BMP图像加载实例（C语言）

bmp图像常被称为位图，这实际是对位图的误解，具体可见opengl superbible中对图像的说明。

代码如下：

#include <stdio.h>
#include <stdlib.h>
#include <GL/glew.h>

#ifdef _APPLE_
#include <glut/glut.h>
#else
#define FREEGLUT_STATIC
#include <GL/glut.h>
#endif

GLuint loadBMP_custom(const char * imagepath);

// Data read from the header of the BMP file
unsigned char header[54]; // Each BMP file begins by a 54-bytes header

unsigned int dataPos; // Position in the file where the actual data begins

unsigned int width, height;

unsigned int imageSize; // = width*height*3
// Actual RGB data
unsigned char * data;

int main(int argc, char **argv)
{
	FILE * file = fopen("1.bmp", "rb");
	if (!file)
	{
			printf("Image could not be openedn"); 
			return 0;
	}

	if ( fread(header, 1, 54, file)!=54 )
	{ // If not 54 bytes read :problem
		printf("Not a correct BMP filen");
		return 0;
	}

	if ( header[0]!=‘B‘ || header[1]!=‘M‘ )
	{
		printf("Not a correct BMP filen");
		return 0;
	}

	// Read ints from the byte array
	dataPos = *(int*)&(header[0x0A]);
	imageSize = *(int*)&(header[0x22]);
	width = *(int*)&(header[0x12]);
	height = *(int*)&(header[0x16]);

	printf("%d \t %d \t %d \t %d \n", dataPos, imageSize, width, height);
	printf("%d \t %d \t %d \t %d \n", &(header[0x0A]),&(header[0x22]),&(header[0x12]), &(header[0x16]));
	printf("%d \t %d \t %d \t %d \n", &(header[0x0A]),&(header[0x22]),(int *)&(header[0x12]), &(header[0x16]));
	printf("%d\t %d\t",*(int*)&(header[0x12]), *(char*)&(header[0x16]));

	getchar();
	return 0;
}

测试结果如下：