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我試圖加載六張圖片作爲紋理並繪製天空盒，但結果很奇怪，每張圖片在其相應的矩形上以灰色映射三次。問題是什麼？我的代碼無法正確加載圖片到opengl
#include <stdlib.h>
#include <stdio.h>
#include <glut.h>
#include <gl.h>
#include <glu.h>
#include <math.h>
#include <windows.h>
GLuint texture [6]; //the array for our texture
void init(void)
{
glClearColor (0.0, 0.0, 0.0, 1.0);
glShadeModel (GL_SMOOTH);
glEnable(GL_LIGHTING);
glEnable(GL_LIGHT0);
glEnable(GL_DEPTH_TEST);
glEnable(GL_NORMALIZE);
glEnable(GL_TEXTURE_2D);
}
GLuint LoadTexture(const char * filename, int width, int height) {
GLuint texture;
unsigned char * data;
FILE* file;
file = fopen(filename, "r");
if (file == NULL) return 0;
data = (unsigned char *)malloc(width * height * 3);
fread(data, width * height * 3, 1, file);
fclose(file);
glGenTextures(1, &texture);
glBindTexture(GL_TEXTURE_2D, texture);
glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_DECAL);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_DECAL);
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); // texture should tile
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
gluBuild2DMipmaps(GL_TEXTURE_2D, 3, width, height, GL_RGB, GL_UNSIGNED_BYTE,data);
free(data);
return texture;
}
void FreeTexture(GLuint texture)
{
glDeleteTextures(1, &texture);
}
void skybox (void) {
float x = 0;
float y = 0;
float z = 0;
float width = 100;
float height = 100;
float length = 100;
glPushAttrib(GL_ENABLE_BIT);
glEnable(GL_TEXTURE_2D);
glDisable(GL_DEPTH_TEST);
glDisable(GL_LIGHTING);
glDisable(GL_BLEND);
// Bind the BACK texture of the sky map to the BACK side of the cube
glBindTexture(GL_TEXTURE_2D, texture[0]);
// Center the skybox
x = x - width/2;
y = y - height/2;
z = z - length/2;
glBegin(GL_QUADS);
glTexCoord2f(1.0f, 0.0f); glVertex3f(x + width, y, z);
glTexCoord2f(1.0f, 1.0f); glVertex3f(x + width, y + height, z);
glTexCoord2f(0.0f, 1.0f); glVertex3f(x, y + height, z);
glTexCoord2f(0.0f, 0.0f); glVertex3f(x, y, z);
glEnd();
glBindTexture(GL_TEXTURE_2D, texture[1]);
glBegin(GL_QUADS);
glTexCoord2f(1.0f, 0.0f); glVertex3f(x, y, z + length);
glTexCoord2f(1.0f, 1.0f); glVertex3f(x, y + height, z + length);
glTexCoord2f(0.0f, 1.0f); glVertex3f(x + width, y + height, z + length);
glTexCoord2f(0.0f, 0.0f); glVertex3f(x + width, y, z + length);
glEnd();
glBindTexture(GL_TEXTURE_2D, texture[4]);
glBegin(GL_QUADS);
glTexCoord2f(1.0f, 0.0f); glVertex3f(x, y, z);
glTexCoord2f(1.0f, 1.0f); glVertex3f(x, y, z + length);
glTexCoord2f(0.0f, 1.0f); glVertex3f(x + width, y, z + length);
glTexCoord2f(0.0f, 0.0f); glVertex3f(x + width, y, z);
glEnd();
glBindTexture(GL_TEXTURE_2D, texture[5]);
glBegin(GL_QUADS);
glTexCoord2f(0.0f, 0.0f); glVertex3f(x + width, y + height, z);
glTexCoord2f(1.0f, 0.0f); glVertex3f(x + width, y + height, z + length);
glTexCoord2f(1.0f, 1.0f); glVertex3f(x, y + height, z + length);
glTexCoord2f(0.0f, 1.0f); glVertex3f(x, y + height, z);
glEnd();
glBindTexture(GL_TEXTURE_2D, texture[2]);
glBegin(GL_QUADS);
glTexCoord2f(1.0f, 1.0f); glVertex3f(x, y + height, z);
glTexCoord2f(0.0f, 1.0f); glVertex3f(x, y + height, z + length);
glTexCoord2f(0.0f, 0.0f); glVertex3f(x, y, z + length);
glTexCoord2f(1.0f, 0.0f); glVertex3f(x, y, z);
glEnd();
glBindTexture(GL_TEXTURE_2D, texture[3]);
glBegin(GL_QUADS);
glTexCoord2f(0.0f, 0.0f); glVertex3f(x + width, y, z);
glTexCoord2f(1.0f, 0.0f); glVertex3f(x + width, y, z + length);
glTexCoord2f(1.0f, 1.0f); glVertex3f(x + width, y + height, z + length);
glTexCoord2f(0.0f, 1.0f); glVertex3f(x + width, y + height, z);
glEnd();
//glBindTexture(GL_TEXTURE_CUBE_MAP, texture[0]); //bind the texture
//glRotatef(angle, 1.0f, 1.0f, 1.0f);
//glutSolidSphere(2, 40, 40);
}
void display (void) {
glClearColor (0.0,0.0,0.0,1.0);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
GLfloat light_ambient[] = { 1.0, 1.0, 1.0, 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[] = { 0.0, 0.0, 30.0, 0.0 };
glLightfv(GL_LIGHT0, GL_AMBIENT, light_ambient);
glLightfv(GL_LIGHT0, GL_DIFFUSE, light_diffuse);
glLightfv(GL_LIGHT0, GL_SPECULAR, light_specular);
glLightfv(GL_LIGHT0, GL_POSITION, light_position);
glLoadIdentity();
glPushMatrix();
gluLookAt (20.0, 20.0, 20.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0);
glPushMatrix();
texture[0] = LoadTexture("back.bmp", 256, 256); //load the texture
texture[1] = LoadTexture("front.bmp", 256, 256); //load the texture
texture[2] = LoadTexture("left.bmp", 256, 256); //load the texture
texture[3] = LoadTexture("right.bmp", 256, 256); //load the texture
texture[4] = LoadTexture("bottom.bmp", 256, 256); //load the texture
texture[5] = LoadTexture("top.bmp", 256, 256); //load the texture
glPopMatrix();
glPopMatrix();
//glEnable(GL_TEXTURE_GEN_S); //enable texture coordinate generation
//glEnable(GL_TEXTURE_GEN_T);
skybox();
for (int i = 0; i < 6; i++) {
FreeTexture(texture[i]);
}
glutSwapBuffers();
}
void reshape (int w, int h)
{
glViewport (0, 0, (GLsizei) w, (GLsizei) h);
glMatrixMode (GL_PROJECTION);
glLoadIdentity();
glOrtho(-100.0, 100.0, -100.0, 100.0,-100.0,100.0);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
}
int main (int argc, char **argv) {
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_DOUBLE);
glutInitWindowSize(500, 500);
glutInitWindowPosition(100, 100);
glutCreateWindow("A basic OpenGL Window");
init();
glutDisplayFunc(display);
glutIdleFunc(display);
glutReshapeFunc(reshape);
glutMainLoop();
}
你是對的，datenwolf，我也嘗試nehe的代碼，它使用AUX_RGBImageRec，我的編譯器說'無法打開DIB文件'。但我是初學者，我不知道DIB解析器，有沒有例子？ – phil
嘗試使用類似['stb_image.c']（http://nothings.org/stb_image.c）。 – genpfault
@ phil：好的，有兩種方法可以解決您的問題。你自己編寫一個DIB解析器，遵循DIB文件格式規範http://en.wikipedia.org/wiki/BMP_file_format - 或者你可以使用一個圖像閱讀器庫（它也可以支持多種文件格式）。我個人很喜歡Imlib2 http://docs.enlightenment.org/api/imlib2/html/ – datenwolf