하면 화면이 비어있게됩니다.

void Resize(int width, int height) 
{ 
    CurrentWidth = width; 
    CurrentHeight = height; 


    glViewport(0, 0, (GLsizei)CurrentWidth, (GLsizei)CurrentHeight); 

    glMatrixMode(GL_PROJECTION); 
    glLoadIdentity(); 
    glOrtho(0, CurrentWidth, CurrentHeight, 0, NearPlane, FarPlane); 
    glMatrixMode(GL_MODELVIEW); 
    glLoadIdentity(); 

    glutPostRedisplay(); 
} 

나는 OpenGL을 세계에 아주 새로운 오전하지만 내가 배운 것을에서이 작동하도록되어있다 :

이

는 모양 변경 콜백 funciton에 대한 코드입니다.

그리고이 함께 넣어 모든 코드입니다 :

#include <stdlib.h> 
#include <stdio.h> 
#include <string.h> 
#include <GL/glew.h> 
#include <GL/freeglut.h> 
#include <gl/glut.h> 

#include "Utils.h" 

int LEFT = 0; 
int RIGHT = 0; 
int UP = 0; 
int DOWN = 0; 

int CurrentWidth = 800, 
    CurrentHeight = 800, 
    WindowHandle = 0; 

float NearPlane = 1.0f, 
     FarPlane = 100.0f; 

float lightX, 
     lightY; 

void Initialize(int, char*[]); 
void InitWindow(int, char*[]); 
void Idle(void); 
void Resize(int, int); 
void KeyPressed(unsigned char, int, int); 
void SpecialPressed(int, int, int); 
void SpecialReleased(int, int, int); 
void Update(void); 
void Render(void); 
void FillZBuffer(void); 
void ClearAlpha(void); 
void RenderLightAlpha(float); 
void GeometryPass(void); 
void Draw(void); 

int main (int argc, char* argv[]) 
{ 
    Initialize(argc, argv); 

    glutMainLoop(); 

    exit(EXIT_SUCCESS); 
} 

void Initialize(int argc, char* argv[]) 
{ 
    InitWindow(argc, argv); 

    fprintf(
     stdout, 
     "INFO: OpenGL Version: %s\n", 
     glGetString(GL_VERSION) 
    ); 

    lightX = 300.0f; 
    lightY = 300.0f; 
} 

void InitWindow(int argc, char* argv[]) 
{ 
    glutInit(&argc, argv); 

    glutInitContextVersion(3, 3); 
    glutInitContextProfile(GLUT_COMPATIBILITY_PROFILE); 

    glutSetOption(
     GLUT_ACTION_ON_WINDOW_CLOSE, 
     GLUT_ACTION_GLUTMAINLOOP_RETURNS 
    ); 

    glutInitWindowSize (CurrentWidth, CurrentHeight); 
    glutInitWindowPosition (100, 100); 

    glutInitDisplayMode (GLUT_DOUBLE | GLUT_RGBA | GLUT_ALPHA); 

    WindowHandle = glutCreateWindow ("Shadows"); 

    if(WindowHandle < 1) { 
     fprintf(
      stderr, 
      "ERROR: Could not create a new rendering window.\n" 
     ); 
     exit(EXIT_FAILURE); 
    } 

    glutDisplayFunc(Render); 
    glutReshapeFunc(Resize); 
    glutIdleFunc(Idle); 
    glutKeyboardFunc(KeyPressed); 
    glutSpecialFunc(SpecialPressed); 
    glutSpecialUpFunc(SpecialReleased); 
} 

void Update() 
{ 
    int speed = 10; 
    if (LEFT) 
    { 
     lightX -= speed; 
    } 
    if (RIGHT) 
    { 
     lightX += speed; 
    } 
    if (UP) 
    { 
     lightY -= speed; 
    } 
    if (DOWN) 
    { 
     lightY += speed; 
    } 
} 

void Draw() 
{ 
    float x = 200; 
    float y = 200; 
    float w = 100; 
    float h = 100; 
    float depth = 0.0f; 

    // floor 
    glColor4f(0.5f, 0.5f, 0.5f, 1.0f); 
    depth = -10.0f; 
    glBegin(GL_QUADS); 
    { 
     glVertex3f(0, 0, depth); 
     glVertex3f((float)CurrentWidth, 0, depth); 
     glVertex3f((float)CurrentWidth, (float)CurrentHeight, depth); 
     glVertex3f(0, (float)CurrentHeight, depth); 
    } 
    glEnd(); 

    // square 
    glColor4f(1.0f, 0.0f, 0.0f, 1.0f); 
    depth = -5.0; 
    glBegin(GL_QUADS); 
    { 
     glVertex3f(x, y, depth); 
     glVertex3f(x + w, y, depth); 
     glVertex3f(x + w, y + h, depth); 
     glVertex3f(x, y + h, depth); 
    } 
    glEnd(); 
} 

void Render() 
{ 
    glClearColor(0.0f, 0.0f, 0.0f, 0.0f); 
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); 

    glDisable(GL_CULL_FACE); 

    Update(); 

    FillZBuffer(); 

    ClearAlpha(); 

    RenderLightAlpha(1.0f); 

    GeometryPass(); 

    glutSwapBuffers(); 
    glutPostRedisplay(); 
} 

void FillZBuffer() 
{ 
    glEnable(GL_DEPTH_TEST); 
    glDepthFunc(GL_LESS); 
    glColorMask(GL_FALSE, GL_FALSE, GL_FALSE, GL_FALSE); 
    glDepthMask(GL_TRUE); 

    Draw(); 

    glColorMask(GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE); 
    glDepthMask(GL_FALSE); 
} 

void ClearAlpha() 
{ 
    glDisable(GL_BLEND); 
    glDisable(GL_DEPTH_TEST); 
    glColorMask(GL_FALSE, GL_FALSE, GL_FALSE, GL_TRUE); 
    glColor4f(0.0f, 0.0f, 0.0f, 0.0f); 

    glBegin (GL_QUADS); 
    { 
     glVertex2f(0, 0); 
     glVertex2f((float)CurrentWidth, 0); 
     glVertex2f((float)CurrentWidth, (float)CurrentHeight); 
     glVertex2f(0, (float)CurrentHeight); 
    } 
    glEnd(); 
} 

void RenderLightAlpha(float intensity) 
{ 
    float depth = -1.0f; 
    float radius = 300.0f; 
    float angle; 
    int numSubdivisions = 32; 

    glDisable(GL_BLEND); 
    glEnable(GL_DEPTH_TEST); 
    glDepthFunc(GL_LEQUAL); 

    glBegin(GL_TRIANGLE_FAN); 
    { 
     glColor4f(0.0f, 0.0f, 0.0f, intensity); 
     glVertex3f(lightX, lightY, depth); 

     // Set edge colour for rest of shape 
     glColor4f(0.0f, 0.0f, 0.0f, 0.0f); 

     for (angle = 0; angle <= (float)PI * 2; angle += (((float)PI * 2)/numSubdivisions)) 
     { 
      glVertex3f(radius*(float)cos(angle) + lightX, radius*(float)sin(angle) + lightY, depth); 
     } 

     glVertex3f(lightX + radius, lightY, depth); 
    } 
    glEnd(); 
} 

void GeometryPass() 
{ 
    glColorMask(GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE); 
    glEnable(GL_DEPTH_TEST); 
    glDepthFunc(GL_LEQUAL); 
    glEnable(GL_BLEND); 
    glBlendFunc(GL_DST_ALPHA, GL_ONE); 

    Draw(); 
} 

void Idle() 
{ 
    glutPostRedisplay(); 
} 

void Resize(int width, int height) 
{ 
    CurrentWidth = width; 
    CurrentHeight = height; 


    glViewport(0, 0, (GLsizei)CurrentWidth, (GLsizei)CurrentHeight); 

    glMatrixMode(GL_PROJECTION); 
    glLoadIdentity(); 
    glOrtho(0, CurrentWidth, CurrentHeight, 0, NearPlane, FarPlane); 
    glMatrixMode(GL_MODELVIEW); 
    glLoadIdentity(); 

    glutPostRedisplay(); 
} 

void KeyPressed(unsigned char key, int x, int y) 
{ 
    UNREFERENCED_PARAMETER(x); 
    UNREFERENCED_PARAMETER(y); 

    // escape key 
    if (key == 27) 
    { 
     exit(0); 
    } 
} 

void SpecialPressed(int keyCode, int x, int y) 
{ 
    UNREFERENCED_PARAMETER(x); 
    UNREFERENCED_PARAMETER(y); 

    if (keyCode == GLUT_KEY_LEFT) 
    { 
     LEFT = 1; 
    } 
    else if (keyCode == GLUT_KEY_RIGHT) 
    { 
     RIGHT = 1; 
    } 
    else if (keyCode == GLUT_KEY_UP) 
    { 
     UP = 1; 
    } 
    else if (keyCode == GLUT_KEY_DOWN) 
    { 
     DOWN = 1; 
    } 
} 

void SpecialReleased(int keyCode, int x, int y) 
{ 
    UNREFERENCED_PARAMETER(x); 
    UNREFERENCED_PARAMETER(y); 
    if (keyCode == GLUT_KEY_LEFT) 
    { 
     LEFT = 0; 
    } 
    else if (keyCode == GLUT_KEY_RIGHT) 
    { 
     RIGHT = 0; 
    } 
    else if (keyCode == GLUT_KEY_UP) 
    { 
     UP = 0; 
    } 
    else if (keyCode == GLUT_KEY_DOWN) 
    { 
     DOWN = 0; 
    } 
} 

는 더 이상 정보가 필요하면 알려주세요.

Answer 1

FillZBuffer 함수에서 깊이 마스크는 끝에서 비활성화되고 동일한 함수의 시작 부분에서만 다시 활성화됩니다. 그래서 Render가 다시 호출 될 때, 깊이 마스크가 사용 불가능하기 때문에 깊이 버퍼 비트를 지우라는 호출은 아무 것도하지 않습니다.

이 문제를 해결하려면 깊이 버퍼 비트를 지우려면 호출 전에 깊이 마스크를 다시 활성화해야합니다.

그래서 Render는 다음과 같이 보입니다.

void Render() 
{ 
    glDepthMask(GL_TRUE); // insert this line 
    glClearColor(0.0f, 0.0f, 0.0f, 0.0f); 
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); 

    glDisable(GL_CULL_FACE); 

    Update(); 

    FillZBuffer(); 

    ClearAlpha(); 

    RenderLightAlpha(1.0f); 

    GeometryPass(); 

    glutSwapBuffers(); 
    glutPostRedisplay(); 
}