移動2D對象的位置openGL

我有一個對象在x軸上來回移動，但是我無法將它沿x軸進一步定位。移動2D對象的位置openGL

這是我的代碼，我該怎麼做？

float moveRad = 0.0; 
     moveRad = moveBee * (PI/180.0);  
     moveBee += 0.1; 

     glPushMatrix(); 
      glTranslatef(50.0 * sinf(moveRad), -100,0); 
      e[0] = new Platform(0, 0, 0, 40, 33, 40, 33, 00, textures[23], (50.0 * sinf(moveRad)), -100); 
     glPopMatrix();

Platform.cpp創建像這樣的對象：

glBegin(GL_QUADS); 
     glTexCoord2f(0.0, 0.0); glVertex2f(x1,y1); 
     glTexCoord2f(0.0, 1.0); glVertex2f(x2,y2); 
     glTexCoord2f(1.0, 1.0); glVertex2f(x3,y3); 
     glTexCoord2f(1.0, 0.0); glVertex2f(x4,y4); 
    glEnd();

來源

2011-03-10 user195257

你爲什麼不以您的來電glTranslatef調整x軸縮放？

glTranslatef(amplitude * sinf(moveRad), -100,0);

來源

2011-03-10 19:23:07

我有一種感覺，你不知道你的代碼到底在做什麼（糾正我，如果我錯了）。如果你想把它移到右邊，只需在這裏添加一個數字。（50.0 * sinf（moveRad）+ 30，-100,0）;以及其中，

如果有必要，我會更新我的答案。

來源

2011-03-10 19:23:52 Hannesh

我覺得你的問題是'50 .0 * SINF（moveRad）」 - 將oscilate嘗試-50到50之間增加一個值，而不是或者以及相乘。

來源

2011-03-10 19:24:12 Luther

我中有你從OpenGL的工作原理的誤解遭受的感覺。你寫了「Platform.cpp創建對象，就像這樣：」，然後在代碼片段中看到你正在創建一些被OpenGL矩陣堆棧操作包圍的Plattform類的實例。我懷疑你認爲OpenGL會以某種方式「存儲」這個「對象」。 這不是OpenGL的工作方式您正在考慮場景圖。 OpenGL不是一個場景圖。

OpenGL是一個繪圖API。電話

glBegin(GL_QUADS); 
    glTexCoord2f(0.0, 0.0); glVertex2f(x1,y1); 
    glTexCoord2f(0.0, 1.0); glVertex2f(x2,y2); 
    glTexCoord2f(1.0, 1.0); glVertex2f(x3,y3); 
    glTexCoord2f(1.0, 0.0); glVertex2f(x4,y4); 
glEnd();

在屏幕上繪製一個四元組。再次：他們畫它。在這些命令發佈後，它們被OpenGL遺忘了。 OpenGL轉換矩陣用於轉換繪圖命令的輸入數據。但再次沒有持久性。繪製命令必須爲繪製的每個幀發佈。我首先想到我可以重寫你的一些代碼，但是如果我可以這樣說的話，它需要重新編寫。

典型的OpenGL程序看起來像這樣（我慷慨忽略所有的類和類型的定義和期待一些常識解釋變量，成員和方法名）。

/* draw_scene is called on every iteration of the program main loop or 
    the drawing callback handler to update the screen */ 
void Scene::draw_scene(ScreenInfo si) 
{ 
    glViewport(si.viewport.x, si.viewport.y, si.viewport.width, si.viewport.height); 
    glClearColor(this->clear.r, this->clear.g, this->clear.b, this->clear.a); 
    glClearDepth(this->clear.d); 
    glColorMask(GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE); 
    glDepthMask(GL_TRUE); 
    glClear((this->clear.color ? GL_COLOR_BUFFER_BIT) | 
      (this->clear.depth ? GL_DEPTH_BUFFER_BTT)); 

    std::list<SceneObjects*> objects_by_distance = 
     sort_objects_by_direction(scene->objects, 
            scene->active_camera->position 
            scene->active_camera->direction); 

    SceneObjects *closest_object = objects_by_distance.front(); 
    SceneObjects *farthest_object = objects_by_distance.back(); 

    float near_clip = max(NEAR_CLIP_LIMIT, 
         length(closest_object->position - scene->active_camera->position) 
         - closest_object->bounding_sphere.radius); 

    float far_clip = min(FAR_CLIP_LIMIT, 
        length(farthest_object->position - scene->active_camera->position) 
        + farthest_object->bounding_sphere.radius); 

    glMatrixMode(GL_PROJECTION); 
    glLoadIdentity(); 
    switch(scene->projection.type) { 
    case Projection::perspective: { 
     gluPerspective(scene->projection.fov, 
         (float)si.viewport.width/(float)si.viewport.height, 
         near_clip, far_clip); 
    } break; 
    case Projection::orthographic: { 
     float aspect = (float)si.viewport.width/(float)si.viewport.height; 
     glOrtho(-0.5 * scene->projection.size * aspect, 0.5 * scene->projection.size * aspect 
       -0.5 * scene->projection.size   0.5 * scene->projection.size); 
    } break; 
    } 

    glMatrixMode(GL_MODELVIEW); 
    glLoadIdentity(); 
    /* I normally disregard using gluLookAt, but in this case I use it 
     to show as much as possible! */ 
    gluLookAt(scene->active_camera->position.x, scene->active_camera->position.y, scene->active_camera->position.z, 
       scene->active_camera->position.x + scene->active_camera->direction.x, 
       scene->active_camera->position.y + scene->active_camera->direction.y, 
       scene->active_camera->position.z + scene->active_camera->direction.z, 
       scene->active_camera->up.x, scene->active_camera->up.y, scene->active_camera->up.z); 

    for_each(scene->objects.begin(), scene->objects.end(), draw_object) 
} 

void draw_object(SceneObject *object) 
{ 
    glMatrixMode(GL_MODELVIEW); 
    glPushMatrix(); 

    glTranslatef(object->position.x, object->position.y, object->position.z); 
    glRotatef(object->rotation.axis.angle, object->rotation.axis.x, object->rotation.axis.y, object->rotation.axis.z); 

    GLfloat *(vertex_ptr[3][3]) = object->mesh->vertices; 
    GLuint *vertex_indices = object->mesh->face_vertex_indices; 
#ifdef USE_IMMEDIATE_MODE 
    glBegin(GL_TRIANGLES); 
    for(int i = 0; i < object->mesh->face_count; i++) { 
      glNormalfv(&vertex_ptr[vertex_indices[i]][0]); 
     glTexCoord3fv(&vertex_ptr[vertex_indices[i]][1]); 
      glVertex3fv(&vertex_ptr[vertex_indices[i]][2]); 

      glNormalfv(&vertex_ptr[vertex_indices[i+1]][0]); 
     glTexCoord3fv(&vertex_ptr[vertex_indices[i+1]][1]); 
      glVertex3fv(&vertex_ptr[vertex_indices[i+1]][2]); 

      glNormalfv(&vertex_ptr[vertex_indices[i+2]][0]); 
     glTexCoord3fv(&vertex_ptr[vertex_indices[i+2]][1]); 
      glVertex3fv(&vertex_ptr[vertex_indices[i+2]][2]); 
    } 
    glEnd(); 
#else 
    glEnableClientState(GL_NORMAL_ARRAY); 
    glEnableClientState(GL_TEXTURE_COORD_ARRAY); 
    glEnableClientState(GL_VERTEX_ARRAY); 

    /* This is direct vertex array mode. 
     A more modern approach is using Vertex Buffer Objects, which reused this 
     API, but adds further function calls. */ 
    glNormalPointer(GL_FLOAT, 3*3*sizeof(GLfloat), &vertex_ptr[0][0]); 
    glTexCoordPointer(3, GL_FLOAT, 3*3*sizeof(GLfloat), &vertex_ptr[0][1]); 
    glVertexPointer(3, GL_FLOAT, 3*3*sizeof(GLfloat), &vertex_ptr[0][2]); 

    glDrawElements(GL_TRIANGLES, object->mesh->face_count*3, GL_UNSIGNED_INT, vertex_indices); 
#endif 
    glPopMatrix(); 
}

這是認真使用OpenGL的最基本的方法。我詳細地寫了這篇文章，告訴你如何使用它以及它是如何工作的。

來源

2011-03-10 21:51:45 datenwolf

移動2D對象的位置openGL

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