/** Dato il path, carica la texture e restituisce l'id */
unsigned GlCanvas::loadTexture(char *path)
{
/* Carica l'immagine png in memoria, usando la libreria pnglite */
png_t png;
unsigned int id;
png_init(malloc, free);
if(png_open_file_read(&png, path) != PNG_NO_ERROR)
return 0;
unsigned char *data = (unsigned char *) malloc(png.width * png.height * png.bpp);
png_get_data(&png, (unsigned char *) data);
/* Crea la texture in opengl */
glGenTextures(1, &id);
glBindTexture(GL_TEXTURE_2D, id);
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MIN_FILTER,GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D,GL_TEXTURE_MAG_FILTER,GL_LINEAR);
glTexImage2D(GL_TEXTURE_2D, 0, png.bpp, png.width, png.height, 0, GL_RGB, GL_UNSIGNED_BYTE, data);
/* Libera la risorsa png */
png_close_file(&png);
free(data);
/* Restituisce l'id della texture */
return id;
}
static void LoadTexture()
{
png_t gandhi;
unsigned char* data;
GLuint textureHandle;
png_init(0, 0);
png_open_file_read(&gandhi, "../demo/Gandhi.png");
data = (unsigned char*) malloc(gandhi.width * gandhi.height * gandhi.bpp);
png_get_data(&gandhi, data);
glGenTextures(1, &textureHandle);
glBindTexture(GL_TEXTURE_2D, textureHandle);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, gandhi.width, gandhi.height, 0, GL_RGB, GL_UNSIGNED_BYTE, data);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
png_close_file(&gandhi);
free(data);
}
static Colour *buffer_from_png(const char *filename, int *width, int *height)
{
unsigned char *data;
Colour *buffer;
png_t png;
png_init(NULL, NULL);
if (png_open_file_read(&png, filename) != PNG_NO_ERROR)
{
printf("Couldn't open file %s\n", filename);
return NULL;
}
*width = png.width;
*height = png.height;
assert(png.bpp == 4 || png.bpp == 3);
data = calloc(png.width * png.height * png.bpp, 1);
int ret = png_get_data(&png, data);
if (ret != PNG_NO_ERROR)
{
printf("%d\n", ret);
free(data);
printf("Error getting data from png %s\n", filename);
return NULL;
}
if (png.bpp == 4)
buffer = colour_buffer_from_rgba(data, png.width, png.height);
else
buffer = colour_buffer_from_rgb(data, png.width, png.height);
free(data);
return buffer;
}
