/** 
 * @file llbox.cpp
 * @brief Draws a box using display lists for speed.
 *
 * Copyright (c) 2001-$CurrentYear$, Linden Research, Inc.
 * $License$
 */

#include "llviewerprecompiledheaders.h"

#include "llbox.h"

#include "llgl.h"
#include "llglheaders.h"

LLBox		gBox;

// These routines support multiple textures on a box
void LLBox::prerender()
{
	F32 size = 1.f;

	mTriangleCount = 6 * 2;

	mVertex[0][0] = mVertex[1][0] = mVertex[2][0] = mVertex[3][0] = -size / 2;
	mVertex[4][0] = mVertex[5][0] = mVertex[6][0] = mVertex[7][0] =  size / 2;
	mVertex[0][1] = mVertex[1][1] = mVertex[4][1] = mVertex[5][1] = -size / 2;
	mVertex[2][1] = mVertex[3][1] = mVertex[6][1] = mVertex[7][1] =  size / 2;
	mVertex[0][2] = mVertex[3][2] = mVertex[4][2] = mVertex[7][2] = -size / 2;
	mVertex[1][2] = mVertex[2][2] = mVertex[5][2] = mVertex[6][2] =  size / 2;
}

// These routines support multiple textures on a box
void LLBox::cleanupGL()
{
	// No GL state, a noop.
}

void LLBox::renderface(S32 which_face)
{
	static F32 normals[6][3] =
	{
		{-1.0f,  0.0f,  0.0f},
		{ 0.0f,  1.0f,  0.0f},
		{ 1.0f,  0.0f,  0.0f},
		{ 0.0f, -1.0f,  0.0f},
		{ 0.0f,  0.0f,  1.0f},
		{ 0.0f,  0.0f, -1.0f}
	};
	static S32 faces[6][4] =
	{
		{0, 1, 2, 3},
		{3, 2, 6, 7},
		{7, 6, 5, 4},
		{4, 5, 1, 0},
		{5, 6, 2, 1},
		{7, 4, 0, 3}
	};

	glBegin(GL_QUADS);
		glNormal3fv(&normals[which_face][0]);
		glTexCoord2f(1,0);
		glVertex3fv(&mVertex[ faces[which_face][0] ][0]);
		glTexCoord2f(1,1);
		glVertex3fv(&mVertex[ faces[which_face][1] ][0]);
		glTexCoord2f(0,1);
		glVertex3fv(&mVertex[ faces[which_face][2] ][0]);
		glTexCoord2f(0,0);
		glVertex3fv(&mVertex[ faces[which_face][3] ][0]);
	glEnd();
}

void LLBox::render()
{
    // This is a flattend representation of the box as render here
    //                                       .
    //              (-++)        (+++)      /|\t
    //                +------------+         | (texture coordinates)
    //                |2          1|         |
    //                |     4      |        (*) --->s
    //                |    TOP     |
    //                |            |
    // (-++)     (--+)|3          0|(+-+)     (+++)        (-++)
    //   +------------+------------+------------+------------+
    //   |2          1|2          1|2          1|2          1|
    //   |     0      |     1      |     2      |     3      |
    //   |   BACK     |   RIGHT    |   FRONT    |   LEFT     |
    //   |            |            |            |            |
    //   |3          0|3          0|3          0|3          0|
    //   +------------+------------+------------+------------+
    // (-+-)     (---)|2          1|(+--)     (++-)        (-+-)
    //                |     5      |
    //                |   BOTTOM   |
    //                |            |
    //                |3          0|
    //                +------------+
    //              (-+-)        (++-)

	renderface(5);
	renderface(4);
	renderface(3);
	renderface(2);
	renderface(1);
	renderface(0);
}