/*
	glsl_draw.c

	2D drawing support for GLSL

	Copyright (C) 2011 Bill Currie <bill@taniwha.org>

	Author: Bill Currie <bill@taniwha.org>
	Date: 2011/12/23

	This program 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.

	This program 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 this program; if not, write to:

		Free Software Foundation, Inc.
		59 Temple Place - Suite 330
		Boston, MA  02111-1307, USA

*/
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

static __attribute__ ((used)) const char rcsid[] = "$Id$";

#include "QF/draw.h"
#include "QF/dstring.h"
#include "QF/sys.h"
#include "QF/vid.h"

#include "QF/GLSL/defines.h"
#include "QF/GLSL/funcs.h"
#include "QF/GLSL/qf_vid.h"

#include "gl_draw.h"
#include "r_shared.h"

static const char quaketext_vert[] =
#include "quaketxt.vc"
;

static const char quake2d_frag[] =
#include "quake2d.fc"
;

static float proj_matrix[16];

static struct {
	int         program;
	shaderparam_t charmap;
	shaderparam_t palette;
	shaderparam_t matrix;
	shaderparam_t vertex;
	shaderparam_t dchar;
} quake_text = {
	0,
	{"texture", 1},
	{"palette", 1},
	{"mvp_mat", 1},
	{"vertex", 0},
	{"char", 0},
};

VISIBLE byte *draw_chars;
static dstring_t *char_queue;
static int  char_texture;

VISIBLE qpic_t *
Draw_PicFromWad (const char *name)
{
	return 0;
}

VISIBLE qpic_t *
Draw_CachePic (const char *path, qboolean alpha)
{
	return 0;
}

VISIBLE void
Draw_TextBox (int x, int y, int width, int lines, byte alpha)
{
}

VISIBLE void
Draw_Init (void)
{
	GLuint      tnum;
	int         i;
	int         frag, vert;

	char_queue = dstring_new ();
	vert = GL_CompileShader ("quaketxt.vert", quaketext_vert, GL_VERTEX_SHADER);
	frag = GL_CompileShader ("quake2d.frag", quake2d_frag, GL_FRAGMENT_SHADER);
	quake_text.program = GL_LinkProgram ("quaketxt", vert, frag);
	GL_ResolveShaderParam (quake_text.program, &quake_text.charmap);
	GL_ResolveShaderParam (quake_text.program, &quake_text.palette);
	GL_ResolveShaderParam (quake_text.program, &quake_text.matrix);
	GL_ResolveShaderParam (quake_text.program, &quake_text.vertex);
	GL_ResolveShaderParam (quake_text.program, &quake_text.dchar);

	draw_chars = W_GetLumpName ("conchars");
	for (i = 0; i < 256 * 64; i++)
		if (draw_chars[i] == 0)
			draw_chars[i] = 255;		// proper transparent color

	qfglGenTextures (1, &tnum);
	char_texture = tnum;
	qfglBindTexture (GL_TEXTURE_2D, char_texture);
	qfglTexImage2D (GL_TEXTURE_2D, 0, GL_LUMINANCE,
					128, 128, 0, GL_LUMINANCE, GL_UNSIGNED_BYTE, draw_chars);
	qfglTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
	qfglTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
	qfglTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
	qfglTexParameteri (GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
	qfglGenerateMipmap (GL_TEXTURE_2D);
}

static inline void
queue_character (int x, int y, byte chr)
{
	unsigned short *v;
	unsigned    i, c;
	const int   size = 5 * 2 * 6;

	char_queue->size += size;
	dstring_adjust (char_queue);
	v = (unsigned short *) (char_queue->str + char_queue->size - size);
	c = 0x738;
	for (i = 0; i < 6; i++, c >>= 2) {
		*v++ = x;
		*v++ = y;
		*v++ = c & 1;
		*v++ = (c >> 1) & 1;
		*v++ = chr;
	}
}

static void
flush_text (void)
{
	qfglUseProgram (quake_text.program);
	qfglEnableVertexAttribArray (quake_text.vertex.location);
	qfglEnableVertexAttribArray (quake_text.dchar.location);

	qfglUniformMatrix4fv (quake_text.matrix.location, 1, false, proj_matrix);

	qfglUniform1i (quake_text.charmap.location, 0);
	qfglActiveTexture (GL_TEXTURE0 + 0);
	qfglEnable (GL_TEXTURE_2D);
	qfglBindTexture (GL_TEXTURE_2D, char_texture);

	qfglUniform1i (quake_text.palette.location, 1);
	qfglActiveTexture (GL_TEXTURE0 + 1);
	qfglEnable (GL_TEXTURE_2D);
	qfglBindTexture (GL_TEXTURE_2D, glsl_palette);

	qfglVertexAttribPointer (quake_text.vertex.location, 4, GL_UNSIGNED_SHORT,
							 0, 10, char_queue->str);
	qfglVertexAttribPointer (quake_text.dchar.location, 1, GL_UNSIGNED_SHORT,
							 0, 10, char_queue->str + 8);

	qfglDrawArrays (GL_TRIANGLES, 0, char_queue->size / 10);

	qfglDisableVertexAttribArray (quake_text.dchar.location);
	qfglDisableVertexAttribArray (quake_text.vertex.location);
	char_queue->size = 0;
}

VISIBLE void
Draw_Character (int x, int y, unsigned int chr)
{
	chr &= 255;

	if (chr == 32)
		return;							// space
	if (y <= -8)
		return;							// totally off screen

	queue_character (x, y, chr);
}

VISIBLE void
Draw_String (int x, int y, const char *str)
{
	byte        chr;

	if (!str || !str[0])
		return;							// totally off screen
	if (y <= -8)
		return;							// totally off screen

	while (*str) {
		if ((chr = *str++) != 32)
			queue_character (x, y, chr);
		x += 8;
	}
}

VISIBLE void
Draw_nString (int x, int y, const char *str, int count)
{
	byte        chr;

	if (!str || !str[0])
		return;							// totally off screen
	if (y <= -8)
		return;							// totally off screen

	while (count-- && *str) {
		if ((chr = *str++) != 32)
			queue_character (x, y, chr);
		x += 8;
	}
}

void
Draw_AltString (int x, int y, const char *str)
{
}

VISIBLE void
Draw_Crosshair (void)
{
}

void
Draw_CrosshairAt (int ch, int x, int y)
{
}

VISIBLE void
Draw_Pic (int x, int y, qpic_t *pic)
{
}

VISIBLE void
Draw_SubPic (int x, int y, qpic_t *pic, int srcx, int srcy, int width,
			 int height)
{
}

VISIBLE void
Draw_ConsoleBackground (int lines, byte alpha)
{
}

VISIBLE void
Draw_TileClear (int x, int y, int w, int h)
{
}

VISIBLE void
Draw_Fill (int x, int y, int w, int h, int c)
{
}

VISIBLE void
Draw_FadeScreen (void)
{
}

static void
ortho_mat (float *proj, float xmin, float xmax, float ymin, float ymax,
		   float znear, float zfar)
{
	proj[0] = 2/(xmax-xmin);
	proj[4] = 0;
	proj[8] = 0;
	proj[12] = -(xmax+xmin)/(xmax-xmin);

	proj[1] = 0;
	proj[5] = 2/(ymax-ymin);
	proj[9] = 0;
	proj[13] = -(ymax+ymin)/(ymax-ymin);

	proj[2] = 0;
	proj[6] = 0;
	proj[10] = -2/(zfar-znear);
	proj[14] = -(zfar+znear)/(zfar-znear);

	proj[3] = 0;
	proj[7] = 0;
	proj[11] = 0;
	proj[15] = 1;
}

static void
set_2d (int width, int height)
{
	qfglViewport (0, 0, vid.width, vid.height);

	qfglDisable (GL_DEPTH_TEST);
	qfglDisable (GL_CULL_FACE);

	ortho_mat (proj_matrix, 0, width, height, 0, -99999, 99999);
}

void
GL_Set2D (void)
{
    set_2d (vid.width, vid.height);
}

void
GL_Set2DScaled (void)
{
    set_2d (vid.conwidth, vid.conheight);
}

void
GL_DrawReset (void)
{
	char_queue->size = 0;
}

void
GL_FlushText (void)
{
	if (char_queue->size)
		flush_text ();
}