three.js/examples/js/renderers/SoftwareRenderer.js

/**
 * @author mrdoob / http://mrdoob.com/
 * @author ryg / http://farbrausch.de/~fg
 * @author mraleph / http://mrale.ph/
 * @author daoshengmu / http://dsmu.me/
 */

THREE.SoftwareRenderer = function ( parameters ) {

	console.log( 'THREE.SoftwareRenderer', THREE.REVISION );

	parameters = parameters || {};

	var canvas = parameters.canvas !== undefined
			 ? parameters.canvas
			 : document.createElement( 'canvas' );
	var context = canvas.getContext( '2d', {
		alpha: parameters.alpha === true
	} );

	var shaders = {};

	var canvasWidth, canvasHeight;
	var canvasWBlocks, canvasHBlocks;
	var viewportXScale, viewportYScale, viewportZScale;
	var viewportXOffs, viewportYOffs, viewportZOffs;

	var clearColor = new THREE.Color( 0x000000 );

	var imagedata, data, zbuffer;
	var numBlocks, blockMaxZ, blockFlags;

	var BLOCK_ISCLEAR = (1 << 0);
	var BLOCK_NEEDCLEAR = (1 << 1);

	var subpixelBits = 4;
	var subpixelBias = (1 << subpixelBits) - 1;
	var blockShift = 3;
	var blockSize = 1 << blockShift;
	var maxZVal = (1 << 24); // Note: You want to size this so you don't get overflows.

	var rectx1 = Infinity, recty1 = Infinity;
	var rectx2 = 0, recty2 = 0;

	var prevrectx1 = Infinity, prevrecty1 = Infinity;
	var prevrectx2 = 0, prevrecty2 = 0;

	var projector = new THREE.Projector();

	var vector1 = new THREE.Vector3();
	var vector2 = new THREE.Vector3();
	var vector3 = new THREE.Vector3();

	this.domElement = canvas;

	this.autoClear = true;

	// WebGLRenderer compatibility

	this.supportsVertexTextures = function () {};
	this.setFaceCulling = function () {};

	this.setClearColor = function ( color, alpha ) {

		clearColor.set( color );
		cleanColorBuffer();
	};

	this.setSize = function ( width, height ) {

		canvasWBlocks = Math.floor( width / blockSize );
		canvasHBlocks = Math.floor( height / blockSize );
		canvasWidth   = canvasWBlocks * blockSize;
		canvasHeight  = canvasHBlocks * blockSize;

		var fixScale = 1 << subpixelBits;

		viewportXScale =  fixScale * canvasWidth  / 2;
		viewportYScale = -fixScale * canvasHeight / 2;
		viewportZScale =			 maxZVal	  / 2;

		viewportXOffs  =  fixScale * canvasWidth  / 2 + 0.5;
		viewportYOffs  =  fixScale * canvasHeight / 2 + 0.5;
		viewportZOffs  =			 maxZVal	  / 2 + 0.5;

		canvas.width = canvasWidth;
		canvas.height = canvasHeight;

		context.fillStyle = clearColor.getStyle();
		context.fillRect( 0, 0, canvasWidth, canvasHeight );

		imagedata = context.getImageData( 0, 0, canvasWidth, canvasHeight );
		data = imagedata.data;

		zbuffer = new Int32Array( data.length / 4 );

		numBlocks = canvasWBlocks * canvasHBlocks;
		blockMaxZ = new Int32Array( numBlocks );
		blockFlags = new Uint8Array( numBlocks );

		for ( var i = 0, l = zbuffer.length; i < l; i ++ ) {

			zbuffer[ i ] = maxZVal;

		}

		for ( var i = 0; i < numBlocks; i ++ ) {

			blockFlags[ i ] = BLOCK_ISCLEAR;

		}

		cleanColorBuffer();

	};

	this.setSize( canvas.width, canvas.height );

	this.clear = function () {

		rectx1 = Infinity;
		recty1 = Infinity;
		rectx2 = 0;
		recty2 = 0;

		for ( var i = 0; i < numBlocks; i ++ ) {

			blockMaxZ[ i ] = maxZVal;
			blockFlags[ i ] = (blockFlags[ i ] & BLOCK_ISCLEAR) ? BLOCK_ISCLEAR : BLOCK_NEEDCLEAR;

		}

	};

	this.render = function ( scene, camera ) {

		if ( this.autoClear === true ) this.clear();

		var renderData = projector.projectScene( scene, camera, false, false );
		var elements = renderData.elements;

		for ( var e = 0, el = elements.length; e < el; e ++ ) {

			var element = elements[ e ];
			var material = element.material;
			var shader = getMaterialShader( material );

			if ( element instanceof THREE.RenderableFace ) {

				drawTriangle(
					element.v1.positionScreen,
					element.v2.positionScreen,
					element.v3.positionScreen,
					shader, element, material
				);

			} else if ( element instanceof THREE.RenderableSprite ) {

				var scaleX = element.scale.x * 0.5;
				var scaleY = element.scale.y * 0.5;

				vector1.copy( element );
				vector1.x -= scaleX;
				vector1.y += scaleY;

				vector2.copy( element );
				vector2.x -= scaleX;
				vector2.y -= scaleY;

				vector3.copy( element );
				vector3.x += scaleX;
				vector3.y += scaleY;

				drawTriangle(
					vector1, vector2, vector3,
					shader, element, material
				);

				vector1.copy( element );
				vector1.x += scaleX;
				vector1.y += scaleY;

				vector2.copy( element );
				vector2.x -= scaleX;
				vector2.y -= scaleY;

				vector3.copy( element );
				vector3.x += scaleX;
				vector3.y -= scaleY;

				drawTriangle(
					vector1, vector2, vector3,
					shader, element, material
				);

			}

		}

		finishClear();

		var x = Math.min( rectx1, prevrectx1 );
		var y = Math.min( recty1, prevrecty1 );
		var width = Math.max( rectx2, prevrectx2 ) - x;
		var height = Math.max( recty2, prevrecty2 ) - y;

		/*
		// debug; draw zbuffer

		for ( var i = 0, l = zbuffer.length; i < l; i++ ) {

			var o = i * 4;
			var v = (65535 - zbuffer[ i ]) >> 3;
			data[ o + 0 ] = v;
			data[ o + 1 ] = v;
			data[ o + 2 ] = v;
			data[ o + 3 ] = 255;
		}
		*/

		if ( x !== Infinity ) {

			context.putImageData( imagedata, 0, 0, x, y, width, height );

		}

		prevrectx1 = rectx1; prevrecty1 = recty1;
		prevrectx2 = rectx2; prevrecty2 = recty2;

	};

	function cleanColorBuffer() {

		var size = canvasWidth * canvasHeight * 4;

		for ( var i = 0; i < size; i+=4 ) {

			data[ i ] = clearColor.r * 255 | 0;
			data[ i+1 ] = clearColor.g * 255 | 0;
			data[ i+2 ] = clearColor.b * 255 | 0;
			data[ i+3 ] = 255;

		}

		context.fillStyle = clearColor.getStyle();
		context.fillRect( 0, 0, canvasWidth, canvasHeight );

	}

	function getPalette( material, bSimulateSpecular ) {
		var diffuseR = material.ambient.r + material.color.r * 255;
		var diffuseG = material.ambient.g + material.color.g * 255;
		var diffuseB = material.ambient.b + material.color.b * 255;
		var palette = new Uint8Array(256*3);

		if ( bSimulateSpecular ) {

			var i = 0, j = 0;

			while(i < 204) {

				var r = i * diffuseR / 204;
				var g = i * diffuseG / 204;
				var b = i * diffuseB / 204;

				palette[j++] = r > 255 ? 255 : r;
				palette[j++] = g > 255 ? 255 : g;
				palette[j++] = b > 255 ? 255 : b;

				++i;

			}

			while(i < 256) { // plus specular highlight

				var r = diffuseR + (i - 204) * (255 - diffuseR) / 82;
				var g = diffuseG + (i - 204) * (255 - diffuseG) / 82;
				var b = diffuseB + (i - 204) * (255 - diffuseB) / 82;

				palette[j++] = r > 255 ? 255 : r;
				palette[j++] = g > 255 ? 255 : g;
				palette[j++] = b > 255 ? 255 : b;

				++i;

			}

		} else {

			var i = 0, j = 0;
			while(i < 256) {
				var r = i * diffuseR / 255;
				var g = i * diffuseG / 255;
				var b = i * diffuseB / 255;
				if(r > 255)
					r = 255;
				if(g > 255)
					g = 255;
				if(b > 255)
					b = 255;

				palette[j++] = r;
				palette[j++] = g;
				palette[j++] = b;
				++i;
			}

		}

		return palette;
	}

	function basicMaterialShader( buffer, offset, u, v, n, face, material ) {

		if ( material.map.needsUpdate ) {
			material.texture.CreateFromImage( material.map.image );
			material.map.needsUpdate = false;
		}

		if ( !material.texture.data )
			return;

		var tdim = material.texture.width;
		var isTransparent = material.transparent;
		var tbound = tdim - 1;
		var tdata = material.texture.data;
		var tIndex = (((v * tdim) & tbound) * tdim + ((u * tdim) & tbound)) * 4;

		if ( !isTransparent ) {
			buffer[ offset ] = tdata[tIndex];
			buffer[ offset + 1 ] = tdata[tIndex+1];
			buffer[ offset + 2 ] = tdata[tIndex+2];
			buffer[ offset + 3 ] = material.opacity * 255;
		} else {
			var opaci = tdata[tIndex+3] * material.opacity;
			var texel = tdata[tIndex] << 16 + tdata[tIndex+1] << 8 + tdata[tIndex+2];
			if(opaci < 250) {
				var backColor = buffer[ offset ] << 24 + buffer[ offset + 1 ] << 16 + buffer[ offset + 2 ] << 8;
				texel = texel * opaci + backColor * (1-opaci);
			}

			buffer[ offset ] = (texel & 0xff0000) >> 16;
			buffer[ offset + 1 ] = (texel & 0xff00) >> 8;
			buffer[ offset + 2 ] = (texel & 0xff);
			buffer[ offset + 3 ] = material.opacity * 255;
		}
	}

	function lightingMaterialShader( buffer, offset, u, v, n, face, material ) {

		if ( material.map.needsUpdate ) {
			material.texture.CreateFromImage( material.map.image );
			material.map.needsUpdate = false;

			return;
		}

		if ( !material.texture.data )
			return;

		var tdim = material.texture.width;
		var isTransparent = material.transparent;
		var cIndex = (n > 0 ? (~~n) : 0) * 3;
		var tbound = tdim - 1;
		var tdata = material.texture.data;
		var tIndex = (((v * tdim) & tbound) * tdim + ((u * tdim) & tbound)) * 4;

		if ( !isTransparent ) {
			buffer[ offset ] = (material.palette[cIndex] * tdata[tIndex]) >> 8;
			buffer[ offset + 1 ] = (material.palette[cIndex+1] * tdata[tIndex+1]) >> 8;
			buffer[ offset + 2 ] = (material.palette[cIndex+2] * tdata[tIndex+2]) >> 8;
			buffer[ offset + 3 ] = material.opacity * 255;
		} else {
			var opaci = tdata[tIndex+3] * material.opacity;
			var foreColor = ((material.palette[cIndex] * tdata[tIndex]) << 16)
						+ ((material.palette[cIndex+1] * tdata[tIndex+1]) << 8 )
						+ (material.palette[cIndex+2] * tdata[tIndex+2]);

			if(opaci < 250) {
				var backColor = buffer[ offset ] << 24 + buffer[ offset + 1 ] << 16 + buffer[ offset + 2 ] << 8;
				foreColor = foreColor * opaci + backColor * (1-opaci);
			}
			buffer[ offset ] = (foreColor & 0xff0000) >> 16;
			buffer[ offset + 1 ] = (foreColor & 0xff00) >> 8;
			buffer[ offset + 2 ] = (foreColor & 0xff);
			buffer[ offset + 3 ] = material.opacity * 255;
		}

	}

	function getMaterialShader( material ) {

		var id = material.id;
		var shader = shaders[ id ];

		if ( shader === undefined ) {

			if ( material instanceof THREE.MeshBasicMaterial ||
				 material instanceof THREE.MeshLambertMaterial ||
				 material instanceof THREE.MeshPhongMaterial ||
				 material instanceof THREE.SpriteMaterial ) {

				if ( material instanceof THREE.MeshLambertMaterial ) {
					// Generate color palette
					if ( !material.palette ) {
						material.palette = getPalette( material, false );
					}

				} else if ( material instanceof THREE.MeshPhongMaterial ) {
					// Generate color palette
					if ( !material.palette ) {
						material.palette = getPalette( material, true );
					}
				}

				var string;

				if ( material.map ) {

					var texture = new THREE.SoftwareRenderer.Texture();
					material.texture = texture;

					if ( material instanceof THREE.MeshBasicMaterial ) {

						shader = basicMaterialShader;

					} else {

						shader = lightingMaterialShader;

					}

				} else {

					if ( material.vertexColors === THREE.FaceColors ) {

						string = [
							'buffer[ offset ] = face.color.r * 255;',
							'buffer[ offset + 1 ] = face.color.g * 255;',
							'buffer[ offset + 2 ] = face.color.b * 255;',
							'buffer[ offset + 3 ] = material.opacity * 255;'
						].join('\n');

					} else {

						string = [
							'buffer[ offset ] = material.color.r * 255;',
							'buffer[ offset + 1 ] = material.color.g * 255;',
							'buffer[ offset + 2 ] = material.color.b * 255;',
							'buffer[ offset + 3 ] = material.opacity * 255;'
						].join('\n');

					}

					shader = new Function( 'buffer, offset, u, v, n, face, material', string );
				}

			} else {

				var string = [
					'buffer[ offset ] = u * 255;',
					'buffer[ offset + 1 ] = v * 255;',
					'buffer[ offset + 2 ] = 0;',
					'buffer[ offset + 3 ] = 255;'
				].join('\n');

				shader = new Function( 'buffer, offset, u, v', string );

			}

			shaders[ id ] = shader;

		}

		return shader;

	}

	function clearRectangle( x1, y1, x2, y2 ) {

		var xmin = Math.max( Math.min( x1, x2 ), 0 );
		var xmax = Math.min( Math.max( x1, x2 ), canvasWidth );
		var ymin = Math.max( Math.min( y1, y2 ), 0 );
		var ymax = Math.min( Math.max( y1, y2 ), canvasHeight );

		var offset = ( xmin + ymin * canvasWidth ) * 4 + 3;
		var linestep = ( canvasWidth - ( xmax - xmin ) ) * 4;

		for ( var y = ymin; y < ymax; y ++ ) {

			for ( var x = xmin; x < xmax; x ++ ) {

				data[ offset += 4 ] = 0;

			}

			offset += linestep;

		}

	}

	function drawTriangle( v1, v2, v3, shader, face, material ) {

		// TODO: Implement per-pixel z-clipping

		if ( v1.z < -1 || v1.z > 1 || v2.z < -1 || v2.z > 1 || v3.z < -1 || v3.z > 1 ) return;

		// https://gist.github.com/2486101
		// explanation: http://pouet.net/topic.php?which=8760&page=1

		// 28.4 fixed-point coordinates

		var x1 = (v1.x * viewportXScale + viewportXOffs) | 0;
		var x2 = (v2.x * viewportXScale + viewportXOffs) | 0;
		var x3 = (v3.x * viewportXScale + viewportXOffs) | 0;

		var y1 = (v1.y * viewportYScale + viewportYOffs) | 0;
		var y2 = (v2.y * viewportYScale + viewportYOffs) | 0;
		var y3 = (v3.y * viewportYScale + viewportYOffs) | 0;

		// Z values (.28 fixed-point)

		var z1 = (v1.z * viewportZScale + viewportZOffs) | 0;
		var z2 = (v2.z * viewportZScale + viewportZOffs) | 0;
		var z3 = (v3.z * viewportZScale + viewportZOffs) | 0;

		// UV values

		var tu1 = face.uvs[0].x;
		var tv1 = 1-face.uvs[0].y;
		var tu2 = face.uvs[1].x;
		var tv2 = 1-face.uvs[1].y;
		var tu3 = face.uvs[2].x;
		var tv3 = 1-face.uvs[2].y;

		// Normal values
		var n1 = face.vertexNormalsModel[0], n2 = face.vertexNormalsModel[1], n3 = face.vertexNormalsModel[2];
		var nz1 = n1.z * 255;
		var nz2 = n2.z * 255;
		var nz3 = n3.z * 255;
		// Deltas

		var dx12 = x1 - x2, dy12 = y2 - y1;
		var dx23 = x2 - x3, dy23 = y3 - y2;
		var dx31 = x3 - x1, dy31 = y1 - y3;

		// Bounding rectangle

		var minx = Math.max( ( Math.min( x1, x2, x3 ) + subpixelBias ) >> subpixelBits, 0 );
		var maxx = Math.min( ( Math.max( x1, x2, x3 ) + subpixelBias ) >> subpixelBits, canvasWidth );
		var miny = Math.max( ( Math.min( y1, y2, y3 ) + subpixelBias ) >> subpixelBits, 0 );
		var maxy = Math.min( ( Math.max( y1, y2, y3 ) + subpixelBias ) >> subpixelBits, canvasHeight );

		rectx1 = Math.min( minx, rectx1 );
		rectx2 = Math.max( maxx, rectx2 );
		recty1 = Math.min( miny, recty1 );
		recty2 = Math.max( maxy, recty2 );

		// Block size, standard 8x8 (must be power of two)

		var q = blockSize;

		// Start in corner of 8x8 block

		minx &= ~(q - 1);
		miny &= ~(q - 1);

		// Constant part of half-edge functions

		var minXfixscale = (minx << subpixelBits);
		var minYfixscale = (miny << subpixelBits);

		var c1 = dy12 * ((minXfixscale) - x1) + dx12 * ((minYfixscale) - y1);
		var c2 = dy23 * ((minXfixscale) - x2) + dx23 * ((minYfixscale) - y2);
		var c3 = dy31 * ((minXfixscale) - x3) + dx31 * ((minYfixscale) - y3);

		// Correct for fill convention

		if ( dy12 > 0 || ( dy12 == 0 && dx12 > 0 ) ) c1 ++;
		if ( dy23 > 0 || ( dy23 == 0 && dx23 > 0 ) ) c2 ++;
		if ( dy31 > 0 || ( dy31 == 0 && dx31 > 0 ) ) c3 ++;

		// Note this doesn't kill subpixel precision, but only because we test for >=0 (not >0).
		// It's a bit subtle. :)
		c1 = (c1 - 1) >> subpixelBits;
		c2 = (c2 - 1) >> subpixelBits;
		c3 = (c3 - 1) >> subpixelBits;

		// Z interpolation setup

		var dz12 = z1 - z2, dz31 = z3 - z1;
		var invDet = 1.0 / (dx12*dy31 - dx31*dy12);
		var dzdx = (invDet * (dz12*dy31 - dz31*dy12)); // dz per one subpixel step in x
		var dzdy = (invDet * (dz12*dx31 - dx12*dz31)); // dz per one subpixel step in y

		// Z at top/left corner of rast area

		var cz = ( z1 + ((minXfixscale) - x1) * dzdx + ((minYfixscale) - y1) * dzdy ) | 0;

		// Z pixel steps

		var fixscale = (1 << subpixelBits);
		dzdx = (dzdx * fixscale) | 0;
		dzdy = (dzdy * fixscale) | 0;

		// UV interpolation setup

		var dtu12 = tu1 - tu2, dtu31 = tu3 - tu1;
		var dtudx = (invDet * (dtu12*dy31 - dtu31*dy12)); // dtu per one subpixel step in x
		var dtudy = (invDet * (dtu12*dx31 - dx12*dtu31)); // dtu per one subpixel step in y
		var dtv12 = tv1 - tv2, dtv31 = tv3 - tv1;
		var dtvdx = (invDet * (dtv12*dy31 - dtv31*dy12)); // dtv per one subpixel step in x
		var dtvdy = (invDet * (dtv12*dx31 - dx12*dtv31)); // dtv per one subpixel step in y

		// UV at top/left corner of rast area

		var ctu = ( tu1 + (minXfixscale - x1) * dtudx + (minYfixscale - y1) * dtudy );
		var ctv = ( tv1 + (minXfixscale - x1) * dtvdx + (minYfixscale - y1) * dtvdy );

		// UV pixel steps

		dtudx = dtudx * fixscale;
		dtudy = dtudy * fixscale;
		dtvdx = dtvdx * fixscale;
		dtvdy = dtvdy * fixscale;

		// Normal interpolation setup

		var dnz12 = nz1 - nz2, dnz31 = nz3 - nz1;
		var dnzdx = (invDet * (dnz12*dy31 - dnz31*dy12)); // dnz per one subpixel step in x
		var dnzdy = (invDet * (dnz12*dx31 - dx12*dnz31)); // dnz per one subpixel step in y

		 // Normal at top/left corner of rast area

		var cnz = ( nz1 + (minXfixscale - x1) * dnzdx + (minYfixscale - y1) * dnzdy );

		// Normal pixel steps

		dnzdx = (dnzdx * fixscale);
		dnzdy = (dnzdy * fixscale);

		// Set up min/max corners
		var qm1 = q - 1; // for convenience
		var nmin1 = 0, nmax1 = 0;
		var nmin2 = 0, nmax2 = 0;
		var nmin3 = 0, nmax3 = 0;
		var nminz = 0, nmaxz = 0;
		if (dx12 >= 0) nmax1 -= qm1*dx12; else nmin1 -= qm1*dx12;
		if (dy12 >= 0) nmax1 -= qm1*dy12; else nmin1 -= qm1*dy12;
		if (dx23 >= 0) nmax2 -= qm1*dx23; else nmin2 -= qm1*dx23;
		if (dy23 >= 0) nmax2 -= qm1*dy23; else nmin2 -= qm1*dy23;
		if (dx31 >= 0) nmax3 -= qm1*dx31; else nmin3 -= qm1*dx31;
		if (dy31 >= 0) nmax3 -= qm1*dy31; else nmin3 -= qm1*dy31;
		if (dzdx >= 0) nmaxz += qm1*dzdx; else nminz += qm1*dzdx;
		if (dzdy >= 0) nmaxz += qm1*dzdy; else nminz += qm1*dzdy;

		// Loop through blocks
		var linestep = canvasWidth - q;
		var scale = 1.0 / (c1 + c2 + c3);

		var cb1 = c1;
		var cb2 = c2;
		var cb3 = c3;
		var cbz = cz;
		var cbtu = ctu;
		var cbtv = ctv;
		var cbnz = cnz;
		var qstep = -q;
		var e1x = qstep * dy12;
		var e2x = qstep * dy23;
		var e3x = qstep * dy31;
		var ezx = qstep * dzdx;
		var etux = qstep * dtudx;
		var etvx = qstep * dtvdx;
		var enzx = qstep * dnzdx;
		var x0 = minx;

		for ( var y0 = miny; y0 < maxy; y0 += q ) {

			// New block line - keep hunting for tri outer edge in old block line dir
			while ( x0 >= minx && x0 < maxx && cb1 >= nmax1 && cb2 >= nmax2 && cb3 >= nmax3 ) {

				x0 += qstep;
				cb1 += e1x;
				cb2 += e2x;
				cb3 += e3x;
				cbz += ezx;
				cbtu += etux;
				cbtv += etvx;
				cbnz += enzx;
			}

			// Okay, we're now in a block we know is outside. Reverse direction and go into main loop.
			qstep = -qstep;
			e1x = -e1x;
			e2x = -e2x;
			e3x = -e3x;
			ezx = -ezx;
			etux = -etux;
			etvx = -etvx;
			enzx = -enzx;

			while ( 1 ) {

				// Step everything
				x0 += qstep;
				cb1 += e1x;
				cb2 += e2x;
				cb3 += e3x;
				cbz += ezx;
				cbtu += etux;
				cbtv += etvx;
				cbnz += enzx;

				// We're done with this block line when at least one edge completely out
				// If an edge function is too small and decreasing in the current traversal
				// dir, we're done with this line.
				if (x0 < minx || x0 >= maxx) break;
				if (cb1 < nmax1) if (e1x < 0) break; else continue;
				if (cb2 < nmax2) if (e2x < 0) break; else continue;
				if (cb3 < nmax3) if (e3x < 0) break; else continue;

				// We can skip this block if it's already fully covered
				var blockX = x0 >> blockShift;
				var blockY = y0 >> blockShift;
				var blockId = blockX + blockY * canvasWBlocks;
				var minz = cbz + nminz;

				// farthest point in block closer than closest point in our tri?
				if ( blockMaxZ[ blockId ] < minz ) continue;

				// Need to do a deferred clear?
				var bflags = blockFlags[ blockId ];
				if ( bflags & BLOCK_NEEDCLEAR) clearBlock( blockX, blockY );
				blockFlags[ blockId ] = bflags & ~( BLOCK_ISCLEAR | BLOCK_NEEDCLEAR );

				// Offset at top-left corner
				var offset = x0 + y0 * canvasWidth;

				// Accept whole block when fully covered
				if ( cb1 >= nmin1 && cb2 >= nmin2 && cb3 >= nmin3 ) {

					var maxz = cbz + nmaxz;
					blockMaxZ[ blockId ] = Math.min( blockMaxZ[ blockId ], maxz );

					var cy1 = cb1;
					var cy2 = cb2;
					var cyz = cbz;
					var cytu = cbtu;
					var cytv = cbtv;
					var cynz = cbnz;

					for ( var iy = 0; iy < q; iy ++ ) {

						var cx1 = cy1;
						var cx2 = cy2;
						var cxz = cyz;
						var cxtu = cytu;
						var cxtv = cytv;
						var cxnz = cynz;

						for ( var ix = 0; ix < q; ix ++ ) {

							var z = cxz;

							if ( z < zbuffer[ offset ] ) {
								zbuffer[ offset ] = z;
								shader( data, offset * 4, cxtu, cxtv, cxnz, face, material );
							}

							cx1 += dy12;
							cx2 += dy23;
							cxz += dzdx;
							cxtu += dtudx;
							cxtv += dtvdx;
							cxnz += dnzdx;
							offset++;

						}

						cy1 += dx12;
						cy2 += dx23;
						cyz += dzdy;
						cytu += dtudy;
						cytv += dtvdy;
						cynz += dnzdy;
						offset += linestep;

					}

				} else { // Partially covered block

					var cy1 = cb1;
					var cy2 = cb2;
					var cy3 = cb3;
					var cyz = cbz;
					var cytu = cbtu;
					var cytv = cbtv;
					var cynz = cbnz;

					for ( var iy = 0; iy < q; iy ++ ) {

						var cx1 = cy1;
						var cx2 = cy2;
						var cx3 = cy3;
						var cxz = cyz;
						var cxtu = cytu;
						var cxtv = cytv;
						var cxnz = cynz;

						for ( var ix = 0; ix < q; ix ++ ) {

							if ( ( cx1 | cx2 | cx3 ) >= 0 ) {

								var z = cxz;

								if ( z < zbuffer[ offset ] ) {
									zbuffer[ offset ] = z;
									shader( data, offset * 4, cxtu, cxtv, cxnz, face, material );
								}

							}

							cx1 += dy12;
							cx2 += dy23;
							cx3 += dy31;
							cxz += dzdx;
							cxtu += dtudx;
							cxtv += dtvdx;
							cxnz += dnzdx;
							offset++;

						}

						cy1 += dx12;
						cy2 += dx23;
						cy3 += dx31;
						cyz += dzdy;
						cytu += dtudy;
						cytv += dtvdy;
						cynz += dnzdy;
						offset += linestep;

					}

				}

			}

			// Advance to next row of blocks
			cb1 += q*dx12;
			cb2 += q*dx23;
			cb3 += q*dx31;
			cbz += q*dzdy;
			cbtu += q*dtudy;
			cbtv += q*dtvdy;
			cbnz += q*dnzdy;
		}

	}

	function clearBlock( blockX, blockY ) {

		var zoffset = blockX * blockSize + blockY * blockSize * canvasWidth;
		var poffset = zoffset * 4;

		var zlinestep = canvasWidth - blockSize;
		var plinestep = zlinestep * 4;

		for ( var y = 0; y < blockSize; y ++ ) {

			for ( var x = 0; x < blockSize; x ++ ) {

				zbuffer[ zoffset ++ ] = maxZVal;

				data[ poffset ++ ] = clearColor.r * 255 | 0;
				data[ poffset ++ ] = clearColor.g * 255 | 0;
				data[ poffset ++ ] = clearColor.b * 255 | 0;
				data[ poffset ++ ] = 255;

			}

			zoffset += zlinestep;
			poffset += plinestep;

		}

	}

	function finishClear( ) {

		var block = 0;

		for ( var y = 0; y < canvasHBlocks; y ++ ) {

			for ( var x = 0; x < canvasWBlocks; x ++ ) {

				if ( blockFlags[ block ] & BLOCK_NEEDCLEAR ) {

					clearBlock( x, y );
					blockFlags[ block ] = BLOCK_ISCLEAR;

				}

				block ++;
			}

		}

	}

};

THREE.SoftwareRenderer.Texture = function() {

	var canvas = null;

	this.CreateFromImage = function( image ) {

		if(image.width <=0 || image.height <=0)
			return;

		var isCanvasClean = false;
		var canvas = THREE.SoftwareRenderer.Texture.canvas;
		if ( !canvas ) {

			try {

				canvas = document.createElement('canvas');
				THREE.SoftwareRenderer.Texture.canvas = canvas;
				isCanvasClean = true;
			} catch( e ) {
				return;
			}

		}

		var dim = image.width > image.height ? image.width : image.height;
		if(dim <= 32)
			dim = 32;
		else if(dim <= 64)
			dim = 64;
		else if(dim <= 128)
			dim = 128;
		else if(dim <= 256)
			dim = 256;
		else if(dim <= 512)
			dim = 512;
		else
			dim = 1024;

		if(canvas.width != dim || canvas.height != dim) {
			canvas.width = canvas.height = dim;
			isCanvasClean = true;
		}

		var data;
		try {
			var ctx = canvas.getContext('2d');
			if(!isCanvasClean)
				ctx.clearRect(0, 0, dim, dim);
			ctx.drawImage(image, 0, 0, dim, dim);
			var imgData = ctx.getImageData(0, 0, dim, dim);
			data = imgData.data;
		}
		catch(e) {
			return;
		}

		var size = data.length;
		this.data = new Uint8Array(size);
		var alpha;
		for(var i=0, j=0; i<size; ) {
			this.data[i++] = data[j++];
			this.data[i++] = data[j++];
			this.data[i++] = data[j++];
			alpha = data[j++];
			this.data[i++] = alpha;

			if(alpha < 255)
				this.hasTransparency = true;
		}

		this.width = dim;
		this.height = dim;
		this.srcUrl = image.src;
	};
};