Schwemme kann kein 2D-Bild plotten

Question

Ich habe Probleme mit dem Laden src/up.bmp und zeigt es in 2D überlagert in meiner 3D-Umgebung. Aber nichts erscheint. Wo ist mein Fehler?

#define SDL_MAIN_HANDLED 

#include <math.h> 
#include <SDL.h> 
#include <iostream> 
#include <GL/freeglut.h> 

using namespace std; 

int w_width = 800; 
int w_height = 500; 
string w_title = "Model viewer"; 
float line_width = 2.0f; 
float camera_radius = 100.0f; 
float axis_size = 20.0; 

SDL_Surface* button1; 
GLuint TextureID; 


void draw_button(SDL_Surface* button) 
{ 

    glGenTextures(1, &TextureID); 
    glBindTexture(GL_TEXTURE_2D, TextureID); 
    glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE); 
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_NEAREST); 

    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); 
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT); 
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT); 
    gluBuild2DMipmaps(GL_TEXTURE_2D, 3, button->w, button->h, GL_RGB, GL_UNSIGNED_BYTE, button->pixels); 
} 

void display() 
{ 
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); 
    glClearColor(1.0f, 1.0f, 1.0f, 1.0f); 

    const float ratio = (float)glutGet(GLUT_SCREEN_WIDTH)/(float)glutGet(GLUT_SCREEN_HEIGHT); 
    static double t = 0.0; 
    const float deg2rad = 3.1415926f/180.0f; 
    float cam_x = camera_radius*float(cos(20.0f*deg2rad))*float(cos(0.5235*deg2rad)); 
    float cam_y = camera_radius*float(sin(20.f*deg2rad))*float(cos(0.5235*deg2rad)); 
    float cam_z = camera_radius*float(sin(0.5235*deg2rad)); 

    glMatrixMode(GL_PROJECTION); 
    glLoadIdentity(); 
    gluPerspective(90, ratio, 0.01, 10000); 
    glMatrixMode(GL_MODELVIEW); 
    glLoadIdentity(); 
    gluLookAt(cam_x, cam_y, cam_z, 0, 0, 0, 0, 0, 1); 

    // sphere 
    glPushMatrix(); 
    glColor3ub(255, 0, 0); 
    glTranslated(
     0, 
     0, 
     0); 
    glutSolidSphere(1, 20, 20); 
    glPopMatrix(); 

    draw_button(button1); 

    glFlush(); 
    glutSwapBuffers(); 
} 

void timer_event(int value) 
{ 
    glutPostRedisplay(); 
    glutTimerFunc(100, timer_event, value); 
} 

int main(int argc, char *argv[]) 
{ 
    glutInit(&argc, argv); 
    glutSetOption(GLUT_MULTISAMPLE, 8); 
    glutInitDisplayMode(GLUT_RGBA | GLUT_DEPTH | GLUT_DOUBLE | GLUT_MULTISAMPLE); 

    glutTimerFunc(30, timer_event, 1); 
    glutInitWindowSize(w_width, w_height); 
    glutInitWindowPosition(10, 10); 
    glutCreateWindow(argv[0]); 
    glutSetWindowTitle(w_title.c_str()); 
    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA); 
    glEnable(GL_BLEND); 


    glutDisplayFunc(display); 

    glutSetOption(GLUT_ACTION_ON_WINDOW_CLOSE, 
     GLUT_ACTION_GLUTMAINLOOP_RETURNS); 

    glEnable(GL_COLOR_MATERIAL); 
    glEnable(GL_TEXTURE_2D); 
    button1 = SDL_LoadBMP("src/up.bmp"); 
    if (button1 == NULL) 
    { 
     cout << "Image not found" << endl; 
     exit(1); 
    } 
    glutMainLoop(); 

    SDL_FreeSurface(button1); 

    return 0; 
} 

Answer 1

Hier ist ein minimales Beispiel, das ich mit oben kommen kann:

#define SDL_MAIN_HANDLED 

#include <math.h> 
#include <SDL.h> 
#include <iostream> 
#include <GL/gl.h> 
#include <GL/freeglut.h> 

using namespace std; 

int w_width = 800; 
int w_height = 500; 
string w_title = "Model viewer"; 
float line_width = 2.0f; 
float camera_radius = 100.0f; 
float axis_size = 20.0; 

SDL_Surface* button1; 
GLuint TextureID; 


static void prepare_texture(SDL_Surface *button) 
{ 
    glGenTextures(1, &TextureID); 
    glBindTexture(GL_TEXTURE_2D, TextureID); 
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_NEAREST); 
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR); 

    // convert surface to RGB8 
    SDL_Surface *rgb = SDL_CreateRGBSurface(0, button->w, button->h, 24, 0xff, 0xff00, 0xff0000, 0); 
    SDL_BlitSurface(button, NULL, rgb, NULL); 

    gluBuild2DMipmaps(GL_TEXTURE_2D, 3, button->w, button->h, GL_RGB, GL_UNSIGNED_BYTE, rgb->pixels); 

    SDL_FreeSurface(rgb); 
} 

static void draw_button() 
{ 
    glMatrixMode(GL_PROJECTION); 
    glLoadIdentity(); 
    glMatrixMode(GL_MODELVIEW); 
    glLoadIdentity(); 
    glColor4f(1.0f, 1.0f, 1.0f, 1.0f); 
    glBindTexture(GL_TEXTURE_2D, TextureID); 
    glBegin(GL_QUADS); 
     glTexCoord2f(0.0f, 1.0f); 
     glVertex2f(0.1f, 0.1f); 
     glTexCoord2f(0.0f, 0.0f); 
     glVertex2f(0.1f, 0.2f); 
     glTexCoord2f(1.0f, 0.0f); 
     glVertex2f(0.2f, 0.2f); 
     glTexCoord2f(1.0f, 1.0f); 
     glVertex2f(0.2f, 0.1f); 
    glEnd(); 
} 

void display() 
{ 
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); 
    glClearColor(1.0f, 1.0f, 1.0f, 1.0f); 

    const float ratio = (float)glutGet(GLUT_SCREEN_WIDTH)/(float)glutGet(GLUT_SCREEN_HEIGHT); 
    static double t = 0.0; 
    const float deg2rad = 3.1415926f/180.0f; 
    float cam_x = camera_radius*float(cos(20.0f*deg2rad))*float(cos(0.5235*deg2rad)); 
    float cam_y = camera_radius*float(sin(20.f*deg2rad))*float(cos(0.5235*deg2rad)); 
    float cam_z = camera_radius*float(sin(0.5235*deg2rad)); 

    glMatrixMode(GL_PROJECTION); 
    glLoadIdentity(); 
    gluPerspective(90, ratio, 0.01, 10000); 
    glMatrixMode(GL_MODELVIEW); 
    glLoadIdentity(); 
    gluLookAt(cam_x, cam_y, cam_z, 0, 0, 0, 0, 0, 1); 

    // sphere 
    glPushMatrix(); 
    glColor3ub(255, 0, 0); 
    glTranslated(
      0, 
      0, 
      0); 
    glutSolidSphere(1, 20, 20); 
    glPopMatrix(); 

    draw_button(); 

    glFlush(); 
    glutSwapBuffers(); 
} 

void timer_event(int value) 
{ 
    glutPostRedisplay(); 
    glutTimerFunc(100, timer_event, value); 
} 

int main(int argc, char *argv[]) 
{ 
    glutInit(&argc, argv); 
    glutSetOption(GLUT_MULTISAMPLE, 8); 
    glutInitDisplayMode(GLUT_RGBA | GLUT_DEPTH | GLUT_DOUBLE | GLUT_MULTISAMPLE); 

    glutTimerFunc(30, timer_event, 1); 
    glutInitWindowSize(w_width, w_height); 
    glutInitWindowPosition(10, 10); 
    glutCreateWindow(argv[0]); 
    glutSetWindowTitle(w_title.c_str()); 
    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA); 
    glEnable(GL_BLEND); 


    glutDisplayFunc(display); 

    glutSetOption(GLUT_ACTION_ON_WINDOW_CLOSE, 
      GLUT_ACTION_GLUTMAINLOOP_RETURNS); 

    glEnable(GL_COLOR_MATERIAL); 
    glEnable(GL_TEXTURE_2D); 
    button1 = SDL_LoadBMP("up.bmp"); 
    if (button1 == NULL) 
    { 
     cout << "Image not found" << endl; 
     exit(1); 
    } 

    prepare_texture(button1); 
    SDL_FreeSurface(button1); 

    glutMainLoop(); 

    return 0; 
} 

Hinweis Identität Projektion, die auf Bildschirm abbildet [-1,1] Bereich; Vielleicht möchten Sie etwas mehr wie gluOrtho2D.