本文主要是介绍blender中获取虚拟相机渲染图片上每像素对应的纹理上的像素值，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！
示例图：
相机渲染出图后，图片上每个像素点中对应的纹理的像素值。获取这个对应关系存到数据库
基本思路是
从相机圆心发射射线接触到物体时获取接触点（三维坐标）所在三角面，通过这个三角面的三个顶点坐标及其三个纹理坐标，通过重心坐标求出接触点所对应的纹理坐标。在发射射线时，通过相机分辨率中某一点的二维坐标（即渲染出图后图片上的坐标）转三维坐标，结合相机圆心确认射线方向。至此【图片上每个像素点中对应的纹理的像素值】对应关系所需要的数据已具备，
示例代码
如上图，相机视野中存在一个半球模型（已贴图），一个模型船
import bpy
import mathutils
import sqlite3
import time
import numpy as np
from PIL import Image# 虚拟相机名称的变量，用与获取自定义命名方式的物体。
name = 'bow'
# 导出数据库位置
dbpath = 'D:/syncdisk/blender_export/' + name + '.db'
# 渲染出图的位置
export_image_path = 'D:/syncdisk/blender_export/' + name + '.png'
# 获取当前场景中的相机对象
camera = bpy.data.objects[name + ".001"]
# 获取对象的网格数据
back_mesh = bpy.data.objects["球体.001"]
ship = bpy.data.objects["Box5885.001"]
line = bpy.data.objects["Box5885.003"]# 链接数据库的句柄
db = sqlite3.connect(dbpath)
# cursor对象
db_cur = db.cursor()# 获取当前渲染设置
render_settings = bpy.context.scene.render
# 获取渲染图的尺寸
render_width = render_settings.resolution_x
render_height = render_settings.resolution_y
# 获取所有材质,用于获取材质颜色
materials = bpy.data.materialsmesh = back_mesh.data
# 获取模型的世界变换矩阵
world_mat = back_mesh.matrix_world
# 获取uv层,用于遍历获取uv数据
uv_layers_data = back_mesh.data.uv_layers.active.data
# 存储要写入数据库的数据
sql_value = []# 清空表格
def clearTable(tableName, cur):print('开始清空表'+tableName)sql = 'delete from ' + tableName + ' where 1 = 1'try:cur.execute(sql)print('清空表' + tableName + '成功')except Exception as e:print(e)print('清空表' + tableName + '失败')def dissconnectDB(cur):# 关闭游标cur.close()# 关闭连接db.close()print('断开数据库链接')# 执行sql创建表
def createTable(cur):print('开始创建表:pixelmap')# 执行sql创建表sql = 'create table pixelmap(id integer primary key,canvas integer not null,row0 float not null,col0 float not null,source integer not null,row1 float not null,col1 float not null,wt float not null)'try:cur.execute(sql)print('创建表:pixelmap成功')except Exception as e:print(e)print('创建表:pixelmap失败')print('开始创建表:keyvalue')sql = 'create table keyvalue(id integer primary key,key string,value string)'try:cur.execute(sql)print('创建表:keyvalue成功')except Exception as e:print(e)print('创建表:keyvalue失败')def insertValueIntoTable(value, cur):print('开始插入数据到表pixelmap')try:# 执行sql创建表sql = 'insert into pixelmap(canvas,row0,col0,source,row1,col1,wt) values(?,?,?,?,?,?,?)'cur.executemany(sql, value)# 提交事务db.commit()print('插入成功')except Exception as e:print('插入失败')print(e)db.rollback()def insertValueIntoKeyValueTable(value, cur):print('开始插入数据到表keyvalue')try:# 执行sql创建表sql = 'insert into keyvalue(key,value) values(?,?)'cur.executemany(sql, value)# 提交事务db.commit()print('插入成功')except Exception as e:print('插入失败')print(e)db.rollback()def coord2_3d(camera, coord):out = mathutils.Vector(((2.0 * coord[0] / render_width) - 1.0,(2.0 * (1.0 - coord[1] / render_height)) - 1.0,-0.5))# 获取相机的投影矩阵perspective_matrix = camera.calc_matrix_camera(bpy.context.evaluated_depsgraph_get(),x = render_width,y = render_height)persinv = perspective_matrix.inverted()coord_world = camera.matrix_world @ (persinv @ out)return coord_worlddef obj_ray_cast(obj, coord, camera):view_vector = coord2_3d(camera, coord)ray_origin = camera.matrix_world.translationmatrix_inv = obj.matrix_world.copy().inverted()ray_origin_obj = matrix_inv @ ray_originray_target_obj = matrix_inv @ view_vectorray_direction_obj = ray_target_obj - ray_origin_obj# cast the raysuccess, location, normal, face_index = obj.ray_cast(ray_origin_obj, ray_direction_obj)if success:coord_world = back_mesh.matrix_world @ locationreturn (coord_world, face_index)else:return ((-1, -1), -1)# 计算三角形的面积
def triangle_area(v1, v2, v3):AB = v2 - v1AC = v3 - v1area = 0.5 * np.linalg.norm(np.cross(AB, AC))return areadef calculate_barycenter_3d(point, points):A = triangle_area(points[0], points[1], points[2])A1 = triangle_area(point, points[1], points[2])A2 = triangle_area(points[0], point, points[2])A3 = triangle_area(points[0], points[1], point)return (A1 / A, A2 / A, A3 / A, (A1 / A + A2 / A + A3 / A))def calculate_point_from_barycenter(barycenter, points):if len(barycenter) != 3 or len(points) != 3:return Nonex = barycenter[0] * points[0][0] + barycenter[1] * points[1][0] + barycenter[2] * points[2][0]y = barycenter[0] * points[0][1] + barycenter[1] * points[1][1] + barycenter[2] * points[2][1]return x, y# 计算点在三角形中的重心坐标，返回的坐标在值都是大于0的，则在三角形内部
def calculate_barycenter(point, points):if len(point) != 2:return (-1, 1, 0)if len(points) != 3:return (-1, 1, 0)x, y = point[0], point[1]p1, p2, p3 = points[0], points[1], points[2]denominator = (p2[1] - p3[1]) * (p1[0] - p3[0]) + (p3[0] - p2[0]) * (p1[1] - p3[1])if denominator == 0.0:return (-1, -1, -1)alpha = ((p2[1] - p3[1]) * (x - p3[0]) + (p3[0] - p2[0]) * (y - p3[1])) / denominatorbeta = ((p3[1] - p1[1]) * (x - p3[0]) + (p1[0] - p3[0]) * (y - p3[1])) / denominatorgamma = 1.0 - alpha - betareturn (alpha, beta, gamma)def rgba_to_hex(rgb):red = round(rgb[0] * 255)green = round(rgb[1] * 255)blue = round(rgb[2] * 255)hex_color = (red << 16) + (green << 8) + bluereturn hex(hex_color)# 获取材质的颜色(纯色材质)
def getMaterialColor(index):# 获取所有的材质materials = bpy.data.materialsmaterial = materials[index]# 如果材质包含 Principled BSDF Shader，则获取 Base Colorif material.use_nodes:nodes = material.node_tree.nodesprincipled_bsdf = nodes.get("Principled BSDF")if principled_bsdf is not None:base_color = principled_bsdf.inputs["Base Color"].default_valuereturn rgba_to_hex((base_color[0], base_color[1], base_color[2]))# print(f"Material Index: {index}, Base Color: {base_color[0],base_color[1],base_color[2],base_color[3]}")# 否则，尝试获取 Diffuse Shader 的颜色else:diffuse_shader = material.diffuse_colorreturn rgba_to_hex(diffuse_shader)def open_image(filepath):return Image.open(filepath)def get_pixel_color(image, x, y):# 获取指定位置的像素颜色值color = image.getpixel((x, y))red = color[0]green = color[1]blue = color[2]hex_color = (red << 16) + (green << 8) + bluereturn hex(hex_color)try:createTable(db_cur)clearTable('pixelmap',db_cur)clearTable('keyvalue',db_cur)# 渲染图像print("开始渲染图片")bpy.context.scene.render.filepath = export_image_path # 输出路径bpy.context.scene.render.resolution_x = render_width # 分辨率Xbpy.context.scene.render.resolution_y = render_height # 分辨率Ybpy.ops.render.render(write_still=True)print("渲染图片结束")time.sleep(1)# 获取渲染图句柄print("获取渲染图句柄")image = open_image(export_image_path)for y in range(render_height):print("loading y...", y)for x in range(render_width):# 获取面的所有顶点对应的纹理坐标tex_coords = []# 获取面的所有顶点vertices = []coord = x, yship_coord, face_index_ship = obj_ray_cast(ship, coord, camera)# line_coord, face_index_line = obj_ray_cast(line, coord, camera)if ship_coord[0] != -1:sql_value.append((0, y, x, -1, 0.0, 0.0, get_pixel_color(image, x, y)))# elif line_coord[0] != -1:# sql_value.append((0, y, x, -1, 0.0, 0.0, get_pixel_color(image, x, y)))else:coord_world, face_index = obj_ray_cast(back_mesh, coord, camera)if coord_world[0] != -1:face = mesh.polygons[face_index]loop_start = face.loop_startloop_end = face.loop_start + face.loop_totalif face.loop_total == 4:# blender中是使用四角面，也就是两个三角面合并后的面计算# 先获取到四个顶点vertices_0 = mesh.loops[face.loop_start].vertex_indexvertices_0_w = world_mat @ mesh.vertices[vertices_0].cotex_coords.append(uv_layers_data[face.loop_start].uv)vertices.append(vertices_0_w)vertices_1 = mesh.loops[face.loop_start+1].vertex_indexvertices_1_w = world_mat @ mesh.vertices[vertices_1].cotex_coords.append(uv_layers_data[face.loop_start+1].uv)vertices.append(vertices_1_w)vertices_2 = mesh.loops[face.loop_start+2].vertex_indexvertices_2_w = world_mat @ mesh.vertices[vertices_2].cotex_coords.append(uv_layers_data[face.loop_start+2].uv)vertices.append(vertices_2_w)# 计算重心坐标，判断该像素点是否在第一个三角面内barycenter = calculate_barycenter_3d(coord_world, vertices) if (barycenter[3] <= 1.000001):coord_xy = calculate_point_from_barycenter((barycenter[0], barycenter[1], barycenter[2]), tex_coords)sql_value.append((0, y, x, float(face.material_index), 1-coord_xy[1], coord_xy[0], 1.0))# 第二个三角面else:vertices_3 = mesh.loops[face.loop_start+3].vertex_indexvertices_3_w = world_mat @ mesh.vertices[vertices_3].cotex_coords[1] = uv_layers_data[face.loop_start+2].uvtex_coords[2] = uv_layers_data[face.loop_start+3].uvvertices[1] = vertices_2_wvertices[2] = vertices_3_w# 计算重心坐标，判断该像素点是否在第一个三角面内barycenter = calculate_barycenter_3d(coord_world, vertices)if (barycenter[3] <= 1.000001):coord_xy = calculate_point_from_barycenter((barycenter[0], barycenter[1], barycenter[2]), tex_coords)sql_value.append((0, y, x, float(face.material_index), 1-coord_xy[1], coord_xy[0], 1.0))else:vertices_0 = mesh.loops[face.loop_start].vertex_indextex_coords.append(uv_layers_data[face.loop_start].uv)vertices.append(world_mat @ mesh.vertices[vertices_0].co)vertices_1 = mesh.loops[face.loop_start+1].vertex_indextex_coords.append(uv_layers_data[face.loop_start+1].uv)vertices.append(world_mat @ mesh.vertices[vertices_1].co)vertices_2 = mesh.loops[face.loop_start+2].vertex_indextex_coords.append(uv_layers_data[face.loop_start+2].uv)vertices.append(world_mat @ mesh.vertices[vertices_2].co)# 计算重心坐标，判断该像素点是否在第一个三角面内barycenter = calculate_barycenter_3d(coord_world, vertices)if (barycenter[3] <= 1.000001):coord_xy = calculate_point_from_barycenter((barycenter[0], barycenter[1], barycenter[2]), tex_coords)sql_value.append((0, y, x, float(face.material_index), 1-coord_xy[1], coord_xy[0], 1.0))# sql_value.append((0,render_width-x,y, float(face.material_index), 1-coord_xy[1], coord_xy[0], 1.0))insertValueIntoTable(sql_value, db_cur)insertValueIntoKeyValueTable([("canvas_width",render_width),("canvas_height",render_height)],db_cur)dissconnectDB(db_cur)except Exception as e:dissconnectDB(db_cur)这篇关于blender中获取虚拟相机渲染图片上每像素对应的纹理上的像素值的文章就介绍到这儿，希望我们推荐的文章对编程师们有所帮助！
