topical media & game development
mobile-query-three-vendor-three.js-renderers-SoftwareRenderer.js / js
author: mrdoob / mrdoob.com/
author: ryg / farbrausch.de/~fg
author: mraleph / mrale.ph/
THREE.SoftwareRenderer = function () {
console.log( 'THREE.SoftwareRenderer', THREE.REVISION );
var canvas = document.createElement( 'canvas' );
var context = canvas.getContext( '2d' );
var shaders = {};
var canvasWidth, canvasHeight;
var canvasWBlocks, canvasHBlocks;
var viewportXScale, viewportYScale, viewportZScale;
var viewportXOffs, viewportYOffs, viewportZOffs;
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();
this.domElement = canvas;
this.autoClear = true;
// WebGLRenderer compatibility
this.supportsVertexTextures = function () {};
this.setFaceCulling = function () {};
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;
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;
}
};
this.setSize( canvas.width, canvas.height );
this.clear = function () {
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 ) {
rectx1 = Infinity;
recty1 = Infinity;
rectx2 = 0;
recty2 = 0;
if ( this.autoClear ) this.clear();
var renderData = projector.projectScene( scene, camera );
var elements = renderData.elements;
for ( var e = 0, el = elements.length; e < el; e ++ ) {
var element = elements[ e ];
var shader = getMaterialShader( element.material );
if ( element instanceof THREE.RenderableFace3 ) {
drawTriangle(
element.v1.positionScreen,
element.v2.positionScreen,
element.v3.positionScreen,
shader
)
} else if ( element instanceof THREE.RenderableFace4 ) {
drawTriangle(
element.v1.positionScreen,
element.v2.positionScreen,
element.v4.positionScreen,
shader
);
drawTriangle(
element.v2.positionScreen,
element.v3.positionScreen,
element.v4.positionScreen,
shader
);
}
}
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 getMaterialShader( material ) {
var id = material.id;
var shader = shaders[ id ];
if ( shaders[ id ] === undefined ) {
if ( material instanceof THREE.MeshBasicMaterial ) {
shader = new Function(
'buffer, offset, u, v',
[
'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')
);
} else if ( material instanceof THREE.MeshLambertMaterial ) {
shader = new Function(
'buffer, offset, u, v',
[
'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')
);
} else {
shader = new Function(
'buffer, offset, u, v',
[
'buffer[ offset ] = u * 255;',
'buffer[ offset + 1 ] = v * 255;',
'buffer[ offset + 2 ] = 0;',
'buffer[ offset + 3 ] = 255;'
].join('\n')
);
}
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 - 1 ) * 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 ) {
// 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;
// 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;
// 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 c1 = dy12 * ((minx << subpixelBits) - x1) + dx12 * ((miny << subpixelBits) - y1);
var c2 = dy23 * ((minx << subpixelBits) - x2) + dx23 * ((miny << subpixelBits) - y2);
var c3 = dy31 * ((minx << subpixelBits) - x3) + dx31 * ((miny << subpixelBits) - 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 + ((minx << subpixelBits) - x1) * dzdx + ((miny << subpixelBits) - y1) * dzdy ) | 0;
// Z pixel steps
var zfixscale = (1 << subpixelBits);
dzdx = (dzdx * zfixscale) | 0;
dzdy = (dzdy * zfixscale) | 0;
// 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 qstep = -q;
var e1x = qstep * dy12;
var e2x = qstep * dy23;
var e3x = qstep * dy31;
var ezx = qstep * dzdx;
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;
}
// 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;
while ( 1 ) {
// Step everything
x0 += qstep;
cb1 += e1x;
cb2 += e2x;
cb3 += e3x;
cbz += ezx;
// 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;
for ( var iy = 0; iy < q; iy ++ ) {
var cx1 = cy1;
var cx2 = cy2;
var cxz = cyz;
for ( var ix = 0; ix < q; ix ++ ) {
var z = cxz;
if ( z < zbuffer[ offset ] ) {
zbuffer[ offset ] = z;
var u = cx1 * scale;
var v = cx2 * scale;
shader( data, offset * 4, u, v );
}
cx1 += dy12;
cx2 += dy23;
cxz += dzdx;
offset++;
}
cy1 += dx12;
cy2 += dx23;
cyz += dzdy;
offset += linestep;
}
} else { // Partially covered block
var cy1 = cb1;
var cy2 = cb2;
var cy3 = cb3;
var cyz = cbz;
for ( var iy = 0; iy < q; iy ++ ) {
var cx1 = cy1;
var cx2 = cy2;
var cx3 = cy3;
var cxz = cyz;
for ( var ix = 0; ix < q; ix ++ ) {
if ( ( cx1 | cx2 | cx3 ) >= 0 ) {
var z = cxz;
if ( z < zbuffer[ offset ] ) {
var u = cx1 * scale;
var v = cx2 * scale;
zbuffer[ offset ] = z;
shader( data, offset * 4, u, v );
}
}
cx1 += dy12;
cx2 += dy23;
cx3 += dy31;
cxz += dzdx;
offset++;
}
cy1 += dx12;
cy2 += dx23;
cy3 += dx31;
cyz += dzdy;
offset += linestep;
}
}
}
// Advance to next row of blocks
cb1 += q*dx12;
cb2 += q*dx23;
cb3 += q*dx31;
cbz += q*dzdy;
}
}
function clearBlock( blockX, blockY ) {
var zoffset = blockX * blockSize + blockY * blockSize * canvasWidth;
var poffset = zoffset * 4 + 3;
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 ] = 0;
zoffset ++;
poffset += 4;
}
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 ++;
}
}
}
};
(C) Æliens
04/09/2009
You may not copy or print any of this material without explicit permission of the author or the publisher.
In case of other copyright issues, contact the author.