opengl颜色与立方体不能正常工作
#include<stdio.h>
#include<stdlib.h>
#include<math.h>
#include<GL/glut.h>
double cameraAngle;
void grid_and_axes() {
// draw the three major AXES
glBegin(GL_LINES);
//X axis
glColor3f(0, 1, 0); //100% Green
glVertex3f(-150, 0, 0);
glVertex3f(150, 0, 0);
//Y axis
glColor3f(0, 0, 1); //100% Blue
glVertex3f(0, -150, 0); // intentionally extended to -150 to 150, no big deal
glVertex3f(0, 150, 0);
//Z axis
glColor3f(1, 1, 1); //100% White
glVertex3f(0, 0, -150);
glVertex3f(0, 0, 150);
glEnd();
//some gridlines along the field
int i;
glColor3f(0.5, 0.5, 0.5); //grey
glBegin(GL_LINES);
for (i = -10; i <= 10; i++) {
if (i == 0)
continue; //SKIP the MAIN axes
//lines parallel to Y-axis
glVertex3f(i * 10, -100, 0);
glVertex3f(i * 10, 100, 0);
//lines parallel to X-axis
glVertex3f(-100, i * 10, 0);
glVertex3f(100, i * 10, 0);
}
glEnd();
}
void display() {
//codes for Models, Camera
//clear the display
//glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
glClearColor(0, 0, 0, 0); //color black
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); //clear buffers to preset values
/***************************
/set-up camera (view) here
****************************/
//load the correct matrix -- MODEL-VIEW matrix
glMatrixMode(GL_MODELVIEW); //specify which matrix is the current matrix
//initialize the matrix
glLoadIdentity(); //replace the current matrix with the identity matrix [Diagonals have 1, others have 0]
//now give three info
//1. where is the camera (viewer)?
//2. where is the camera looking?
//3. Which direction is the camera's UP direction?
//gluLookAt(0,-150,20, 0,0,0, 0,0,1);
gluLookAt(150 * sin(cameraAngle), -150 * cos(cameraAngle), 50, 0, 0, 0, 0, 0, 1);
/*************************
/Grid and axes Lines
**************************/
grid_and_axes();
/****************************
/Add your objects from here
****************************/
/*glColor3f(1, 0, 0);
glutSolidCone(20, 20, 20, 20);
glColor3f(0, 0, 1);
GLUquadricObj *cyl = gluNewQuadric();
gluCylinder(cyl, 10, 10, 50, 20, 20);
glTranslatef(0, 0, 50);
glColor3f(1, 0, 0);
glutSolidCone(10, 20, 20, 20);
*/
glColor3f(1, 0, 0);
glutSolidCube(1);
我没有在这里得到任何立方体。
但是,如果我使用任何转换属性像缩放或旋转,然后我得到所需的立方体像
glColor3f(1,0,0);
glScalef(50,5,60);
glutSolidCube(1);
有什么问题? 如果我不使用像上面提到的转换属性,我面对的颜色的另一个问题不起作用。如果我写:
glColor3f(1,0,0);
glutSolidCone(20,20,20,20);
以上代码颜色不起作用;我得到默认的彩色圆锥
但是,如果我将这两行改为这3行,那么颜色完美:
glColor3f(1,0,0);
glTranslatef(0,0,50);
glutSolidCone(10,20,20,20);
然后颜色工程;问题是什么?请帮助opengl颜色与立方体不能正常工作
//ADD this line in the end --- if you use double buffer (i.e. GL_DOUBLE)
glutSwapBuffers();
}
void animate() {
//codes for any changes in Models, Camera
cameraAngle += 0.001; // camera will rotate at 0.002 radians per frame.
//codes for any changes in Models
//MISSING SOMETHING? -- YES: add the following
glutPostRedisplay(); //this will call the display AGAIN
}
void init() {
//codes for initialization
cameraAngle = 0; //angle in radian
//clear the screen
glClearColor(0, 0, 0, 0);
/************************
/set-up projection here
************************/
//load the PROJECTION matrix
glMatrixMode(GL_PROJECTION);
//initialize the matrix
glLoadIdentity();
/*
gluPerspective() — set up a perspective projection matrix
fovy - Specifies the field of view angle, in degrees, in the y direction.
aspect ratio - Specifies the aspect ratio that determines the field of view in the x direction. The aspect ratio is the ratio of x (width) to y (height).
zNear - Specifies the distance from the viewer to the near clipping plane (always positive).
zFar - Specifies the distance from the viewer to the far clipping plane (always positive).
*/
gluPerspective(70, 1, 0.1, 10000.0);
}
int main(int argc, char **argv) {
glutInit(&argc, argv); //initialize the GLUT library
glutInitWindowSize(500, 500);
glutInitWindowPosition(100, 100);
/* glutInitDisplayMode - inits显示模式 GLUT_DOUBLE - 允许双缓冲窗口上显示 GLUT_RGBA - 显示颜色(红,绿,蓝)和阿尔法 GLUT_DEPTH - 允许深度缓冲区 */ glutInitDisplayMode(GLUT_DEPTH | GLUT_DOUBLE | GLUT_RGB);
glutCreateWindow("Some Title");
init(); //codes for initialization
glEnable(GL_DEPTH_TEST); //enable Depth Testing
glutDisplayFunc(display); //display callback function
glutIdleFunc(animate); //what you want to do in the idle time (when no drawing is occuring)
glutMainLoop(); //The main loop of OpenGL
return 0;
}
我没有在这里得到任何立方体。
你做得到一个立方体。这只是轴线相交处的小斑点。当你绘制2个大单位,约160个单位,70度视场时,你还会期望看到什么?
如果我不使用像上面提到的转换属性,我面临的另一个问题是颜色不起作用。 [...]我得到了默认的彩色锥体。
我不知道你甚至指的是什么。 “默认颜色”将是GL内置颜色属性的初始值 - 即(1, 1, 1, 1)
- 白色。随着您设置的代码,您将获得您之前设置的颜色。所以我唯一可以猜测的是你没有把GL的状态机考虑在内,让你感到困惑。
但是,除了这一切,你不应该使用这些代码在所有 - 这是使用固定功能管线和直接模式绘图 - 这是过时因为十年了功能,并没有被现代支持可言核心配置文件的OpenGL。试图在2017年学习这些东西是浪费时间。和BTW:
glutMainLoop(); //The main loop of OpenGL
都能跟得上。只是不!。 OpenGL没有“主循环”。 GLUT不是OpenGL。老实说,这一切都很糟糕。
我还没有看过你的问题,但请使用现代的OpenGL。那里有很多老的教程。 https://learnopengl.com是我见过的最好的网站之一。 –