OpenGL 深度测试不起作用

OpenGL depth test is not working

本文关键字:不起作用 深度测试 OpenGL      更新时间:2023-10-16

我正在尝试使用OpenGL创建一个模型,并尝试启用深度测试。

我在main中使用这些命令:

glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
glEnable(GL_DEPTH_TEST);

在我的显示器中:

glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

我什至尝试添加:

glDepthFunc(GL_LEQUAL);

而且它不起作用。我仍然可以看到我认为的深度问题。这是显示问题的视频:https://www.youtube.com/watch?v=OafrRH4Mzjc

  • 注意:在该视频中,电路板是从右到左,从上到下构建的,因此第一个角度是可以的,但任何其他角度都是不好的。

我错过了什么?


编辑:复制的最小示例文件:

#define _CRT_SECURE_NO_WARNINGS
#define SIZE_MOVES 17
#include <stdio.h>
/* Include the GLUT library. This file (glut.h) contains gl.h and glu.h */
#include <GLglew.h>
#include <GLfreeglut.h>
static int  left_click = GLUT_UP;
static int  right_click = GLUT_UP;
static int  xold;
static int  yold;
static float rotate_x = 146;
static float rotate_y = -26;
int width, height;
GLfloat light_ambient[] = { 0.0, 0.0, 0.0, 1.0 };
GLfloat light_diffuse[] = { 1.0, 1.0, 1.0, 1.0 };
GLfloat light_specular[] = { 1.0, 1.0, 1.0, 1.0 };
GLfloat light_position[] = { 0, 5, -10, 0 };
GLfloat mat_specular[] = { 0.3, 0.3, 0.3, 1.0 };
GLfloat mat_shininess[] = { 1 };

// colors
const GLfloat colors[2][4] = {
    { 1.0, 1.0, 1.0, 1.0 }, //white
    { 0.0, 0.0, 0.0, 1.0 } //black
};
// rgb
const GLfloat rgb[3][4] = {
    { 1.0, 0.0, 0.0, 1.0 },
    { 0.0, 1.0, 0.0, 1.0 },
    { 0.0, 0.0, 1.0, 1.0 }
};
void resetMaterial() {
    GLfloat c[] = { 1, 1, 1, 1 };
    glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, c);
    glMaterialfv(GL_FRONT, GL_SPECULAR, mat_specular);
    glMaterialfv(GL_FRONT, GL_SHININESS, mat_shininess);
}
void drawSquare(int color) {
    glPushMatrix(); {
        glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, colors[color]);
        glScalef(1, 0.5, 1);
        glutSolidCube(1);
    } glPopMatrix();
}
void drawBoard() {
    for (int i = 0; i < 8; i++)
        for (int j = 0; j < 8; j++) {
            glPushMatrix(); {
                glTranslatef(i + 0.5, 0, j + 0.5);
                drawSquare((i + j) % 2);
            } glPopMatrix();
        }
}
void drawAxes() {
    glBegin(GL_LINES); {
        glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, rgb[0]);
        glVertex3f(-2, 0, 0); glVertex3f(5, 0, 0);
        glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, rgb[1]);
        glVertex3f(0, -2, 0); glVertex3f(0, 5, 0);
        glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, rgb[2]);
        glVertex3f(0, 0, -2); glVertex3f(0, 0, 5);
    } glEnd();
}
void letThereBeLight() {
    /*Add ambient light*/
    GLfloat ambientLight[] = { 0.2f, 0.2f, 0.2f, 1.0f };
    glLightModelfv(GL_LIGHT_MODEL_AMBIENT, ambientLight);
    /*Add positioned light*/
    GLfloat lightColor1[] = { 0.2f, 0.2f, 0.1f, 1.0f };
    GLfloat lightPosition1[] = { -8, 8, 5, 0.0f };
    glLightfv(GL_LIGHT0, GL_SPECULAR, lightColor1);
    glLightfv(GL_LIGHT0, GL_POSITION, lightPosition1);
    /*Add directed light*/
    GLfloat lightColor2[] = { 0.3, 0.3, 0.3, 1.0f };
    GLfloat lightPosition2[] = { 8, 8, -5, 1.0f };
    glLightfv(GL_LIGHT1, GL_AMBIENT, lightColor2);
    glLightfv(GL_LIGHT1, GL_POSITION, lightPosition2);
}
void display(void) {
    // Clear frame buffer and depth buffer
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    // Set up viewing transformation, looking down -Z axis
    glLoadIdentity();
    gluLookAt(0, 5, -15, 0, 0, 3, 0, 1, 0);
    letThereBeLight();
    resetMaterial();
    // Rotate view:
    glPushMatrix(); {
        glRotatef(rotate_y, 1, 0, 0);
        glRotatef(rotate_x, 0, 1, 0);
        glLightfv(GL_LIGHT0, GL_POSITION, light_position);
        glMaterialfv(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE, colors[0]);
        glPushMatrix(); {
            glTranslatef(-4, 0, -4); // Move to center
            drawBoard();
        } glPopMatrix();
        drawAxes(); // For debuging
    } glPopMatrix();
    /* End */
    glFlush();
    glutSwapBuffers();
}
void mouseFunc(int button, int state, int x, int y) {
    if (GLUT_LEFT_BUTTON == button)
        left_click = state;
    xold = x;
    yold = y;
}
void motionFunc(int x, int y) {
    if (GLUT_DOWN == left_click) {
        rotate_y = rotate_y + (y - yold) / 5.f;
        rotate_x = rotate_x + (x - xold) / 5.f;
        glutPostRedisplay();
    }
    xold = x;
    yold = y;
}

void reshapeFunc(int new_width, int new_height) {
    width = new_width;
    height = new_height;
    glViewport(0, 0, width, height);
    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluPerspective(50, width / height, 1, 20);
    glMatrixMode(GL_MODELVIEW);
    glutPostRedisplay();
}
int main(int argc, char **argv) {
    /* Creation of the window */
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
    glutInitWindowSize(900, 600);
    glEnable(GL_DEPTH_TEST);
    glutCreateWindow("Chess");
    glEnable(GL_CULL_FACE);
    glCullFace(GL_BACK);
    glEnable(GL_POLYGON_SMOOTH);
    glEnable(GL_LINE_SMOOTH);
    glEnable(GL_LIGHTING);
    glEnable(GL_LIGHT0);
    glEnable(GL_LIGHT1);
    glShadeModel(GL_SMOOTH);
    glDisable(GL_COLOR_MATERIAL);
    glEnable(GL_BLEND);
    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
    /* Declaration of the callbacks */
    glutDisplayFunc(&display);
    glutReshapeFunc(&reshapeFunc);
    glutMouseFunc(&mouseFunc);
    glutMotionFunc(&motionFunc);
    /* Loop */
    glutMainLoop();
    /* Never reached */
    return 0;
}
gluPerspective(50, width / height, 0, 20);
                                   ^ wat

zNear需要大于零(强调我的):

深度缓冲区精度受为zNear指定的值的影响 和zFar. zFarzNear的比率越大,越小 有效的深度缓冲区将区分表面 彼此靠近。

如果r = zFar / zNear大量log2(r)深度缓冲区 精度会丢失。 由于 r 在 zNear 接近 0 时接近无穷大,因此 zNear 绝不能设置为 0。


编辑:鉴于新发布的MCVE:

int main(int argc, char **argv) {
    /* Creation of the window */
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_RGB | GLUT_DOUBLE | GLUT_DEPTH);
    glutInitWindowSize(900, 600);
    glEnable(GL_DEPTH_TEST);  // too soon
    glutCreateWindow("Chess");
    ...
}

就像 datenwolf 说的:在你拥有当前的 GL 上下文之前,你正在glEnable()glutCreateWindow()创建上下文并使其当前)。

glutCreateWindow()之后不要调用任何gl*()函数。

   public void onSurfaceChanged(int w, int h)
    {
        Matrix.frustumM(projectionMatrix,0,-(9f/18.5f),(9f/18.5f),-1f,1f,1.0f,1000f);
    }

我不得不将我的近剪裁形式 0.01f 更改为 1.0f。