我应该如何在这个房间里创建一个新对象 - opengl [英] How should I create a new object in this room- opengl
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问题描述
我是 opengl 的新手！我从一些示例代码开始，并尝试在其上添加新对象.但我不确定该怎么做.有谁能教教我吗?我想在这里我只有一个矩阵来生成框.但是我怎样才能在这个环境中创建其他对象呢?谢谢
I am new to opengl! I started with some sample code and trying to add new object on it. But I am not sure the way to do. Can anyone teach me? I think here I just having a matrix to generate boxes. But how can I create other object inside this environment? Thanks
#include <string>
#include <cmath>
#include <GL/glut.h>
#include <SDL/SDL.h>
#include <SDL/SDL_opengl.h>
#include <SDL/SDL_image.h>
#define PI 3.141592653589793
unsigned Textures[3];
unsigned BoxList(0);
double X(0.0), Y(0.0), Z(0.0);
double ViewAngleHor(0.0), ViewAngleVer(0.0);
inline double DegreeToRadian(double degrees)
{
return (degrees / 180.f * PI);
}
这里我想添加一个带灯光效果的茶壶，但是当我在 main 中调用 mydisplay() 时，它不起作用.
Here I want to add a teapot with lighting effect, but when I call the mydisplay() in main, it not working.
void init()
{
//light source
GLfloat light_position[] = { 0,50,-100,1 };
GLfloat ambient[] = { 0.2,0.2,0.2,1 };
GLfloat diffuse[] = { 0.8,0.8,0.8,1 };
GLfloat specular[] = { 1,0.6,0.6,1 };
glLightfv(GL_LIGHT1, GL_POSITION, light_position);
glLightfv(GL_LIGHT1, GL_AMBIENT, ambient);
glLightfv(GL_LIGHT1, GL_DIFFUSE, diffuse);
glLightfv(GL_LIGHT1, GL_SPECULAR, specular);
glEnable(GL_LIGHTING);
glEnable(GL_LIGHT1);
glClearColor(0.3, 0.4, 0.8, 0.1);
glShadeModel(GL_SMOOTH);
}
void mydisplay()
{
glClear(GL_COLOR_BUFFER_BIT);
GLfloat tp_ambient[] = { 0.05,0.05,0.05,1 };
GLfloat tp_diffuse[] = { 0.7,0.3,1,1 };
GLfloat tp_specular[] = { 0.6,0.6,0.6,1 };
glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT, tp_ambient);
glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, tp_diffuse);
glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, tp_specular);
glutSolidTeapot(0.2);
glFlush();
}
GLuint GrabTexObjFromFile(const std::string& fileName)
{
/* Use SDL_image to load the PNG image. */
SDL_Surface *Image = IMG_Load(fileName.c_str());
/* Image doesn't exist or failed loading? Return 0. */
if(!Image)
return 0;
unsigned Object(0);
/* Generate one texture (we're creating only one). */
glGenTextures(1, &Object);
/* Set that texture as current. */
glBindTexture(GL_TEXTURE_2D, Object);
/* You can use these values to specify mipmaps if you want to, such as 'GL_LINEAR_MIPMAP_LINEAR'. */
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
/* We're setting textures to be repeated here. */
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT); //NEW!
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT); //NEW!
/* Create the actual texture object. */
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, Image->w, Image->h, 0, GL_RGBA, GL_UNSIGNED_BYTE, Image->pixels);
/* Free the surface, we are finished with it. */
SDL_FreeSurface(Image);
return Object;
}
void CompileLists()
{
/* Let's generate a display list for a box. */
BoxList = glGenLists(1);
glNewList(BoxList, GL_COMPILE);
/*
* Render everything as you usually would, without texture binding. We're rendering the box from the
* '3D Objects' tutorial here.
*/
glBegin(GL_QUADS);
/* Front */
glTexCoord2d(0, 0); glVertex3d(400, 125, 0.4);
glTexCoord2d(1, 0); glVertex3d(750, 125, 0.4);
glTexCoord2d(1, 1); glVertex3d(750, 475, 0.4);
glTexCoord2d(0, 1); glVertex3d(400, 475, 0.4);
/* Left side */
glTexCoord2d(0, 0); glVertex3d(400, 125, -0.4);
glTexCoord2d(1, 0); glVertex3d(400, 125, 0.4);
glTexCoord2d(1, 1); glVertex3d(400, 475, 0.4);
glTexCoord2d(0, 1); glVertex3d(400, 475, -0.4);
/* Back */
glTexCoord2d(0, 0); glVertex3d(750, 125, -0.4);
glTexCoord2d(1, 0); glVertex3d(400, 125, -0.4);
glTexCoord2d(1, 1); glVertex3d(400, 475, -0.4);
glTexCoord2d(0, 1); glVertex3d(750, 475, -0.4);
/* Right side */
glTexCoord2d(0, 0); glVertex3d(750, 125, 0.4);
glTexCoord2d(1, 0); glVertex3d(750, 125, -0.4);
glTexCoord2d(1, 1); glVertex3d(750, 475, -0.4);
glTexCoord2d(0, 1); glVertex3d(750, 475, 0.4);
/* Top */
glTexCoord2d(0, 0); glVertex3d(400, 125, -0.4);
glTexCoord2d(1, 0); glVertex3d(750, 125, -0.4);
glTexCoord2d(1, 1); glVertex3d(750, 125, 0.4);
glTexCoord2d(0, 1); glVertex3d(400, 125, 0.4);
/* Bottom */
glTexCoord2d(0, 0); glVertex3d(400, 475, -0.4);
glTexCoord2d(1, 0); glVertex3d(750, 475, -0.4);
glTexCoord2d(1, 1); glVertex3d(750, 475, 0.4);
glTexCoord2d(0, 1); glVertex3d(400, 475, 0.4);
glEnd();
glEndList();
}
在这里我可以绘制墙"并插入 .png 以更改视图，但是当我尝试创建新对象时，颜色都被新对象覆盖....
Here I can draw the "wall" and insert the .png to change the view, but when I try to create a new object, the color are all covered by new object....
void DrawRoom()
{
static float WallTexWidth(0.f);
static float WallTexHeight(0.f);
static float FloorTexWidth(0.f);
static float FloorTexHeight(0.f);
static bool Once(false);
/* Perform this check only once. */
if(!Once)
{
/* Bind the wall texture. */
glBindTexture(GL_TEXTURE_2D, Textures[0]);
/* Retrieve the width and height of the current texture (can also be done up front with SDL and saved somewhere). */
glGetTexLevelParameterfv(GL_TEXTURE_2D, 0, GL_TEXTURE_WIDTH, &WallTexWidth);
glGetTexLevelParameterfv(GL_TEXTURE_2D, 0, GL_TEXTURE_HEIGHT, &WallTexHeight);
/* Bind the floor texture. */
glBindTexture(GL_TEXTURE_2D, Textures[1]);
/* Retrieve the width and height of the current texture (can also be done up front with SDL and saved somewhere). */
glGetTexLevelParameterfv(GL_TEXTURE_2D, 0, GL_TEXTURE_WIDTH, &FloorTexWidth);
glGetTexLevelParameterfv(GL_TEXTURE_2D, 0, GL_TEXTURE_HEIGHT, &FloorTexHeight);
Once = true;
}
glPushMatrix();
/* Move the world and rotate the view. */
glRotated(ViewAngleVer, 1, 0, 0);
glRotated(ViewAngleHor, 0, 1, 0);
glTranslated(-X, -Y, -Z);
/* Set the coordinate system. */
glOrtho(0, 800, 600, 0, -1, 1);
/* Draw walls. */
glBindTexture(GL_TEXTURE_2D, Textures[0]);
glBegin(GL_QUADS);
/* Wall in front of you when the app starts. */
glTexCoord2f(0, 0);
glVertex3d(-200, 0, 4.0);
glTexCoord2f(1200.f / WallTexWidth, 0);
glVertex3d(1000, 0, 4.0);
glTexCoord2f(1200.f / WallTexWidth, 400.f / WallTexHeight);
glVertex3d(1000, 500, 4.0);
glTexCoord2f(0, 400.f / WallTexHeight);
glVertex3d(-200, 500, 4.0);
/* Wall left of you. */
glTexCoord2f(0, 0);
glVertex3d(-200, 0,-4.0);
glTexCoord2f(1200.f / WallTexWidth, 0);
glVertex3d(-200, 0, 4.0);
glTexCoord2f(1200.f / WallTexWidth, 400.f / WallTexHeight);
glVertex3d(-200, 500, 4.0);
glTexCoord2f(0, 400.f / WallTexHeight);
glVertex3d(-200, 500,-4.0);
/* Wall right of you. */
glTexCoord2f(0, 0);
glVertex3d(1000, 0, 4.0);
glTexCoord2f(1200.f / WallTexWidth, 0);
glVertex3d(1000, 0,-4.0);
glTexCoord2f(1200.f / WallTexWidth, 400.f / WallTexHeight);
glVertex3d(1000, 500,-4.0);
glTexCoord2f(0, 400.f / WallTexHeight);
glVertex3d(1000, 500, 4.0);
/* Wall behind you (you won't be able to see this just yet, but you will later). */
glTexCoord2f(0, 0);
glVertex3d(1000, 0,-4.0);
glTexCoord2f(1200.f / WallTexWidth, 0);
glVertex3d(-200, 0,-4.0);
glTexCoord2f(1200.f / WallTexWidth, 400.f / WallTexHeight);
glVertex3d(-200, 500,-4.0);
glTexCoord2f(0, 400.f / WallTexHeight);
glVertex3d(1000, 500,-4.0);
glEnd();
glBindTexture(GL_TEXTURE_2D, Textures[1]);
glBegin(GL_QUADS);
glTexCoord2f(0, 0);
glVertex3d(-200, 500, 4.0);
glTexCoord2f(1200.f / FloorTexWidth, 0);
glVertex3d(1000, 500, 4.0);
glTexCoord2f(1200.f / FloorTexWidth, (8.f / 2.f * 600.f) / FloorTexHeight);
glVertex3d(1000, 500,-4.0);
glTexCoord2f(0, (8.f / 2.f * 600.f) / FloorTexHeight);
glVertex3d(-200, 500,-4.0);
/* Ceiling. */
glTexCoord2f(0, 0);
glVertex3d(-200, 0, 4.0);
glTexCoord2f(1200.f / FloorTexWidth, 0);
glVertex3d(1000, 0, 4.0);
glTexCoord2f(1200.f / FloorTexWidth, (8.f / 2.f * 600.f) / FloorTexHeight);
glVertex3d(1000, 0,-4.0);
glTexCoord2f(0, (8.f / 2.f * 600.f) / FloorTexHeight);
glVertex3d(-200, 0,-4.0);
glEnd();
/* Now we're going to render some boxes using display lists. */
glPushMatrix();
/* Let's make it a bit smaller... */
glScaled(0.5, 0.4, 0.5);
glBindTexture(GL_TEXTURE_2D, Textures[2]);
/*
* Because display lists have preset coordinates, we'll need to translate it to move it around. Note that we're
* moving the small version of the cube around, not the big version (because we scaled *before* translating).
*/
glTranslated(-700, 750, 6);
/*
* Let's draw a whole lot of boxes. Note that because we're not pushing and popping matrices, translations
* and changes will 'accumulate' and add to the previous translation.
*/
for(short i(0); i < 12; ++i)
{
glTranslated(350, 0, 0);
/* These make sure that every once in a while, a new row is started. */
if(i == 5) glTranslated(-1575, -350, 0);
if(i == 9) glTranslated(-1225, -350, 0);
/*
* glCallList is all that is really needed to execute the display list. Remember to try the 'K' button
* to turn on wireframe mode, with these extra polygons, it looks pretty neat!
*/
glCallList(BoxList);
}
glPopMatrix();
glPopMatrix();
}
这里是主要的，如果我在glPopMatrix();之后直接调用mydisplay()，程序溢出并停止运行......
Here is the main, if I direct call the mydisplay() after glPopMatrix();, the program overflowed and stop running...
int main(int argc, char **argv)
{
/* Initialize SDL and set up a window. */
SDL_Init(SDL_INIT_VIDEO);
SDL_GL_SetAttribute(SDL_GL_RED_SIZE, 8);
SDL_GL_SetAttribute(SDL_GL_GREEN_SIZE, 8);
SDL_GL_SetAttribute(SDL_GL_BLUE_SIZE, 8);
SDL_GL_SetAttribute(SDL_GL_ALPHA_SIZE, 8);
SDL_GL_SetAttribute(SDL_GL_BUFFER_SIZE, 32);
SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 16);
SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
SDL_WM_SetCaption("OpenGL - Display Lists", 0);
SDL_WM_GrabInput(SDL_GRAB_ON);
SDL_ShowCursor(SDL_DISABLE);
SDL_SetVideoMode(800, 600, 32, SDL_OPENGL);
/* Basic OpenGL initialization, handled in 'The Screen'. */
glShadeModel(GL_SMOOTH);
glClearColor(0, 0, 0, 1);
glViewport(0, 0, 800, 600);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
gluPerspective(80.0, 800.0/600.0, 0.1, 100.0);
/* We now switch to the modelview matrix. */
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
glEnable(GL_DEPTH_TEST);
glDepthFunc(GL_LEQUAL);
glHint(GL_PERSPECTIVE_CORRECTION_HINT, GL_NICEST);
/* Enable 2D texturing. */
glEnable(GL_TEXTURE_2D);
/* Set up alpha blending. */
glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glColor4d(1, 1, 1, 1);
Textures[0] = GrabTexObjFromFile("Data/Wall.png");
Textures[1] = GrabTexObjFromFile("Data/Floor.png");
Textures[2] = GrabTexObjFromFile("Data/Box.png");
//sizeof(Textures) is the size of the entire array in bytes (unsigned int = 4 bytes)
//so sizeof(Textures) would give 3 * 4 = 12 bytes, divide this by 4 bytes and you
//have 3.
for(unsigned i(0); i < sizeof(Textures) / sizeof(unsigned); ++i)
{
if(Textures[i] == 0)
{
#ifdef _WIN32
MessageBoxA(0, "Something went seriously wrong!", "Fatal Error!", MB_OK | MB_ICONERROR);
#endif //_WIN32
return 1;
}
}
/* Compile the display lists. */
CompileLists();
SDL_Event event;
int RelX(0), RelY(0);
int MovementDelay(SDL_GetTicks());
bool Wireframe(false);
bool Keys[4] =
{
false, /* Up arrow down? */
false, /* Down arrow down? */
false, /* Left arrow down? */
false /* Right arrow down? */
};
/* Application loop. */
for(;;)
{
/* Handle events with SDL. */
if(SDL_PollEvent(&event))
{
if(event.type == SDL_QUIT)
break;
/* Mouse events? */
else if(event.type == SDL_MOUSEMOTION)
{
/* Get the relative mouse movement of the mouse (based on CurMouseCoord - PrevMouseCoord). */
SDL_GetRelativeMouseState(&RelX, &RelY);
ViewAngleHor += RelX / 4;
ViewAngleVer += RelY / 4;
/* Prevent the horizontal angle from going over 360 degrees or below 0 degrees. */
if(ViewAngleHor >= 360.0) ViewAngleHor = 0.0;
else if(ViewAngleHor < 0.0) ViewAngleHor = 360.0;
/* Prevent the vertical view from moving too far (comment this out to get a funny effect). */
if(ViewAngleVer > 60.0) ViewAngleVer = 60.0; /* 60 degrees is when you're looking down. */
else if(ViewAngleVer < -60.0) ViewAngleVer = -60.0; /* This is when you're looking up. */
/* This delay might seem strange, but it helps smoothing out the mouse if you're experiencing jittering. */
SDL_Delay(5);
}
else if(event.type == SDL_KEYDOWN)
{
if(event.key.keysym.sym == SDLK_ESCAPE)
break;
if(event.key.keysym.sym == SDLK_k)
glPolygonMode(GL_FRONT_AND_BACK, ((Wireframe = !Wireframe)? GL_LINE : GL_FILL));
if(event.key.keysym.sym == SDLK_UP) Keys[0] = true;
if(event.key.keysym.sym == SDLK_DOWN) Keys[1] = true;
if(event.key.keysym.sym == SDLK_LEFT) Keys[2] = true;
if(event.key.keysym.sym == SDLK_RIGHT) Keys[3] = true;
}
else if(event.type == SDL_KEYUP)
{
if(event.key.keysym.sym == SDLK_UP) Keys[0] = false;
if(event.key.keysym.sym == SDLK_DOWN) Keys[1] = false;
if(event.key.keysym.sym == SDLK_LEFT) Keys[2] = false;
if(event.key.keysym.sym == SDLK_RIGHT) Keys[3] = false;
}
}
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glPushMatrix();
DrawRoom();
glPopMatrix();
/* Move if the keys are pressed, this is explained in the tutorial. */
if(Keys[0])
{
X -= cos(DegreeToRadian(ViewAngleHor + 90.0)) * 0.005;
Z -= sin(DegreeToRadian(ViewAngleHor + 90.0)) * 0.005;
}
if(Keys[1])
{
X += cos(DegreeToRadian(ViewAngleHor + 90.0)) * 0.005;
Z += sin(DegreeToRadian(ViewAngleHor + 90.0)) * 0.005;
}
if(Keys[2])
{
X += cos(DegreeToRadian(ViewAngleHor + 180.0)) * 0.005;
Z += sin(DegreeToRadian(ViewAngleHor + 180.0)) * 0.005;
}
if(Keys[3])
{
X -= cos(DegreeToRadian(ViewAngleHor + 180.0)) * 0.005;
Z -= sin(DegreeToRadian(ViewAngleHor + 180.0)) * 0.005;
}
/* Swap the display buffers. */
SDL_GL_SwapBuffers();
}
/* Delete the created textures. */
glDeleteTextures(3, Textures); //Changed to 3.
glDeleteLists(BoxList, 1);
/* Clean up. */
SDL_Quit();
return 0;
}
推荐答案
您正在使用 SDL 库.但是 glutSolidTeapot 是 GLUT OpenGL Utility Toolkit 的一部分.这不会一起工作.
YOu are using the SDL library. But glutSolidTeapot is part of the GLUT OpenGL Utility Toolkit. That won't work together.
但是为了测试光照，您可以使用 gluSphere.在函数 mydisplay 中，您必须跳过 glClear 指令，该指令将清除整个视口.进一步的 glFlush 是没有用的.
But to test the lighting, you can draw a simple sphere with gluSphere.
In the function mydisplay you have to skip the glClear instruction, which would clear the entire viewport. Further glFlush is of useless.
我建议在设置正交投影后，在DrawRoom´函数中进行灯光的初始化(mydisplayinit).可以调用在DrawRoom`结尾处:
I recommend to do the initialization of the light (init) in the DrawRoom´ function, after the orthographic projection is set up.mydisplaycan be called at the end ofDrawRoom`:
void DrawRoom()
{
.....
glOrtho(0, 800, 600, 0, -1, 1);
init();
.....
mydisplay();
}
void mydisplay()
{
GLfloat tp_ambient[] = { 0.05,0.05,0.05,1 };
GLfloat tp_diffuse[] = { 0.7,0.3,1,1 };
GLfloat tp_specular[] = { 0.6,0.6,0.6,1 };
glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT, tp_ambient);
glMaterialfv(GL_FRONT_AND_BACK, GL_DIFFUSE, tp_diffuse);
glMaterialfv(GL_FRONT_AND_BACK, GL_SPECULAR, tp_specular);
glPushMatrix();
glTranslatef( 0.0f, 0.0f, -0.5f );
GLUquadricObj *quadric = gluNewQuadric();
gluSphere( quadric , 0.1, 16, 16 );
gluDeleteQuadric(quadric);
glPopMatrix();
}
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