I am working on an Environment Map for a skybox in OpenGL and have run into a problem with the textures. My code produces tiles of the texture that I am trying to map, rather than one big texture. The tiles have also lost most of their resolution and are very small.
Here is my code:
#include <windows.h>
#include <stdio.h>
#include <glew.h>
#include <glut.h>
#include "Camera.h"
Camera cam;
GLuint texture [6]; //the array for our texture
GLfloat angle = 0.0;
GLuint LoadTexture( const char * filename, int width, int height) {
GLuint texture;
unsigned char * data;
FILE* file;
file = fopen( filename, "rb" );
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 );
glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR );
glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR_MIPMAP_LINEAR );
glTexParameterf( GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT );
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;
// 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);
glLoadIdentity();
cam.camera();
//gluLookAt (20.0, 20.0, 20.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0);
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
glEnable(GL_TEXTURE_2D); //enable 2D texturing
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();
angle = angle + 0.5;
cam.incAngle();
}
void keyboard (unsigned char key, int x, int y) {
switch (key) {
case 'q': cam.lookUpwards(); break;
case 'z': cam.lookDownwards(); break;
case 'w': cam.slideForward(); break;
case 's': cam.slideBackward(); break;
case 'a': cam.strafeLeft(); break;
case 'd': cam.strafeRight(); break;
case 'e': exit(0); break;
default: break;
}
}
void reshape(int x, int y) {
cam.reshape(x, y);
}
void mouseMovement(int x, int y) {
cam.mouseMovement(x, y);
}
int main (int argc, char **argv) {
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_DOUBLE);
glutInitWindowSize(500, 500);
glutInitWindowPosition(100, 100);
glutCreateWindow("A basic OpenGL Window");
glutDisplayFunc(display);
glutIdleFunc(display);
glutReshapeFunc(reshape);
glutKeyboardFunc(keyboard);
glutPassiveMotionFunc(mouseMovement);
glutMainLoop();
}
