#include "texture_opengl.h"

TextureOpenGL::TextureOpenGL(Pixelmap *image,SamplerState samp,unsigned int flags): Texture(image,samp,flags)
{
	if (!is_valid) return;
	InitTex();
}

static GLenum samp_mode[]=
{
	GL_LINEAR,
	GL_NEAREST,
	GL_LINEAR_MIPMAP_LINEAR
};

static GLenum wrap_mode[]=
{
	GL_REPEAT,
	GL_CLAMP,
	GL_CLAMP_TO_EDGE
};

static GLenum gl_store_format[]=
{
	GL_RGBA4,
    GL_RGBA4,
    GL_RGB5,
    GL_RGB5,
    GL_LUMINANCE,
    GL_ALPHA
};

static GLenum gl_data_format[]=
{
	GL_RGBA,
    GL_BGRA,
    GL_RGB,
    GL_BGR,
    GL_LUMINANCE,
    GL_ALPHA
};

// this is where we really initialize the texture for use
void TextureOpenGL::InitTex()
{
	if (!(is_pow2(image->Width())&&is_pow2(image->Height())))
	{
		if (!GLEE_ARB_texture_non_power_of_two)
		{
			is_valid=false;
			return;
		}
	}

	textarget=GL_TEXTURE_2D;

	glGenTextures(1,&texid);

	glEnable(GL_TEXTURE_2D);
	glBindTexture(textarget,texid);

	glTexParameteri(textarget,GL_TEXTURE_WRAP_S,wrap_mode[samp.wraps]);
	glTexParameteri(textarget,GL_TEXTURE_WRAP_T,wrap_mode[samp.wrapt]);

	glTexParameteri(textarget,GL_TEXTURE_MAG_FILTER,samp_mode[samp.magmode]);
	glTexParameteri(textarget,GL_TEXTURE_MIN_FILTER,samp_mode[samp.minmode]);

	glTexImage2D(GL_TEXTURE_2D,0,gl_store_format[image->Format()],
		image->Width(),image->Height(),
		0,gl_data_format[image->Format()],GL_UNSIGNED_BYTE,
		image->PixPtr());

	if (samp.minmode==RAVEN_MIPMAP_SAMPLE)
		glTexParameteri(textarget,GL_GENERATE_MIPMAP,GL_TRUE);

	glTexParameteri(textarget,GL_TEXTURE_MIN_FILTER,samp_mode[samp.minmode]);

	if (samp.aniso&&GLEE_EXT_texture_filter_anisotropic)
		glTexParameteri(textarget,GL_TEXTURE_MAX_ANISOTROPY_EXT,samp.aniso);
}

TextureOpenGL::~TextureOpenGL()
{
	glDeleteTextures(1,&texid);
}

void *TextureOpenGL::GetID()
{
	return (void *)texid;
}

void TextureOpenGL::Bind(int stage)
{
	glActiveTextureARB(GL_TEXTURE0+stage);
	glBindTexture(textarget,texid);

	glTexEnvi(GL_TEXTURE_ENV,GL_TEXTURE_ENV_MODE,GL_MODULATE);

	glTexEnvi(GL_TEXTURE_ENV,GL_COMBINE_RGB,GL_MODULATE);
	glTexEnvi(GL_TEXTURE_ENV,GL_SRC1_RGB,GL_PREVIOUS);
	glTexEnvi(GL_TEXTURE_ENV,GL_SRC2_RGB,GL_TEXTURE);

	glTexEnvi(GL_TEXTURE_ENV,GL_COMBINE_ALPHA,GL_MODULATE);
	glTexEnvi(GL_TEXTURE_ENV,GL_SRC1_ALPHA,GL_PREVIOUS);
	glTexEnvi(GL_TEXTURE_ENV,GL_SRC2_ALPHA,GL_TEXTURE);
}