/*
	This file is part of Warzone 2100.
	Copyright (C) 1999-2004  Eidos Interactive
	Copyright (C) 2005-2007  Warzone Resurrection Project

	Warzone 2100 is free software; you can redistribute it and/or modify
	it under the terms of the GNU General Public License as published by
	the Free Software Foundation; either version 2 of the License, or
	(at your option) any later version.

	Warzone 2100 is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	GNU General Public License for more details.

	You should have received a copy of the GNU General Public License
	along with Warzone 2100; if not, write to the Free Software
	Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
/***************************************************************************/
/*
 * piefunc.c
 *
 * extended render routines for 3D rendering
 *
 */
/***************************************************************************/

#include "lib/framework/frame.h"

#include <SDL/SDL_opengl.h>

#include "lib/gamelib/gtime.h"
#include "lib/ivis_common/piedef.h"
#include "lib/ivis_common/rendmode.h"
#include "lib/ivis_common/piefunc.h"
#include "lib/ivis_common/piestate.h"
#include "piematrix.h"
#include "pietexture.h"
#include "lib/ivis_common/piemode.h"
#include "lib/ivis_common/pieclip.h"

/***************************************************************************/
/*
 *	Source
 */
/***************************************************************************/

/* ---------------------------------------------------------------------------------- */

void pie_DrawViewingWindow(Vector3i *v, UDWORD x1, UDWORD y1, UDWORD x2, UDWORD y2, UDWORD colour)
{
	TERRAIN_VERTEX pieVrts[pie_MAX_VERTICES_PER_POLYGON];
	TERRAIN_VERTEX clippedVrts[pie_MAX_VERTICES_PER_POLYGON + 2]; // no idea why + 2 but fixes crash - Per
	SDWORD clip, i;

	pie_SetTexturePage(-1);
	pie_SetRendMode(REND_ALPHA_FLAT);

	pieVrts[0].x = v[1].x;
	pieVrts[0].y = v[1].y;
	//cull triangles with off screen points
	pieVrts[0].z  = (int)INTERFACE_DEPTH;

	pieVrts[0].u = 0;
	pieVrts[0].v = 0;
	pieVrts[0].light.argb = colour;//0x7fffffff;
	pieVrts[0].specular.argb = 0;

	pieVrts[1] = pieVrts[0];
	pieVrts[2] = pieVrts[0];
	pieVrts[3] = pieVrts[0];
	pieVrts[4] = pieVrts[0];

	pieVrts[1].x = v[0].x;
	pieVrts[1].y = v[0].y;

	pieVrts[2].x = v[2].x;
	pieVrts[2].y = v[2].y;

	pieVrts[3].x = v[3].x;
	pieVrts[3].y = v[3].y;

	pie_Set2DClip(x1,y1,x2-1,y2-1);
	clip = pie_ClipTextured(4, &pieVrts[0], &clippedVrts[0]);
	ASSERT(clip <= pie_MAX_VERTICES_PER_POLYGON + 2, "clip index exceeds clippedVrts array"); // see above
	pie_Set2DClip(CLIP_BORDER,CLIP_BORDER,psRendSurface->width-CLIP_BORDER,psRendSurface->height-CLIP_BORDER);

	if (clip >= 3) {
		PIELIGHT c;

		c.argb = colour;

		glColor4ub(c.byte.r, c.byte.g, c.byte.b, c.byte.a >> 1);

		glBegin(GL_TRIANGLE_FAN);
			for (i = 0; i < clip; i++)
			{
				glVertex2f(clippedVrts[i].x, clippedVrts[i].y);
			}
		glEnd();

		glColor4ub(c.byte.r, c.byte.g, c.byte.b, c.byte.a);

		glBegin(GL_LINE_STRIP);
			for (i = 0; i < clip; i++)
			{
				glVertex2f(clippedVrts[i].x, clippedVrts[i].y);
			}
		glVertex2f(clippedVrts[0].x, clippedVrts[0].y);
		glEnd();
	}
}

/* ---------------------------------------------------------------------------------- */
void pie_TransColouredTriangle( TERRAIN_VERTEX *vrt, UDWORD rgb )
{
	PIELIGHT c;
	UDWORD i;

	c.argb = rgb;

	pie_SetTexturePage(-1);
	pie_SetRendMode(REND_ALPHA_ITERATED);

	glColor4ub(c.byte.r, c.byte.g, c.byte.b, 128);

	glBegin(GL_TRIANGLE_FAN);
		for (i = 0; i < 3; ++i)
		{
			glVertex3f(vrt[i].x, vrt[i].y, vrt[i].z);
		}
	glEnd();}

/* ---------------------------------------------------------------------------------- */

void pie_DrawSkybox(float scale, int u, int v, int w, int h)
{
	const float r = 1.0f; // just because it is shorter than 1.0f

	glPushAttrib(GL_DEPTH_BUFFER_BIT | GL_COLOR_BUFFER_BIT | GL_ENABLE_BIT | GL_FOG_BIT);
	// no use in updating the depth buffer
	glDepthMask(GL_FALSE);

	// fog should not affect the sky
	glDisable(GL_FOG);

	// So we have realistic colors
	glColor4ub(0xFF,0xFF,0xFF,0xFF);

	// enable alpha
	glEnable(GL_BLEND);
	glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);

	// for the nice blend of the sky with the fog
	glDisable(GL_ALPHA_TEST);

	// Apply scale matrix
	glScalef(scale, scale/2.0f, scale);

	glBegin(GL_QUAD_STRIP);
		// Front
		glTexCoord2f(u + w * 0, v + h);	glVertex3f(-r, 0, r); // bottom left
		glTexCoord2f(u + w * 0, v);		glVertex3f(-r, r, r); // top left
		glTexCoord2f(u + w * 2, v + h);	glVertex3f( r, 0, r); // bottom right
		glTexCoord2f(u + w * 2, v); 	glVertex3f( r, r, r); // top right

		// Right
		glTexCoord2f(u + w * 4, v + h);	glVertex3f( r, 0,-r); // bottom r
		glTexCoord2f(u + w * 4, v); 	glVertex3f( r, r,-r); // top r

		// Back
		glTexCoord2f(u + w * 6, v + h);	glVertex3f(-r, 0, -r); // bottom right
		glTexCoord2f(u + w * 6, v); 	glVertex3f(-r, r, -r); // top right

		// Left
		glTexCoord2f(u + w * 8, v + h);	glVertex3f(-r, 0, r); // bottom r
		glTexCoord2f(u + w * 8, v); 	glVertex3f(-r, r, r); // top r
	glEnd();

	glPopAttrib();
}

/// Draws a fog colored box which is wider at the top
void pie_DrawFogBox(float left, float right, float front, float back, float height, float wider)
{
	PIELIGHT fog_colour;

	fog_colour.argb = pie_GetFogColour();
	glColor4ub(fog_colour.byte.r,fog_colour.byte.g,fog_colour.byte.b,0xFF);

	pie_SetRendMode(REND_FLAT);

	glPushAttrib(GL_DEPTH_BUFFER_BIT | GL_ENABLE_BIT | GL_FOG_BIT);
	// no use in updating the depth buffer
	glDepthMask(GL_FALSE);
	glDisable(GL_FOG);
	glBegin(GL_QUAD_STRIP);
		// Front
		glVertex3f(-left, 0, front); // bottom left
		glVertex3f(-left-wider, height, front+wider); // top left
		glVertex3f( right, 0, front); // bottom right
		glVertex3f( right+wider, height, front+wider); // top right

		// Right
		glVertex3f( right, 0,-back); // bottom r
		glVertex3f( right+wider, height,-back-wider); // top r

		// Back
		glVertex3f(-left, 0, -back); // bottom right
		glVertex3f(-left-wider, height, -back-wider); // top right

		// Left
		glVertex3f(-left, 0, front); // bottom r
		glVertex3f(-left-wider, height, front+wider); // top r
	glEnd();
	glPopAttrib();
}

/* ---------------------------------------------------------------------------------- */

UBYTE pie_ByteScale(UBYTE a, UBYTE b)
{
	return ((UDWORD)a * (UDWORD)b) >> 8;
}