/*
* ===========================================================================
* 
* Wolf3D Browser Version GPL Source Code
* Copyright (C) 2012 id Software LLC, a ZeniMax Media company. 
* 
* This file is part of the Wolf3D Browser Version GPL Source Code ("Wolf3D Browser Source Code").  
* 
* Wolf3D Browser Source Code 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.
* 
* Wolf3D Browser Source Code 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 version 2
* along with Wolf3D Browser Source Code.  If not, see <http://www.gnu.org/licenses/>.
* 
* If you have questions concerning this license, you may contact in writing id Software LLC, c/o ZeniMax Media Inc., Suite 120, Rockville, Maryland 20850 USA.
* 
* ===========================================================================
*/

Wolf.setConsts({
    FOV_RAD             : 75 * Math.PI / 180,
    ISCHROME            : /chrome/.test(navigator.userAgent.toLowerCase()),
    ISSAFARI            : /safari/.test(navigator.userAgent.toLowerCase()),
    ISFIREFOX           : /firefox/.test(navigator.userAgent.toLowerCase()),
    ISXP                : /windows nt 5\./.test(navigator.userAgent.toLowerCase()),
    ISWEBKIT            : /webkit/.test(navigator.userAgent.toLowerCase())
});
Wolf.setConsts({
    VIEW_DIST           : (Wolf.XRES / 2) / Math.tan((Wolf.FOV_RAD / 2)),
    TEXTURERESOLUTION   : Wolf.ISCHROME ? 128 : 64
});


Wolf.Renderer = (function() {
    
    var slices = [],
        useBackgroundImage = Wolf.ISWEBKIT,
        texturePath = "art/walls-shaded/" + Wolf.TEXTURERESOLUTION + "/",
        spritePath = "art/sprites/" + Wolf.TEXTURERESOLUTION + "/",
        sprites = [],
        maxDistZ = 64 * 0x10000,
        hasInit = false;
        visibleSprites = [];
        
    var TILESHIFT = Wolf.TILESHIFT,
        TILEGLOBAL = Wolf.TILEGLOBAL,
        TRACE_HIT_VERT = Wolf.TRACE_HIT_VERT,
        TRACE_HIT_DOOR = Wolf.TRACE_HIT_DOOR,
        WALL_TILE = Wolf.WALL_TILE,
        DOOR_TILE = Wolf.DOOR_TILE,
        TEX_PLATE = Wolf.TEX_PLATE,
        TILE2POS = Wolf.TILE2POS,
        POS2TILE = Wolf.POS2TILE,
        VIEW_DIST = Wolf.VIEW_DIST,
        SLICE_WIDTH = Wolf.SLICE_WIDTH,
        WALL_TEXTURE_WIDTH = Wolf.WALL_TEXTURE_WIDTH,
        FINE2RAD = Wolf.FINE2RAD,
        XRES = Wolf.XRES,
        YRES = Wolf.YRES,
        MINDIST = Wolf.MINDIST,
        cos = Math.cos,
        sin = Math.sin,
        tan = Math.tan,
        atan2 = Math.atan2,
        round = Math.round,
        sqrt = Math.sqrt;

    function init() {
        var image, slice, x;
        if (hasInit) {
            return;
        }
        hasInit = true;
    
        $("#game .renderer")
            .width(Wolf.XRES + "px")
            .height(Wolf.YRES + "px");
            
        for (x=0; x<Wolf.XRES; x += Wolf.SLICE_WIDTH) {
            slice = $("<div>");
            slice.css({
                position : "absolute",
                width : Wolf.SLICE_WIDTH + "px",
                height : Wolf.YRES + "px",
                left : x + "px",
                top : 0,
                overflow : "hidden"
            });
            slice.appendTo("#game .renderer");

            image = useBackgroundImage ? $("<div>") : $("<img>");
            
            image.css({
                position : "absolute",
                display : "block",
                top : 0,
                height : 0,
                width : Wolf.SLICE_WIDTH * Wolf.WALL_TEXTURE_WIDTH + "px",
                backgroundSize : "100% 100%"
            });
            
            var sliceElement = slice[0];
            sliceElement.texture = image[0];
            sliceElement.appendChild(sliceElement.texture);
            slices.push(sliceElement);
        }
    }
    
    function reset() {
        $("#game .renderer .sprite").remove();
        sprites = [];
        visibleSprites = [];
    }
    
    function processTrace(viewport, tracePoint) {
        var x = tracePoint.x,
            y = tracePoint.y,
            vx = viewport.x,
            vy = viewport.y,
            
            dx = viewport.x - tracePoint.x,
            dy = viewport.y - tracePoint.y,
            dist = Math.sqrt(dx*dx + dy*dy),
            frac,
            h, w, offset;

        // correct for fisheye
        dist = dist * cos(FINE2RAD(tracePoint.angle - viewport.angle));
        
        w = WALL_TEXTURE_WIDTH * SLICE_WIDTH;
        h = (VIEW_DIST / dist * TILEGLOBAL) >> 0;
        
        if (tracePoint.flags & TRACE_HIT_DOOR) {
            if (tracePoint.flags & TRACE_HIT_VERT) {
                if (x < vx) {
                    frac = tracePoint.frac;
                } else {
                    frac = 1 - tracePoint.frac;
                }
            } else {
                if (y < vy) {
                    frac = 1 - tracePoint.frac;
                } else {
                    frac = tracePoint.frac;
                }
            }
        } else {
            frac = 1 - tracePoint.frac;
        }
       
        offset = frac * w;
        if (offset > w - SLICE_WIDTH) {
            offset = w - SLICE_WIDTH;
        }
        offset = round(offset / SLICE_WIDTH) * SLICE_WIDTH;
        if (offset < 0) {
            offset = 0;
        }
        
        return {
            w : w,
            h : h,
            dist : dist,
            vert : tracePoint.flags & TRACE_HIT_VERT,
            offset : offset
        };
    }
    
    function clear() {
        var n, sprite;
        for (n=0;n<visibleSprites.length;n++) {
            sprite = visibleSprites[n].sprite;
            if (sprite && sprite.div) {
                sprite.div.style.display = "none";
            }
        }
    }
    
    function draw(viewport, level, tracers, visibleTiles) {
        var n, tracePoint;
        
        for (var n=0,len=tracers.length;n<len;++n) {
            tracePoint = tracers[n];
            if (!tracePoint.oob) {
                if (tracePoint.flags & Wolf.TRACE_HIT_DOOR) {
                    drawDoor(n, viewport, tracePoint, level);
                } else {
                    drawWall(n, viewport, tracePoint, level);
                }
            }
        }
        drawSprites(viewport, level, visibleTiles);
    }
    
    function updateSlice(n, textureSrc, proc) {
        var slice = slices[n],
            image = slice.texture,
            sliceStyle = slice.style,
            imgStyle = image.style,
            top = (Wolf.YRES - proc.h) / 2,
            left = -(proc.offset) >> 0,
            height = proc.h,
            z = (maxDistZ - proc.dist) >> 0,
            itop;
            
        if (Wolf.ISXP && Wolf.ISFIREFOX) {
            itop = (proc.texture % 2) ? 0 : -height;
        } else {
            itop = -(proc.texture-1) * height;
            textureSrc = "art/walls-shaded/64/walls.png";
        }
       
        if (image._src != textureSrc) {
            image._src = textureSrc;
            if (useBackgroundImage) {
                imgStyle.backgroundImage = "url(" + textureSrc + ")";
            } else {
                image.src = textureSrc;
            }
        }
        
        if (slice._zIndex != z) {
            sliceStyle.zIndex = slice._zIndex = z;
        }
        if (image._height != height) {
            sliceStyle.height = (image._height = height) + "px";
            if (Wolf.ISXP && Wolf.ISFIREFOX) {
                imgStyle.height = (height * 2) + "px";
            } else {
                imgStyle.height = (height * 120) + "px";
            }
        }
        
        if (image._itop != itop) {
            imgStyle.top = (image._itop = itop) + "px";
        }
        
        if (image._top != top) {
            sliceStyle.top = (image._top = top) + "px";
        }
        if (image._left != left) {
            imgStyle.left = (image._left = left) + "px";
        }
    }

    function drawWall(n, viewport, tracePoint, level) {
        var x = tracePoint.tileX,
            y = tracePoint.tileY,
            vx = POS2TILE(viewport.x),
            vy = POS2TILE(viewport.y),
            tileMap = level.tileMap,
            proc = processTrace(viewport, tracePoint),
            texture = proc.vert ? level.wallTexX[x][y] : level.wallTexY[x][y],
            textureSrc;
        
        
        // door sides
        if (tracePoint.flags & TRACE_HIT_VERT) {
            if (x >= vx && tileMap[x-1][y] & DOOR_TILE) {
                texture = TEX_PLATE;
            }
            if (x < vx && tileMap[x+1][y] & DOOR_TILE) {
                texture = TEX_PLATE;
            }
        } else {
            if (y >= vy && tileMap[x][y-1] & DOOR_TILE) {
                texture = TEX_PLATE;
            }
            if (y < vy && tileMap[x][y+1] & DOOR_TILE) {
                texture = TEX_PLATE;
            }
        }
        
        texture++;
        
        proc.texture = texture;
        
        if (texture % 2 == 0) {
            texture--;
        }
        textureSrc = texturePath + "w_" + texture + ".png";
        
        updateSlice(n, textureSrc, proc);
    }
    
    function drawDoor(n, viewport, tracePoint, level) {
        var proc = processTrace(viewport, tracePoint),
            texture, textureSrc;
            
        //texture = Wolf.TEX_DDOOR + 1;
        texture = level.state.doorMap[tracePoint.tileX][tracePoint.tileY].texture + 1;
        
        proc.texture = texture;
        
        if (texture % 2 == 0) {
            texture -= 1;
        }
        
        textureSrc = texturePath + "w_" + texture + ".png";
        
        updateSlice(n, textureSrc, proc);
    }
        
    function drawSprites(viewport, level, visibleTiles) {
        var vis, n,
            dist, dx, dy, angle,
            z, width, size,
            div, image,
            divStyle, imgStyle;

      
        // build visible sprites list
        visibleSprites = Wolf.Sprites.createVisList(viewport, level, visibleTiles);
        
        for (n = 0; n < visibleSprites.length; ++n ){
            vis = visibleSprites[n];
            dist = vis.dist;
            
            if (dist < MINDIST / 2 ) {
                //continue; // little hack to save speed & z-buffer
            }

            // make sure sprite is loaded
            if (!vis.sprite.div) {
                loadSprite(vis.sprite)
            }
            
            div = vis.sprite.div;
            divStyle = div.style;
            
            image = div.image;
            imgStyle = image.style;
            
            dx = vis.sprite.x  - viewport.x;
            dy = vis.sprite.y  - viewport.y;
            angle = atan2(dy, dx) - FINE2RAD(viewport.angle);
            
            //dist = dist * Math.cos(angle);
           
            size = (VIEW_DIST / dist * TILEGLOBAL) >> 0;

            divStyle.display = "block";
            divStyle.width = size + "px";
            divStyle.height = size + "px";
            
            divStyle.left = (XRES / 2 - size / 2 - tan(angle) * VIEW_DIST) + "px";
            
            divStyle.top = (YRES / 2 - size / 2) + "px";

            texture = Wolf.Sprites.getTexture(vis.sprite.tex[0]);
            textureSrc = spritePath + texture.sheet;

            if (image._src != textureSrc) {
                image._src = textureSrc;
                if (useBackgroundImage) {
                    imgStyle.backgroundImage = "url(" + textureSrc + ")";
                } else {
                    image.src = textureSrc;
                }
            }

            z = (maxDistZ - dist) >> 0;
            width = texture.num * size;
            left = -texture.idx * size;
                
            if (div._zIndex != z) {
                divStyle.zIndex = div._zIndex = z;
            }
            if (image._width != width) {
                imgStyle.width = (image._width = width) + "px";
            }
            if (image._height != size) {
                imgStyle.height = (image._height = size) + "px";
            }
            if (image._left != left) {
                imgStyle.left = (image._left = left) + "px";
            }
        }
    }
    
    function unloadSprite(sprite) {
        if (sprite.div) {
            $(sprite.div).remove();
            sprite.div = null;
        }
    }
    
    function loadSprite(sprite) {
        var div = document.createElement("div"),
            image;

        div.style.display = "none";
        div.style.position = "absolute";
        div.style.width = "128px";
        div.style.height = "128px";
        div.style.overflow = "hidden";
        div.className = "sprite";

        image = useBackgroundImage ? $("<div>") : $("<img>");
        
        image.css({
            position : "absolute",
            display : "block",
            top : 0,
            height : "100%",
            width : "100%",
            backgroundSize : "100%",
            backgroundRepeat : "no-repeat"
        });
        
        div.image = image[0];
        div.appendChild(div.image);
        
        sprite.div = div;
        $("#game .renderer").append(div);
    }
    
    return {
        init : init,
        draw : draw,
        clear : clear,
        loadSprite : loadSprite,
        unloadSprite : unloadSprite,
        reset : reset
    };

})();