/* ScummVM - Scumm Interpreter
 * Copyright (C) 2001  Ludvig Strigeus
 * Copyright (C) 2001-2003 The ScummVM project
 *
 * 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 the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 */

// FrameBuffer renderer in an OpenGL texture
// Andre Souza <asouza@olinux.com.br>

#include <SDL.h>
#include <SDL_opengl.h>
//#include <GL/gl.h>	NOTE! Before anybody comments out SDL_opengl.h and enables this again, talk to Fingolfin first! GL/gl.h is NOT portable!
#include <stdlib.h>
#include <string.h>

// FLAGS 
#define FB2GL_FS 1      // FULLSCREEN
#define FB2GL_RGBA 2    // Use RGBA (else use palette)
#define FB2GL_320 4     // 320x256 texture (else use 256x256)
#define FB2GL_AUDIO 8   // Activate SDL Audio
#define FB2GL_PITCH 16  // On fb2l_update, use pitch (else bytes per pixel)
#define FB2GL_EXPAND 32 // Create a RGB fb with the color lookup table
#define FB2GL_16BIT 64  // 16 BIT Color Depth

// This extension isn't defined in OpenGL 1.1
#ifndef GL_EXT_paletted_texture
#define GL_EXT_paletted_texture 1
#endif

class FB2GL {
	private:
		// Framebuffer for 8 bpp
		unsigned char ogl_fb[256][256];
		unsigned char ogl_fbb[256][64];
		// Framebuffer for RGBA
		unsigned char ogl_fb1[256][256][4];
		unsigned char ogl_fb2[256][64][4];
		// Framebuffer for the blit function (SDL Blitting)
		unsigned char fb1[256 * 256 * 4]; // Enough room for RGBA
		unsigned char fb2[64 * 256 * 4]; // Enough room for RGBA
		// Texture(s)
		GLuint texture;
		GLuint textureb;
		// Display list
		GLuint dlist;
		// Color Table (256 colors, RGB)
		char ogl_ctable[256][3];
		char ogl_temp_ctable[256][3]; // Support for OpenGL 1.1
		char flags;
		void maketex();
		void makedlist(int xf, int yf);
	public:
		SDL_Surface *screen;
		FB2GL() { 
			flags = 0;
			screen = NULL;
		}
		int init(int width, int height, int xfix, int yfix, char _flags);
		void update(void *fb, int width, int height, int pitch, int xskip, int yskip);
		void palette(int index, int r, int g, int b);
		void setPalette(int first, int ncolors);
		void blit16(SDL_Surface *fb, int num_rect, SDL_Rect *rectlist, int xskip, int yskip);
		void display();
};

void FB2GL::maketex() {
	glGenTextures(0,&texture);
	glBindTexture(GL_TEXTURE_2D,texture);

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

	// Bilinear filtering
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
/*
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
	glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
*/

	if (flags & FB2GL_RGBA) {
		glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 256, 256, 0, GL_RGBA, GL_UNSIGNED_BYTE, ogl_fb1);
	}
	else {
		glTexImage2D(GL_TEXTURE_2D, 0, GL_COLOR_INDEX, 256, 256, 0, GL_COLOR_INDEX, GL_UNSIGNED_BYTE, ogl_fb);
	}

	if (flags & FB2GL_320) {
		glGenTextures(1, &textureb);
		glBindTexture(GL_TEXTURE_2D, textureb);

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

		// Bilinear filtering
		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
/*
		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
		glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
*/

		if (flags & FB2GL_RGBA) {
			glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, 64, 256, 0, GL_RGBA, 
										GL_UNSIGNED_BYTE, ogl_fb2);
		}
		else {
			glTexImage2D(GL_TEXTURE_2D, 0, GL_COLOR_INDEX, 64, 256, 0, GL_COLOR_INDEX,
										GL_UNSIGNED_BYTE, ogl_fbb);
		}
	}
}

void FB2GL::makedlist(int xf, int yf) {
	double xfix = (double)xf / 128; // 128 = 256/2 (half texture => 0.0 to 1.0)
	double yfix = (double)yf / 128;
	// End of 256x256 (from -1.0 to 1.0)
	double texend = (double)96 / 160; // 160=320/2 (== 0.0), 256-160=96.

	if (glIsList(dlist)) 
		glDeleteLists(dlist, 1);

	dlist=glGenLists(1);
	glNewList(dlist, GL_COMPILE);

	glEnable(GL_TEXTURE_2D);

	glBindTexture(GL_TEXTURE_2D, texture);

	if (!(flags & FB2GL_320)) { // Normal 256x256
		glBegin(GL_QUADS);
		glTexCoord2f(0.0, 1.0); glVertex2f(-1.0, -1.0 - yfix); // upper left 
		glTexCoord2f(0.0, 0.0); glVertex2f(-1.0, 1.0); // lower left 
		glTexCoord2f(1.0, 0.0); glVertex2f(1.0 + xfix, 1.0); // lower right 
		glTexCoord2f(1.0, 1.0); glVertex2f(1.0 + xfix, -1.0 - yfix); // upper right 
		glEnd();
	}
	else { // 320x256 

		// First, the 256x256 texture 
		glBegin(GL_QUADS);
		glTexCoord2f(0.0, 1.0); glVertex2f( -1.0, -1.0 - yfix); // upper left 
		glTexCoord2f(0.0, 0.0); glVertex2f(-1.0, 1.0); // lower left 
		glTexCoord2f(1.0, 0.0); glVertex2f(texend + xfix, 1.0); // lower right 
		glTexCoord2f(1.0, 1.0); glVertex2f(texend + xfix, -1.0 - yfix); // upper right
		glEnd();

		// 64x256 
		glBindTexture(GL_TEXTURE_2D, textureb);

		glBegin(GL_QUADS);
		glTexCoord2f(0.0, 1.0); glVertex2f(texend + xfix, -1.0 - yfix); // upper left 
		glTexCoord2f(0.0, 0.0); glVertex2f(texend + xfix, 1.0); // lower left 
		glTexCoord2f(1.0, 0.0); glVertex2f(1.0 + xfix, 1.0); // lower right 
		glTexCoord2f(1.0, 1.0); glVertex2f(1.0 + xfix, -1.0 - yfix); // upper right 
		glEnd();
	}

	glDisable(GL_TEXTURE_2D);

	glEndList();
}

int FB2GL::init(int width, int height, int xfix, int yfix, char _flags) {
	char gl_ext[4096];
	gl_ext[0]='\0';

	flags = _flags;

	// Fullscreen?
	if (!screen) {
		screen = SDL_SetVideoMode(width, height, (flags & FB2GL_16BIT ? 16: 0),
				SDL_HWPALETTE | SDL_HWSURFACE | SDL_OPENGL | SDL_GL_DOUBLEBUFFER |
				(flags & FB2GL_FS? SDL_FULLSCREEN: 0));
	}

	warning("Screen BitsPerPixel: %d\n",screen->format->BitsPerPixel);

	if (!screen) {
		fprintf(stderr, "Couldn't start video res %dx%d\n", width, height);
		return 0;
	}


	if (!(flags & FB2GL_RGBA)) { // Check for Paletted Texture Extension 
		
		strcpy(gl_ext, (char *)glGetString(GL_EXTENSIONS));
	fprintf(stderr,"gl_ext= %s\n",gl_ext);

		if ( strstr( gl_ext , "GL_EXT_paletted_texture") )
			glEnable(GL_EXT_paletted_texture);
		else {
			fprintf(stderr,"Your OpenGL version doesn't support paletted texture\n");
			return 0;
		}
	}
	
	if (width>0 && height>0) 
		maketex();
	makedlist(xfix, yfix);

/*	glEnable(GL_ALPHA_TEST);
	glEnable(GL_BLEND);
	glAlphaFunc(GL_GREATER,0);
	glBlendFunc(GL_SRC_ALPHA,GL_ONE_MINUS_SRC_ALPHA);*/
	
	return 1;
}

void FB2GL::display()
{
	glCallList(dlist);
	SDL_GL_SwapBuffers();
}

void FB2GL::update(void *fb, int w, int h, int pitch, int xskip, int yskip) {
	unsigned char *fb1=(unsigned char *)fb;
	int x,y,scr_pitch,byte=0;

	if (flags & FB2GL_PITCH) scr_pitch=pitch;
	else {
		scr_pitch=w*pitch;
		byte = pitch; // Bytes perl pixel (for RGBA mode)
	}

	if (flags & FB2GL_RGBA) {
		
		if (flags & FB2GL_EXPAND) { // Expand the 8 bit fb into a RGB fb
	
			for (y=yskip; y<h; y++) {
	for (x=xskip; x<w; x++) {
		if (x<256) { 
			ogl_fb1[y][x][0] = ogl_ctable[*(fb1+x)][0];
			ogl_fb1[y][x][1] = ogl_ctable[*(fb1+x)][1]; 
			ogl_fb1[y][x][2] = ogl_ctable[*(fb1+x)][2]; 
			ogl_fb1[y][x][3] = 255;
		}
		else {
			ogl_fb2[y][x-256][0] = ogl_ctable[*(fb1+x)][0]; 
			ogl_fb2[y][x-256][1] = ogl_ctable[*(fb1+x)][1]; 
			ogl_fb2[y][x-256][2] = ogl_ctable[*(fb1+x)][2]; 
			ogl_fb2[y][x-256][3] = 255;
		}
	}
	fb1 += scr_pitch;
			}
		}
		else { // No expansion
			for (y=yskip; y<h; y++) {
	for (x=xskip; x<w; x++) {
		if (x<256) { 
			ogl_fb1[y-yskip][x-xskip][0] = *(fb1+(x*byte)); 
			ogl_fb1[y-yskip][x-xskip][1] = *(fb1+(x*byte)+1); 
			ogl_fb1[y-yskip][x-xskip][2] = *(fb1+(x*byte)+2); 
		}
		else {
			ogl_fb2[y-yskip][x-256][0] = *(fb1+(x*byte)); 
			ogl_fb2[y-yskip][x-256][1] = *(fb1+(x*byte)+1); 
			ogl_fb2[y-yskip][x-256][2] = *(fb1+(x*byte)+2); 
		}
	}
	fb1 += scr_pitch;
			}
		}

		// Update 256x256 texture
		glBindTexture(GL_TEXTURE_2D,texture);
		glFlush();
		glTexSubImage2D(GL_TEXTURE_2D,0,xskip,yskip,256-xskip,256-yskip,GL_RGBA,
	GL_UNSIGNED_BYTE,ogl_fb1);

		if (flags & FB2GL_320) {
			// Update 64x256 texture
			glBindTexture(GL_TEXTURE_2D,textureb);
			glFlush();
			glTexSubImage2D(GL_TEXTURE_2D,0,xskip,yskip,64-xskip,256-yskip,GL_RGBA,
	GL_UNSIGNED_BYTE,ogl_fb2);
		}

	}
	else { // non RGBA (paletted)

		for (y=0; y<h; y++)
			for (x=0; x<w; x++) {
	if (x<256) { 
		ogl_fb[ y ][ x ] = *(fb1 + (y)*scr_pitch + x);
	}
	else { 
		ogl_fbb[ y ][ x - 256 ] = *(fb1 + y*scr_pitch + x);
	}
			}

		// Update 256x256 texture
		glBindTexture(GL_TEXTURE_2D,texture);
		glTexSubImage2D(GL_TEXTURE_2D,0,xskip,yskip,256-xskip,256-yskip,
	GL_COLOR_INDEX, GL_UNSIGNED_BYTE,ogl_fb);
		
		if (flags & FB2GL_320) {
			// Update 64x256 texture
			glBindTexture(GL_TEXTURE_2D,textureb);
			glTexSubImage2D(GL_TEXTURE_2D,0,xskip,yskip,64-xskip,256-yskip,
		GL_COLOR_INDEX, GL_UNSIGNED_BYTE,ogl_fbb);
		}

	}

	display();

}

void FB2GL::blit16(SDL_Surface *fb, int num_rect, SDL_Rect *rect, int xskip, int yskip) {
	int x, y, i;
	int rx, ry, rw, rh;
	int xend=0, yend=0;
	int pitch = fb->pitch/2; // 16 bit pointer access (not char *)
	int tex1_w = 0, tex2_w = 0, tex2_x = 0;

	for (i=0; i<num_rect; i++) {
		tex1_w = tex2_w = tex2_x = 0;
		rx = rect[i].x;
		ry = rect[i].y;
		rw = rect[i].w;
		rh = rect[i].h;
		xend = rx + rw;
		yend = ry + rh;
		if (xend > fb->w) continue;
		if (yend > fb->h) continue;

		if (rx < 256) { // Begins before the end of the 1st texture
			if (xend >= 256) { // Ends after the first texture
	tex2_w = xend-256; // For the 2nd texture
	tex1_w = rw - tex2_w; // For the 1st texture
			}
			else tex1_w = rw; 
		}
		else {
			tex2_w = rw;
			tex2_x = rx - 256;
		}

		for (y = ry; y < yend; y++) {
			for (x = rx; x < xend; x++) {
			
				if (x < 256 && tex1_w) { 
		int pos = (x-rx+(y-ry)*tex1_w)*4; // RGBA
		SDL_GetRGB(((Uint16 *)fb->pixels)[x+y*(pitch)],fb->format,
			&fb1[pos],
			&fb1[pos+1],
			&fb1[pos+2]);
	}
	else if (x >= 256 && tex2_w) {
		int rx2 = rx < 256? 256: rx;
		int pos = (x-rx2+(y-ry)*tex2_w)*4; // RGBA
		SDL_GetRGB(((Uint16 *)fb->pixels)[x+y*(pitch)],fb->format,
			&fb2[pos],
			&fb2[pos+1],
			&fb2[pos+2]);
	}
			}
		}

		if (tex1_w > 0) {
			// Update 256x256 texture
			glBindTexture(GL_TEXTURE_2D,texture);
			glFlush();
			glTexSubImage2D(GL_TEXTURE_2D,0,rx+xskip,ry+yskip,tex1_w,rh,GL_RGBA,
				GL_UNSIGNED_BYTE,fb1);
		}
		if (tex2_w > 0) { // What was left for this texture
			// Update 64x256 texture
			glBindTexture(GL_TEXTURE_2D,textureb);
			glFlush();
			glTexSubImage2D(GL_TEXTURE_2D,0,tex2_x+xskip,ry+yskip,tex2_w,rh,GL_RGBA,
				GL_UNSIGNED_BYTE,fb2);
		}
	}
}

void FB2GL::palette(int i, int r, int g, int b) {
	if (flags & FB2GL_EXPAND) {
		ogl_temp_ctable[i][0]=r;
		ogl_temp_ctable[i][1]=g;
		ogl_temp_ctable[i][2]=b;
	}
	else { // Paletted texture
		ogl_ctable[i][0]=r;
		ogl_ctable[i][1]=g;
		ogl_ctable[i][2]=b;
	}
}

void FB2GL::setPalette(int f, int n) {
	char temp[256][3];
	int i;
 
	if (flags & FB2GL_EXPAND) {
		for (i=f; i<n; i++) {
			ogl_ctable[i][0] = ogl_temp_ctable[i][0];
			ogl_ctable[i][1] = ogl_temp_ctable[i][1];
			ogl_ctable[i][2] = ogl_temp_ctable[i][2];
		}
	}
	else { // Paletted texture
		glBindTexture(GL_TEXTURE_2D,texture);
		glGetColorTable(GL_TEXTURE_2D,GL_RGB,GL_UNSIGNED_BYTE,&temp);
	
		for (i=f; i<n; i++) {
			temp[i][0] = ogl_ctable[i][0];
			temp[i][1] = ogl_ctable[i][1];
			temp[i][2] = ogl_ctable[i][2];
		}
	
		glColorTable(GL_TEXTURE_2D,GL_RGB,256,GL_RGB,GL_UNSIGNED_BYTE,&temp);

		if (flags & FB2GL_320) {
			glBindTexture(GL_TEXTURE_2D,textureb);
			glColorTable(GL_TEXTURE_2D,GL_RGB,256,GL_RGB,GL_UNSIGNED_BYTE,&temp);
		}

	}

}