glpng.c

a 3d car ....with color texture..

	if (fclose(fp) != 0) return 0;

	return result;
}

int APIENTRY pngLoadF(FILE *fp, int mipmap, int trans, pngInfo *pinfo) {
	GLint pack, unpack;
	unsigned char header[8];
	png_structp png;
	png_infop   info;
	png_infop   endinfo;
	png_bytep   data, data2;
   png_bytep  *row_p;
   double	fileGamma;

	png_uint_32 width, height, rw, rh;
	int depth, color;

	png_uint_32 i;

	fread(header, 1, 8, fp);
	if (!png_check_sig(header, 8)) return 0;

	png = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
	info = png_create_info_struct(png);
	endinfo = png_create_info_struct(png);

	// DH: added following lines
	if (setjmp(png->jmpbuf))
	{
		png_destroy_read_struct(&png, &info, &endinfo);
		return 0;
	}
	// ~DH

	png_init_io(png, fp);
	png_set_sig_bytes(png, 8);
	png_read_info(png, info);
	png_get_IHDR(png, info, &width, &height, &depth, &color, NULL, NULL, NULL);

	if (pinfo != NULL) {
		pinfo->Width  = width;
		pinfo->Height = height;
		pinfo->Depth  = depth;
	}

	if (MaxTextureSize == 0)
		glGetIntegerv(GL_MAX_TEXTURE_SIZE, &MaxTextureSize);

	#ifdef SUPPORTS_PALETTE_EXT
	#ifdef _WIN32
		if (PalettedTextures == -1)
			PalettedTextures = ExtSupported("GL_EXT_paletted_texture") && (strstr((const char *) glGetString(GL_VERSION), "1.1.0 3Dfx Beta") == NULL);

		if (PalettedTextures) {
			if (glColorTableEXT == NULL) {
				glColorTableEXT = (PFNGLCOLORTABLEEXTPROC) wglGetProcAddress("glColorTableEXT");
				if (glColorTableEXT == NULL)
					PalettedTextures = 0;
			}
		}
	#endif
	#endif

	if (PalettedTextures == -1)
		PalettedTextures = 0;

	if (color == PNG_COLOR_TYPE_GRAY || color == PNG_COLOR_TYPE_GRAY_ALPHA)
		png_set_gray_to_rgb(png);

	if (color&PNG_COLOR_MASK_ALPHA && trans != PNG_ALPHA) {
		png_set_strip_alpha(png);
		color &= ~PNG_COLOR_MASK_ALPHA;
	}

	if (!(PalettedTextures && mipmap >= 0 && trans == PNG_SOLID))
		if (color == PNG_COLOR_TYPE_PALETTE)
			png_set_expand(png);

	/*--GAMMA--*/
	checkForGammaEnv();
	if (png_get_gAMA(png, info, &fileGamma))
		png_set_gamma(png, screenGamma, fileGamma);
	else
		png_set_gamma(png, screenGamma, 1.0/2.2);

	png_read_update_info(png, info);

	data = (png_bytep) malloc(png_get_rowbytes(png, info)*height);
	row_p = (png_bytep *) malloc(sizeof(png_bytep)*height);

	for (i = 0; i < height; i++) {
		if (StandardOrientation)
			row_p[height - 1 - i] = &data[png_get_rowbytes(png, info)*i];
		else
			row_p[i] = &data[png_get_rowbytes(png, info)*i];
	}

	png_read_image(png, row_p);
	free(row_p);

	rw = SafeSize(width), rh = SafeSize(height);

	if (rw != width || rh != height) {
		const int channels = png_get_rowbytes(png, info)/width;

		data2 = (png_bytep) malloc(rw*rh*channels);

 		/* Doesn't work on certain sizes */
/* 		if (gluScaleImage(glformat, width, height, GL_UNSIGNED_BYTE, data, rw, rh, GL_UNSIGNED_BYTE, data2) != 0)
 			return 0;
*/
		Resize(channels, data, width, height, data2, rw, rh);

		width = rw, height = rh;
		free(data);
		data = data2;
	}

	{ /* OpenGL stuff */
		glGetIntegerv(GL_PACK_ALIGNMENT, &pack);
		glGetIntegerv(GL_UNPACK_ALIGNMENT, &unpack);
		glPixelStorei(GL_PACK_ALIGNMENT, 1);
		glPixelStorei(GL_UNPACK_ALIGNMENT, 1);

		#ifdef SUPPORTS_PALETTE_EXT
		if (PalettedTextures && mipmap >= 0 && trans == PNG_SOLID && color == PNG_COLOR_TYPE_PALETTE) {
			png_colorp pal;
			int cols;
			GLint intf;

			if (pinfo != NULL) pinfo->Alpha = 0;
			png_get_PLTE(png, info, &pal, &cols);

			switch (cols) {
				case 1<<1:  intf = GL_COLOR_INDEX1_EXT;  break;
				case 1<<2:  intf = GL_COLOR_INDEX2_EXT;  break;
				case 1<<4:  intf = GL_COLOR_INDEX4_EXT;  break;
				case 1<<8:  intf = GL_COLOR_INDEX8_EXT;  break;
				case 1<<12: intf = GL_COLOR_INDEX12_EXT; break;
				case 1<<16: intf = GL_COLOR_INDEX16_EXT; break;
				default:
					/*printf("Warning: Colour depth %i not recognised\n", cols);*/
					return 0;
			}
			glColorTableEXT(GL_TEXTURE_2D, GL_RGB8, cols, GL_RGB, GL_UNSIGNED_BYTE, pal);
			glTexImage2D(GL_TEXTURE_2D, mipmap, intf, width, height, 0, GL_COLOR_INDEX, GL_UNSIGNED_BYTE, data);
		}
		else
		#endif
		if (trans == PNG_SOLID || trans == PNG_ALPHA || color == PNG_COLOR_TYPE_RGB_ALPHA || color == PNG_COLOR_TYPE_GRAY_ALPHA) {
			GLenum glformat;
			GLint glcomponent;

			switch (color) {
				case PNG_COLOR_TYPE_GRAY:
				case PNG_COLOR_TYPE_RGB:
				case PNG_COLOR_TYPE_PALETTE:
					glformat = GL_RGB;
					glcomponent = 3;
					if (pinfo != NULL) pinfo->Alpha = 0;
					break;

				case PNG_COLOR_TYPE_GRAY_ALPHA:
				case PNG_COLOR_TYPE_RGB_ALPHA:
					glformat = GL_RGBA;
					glcomponent = 4;
					if (pinfo != NULL) pinfo->Alpha = 8;
					break;

				default:
					/*puts("glformat not set");*/
					return 0;
			}

			if (mipmap == PNG_BUILDMIPMAPS)
				Build2DMipmaps(glcomponent, width, height, glformat, data, 1);
			else if (mipmap == PNG_SIMPLEMIPMAPS)
				Build2DMipmaps(glcomponent, width, height, glformat, data, 0);
			else
				glTexImage2D(GL_TEXTURE_2D, mipmap, glcomponent, width, height, 0, glformat, GL_UNSIGNED_BYTE, data);
		}
		else {
			png_bytep p, endp, q;
			int r, g, b, a;

			p = data, endp = p+width*height*3;
			q = data2 = (png_bytep) malloc(sizeof(png_byte)*width*height*4);

			if (pinfo != NULL) pinfo->Alpha = 8;

			#define FORSTART \
				do { \
					r = *p++; /*red  */ \
					g = *p++; /*green*/ \
					b = *p++; /*blue */ \
					*q++ = r; \
					*q++ = g; \
					*q++ = b;

			#define FOREND \
					q++; \
				} while (p != endp);

			#define ALPHA *q

			switch (trans) {
				case PNG_CALLBACK:
					FORSTART
						ALPHA = AlphaCallback((unsigned char) r, (unsigned char) g, (unsigned char) b);
					FOREND
					break;

				case PNG_STENCIL:
					FORSTART
						if (r == StencilRed && g == StencilGreen && b == StencilBlue)
							ALPHA = 0;
						else
							ALPHA = 255;
					FOREND
					break;

				case PNG_BLEND1:
					FORSTART
						a = r+g+b;
						if (a > 255) ALPHA = 255; else ALPHA = a;
					FOREND
					break;

				case PNG_BLEND2:
					FORSTART
						a = r+g+b;
						if (a > 255*2) ALPHA = 255; else ALPHA = a/2;
					FOREND
					break;

				case PNG_BLEND3:
					FORSTART
						ALPHA = (r+g+b)/3;
					FOREND
					break;

				case PNG_BLEND4:
					FORSTART
						a = r*r+g*g+b*b;
						if (a > 255) ALPHA = 255; else ALPHA = a;
					FOREND
					break;

				case PNG_BLEND5:
					FORSTART
						a = r*r+g*g+b*b;
						if (a > 255*2) ALPHA = 255; else ALPHA = a/2;
					FOREND
					break;

				case PNG_BLEND6:
					FORSTART
						a = r*r+g*g+b*b;
						if (a > 255*3) ALPHA = 255; else ALPHA = a/3;
					FOREND
					break;

				case PNG_BLEND7:
					FORSTART
						a = r*r+g*g+b*b;
						if (a > 255*255) ALPHA = 255; else ALPHA = (int) sqrt(a);
					FOREND
					break;
			}

			#undef FORSTART
			#undef FOREND
			#undef ALPHA

			if (mipmap == PNG_BUILDMIPMAPS)
				Build2DMipmaps(4, width, height, GL_RGBA, data2, 1);
			else if (mipmap == PNG_SIMPLEMIPMAPS)
				Build2DMipmaps(4, width, height, GL_RGBA, data2, 0);
			else
				glTexImage2D(GL_TEXTURE_2D, mipmap, 4, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, data2);

			free(data2);
		}

		glPixelStorei(GL_PACK_ALIGNMENT, pack);
		glPixelStorei(GL_UNPACK_ALIGNMENT, unpack);
	} /* OpenGL end */

   png_read_end(png, endinfo);
	png_destroy_read_struct(&png, &info, &endinfo);

	free(data);

	return 1;
}

static unsigned int SetParams(int wrapst, int magfilter, int minfilter) {
	unsigned int id;

	glGenTextures(1, &id);
	glBindTexture(GL_TEXTURE_2D, id);

	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, wrapst);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, wrapst);

	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, magfilter);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, minfilter);

	return id;
}

unsigned int APIENTRY pngBind(const char *filename, int mipmap, int trans, pngInfo *info, int wrapst, int minfilter, int magfilter) {
	unsigned int id = SetParams(wrapst, magfilter, minfilter);

	if (id != 0 && pngLoad(filename, mipmap, trans, info))
		return id;
	return 0;
}

unsigned int APIENTRY pngBindF(FILE *file, int mipmap, int trans, pngInfo *info, int wrapst, int minfilter, int magfilter) {
	unsigned int id = SetParams(wrapst, magfilter, minfilter);

	if (id != 0 && pngLoadF(file, mipmap, trans, info))
		return id;
	return 0;
}

void APIENTRY pngSetStencil(unsigned char red, unsigned char green, unsigned char blue) {
	StencilRed = red, StencilGreen = green, StencilBlue = blue;
}

void APIENTRY pngSetAlphaCallback(unsigned char (*callback)(unsigned char red, unsigned char green, unsigned char blue)) {
	if (callback == NULL)
		AlphaCallback = DefaultAlphaCallback;
	else
		AlphaCallback = callback;
}

void APIENTRY pngSetViewingGamma(double viewingGamma) {
	if(viewingGamma > 0) {
		gammaExplicit = 1;
		screenGamma = 2.2/viewingGamma;
	}
	else {
		gammaExplicit = 0;
		screenGamma = 2.2;
	}
}

void APIENTRY pngSetStandardOrientation(int standardorientation) {
	StandardOrientation = standardorientation;
}