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texture.cpp
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texture.cpp
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#include "texture.h"
// reference code: https://github.com/vivek2612/Human-Model-OpenGL/blob/master/src/tex.cpp
GLuint Texture::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;
// Open the file
FILE * file = fopen(imagepath, "rb");
if (!file) {
printf("Image could not be opened\n");
return 0;
}
if (fread(header, 1, 54, file) != 54) { // If not 54 bytes read : problem
printf("Not a correct BMP file\n");
return false;
}
if (header[0] != 'B' || header[1] != 'M') {
printf("Not a correct BMP file\n");
return 0;
}
// Read ints from the byte array
dataPos = *(int*)&(header[0x0A]);
imageSize = *(int*)&(header[0x22]);
width = *(int*)&(header[0x12]);
height = *(int*)&(header[0x16]);
// Some BMP files are misformatted, guess missing information
if (imageSize == 0) imageSize = width*height * 3; // 3 : one byte for each Red, Green and Blue component
if (dataPos == 0) dataPos = 54; // The BMP header is done that way
// Create a buffer
data = new unsigned char[imageSize];
// Read the actual data from the file into the buffer
fread(data, 1, imageSize, file);
//Everything is in memory now, the file can be closed
fclose(file);
// Create one OpenGL texture
GLuint textureID;
glGenTextures(1, &textureID);
// "Bind" the newly created texture : all future texture functions will modify this texture
glBindTexture(GL_TEXTURE_2D, textureID);
// Give the image to OpenGL
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, data);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
return textureID;
}