alternativa引擎<一>：Sprite3D解析
1 public function render(stage3D:Stage3D):void { 2 var i:int; 3 var j:int; 4 var light:Light3D; 5 var occluder:Occluder; 6 // Error checking 7 if (stage3D == null) throw new TypeError("Parameter stage3D must be non-null."); 8 // Reset the counters 9 numDraws = 0; 10 numTriangles = 0; 11 // Reset the occluders 12 occludersLength = 0; 13 // Reset the lights 14 lightsLength = 0; 15 ambient[0] = 0; 16 ambient[1] = 0; 17 ambient[2] = 0; 18 ambient[3] = 1; 19 // Receiving the context 20 var currentContext3D:Context3D = stage3D.context3D; 21 if (currentContext3D != context3D) { 22 if (currentContext3D != null) { 23 context3DProperties = context3DPropertiesPool[currentContext3D]; 24 if (context3DProperties == null) { 25 context3DProperties = new RendererContext3DProperties(); 26 context3DProperties.isConstrained = currentContext3D.driverInfo.lastIndexOf("(Baseline Constrained)") >= 0; 27 context3DPropertiesPool[currentContext3D] = context3DProperties; 28 } 29 context3D = currentContext3D; 30 } else { 31 context3D = null; 32 context3DProperties = null; 33 } 34 } 35 if (context3D != null && view != null && renderer != null && (view.stage != null || view._canvas != null)) { 36 renderer.camera = this; 37 // Projection argument calculating 38 calculateProjection(view._width, view._height); 39 // Preparing to rendering 40 view.configureContext3D(stage3D, context3D, this); 41 // Transformations calculating 42 if (transformChanged) composeTransforms(); 43 localToGlobalTransform.copy(transform); 44 globalToLocalTransform.copy(inverseTransform); 45 // Searching for upper hierarchy point 46 var root:Object3D = this; 47 while (root.parent != null) { 48 root = root.parent; 49 if (root.transformChanged) root.composeTransforms(); 50 localToGlobalTransform.append(root.transform); 51 globalToLocalTransform.prepend(root.inverseTransform); 52 } 53 54 // Check if object of hierarchy is visible 55 if (root.visible) { 56 // Calculating the matrix to transform from the camera space to local space 57 root.cameraToLocalTransform.combine(root.inverseTransform, localToGlobalTransform); 58 // Calculating the matrix to transform from local space to the camera space 59 root.localToCameraTransform.combine(globalToLocalTransform, root.transform); 60 61 globalMouseHandlingType = root.mouseHandlingType; 62 // Checking the culling 63 if (root.boundBox != null) { 64 calculateFrustum(root.cameraToLocalTransform); 65 root.culling = root.boundBox.checkFrustumCulling(frustum, 63); 66 } else { 67 root.culling = 63; 68 } 69 // Calculations of content visibility 70 if (root.culling >= 0) root.calculateVisibility(this); 71 // Calculations visibility of children 72 root.calculateChildrenVisibility(this); 73 // Calculations of transformations from occluder space to the camera space 74 for (i = 0; i < occludersLength; i++) { 75 occluder = occluders[i]; 76 occluder.localToCameraTransform.calculateInversion(occluder.cameraToLocalTransform); 77 occluder.transformVertices(correctionX, correctionY); 78 occluder.distance = orthographic ? occluder.localToCameraTransform.l : (occluder.localToCameraTransform.d * occluder.localToCameraTransform.d + occluder.localToCameraTransform.h * occluder.localToCameraTransform.h + occluder.localToCameraTransform.l * occluder.localToCameraTransform.l); 79 occluder.enabled = true; 80 } 81 // Sorting the occluders by disance 82 if (occludersLength > 1) sortOccluders(); 83 // Constructing the volumes of occluders, their intersections, starts from closest 84 for (i = 0; i < occludersLength; i++) { 85 occluder = occluders[i]; 86 if (occluder.enabled) { 87 occluder.calculatePlanes(this); 88 if (occluder.planeList != null) { 89 for (j = i + 1; j < occludersLength; j++) { // It is possible, that start value should be 0 90 var compared:Occluder = occluders[j]; 91 if (compared.enabled && compared != occluder && compared.checkOcclusion(occluder, correctionX, correctionY)) compared.enabled = false; 92 } 93 } else { 94 occluder.enabled = false; 95 } 96 } 97 // Reset of culling 98 occluder.culling = -1; 99 } 100 // Gather the occluders which will affects now 101 for (i = 0, j = 0; i < occludersLength; i++) { 102 occluder = occluders[i]; 103 if (occluder.enabled) { 104 // Debug 105 occluder.collectDraws(this, null, 0, false); 106 if (debug && occluder.boundBox != null && (checkInDebug(occluder) & Debug.BOUNDS)) Debug.drawBoundBox(this, occluder.boundBox, occluder.localToCameraTransform); 107 occluders[j] = occluder; 108 j++; 109 } 110 } 111 occludersLength = j; 112 occluders.length = j; 113 // Check light influence 114 for (i = 0, j = 0; i < lightsLength; i++) { 115 light = lights[i]; 116 light.localToCameraTransform.calculateInversion(light.cameraToLocalTransform); 117 if (light.boundBox == null || occludersLength == 0 || !light.boundBox.checkOcclusion(occluders, occludersLength, light.localToCameraTransform)) { 118 light.red = ((light.color >> 16) & 0xFF) * light.intensity / 255; 119 light.green = ((light.color >> 8) & 0xFF) * light.intensity / 255; 120 light.blue = (light.color & 0xFF) * light.intensity / 255; 121 // Debug 122 light.collectDraws(this, null, 0, false); 123 if (debug && light.boundBox != null && (checkInDebug(light) & Debug.BOUNDS)) Debug.drawBoundBox(this, light.boundBox, light.localToCameraTransform); 124 125 // Shadows preparing 126 if (light.shadow != null) { 127 light.shadow.process(this); 128 } 129 lights[j] = light; 130 j++; 131 } 132 light.culling = -1; 133 } 134 lightsLength = j; 135 lights.length = j; 136 137 // Sort lights by types 138 if (lightsLength > 0) sortLights(0, lightsLength - 1); 139 140 // Calculating the rays of mouse events 141 view.calculateRays(this, (globalMouseHandlingType & Object3D.MOUSE_HANDLING_MOVING) != 0, 142 (globalMouseHandlingType & Object3D.MOUSE_HANDLING_PRESSING) != 0, 143 (globalMouseHandlingType & Object3D.MOUSE_HANDLING_WHEEL) != 0, 144 (globalMouseHandlingType & Object3D.MOUSE_HANDLING_MIDDLE_BUTTON) != 0, 145 (globalMouseHandlingType & Object3D.MOUSE_HANDLING_RIGHT_BUTTON) != 0); 146 for (i = origins.length; i < view.raysLength; i++) { 147 origins[i] = new Vector3D(); 148 directions[i] = new Vector3D(); 149 } 150 raysLength = view.raysLength; 151 152 if (renderClearsContext) { 153 var r:Number = ((view.backgroundColor >> 16) & 0xff)/0xff; 154 var g:Number = ((view.backgroundColor >> 8) & 0xff)/0xff; 155 var b:Number = (view.backgroundColor & 0xff)/0xff; 156 if (view._canvas != null) { 157 r *= view.backgroundAlpha; 158 g *= view.backgroundAlpha; 159 b *= view.backgroundAlpha; 160 } 161 context3D.clear(r, g, b, view.backgroundAlpha); 162 } 163 164 // Check getting in frustum and occluding 165 if (root.culling >= 0 && (root.boundBox == null || occludersLength == 0 || !root.boundBox.checkOcclusion(occluders, occludersLength, root.localToCameraTransform))) { 166 // Check if the ray crossing the bounding box 167 if (globalMouseHandlingType > 0 && root.boundBox != null) { 168 calculateRays(root.cameraToLocalTransform); 169 root.listening = root.boundBox.checkRays(origins, directions, raysLength); 170 } else { 171 root.listening = globalMouseHandlingType > 0; 172 } 173 // Check if object needs in lightning 174 var excludedLightLength:int = root._excludedLights.length; 175 if (lightsLength > 0 && root.useLights) { 176 // Pass the lights to children and calculate appropriate transformations 177 var childLightsLength:int = 0; 178 if (root.boundBox != null) { 179 for (i = 0; i < lightsLength; i++) { 180 light = lights[i]; 181 // Checking light source for existing in excludedLights 182 j = 0; 183 while (j<excludedLightLength && root._excludedLights[j]!=light) j++; 184 if (j<excludedLightLength) continue; 185 186 light.lightToObjectTransform.combine(root.cameraToLocalTransform, light.localToCameraTransform); 187 // Detect influence 188 if (light.boundBox == null || light.checkBound(root)) { 189 childLights[childLightsLength] = light; 190 childLightsLength++; 191 } 192 } 193 } else { 194 // Calculate transformation from light space to object space 195 for (i = 0; i < lightsLength; i++) { 196 light = lights[i]; 197 // Checking light source for existing in excludedLights 198 j = 0; 199 while (j<excludedLightLength && root._excludedLights[j]!=light) j++; 200 if (j<excludedLightLength) continue; 201 202 light.lightToObjectTransform.combine(root.cameraToLocalTransform, light.localToCameraTransform); 203 204 childLights[childLightsLength] = light; 205 childLightsLength++; 206 } 207 } 208 root.collectDraws(this, childLights, childLightsLength, root.useShadow); 209 } else { 210 root.collectDraws(this, null, 0, root.useShadow); 211 } 212 // Debug the boundbox 213 if (debug && root.boundBox != null && (checkInDebug(root) & Debug.BOUNDS)) Debug.drawBoundBox(this, root.boundBox, root.localToCameraTransform); 214 } 215 // Gather the draws for children 216 root.collectChildrenDraws(this, lights, lightsLength, root.useShadow); 217 // Mouse events prosessing 218 view.processMouseEvents(context3D, this); 219 // Render 220 renderer.render(context3D); 221 } 222 // Output 223 if (view._canvas == null) { 224 if (renderPresentsContext) { 225 context3D.present(); 226 } 227 } else { 228 context3D.drawToBitmapData(view._canvas); 229 context3D.present(); 230 } 231 } 232 // Clearing 233 lights.length = 0; 234 childLights.length = 0; 235 occluders.length = 0; 236 }
看到上面的216行：root.collectChildrenDraws(this, lights, lightsLength, root.useShadow)，这句话的意思就是收集所有子节点的绘制信息。
下面详细介绍一下，是如何把各种顶点，纹理，法线信息传送到context3D的。
1 alternativa3d function collectChildrenDraws(camera:Camera3D, lights:Vector.<Light3D>, lightsLength:int, useShadow:Boolean):void { 2 var i:int; 3 var light:Light3D; 4 5 for (var child:Object3D = childrenList; child != null; child = child.next) { 6 // Checking visibility flag 7 if (child.visible) { 8 // Check getting in frustum and occluding 9 if (child.culling >= 0 && (child.boundBox == null || camera.occludersLength == 0 || !child.boundBox.checkOcclusion(camera.occluders, camera.occludersLength, child.localToCameraTransform))) { 10 // Check if the ray crossing the bounding box 11 if (child.boundBox != null) { 12 camera.calculateRays(child.cameraToLocalTransform); 13 child.listening = child.boundBox.checkRays(camera.origins, camera.directions, camera.raysLength); 14 } else { 15 child.listening = true; 16 } 17 // Check if object needs in lightning 18 var excludedLightLength:int = child._excludedLights.length; 19 if (lightsLength > 0 && child.useLights) { 20 // Pass the lights to children and calculate appropriate transformations 21 var childLightsLength:int = 0; 22 var j:int; 23 if (child.boundBox != null) { 24 for (i = 0; i < lightsLength; i++) { 25 light = lights[i]; 26 // Checking object for existing in excludedLights 27 j = 0; 28 while (j<excludedLightLength && child._excludedLights[j]!=light) j++; 29 if (j<excludedLightLength) continue; 30 31 light.lightToObjectTransform.combine(child.cameraToLocalTransform, light.localToCameraTransform); 32 // Detect influence 33 if (light.boundBox == null || light.checkBound(child)) { 34 camera.childLights[childLightsLength] = light; 35 childLightsLength++; 36 } 37 } 38 } else { 39 // Calculate transformation from light space to object space 40 for (i = 0; i < lightsLength; i++) { 41 light = lights[i]; 42 // Проверка источника света на отсутствие в excludedLights 43 j = 0; 44 while (j<excludedLightLength && child._excludedLights[j]!=light) j++; 45 if (j<excludedLightLength) continue; 46 light.lightToObjectTransform.combine(child.cameraToLocalTransform, light.localToCameraTransform); 47 camera.childLights[childLightsLength] = light; 48 childLightsLength++; 49 } 50 } 51 child.collectDraws(camera, camera.childLights, childLightsLength, useShadow&&child.useShadow); 52 } else { 53 child.collectDraws(camera, null, 0, useShadow&&child.useShadow); 54 } 55 // Debug the boundbox 56 if (camera.debug && child.boundBox != null && (camera.checkInDebug(child) & Debug.BOUNDS)) Debug.drawBoundBox(camera, child.boundBox, child.localToCameraTransform); 57 } 58 // Gather the draws for children 59 if (child.childrenList != null) child.collectChildrenDraws(camera, lights, lightsLength, useShadow && child.useShadow); 60 } 61 } 62 }
看上面代码的51行：child.collectDraws(camera, camera.childLights, childLightsLength, useShadow&&child.useShadow);每个Child都有一个collectDraws方法，这个方法是整个程序的关键之处。看下面代码
1 override alternativa3d function collectDraws(camera:Camera3D, lights:Vector.<Light3D>, lightsLength:int, useShadow:Boolean):void { 2 var geometry:Geometry = getGeometry(camera.context3D); 3 if (surface.material != null) surface.material.collectDraws(camera, surface, geometry, lights, lightsLength, useShadow, alwaysOnTop ? Renderer.NEXT_LAYER : -1); 4 // Mouse events. 5 if (listening) camera.view.addSurfaceToMouseEvents(surface, geometry, transformProcedure); 6 }
看第二行的GetGeometry方法，这个方法就是收集各种顶点信息的。
1 alternativa3d function getGeometry(context:Context3D):Geometry { 2 var geometry:Geometry = geometries[context]; 3 if (geometry == null) { 4 geometry = new Geometry(4); 5 6 var attributes:Array = []; 7 attributes[0] = VertexAttributes.POSITION; 8 attributes[1] = VertexAttributes.POSITION; 9 attributes[2] = VertexAttributes.POSITION; 10 attributes[3] = VertexAttributes.NORMAL; 11 attributes[4] = VertexAttributes.NORMAL; 12 attributes[5] = VertexAttributes.NORMAL; 13 attributes[6] = VertexAttributes.TEXCOORDS[0]; 14 attributes[7] = VertexAttributes.TEXCOORDS[0]; 15 attributes[8] = VertexAttributes.TEXCOORDS[1]; 16 attributes[9] = VertexAttributes.TEXCOORDS[1]; 17 attributes[10] = VertexAttributes.TEXCOORDS[2]; 18 attributes[11] = VertexAttributes.TEXCOORDS[2]; 19 attributes[12] = VertexAttributes.TEXCOORDS[3]; 20 attributes[13] = VertexAttributes.TEXCOORDS[3]; 21 attributes[14] = VertexAttributes.TEXCOORDS[4]; 22 attributes[15] = VertexAttributes.TEXCOORDS[4]; 23 attributes[16] = VertexAttributes.TEXCOORDS[5]; 24 attributes[17] = VertexAttributes.TEXCOORDS[5]; 25 attributes[18] = VertexAttributes.TEXCOORDS[6]; 26 attributes[19] = VertexAttributes.TEXCOORDS[6]; 27 attributes[20] = VertexAttributes.TEXCOORDS[7]; 28 attributes[21] = VertexAttributes.TEXCOORDS[7]; 29 attributes[22] = VertexAttributes.TANGENT4; 30 attributes[23] = VertexAttributes.TANGENT4; 31 attributes[24] = VertexAttributes.TANGENT4; 32 attributes[25] = VertexAttributes.TANGENT4; 33 geometry.addVertexStream(attributes); 34 35 geometry.setAttributeValues(VertexAttributes.POSITION, Vector.<Number>([0, 0, 0, 0, 1, 0, 1, 1, 0, 1, 0, 0])); 36 geometry.setAttributeValues(VertexAttributes.NORMAL, Vector.<Number>([0, 0, -1, 0, 0, -1, 0, 0, -1, 0, 0, -1])); 37 geometry.setAttributeValues(VertexAttributes.TEXCOORDS[0], Vector.<Number>([0, 0, 0, 1, 1, 1, 1, 0])); 38 geometry.setAttributeValues(VertexAttributes.TEXCOORDS[1], Vector.<Number>([0, 0, 0, 1, 1, 1, 1, 0])); 39 geometry.setAttributeValues(VertexAttributes.TEXCOORDS[2], Vector.<Number>([0, 0, 0, 1, 1, 1, 1, 0])); 40 geometry.setAttributeValues(VertexAttributes.TEXCOORDS[3], Vector.<Number>([0, 0, 0, 1, 1, 1, 1, 0])); 41 geometry.setAttributeValues(VertexAttributes.TEXCOORDS[4], Vector.<Number>([0, 0, 0, 1, 1, 1, 1, 0])); 42 geometry.setAttributeValues(VertexAttributes.TEXCOORDS[5], Vector.<Number>([0, 0, 0, 1, 1, 1, 1, 0])); 43 geometry.setAttributeValues(VertexAttributes.TEXCOORDS[6], Vector.<Number>([0, 0, 0, 1, 1, 1, 1, 0])); 44 geometry.setAttributeValues(VertexAttributes.TEXCOORDS[7], Vector.<Number>([0, 0, 0, 1, 1, 1, 1, 0])); 45 46 geometry.indices = Vector.<uint>([0, 1, 3, 2, 3, 1]); 47 48 geometry.upload(context); 49 geometries[context] = geometry; 50 } 51 return geometry; 52 }
请看48行的代码；看到没有，对了，这个时候，顶点信息就已经上传到context3d中了。
1 override public function upload(context3D:Context3D):void { 2 var vBuffer:VertexStream; 3 var i:int; 4 var numBuffers:int = _vertexStreams.length; 5 if (_indexBuffer != null) { 6 // Clear old resources 7 _indexBuffer.dispose(); 8 _indexBuffer = null; 9 for (i = 0; i < numBuffers; i++) { 10 vBuffer = _vertexStreams[i]; 11 if (vBuffer.buffer != null) { 12 vBuffer.buffer.dispose(); 13 vBuffer.buffer = null; 14 } 15 } 16 } 17 if (_indices.length <= 0 || _numVertices <= 0) { 18 return; 19 } 20 21 for (i = 0; i < numBuffers; i++) { 22 vBuffer = _vertexStreams[i]; 23 var numMappings:int = vBuffer.attributes.length; 24 var data:ByteArray = vBuffer.data; 25 if (data == null) { 26 throw new Error("Cannot upload without vertex buffer data."); 27 } 28 vBuffer.buffer = context3D.createVertexBuffer(_numVertices, numMappings); 29 vBuffer.buffer.uploadFromByteArray(data, 0, 0, _numVertices); 30 } 31 var numIndices:int = _indices.length; 32 _indexBuffer = context3D.createIndexBuffer(numIndices); 33 _indexBuffer.uploadFromVector(_indices, 0, numIndices); 34 }
至此，这个3d引擎的Sprite3D就介绍完了。
