mirror of
https://github.com/xiaoqidun/ofdgo.git
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351 lines
11 KiB
Go
351 lines
11 KiB
Go
// Copyright 2025-2026 肖其顿 (XIAO QI DUN)
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package ofdgo
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import (
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"fmt"
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"math"
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)
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// U3DRenderMode 定义静态几何的呈现方式，边线和顶点使用单像素覆盖
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type U3DRenderMode uint8
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const (
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U3DRenderSolid U3DRenderMode = iota // 实体
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U3DRenderSolidWireframe // 实体线框
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U3DRenderWireframe // 线框
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U3DRenderShadedWireframe // 着色线框
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U3DRenderHiddenWireframe // 隐藏线框
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U3DRenderVertices // 顶点
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U3DRenderShadedVertices // 着色顶点
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U3DRenderBoundingBox // 包围盒线框
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U3DRenderBoundingBoxFaces // 包围盒面
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U3DRenderBoundingBoxOutline // 包围盒面及线框
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U3DRenderIllustration // 插图
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U3DRenderSolidOutline // 实体轮廓
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U3DRenderShadedIllustration // 着色插图
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)
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// u3dPrimitiveKey 区分共享点线的颜色及混合状态，避免透明边点重复叠加
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type u3dPrimitiveKey struct {
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a, b u3dVertex
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blend uint32
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function uint32
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reference float32
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}
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// uniquePrimitive 在当前网格内去重着色边点，缓存按条目计入绘制预算
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// 入参: a 起点或顶点, b 终点或相同顶点, shader 着色器
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// 返回: bool 是否首次绘制, error 预算或取消错误
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func (r *u3dRender) uniquePrimitive(a, b u3dVertex, shader U3DShader) (bool, error) {
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if r.primitives == nil {
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return true, nil
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}
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left := [7]float64{a.point[0], a.point[1], a.point[2], a.color[0], a.color[1], a.color[2], a.color[3]}
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right := [7]float64{b.point[0], b.point[1], b.point[2], b.color[0], b.color[1], b.color[2], b.color[3]}
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for i := range left {
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if left[i] != right[i] {
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if left[i] > right[i] {
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a, b = b, a
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}
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break
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}
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}
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key := u3dPrimitiveKey{a: a, b: b, blend: shader.Blend}
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if shader.Attributes&2 != 0 {
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key.function, key.reference = shader.AlphaFunction, shader.AlphaReference
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}
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if _, ok := r.primitives[key]; ok {
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return false, nil
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}
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if err := r.reserve(1, 512); err != nil {
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return false, err
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}
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r.primitives[key] = struct{}{}
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return true, nil
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}
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// shaded 判断绘制模式是否使用材质、法线和灯光
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// 返回: bool 是否着色
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func (mode U3DRenderMode) shaded() bool {
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return mode == U3DRenderSolid || mode == U3DRenderSolidWireframe || mode == U3DRenderShadedWireframe || mode == U3DRenderShadedVertices || mode == U3DRenderSolidOutline || mode == U3DRenderShadedIllustration
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}
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// silhouette 判断绘制模式是否仅描绘轮廓边
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// 返回: bool 是否使用轮廓边
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func (mode U3DRenderMode) silhouette() bool {
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return mode >= U3DRenderIllustration && mode <= U3DRenderShadedIllustration
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}
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// modeTriangle 根据当前模式绘制原三角面、原始边或顶点，不为裁剪边界生成网格边
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// 入参: triangle 相机空间顶点, shader 着色器, pass 绘制轮次
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// 返回: error 数值、资源或取消错误
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func (r *u3dRender) modeTriangle(triangle [3]u3dVertex, shader U3DShader, pass U3DViewPass) error {
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if r.depthOnly || r.mode == U3DRenderSolid || r.mode.silhouette() {
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return r.sectionTriangle(triangle, shader, pass)
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}
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if r.mode == U3DRenderSolidWireframe {
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if err := r.sectionTriangle(triangle, shader, pass); err != nil {
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return err
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}
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}
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if r.mode != U3DRenderShadedWireframe && r.mode != U3DRenderShadedVertices {
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for i := range triangle {
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triangle[i].color = [4]float64{r.auxiliaryColor[0], r.auxiliaryColor[1], r.auxiliaryColor[2], 1}
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}
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shader = U3DShader{Blend: 0x606}
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}
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normal := u3dTriangleNormal([3]u3dVector{triangle[0].point, triangle[1].point, triangle[2].point})
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for i, vertex := range triangle {
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var err error
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if r.mode == U3DRenderVertices || r.mode == U3DRenderShadedVertices {
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fresh, uniqueErr := r.uniquePrimitive(vertex, vertex, shader)
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if uniqueErr != nil {
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return uniqueErr
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}
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if !fresh {
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continue
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}
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err = r.modePoint(vertex, shader, pass)
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} else {
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fresh, uniqueErr := r.uniquePrimitive(vertex, triangle[(i+1)%3], shader)
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if uniqueErr != nil {
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return uniqueErr
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}
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if !fresh {
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continue
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}
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err = r.modeLine(vertex, triangle[(i+1)%3], normal, triangle[0].point, shader, pass)
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}
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if err != nil {
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return err
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}
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}
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if r.mode != U3DRenderSolidWireframe {
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for i, section := range r.sections {
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if section.intersection != nil {
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if err := r.sectionIntersection(triangle, i); err != nil {
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return err
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}
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}
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}
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}
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return nil
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}
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// modeLine 对原始网格边应用剖切与视锥裁剪，再按像素深度绘制
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// 入参: a 起点, b 终点, normal 面法线, origin 面上点, shader 着色器, pass 绘制轮次
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// 返回: error 数值、资源或取消错误
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func (r *u3dRender) modeLine(a, b u3dVertex, normal, origin u3dVector, shader U3DShader, pass U3DViewPass) error {
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for i, section := range r.sections {
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if i%256 == 0 {
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if err := r.ctx.Err(); err != nil {
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return err
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}
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}
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keep, err := u3dClipLine(&a, &b, section.plane)
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if err != nil || !keep {
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return err
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}
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}
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for i, plane := range r.frustumPlanes() {
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if i == 1 && r.camera.Far == 0 && !r.camera.ClipFar {
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continue
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}
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keep, err := u3dClipLine(&a, &b, plane)
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if err != nil || !keep {
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return err
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}
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}
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return r.rasterLine(a, b, normal, origin, shader, pass)
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}
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// modePoint 绘制原始顶点，不在裁剪边界补充顶点
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// 入参: vertex 顶点, shader 着色器, pass 绘制轮次
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// 返回: error 数值、资源或取消错误
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func (r *u3dRender) modePoint(vertex u3dVertex, shader U3DShader, pass U3DViewPass) error {
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if err := r.ctx.Err(); err != nil {
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return err
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}
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for i, section := range r.sections {
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if i%256 == 0 {
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if err := r.ctx.Err(); err != nil {
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return err
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}
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}
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distance := u3dPlaneDistance(section.plane, vertex.point)
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if !finite(distance) {
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return fmt.Errorf("invalid U3D point clip distance")
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}
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if distance < 0 {
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return nil
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}
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}
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for i, plane := range r.frustumPlanes() {
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if i == 1 && r.camera.Far == 0 && !r.camera.ClipFar {
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continue
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}
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distance := u3dPlaneDistance(plane, vertex.point)
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if !finite(distance) {
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return fmt.Errorf("invalid U3D point clip distance")
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}
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if distance < 0 {
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return nil
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}
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}
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q := 1.0
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if r.camera.Perspective {
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q = 1 / vertex.point[2]
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}
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x := math.Floor(r.viewport[0] + r.viewport[2]/2 + r.camera.ShiftX + vertex.point[0]*r.camera.ScaleX*q)
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y := math.Floor(r.viewport[1] + r.viewport[3]/2 + r.camera.ShiftY - vertex.point[1]*r.camera.ScaleY*q)
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if !finite(x) || !finite(y) {
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return fmt.Errorf("invalid U3D projected vertex")
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}
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if x < 0 || y < 0 || x >= float64(r.output.Rect.Dx()) || y >= float64(r.output.Rect.Dy()) {
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return nil
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}
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pixel := int(y)*r.output.Rect.Dx() + int(x)
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if vertex.point[2] > r.frame[pixel].depth {
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return nil
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}
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visible, err := u3dFragmentColor(&vertex.color, vertex.point, &shader, &pass)
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if err != nil || !visible {
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return err
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}
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r.order++
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return r.fragment(pixel, vertex.point[2], vertex.color, shader.Blend)
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}
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// drawBounds 在模型局部空间计算包围盒，再应用实例变换，不以世界坐标轴重建包围盒
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// 入参: instance 场景实例, node 模型节点, mesh 网格, pass 绘制轮次, passIndex 轮次索引
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// 返回: error 几何、数值、预算或取消错误
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func (r *u3dRender) drawBounds(instance u3dInstance, node *U3DNode, mesh *U3DMesh, pass U3DViewPass, passIndex int) error {
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minimum := u3dVector{math.Inf(1), math.Inf(1), math.Inf(1)}
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maximum := u3dVector{math.Inf(-1), math.Inf(-1), math.Inf(-1)}
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visible := false
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for i := range len(mesh.Faces) + len(mesh.Lines) + len(mesh.Points) {
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shading, corners := mesh.primitive(i)
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shaders := node.Shaders
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if i >= len(mesh.Faces) {
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shaders = node.LineShaders
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}
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if i >= len(mesh.Faces)+len(mesh.Lines) {
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shaders = node.PointShaders
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}
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if i%256 == 0 {
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if err := r.ctx.Err(); err != nil {
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return err
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}
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}
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if uint64(shading) >= uint64(len(shaders)) {
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visible = true
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} else if !visible {
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for _, name := range shaders[shading] {
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index, ok := r.shaders[name]
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if !ok || r.model.Shaders[index].RenderPass&(1<<passIndex) != 0 {
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visible = true
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break
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}
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}
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}
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for _, corner := range corners {
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if uint64(corner.Position) >= uint64(len(mesh.Positions)) {
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return fmt.Errorf("invalid U3D bounds position index")
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}
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for j, value := range mesh.Positions[corner.Position] {
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v := float64(value)
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if !finite(v) {
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return fmt.Errorf("invalid U3D bounds position")
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}
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minimum[j], maximum[j] = min(minimum[j], v), max(maximum[j], v)
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}
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}
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}
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if !visible || math.IsInf(minimum[0], 1) {
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return nil
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}
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opacity := 1.0
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if instance.opacity >= 0 {
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opacity = instance.opacity
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}
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if r.opacity >= 0 {
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opacity *= r.opacity
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}
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if r.mode == U3DRenderBoundingBox {
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opacity = 0
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}
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var vertices [8]u3dVertex
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for i := range vertices {
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point := minimum
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for j := range 3 {
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if i&(1<<j) != 0 {
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point[j] = maximum[j]
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}
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}
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vertices[i].point = r.toCamera.point(instance.world.point(point))
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for _, v := range vertices[i].point {
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if !finite(v) {
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return fmt.Errorf("invalid U3D transformed bounds")
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}
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}
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vertices[i].color = [4]float64{r.faceColor[0], r.faceColor[1], r.faceColor[2], opacity}
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}
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shader := U3DShader{Blend: 0x606}
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var edges [12][2]u3dVector
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edgeCount := 0
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for index, face := range [6][4]int{{0, 2, 3, 1}, {4, 5, 7, 6}, {0, 1, 5, 4}, {2, 6, 7, 3}, {0, 4, 6, 2}, {1, 3, 7, 5}} {
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if index%2 == 1 && minimum[2-index/2] == maximum[2-index/2] {
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continue
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}
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for i := 1; i < 3; i++ {
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triangle := [3]u3dVertex{vertices[face[0]], vertices[face[i]], vertices[face[i+1]]}
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r.order++
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if err := r.sectionTriangle(triangle, shader, pass); err != nil {
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return err
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}
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}
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if r.mode == U3DRenderBoundingBoxFaces {
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continue
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}
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normal := u3dTriangleNormal([3]u3dVector{vertices[face[0]].point, vertices[face[1]].point, vertices[face[2]].point})
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for i, index := range face {
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a, b := vertices[index], vertices[face[(i+1)%4]]
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alpha := 1.0
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if r.mode == U3DRenderBoundingBoxOutline {
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alpha = opacity
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duplicate := a.point == b.point
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for _, edge := range edges[:edgeCount] {
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if edge == ([2]u3dVector{a.point, b.point}) || edge == ([2]u3dVector{b.point, a.point}) {
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duplicate = true
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break
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}
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}
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if duplicate {
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continue
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}
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edges[edgeCount] = [2]u3dVector{a.point, b.point}
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edgeCount++
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}
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a.color = [4]float64{r.auxiliaryColor[0], r.auxiliaryColor[1], r.auxiliaryColor[2], alpha}
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b.color = a.color
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if err := r.modeLine(a, b, normal, a.point, shader, pass); err != nil {
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return err
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}
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}
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}
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return nil
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}
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