{"id":3623,"date":"2018-01-21T12:51:51","date_gmt":"2018-01-21T04:51:51","guid":{"rendered":"http:\/\/www.bookcard.net\/wordpress\/?p=3623"},"modified":"2018-10-14T21:24:16","modified_gmt":"2018-10-14T13:24:16","slug":"opengl_normal","status":"publish","type":"post","link":"https:\/\/www.bookcard.net\/wordpress\/opengl_normal\/","title":{"rendered":"OpenGL\u4e4b\u6cd5\u7dda"},"content":{"rendered":"
\"\"<\/a>
OpenGL\u4e4b\u6cd5\u7dda<\/figcaption><\/figure>\n

\u6cd5\u7dda:\u5373\u5782\u76f4\u65bc\u5176\u8868\u9762\u7684\u55ae\u4f4d\u77e2\u91cf<\/p>\n

OpenGL\u5728\u9032\u884c\u5149\u7167\u904b\u7b97\u524d\u9700\u5148\u8a08\u7b97\u6cd5\u7dda,\u5149\u8207\u8868\u9762\u76f8\u4ea4\u7684\u89d2\u5ea6\u5229\u7528\u6cd5\u5148\u8a08\u7b97\u51fa\u53cd\u5c04\u89d2\u5ea6,\u7d50\u5408\u5149\u7167\u8207\u6750\u8cea\u8a08\u7b97\u8868\u9762\u7684\u984f\u8272<\/p>\n\n\n\n\n
\u6cd5\u7dda\u51fd\u5f0f<\/td>\n\u7c21\u4ecb<\/td>\n<\/tr>\n
void glNormal3f (GLfloat nx, GLfloat ny, GLfloat nz);<\/td>\n\u8a2d\u7f6e\u6cd5\u7dda<\/p>\n

(nx,ny,nz):\u6cd5\u7dda\u5750\u6a19\u5206\u91cf<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

\u6cd5\u7dda\u51fd\u5f0f\u793a\u4f8b<\/p>\n

glBegin(GL_POLYGON);<\/p>\n

glNormal3f(0.0f,1.0f,0.0f);\/\/ \u6cd5\u7dda<\/p>\n

glVertex3f( 0.5f, 0.5f, 0.5f);<\/p>\n

glVertex3f( 0.5f, 0.5f,-0.5f);<\/p>\n

glVertex3f(-0.5f, 0.5f,-0.5f);<\/p>\n

glVertex3f(-0.5f, 0.5f, 0.5f);<\/p>\n

glEnd();<\/p>\n\n\n\n\n
\u6cd5\u7dda\u7684\u8a08\u7b97<\/td>\n\u7c21\u4ecb<\/td>\n<\/tr>\n
A*B=(Ax*Bz-Az*By, Az*Bx-Ax*Bz, Ax*By-Ay*Bx)<\/td>\n\u77e2\u91cfA\u548cB\u53c9\u7a4d\u65b9\u7a0b<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

\u8a08\u7b97\u5169\u500b3D\u5411\u91cf\u7684\u6cd5\u7dda(\u53c9\u7a4d)<\/p>\n

void Cross(float pa[3], float pb[3], float pc[3],float normal[3])<\/p>\n

{<\/p>\n

float va[3],vb[3];\/\/\u77e2\u91cf1,\u77e2\u91cf2<\/p>\n

float length;\/\/\u77e2\u91cf\u9577\u5ea6<\/p>\n

\/\/ \u8a08\u7b97\u77e2\u91cf1<\/p>\n

va[0] = pa[0] – pb[0];<\/p>\n

va[1] = pa[1] – pb[1];<\/p>\n

va[2] = pa[2] – pb[2];<\/p>\n

\/\/ \u8a08\u7b97\u77e2\u91cf2<\/p>\n

vb[0] = pb[0] – pc[0];<\/p>\n

vb[1] = pb[1] – pc[1];<\/p>\n

vb[2] = pb[2] – pc[2];<\/p>\n

\/\/ \u8a08\u7b97\u53c9\u7a4d<\/p>\n

normal[0] = va[1]vb[2] – va[2]<\/em>vb[1];<\/p>\n

normal[1] = va[2]vb[0] – va[0]<\/em>vb[2];<\/p>\n

normal[2] = va[0]vb[1] – va[1]<\/em>vb[0];<\/p>\n

\/\/ \u8a08\u7b97\u9577\u5ea6<\/p>\n

length = sqrt(normal[0]normal[0] + normal[1]<\/em>normal[1] + normal[2]*normal[2]);<\/p>\n

\/\/ \u8a08\u7b97\u55ae\u4f4d\u77e2\u91cf<\/p>\n

normal[0] = normal[0] \/ length;<\/p>\n

normal[1] = normal[1] \/ length;<\/p>\n

normal[2] = normal[2] \/ length;<\/p>\n

}<\/p>\n

\u6cd5\u7dda\u6f14\u793a\u7a0b\u5f0f,\u65cb\u8f49\u6b63\u65b9\u9ad4\u89c0\u770b\u5149\u7167\u7684\u8b8a\u5316\u5982\u4e0a\u5716:\u4e0b\u8f09<\/a><\/p>\n

    \n
  1. \u6309+\/-\u9375\u589e\u52a0\u6216\u6e1b\u5c0f\u5149\u7167\u4eae\u5ea6<\/li>\n
  2. \u6309SPACE(\u7a7a\u683c)\u9375\u555f\u7528\u6216\u7981\u7528\u5149\u7167<\/li>\n
  3. \u6309UP\/DOWN\u9375\u6b63\u65b9\u9ad4\u7e5eX\u8ef8\u65cb\u8f49<\/li>\n
  4. \u6309LEFT\/RIGHT\u9375\u6b63\u65b9\u9ad4\u7e5eY\u8ef8\u65cb\u8f49<\/li>\n
  5. \u6309Z+LEFT\/Z+RIGHT\u9375\u6b63\u65b9\u9ad4\u7e5eZ\u8ef8\u65cb\u8f49<\/li>\n
  6. \u6309F1\u9375\u6253\u958b\u5e6b\u52a9<\/li>\n
  7. \u6309ESC\u9375\u91cd\u7f6e\u6a21\u578b\u65cb\u8f49\u89d2\u5ea6<\/li>\n<\/ol>\n

     <\/p>\n","protected":false},"excerpt":{"rendered":"

    \u6cd5\u7dda:\u5373\u5782\u76f4\u65bc\u5176\u8868\u9762\u7684\u55ae\u4f4d\u77e2\u91cf OpenGL\u5728\u9032\u884c\u5149\u7167\u904b\u7b97\u524d\u9700\u5148\u8a08\u7b97\u6cd5\u7dda,\u5149\u8207\u8868\u9762\u76f8\u4ea4\u7684\u89d2\u5ea6\u5229\u7528\u6cd5\u5148\u8a08\u7b97\u51fa\u53cd\u5c04 … <\/p>\n

    \u7e7c\u7e8c\u95b1\u8b80 OpenGL\u4e4b\u6cd5\u7dda<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[62],"tags":[50],"class_list":["post-3623","post","type-post","status-publish","format-standard","hentry","category-opengl","tag-opengl","entry"],"amp_enabled":true,"_links":{"self":[{"href":"https:\/\/www.bookcard.net\/wordpress\/wp-json\/wp\/v2\/posts\/3623","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.bookcard.net\/wordpress\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.bookcard.net\/wordpress\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.bookcard.net\/wordpress\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.bookcard.net\/wordpress\/wp-json\/wp\/v2\/comments?post=3623"}],"version-history":[{"count":1,"href":"https:\/\/www.bookcard.net\/wordpress\/wp-json\/wp\/v2\/posts\/3623\/revisions"}],"predecessor-version":[{"id":3626,"href":"https:\/\/www.bookcard.net\/wordpress\/wp-json\/wp\/v2\/posts\/3623\/revisions\/3626"}],"wp:attachment":[{"href":"https:\/\/www.bookcard.net\/wordpress\/wp-json\/wp\/v2\/media?parent=3623"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.bookcard.net\/wordpress\/wp-json\/wp\/v2\/categories?post=3623"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.bookcard.net\/wordpress\/wp-json\/wp\/v2\/tags?post=3623"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}