Texture Map shows all white in the cube not the pictures

**christina123y** · 08-25-2010

Hi, everyone! I'm a newer to OpenGL. I need to paint BMP format pictures to a cube with texture map. I read as BMP format, and the texture map process was correct. I have use VS debugger and seems that the value were all right, however, the whole cube was all white. I have asked others to help me, they said that the process was right, but still couldn't found the resolution. Wish you can help me!
Thank for any help! Wish your reply soon!
Here is my code.

Code:

#include "stdafx.h"

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <GL/glut.h>
#include <GL/GLAux.h>

GLuint textureid[6];
static GLfloat theta[] = {0.0,0.0,0.0};
static GLint axis = 2;

// 'LoadDIBitmap()' - Load a DIB/BMP file from disk.
// Returns a pointer to the bitmap if successful, NULL otherwise...
GLubyte *LoadDIBitmap(const char *filename, BITMAPINFO **info)
{
	FILE *fp;                    // Open file pointer
	BITMAPFILEHEADER header;    
	DWORD infosize;              // Size of header information
	DWORD bitsize;               // Size of bitmap
	GLubyte *bits;               // Bitmap pixel bits
	GLubyte *ptr;                // Pointer into bitmap 
	GLubyte temp;                // Temporary variable to swap red and blue
	int x, y;                    // X and Y position in image
	int length;               

	// Try opening the file; use "rb" mode to read this *binary* file.
	if ((fp = fopen(filename, "rb")) == NULL)
	{   
		// Couldn't read the file header
		printf("Couldn't read the file header!\n");
		return NULL;
	}

	// Read the file header and any following bitmap information
	if (fread(&header, sizeof(BITMAPFILEHEADER), 1, fp) < 1)
	{
		// Couldn't read the file header
		printf("Couldn't read the file header!\n");
		fclose(fp);
		return NULL;
	}

	// Check for BM reversed
	if (header.bfType != 'MB')
	{
		printf("Not a bitmap file!\n");
		fclose(fp);
		return NULL;
	}

		infosize = header.bfOffBits - sizeof(BITMAPFILEHEADER);  
	if ((*info = (BITMAPINFO *)malloc(infosize)) == NULL)
	{
		// Couldn't allocate memory for bitmap info
		printf("Couldn't allocate memory for bitmap info!\n");
		fclose(fp);
		return NULL;
	}

	if (fread(*info, 1, infosize, fp) < infosize)
	{
		// Couldn't read the bitmap header
		printf("Couldn't read the bitmap header!\n");
		free(*info);
		fclose(fp);
		return NULL;
	}

	// Now that we have all the header info read in, allocate memory for the bitmap and read *it* in
	if ((bitsize = (*info)->bmiHeader.biSizeImage) == 0)
	{
		bitsize = ((*info)->bmiHeader.biWidth * abs((*info)->bmiHeader.biHeight) *
			(*info)->bmiHeader.biBitCount) / 8;
	}

	if ((bits = (GLubyte *)malloc(bitsize)) == NULL)
	{
		// Couldn't allocate memory 
		printf("Couldn't allocate memory !\n");
		free(*info);
		fclose(fp);
		return NULL;
	}

	if (fread(bits, 1, bitsize, fp) < bitsize)
	{
		// Couldn't read bitmap - free memory and return NULL!
		printf("Couldn't read bitmap\n");
		free(*info);
		free(bits);
		fclose(fp);
		return NULL;
	}


	length = ((*info)->bmiHeader.biWidth * 3 + 3) & ~3;
	for (y = 0; y < (*info)->bmiHeader.biHeight; y++)
		for (x = 0, ptr = bits + y * length; x < (*info)->bmiHeader.biWidth; x++, ptr += 3)
		{
			temp = ptr[0];
			ptr[0] = ptr[2];
			ptr[2] = temp;
		}

		// OK, everything went fine - return the allocated bitmap.
		fclose(fp);
		return bits;
}



int LoadGLTextures()   
{
	int Status = 0;        

	GLubyte *TextureImage[6];     
                TextureImage[0] = (GLubyte*)malloc(sizeof(void*));
	TextureImage[1] = (GLubyte*)malloc(sizeof(void*));
	TextureImage[2] = (GLubyte*)malloc(sizeof(void*));
	TextureImage[3] = (GLubyte*)malloc(sizeof(void*));
	TextureImage[4] = (GLubyte*)malloc(sizeof(void*));
	TextureImage[5] = (GLubyte*)malloc(sizeof(void*));
	memset(TextureImage,0,sizeof(void *)*6);   
	char *pictures[] = 
                { 		
                     "E:/TestProject/MyTexture/rec/1.bmp", 
		"E:/TestProject/MyTexture/rec/2.bmp", 
		"E:/TestProject/MyTexture/rec/3.bmp",  
		"E:/TestProject/MyTexture/rec/4.bmp", 
		"E:/TestProject/MyTexture/rec/5.bmp", 
		"E:/TestProject/MyTexture/rec/6.bmp"
	};
	glGenTextures(6, &textureid[0]);    
	for(int i=0; i<6; i++) 
	{
		BITMAPINFO *BitmapInfo;
		if (TextureImage[i] = LoadDIBitmap(pictures[i], &BitmapInfo)) 
		{
			Status = 1;        

			glBindTexture(GL_TEXTURE_2D, textureid[i]); 
			glTexImage2D(GL_TEXTURE_2D, 0, 3, BitmapInfo->bmiHeader.biWidth, BitmapInfo->bmiHeader.biHeight, 0, GL_RGB, GL_UNSIGNED_BYTE, TextureImage[i]);
			glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
			glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
		}
	}
	
	for(int i=0;i<6;i++)
	{
		if(TextureImage[i])
		{
			free(TextureImage[i]);    
		}
	}
	return Status;          
}

void DrawGLScene(GLvoid)         
{
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); 
	glEnable(GL_DEPTH_TEST);
	glEnable(GL_TEXTURE_2D);
   glTexEnvf(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_DECAL);

	glLoadIdentity();         
	glTranslatef(0.0f,0.0f,-5.0f);

	glRotatef(theta[0],1.0f,0.0f,0.0f);
	glRotatef(theta[1],0.0f,1.0f,0.0f);
	glRotatef(theta[2],0.0f,0.0f,1.0f);

	// Front Face
	glBindTexture(GL_TEXTURE_2D, textureid[0]); 
	glBegin(GL_QUADS);
	glTexCoord2f(0.0f, 0.0f); glVertex3f(-1.0f, -1.0f, 1.0f);
	glTexCoord2f(1.0f, 0.0f); glVertex3f( 1.0f, -1.0f, 1.0f);
	glTexCoord2f(1.0f, 1.0f); glVertex3f( 1.0f, 1.0f, 1.0f);
	glTexCoord2f(0.0f, 1.0f); glVertex3f(-1.0f, 1.0f, 1.0f);
	glEnd();

	// Back Face
	glBindTexture(GL_TEXTURE_2D, textureid[1]); 
	glBegin(GL_QUADS);
	glTexCoord2f(1.0f, 0.0f); glVertex3f(-1.0f, -1.0f, -1.0f);
	glTexCoord2f(1.0f, 1.0f); glVertex3f(-1.0f, 1.0f, -1.0f);
	glTexCoord2f(0.0f, 1.0f); glVertex3f( 1.0f, 1.0f, -1.0f);
	glTexCoord2f(0.0f, 0.0f); glVertex3f( 1.0f, -1.0f, -1.0f);
	glEnd();

	// Top Face
	glBindTexture(GL_TEXTURE_2D, textureid[2]); 
	glBegin(GL_QUADS);
	glTexCoord2f(0.0f, 1.0f); glVertex3f(-1.0f, 1.0f, -1.0f);
	glTexCoord2f(0.0f, 0.0f); glVertex3f(-1.0f, 1.0f, 1.0f);
	glTexCoord2f(1.0f, 0.0f); glVertex3f( 1.0f, 1.0f, 1.0f);
	glTexCoord2f(1.0f, 1.0f); glVertex3f( 1.0f, 1.0f, -1.0f);
	glEnd();

	// Bottom Face
	glBindTexture(GL_TEXTURE_2D, textureid[3]); 
	glBegin(GL_QUADS);
	glTexCoord2f(1.0f, 1.0f); glVertex3f(-1.0f, -1.0f, -1.0f);
	glTexCoord2f(0.0f, 1.0f); glVertex3f( 1.0f, -1.0f, -1.0f);
	glTexCoord2f(0.0f, 0.0f); glVertex3f( 1.0f, -1.0f, 1.0f);
	glTexCoord2f(1.0f, 0.0f); glVertex3f(-1.0f, -1.0f, 1.0f);
	glEnd();

	// Right face
	glBindTexture(GL_TEXTURE_2D, textureid[4]);
	glBegin(GL_QUADS);
	glTexCoord2f(1.0f, 0.0f); glVertex3f( 1.0f, -1.0f, -1.0f);
	glTexCoord2f(1.0f, 1.0f); glVertex3f( 1.0f, 1.0f, -1.0f);
	glTexCoord2f(0.0f, 1.0f); glVertex3f( 1.0f, 1.0f, 1.0f);
	glTexCoord2f(0.0f, 0.0f); glVertex3f( 1.0f, -1.0f, 1.0f);
	glEnd();

	// Left Face
	glBindTexture(GL_TEXTURE_2D, textureid[5]); 
	glBegin(GL_QUADS);
	glTexCoord2f(0.0f, 0.0f); glVertex3f(-1.0f, -1.0f, -1.0f);
	glTexCoord2f(1.0f, 0.0f); glVertex3f(-1.0f, -1.0f, 1.0f);
	glTexCoord2f(1.0f, 1.0f); glVertex3f(-1.0f, 1.0f, 1.0f);
	glTexCoord2f(0.0f, 1.0f); glVertex3f(-1.0f, 1.0f, -1.0f);
	glEnd();
	//glFlush();
	glutSwapBuffers();
	glDisable(GL_TEXTURE_2D); 

}

void spinCube()
{
	theta[axis] += 0.1;
	if( theta[axis] > 360.0 ) theta[axis] -= 360.0;

	glutPostRedisplay();
}


void init(void)
{    
	LoadGLTextures();
	glClearColor (0.0, 0.0, 0.0, 0.0);
	glClearDepth(1.0);

	glShadeModel(GL_FLAT);
	glEnable(GL_DEPTH_TEST);
	glEnable(GL_TEXTURE_2D);
}

void mouse(int btn, int state, int x, int y)
{
	if(btn==GLUT_LEFT_BUTTON && state == GLUT_DOWN) axis = 0;
	if(btn==GLUT_MIDDLE_BUTTON && state == GLUT_DOWN) axis = 1;
	if(btn==GLUT_RIGHT_BUTTON && state == GLUT_DOWN) axis = 2;
}

void reshape(int w, int h)
{
	glViewport(0, 0, (GLsizei) w, (GLsizei) h);
	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	gluPerspective(60.0, (GLfloat) w/(GLfloat) h, 1.0, 30.0);
	glMatrixMode(GL_MODELVIEW);
	glLoadIdentity();
	glTranslatef(0.0, 0.0, -3.6);
}

void key(unsigned char k, int x, int y)
{
	if(k == '1') glutIdleFunc(spinCube);
	if(k == '2') glutIdleFunc(NULL);
}

int main(int argc, char** argv)
{
	glutInit(&argc, argv);
	glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
	glutInitWindowSize(800, 600);
	glutInitWindowPosition(100, 100);
	glutCreateWindow(argv[0]);
	init();
	glutDisplayFunc(DrawGLScene);
	glutIdleFunc(spinCube);
	glutMouseFunc(mouse);
	glutKeyboardFunc(key);

	glutReshapeFunc(reshape);
	glutMainLoop();
	return 0; 
}

**MWAAAHAAA** · 08-25-2010

A few things to check first:

* Make sure that the bitmaps you are loading are not all-white?
* You are assuming that your bitmap data consists of 3 component 24-bit RGB data, is this indeed the case?
* Make sure that glGetError() does not report an error.

These lines are fishy (actually, they are not doing what you intend them to do, go through them line by line with pen and paper and figure out why yourself):

Code:

        length = ((*info)->bmiHeader.biWidth * 3 + 3) & ~3;
        for (y = 0; y < (*info)->bmiHeader.biHeight; y++)
                for (x = 0, ptr = bits + y * length; x < (*info)->bmiHeader.biWidth; x++, ptr += 3)
                {
                        temp = ptr[0];
                        ptr[0] = ptr[2];
                        ptr[2] = temp;
                }

If you want to loop through all pixels in your buffer, why not just do so, instead of using unnecessarily fancy code:

Code:

ptr = bits;
for(i = 0; i < width * height; ++i) 
{ 
     swap_rgb(ptr); 
     ptr+= 3;
}

Upon further inspection the following is strange too:

Code:

GLubyte *TextureImage[6];     
                TextureImage[0] = (GLubyte*)malloc(sizeof(void*));
        TextureImage[1] = (GLubyte*)malloc(sizeof(void*));
        TextureImage[2] = (GLubyte*)malloc(sizeof(void*));
        TextureImage[3] = (GLubyte*)malloc(sizeof(void*));
        TextureImage[4] = (GLubyte*)malloc(sizeof(void*));
        TextureImage[5] = (GLubyte*)malloc(sizeof(void*));
        memset(TextureImage,0,sizeof(void *)*6);

So you allocate space for 6 pointers, then immediately proceed to allocate space for exactly one pointer at the locations of these pointers, why? Further on, you then overwrite the allocated pointer:

Code:

if (TextureImage[i] = LoadDIBitmap(pictures[i], &BitmapInfo))

There you have something called a memory leak.

In attempting to fix your code do the following, which you should do whenever you encounter a problem (it's the application of what you could call a systematic approach to problem solving):
1. Make sure that your bitmap loading code actually does what it is supposed to do, i.e., load the bitmap, then write the data you just read back to a file and see if what you get back is the original image. If not, your code is obviously broken (which it is by the way).
2. Make sure that your renderer is actually working. Generate a simple texture (e.g. a 2 x 2 checkerboard pattern) and draw it onto a single quad. Then show the quad. If the textured quad is rendered correctly, your rendering code is OK.
3. Once you ascertained that you can both read the bitmap correctly, and draw a textured quad correctly, you can do the more fancy stuff you've been trying to do (load a fancy bitmap, use it to texture a rotating cube, ...)

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