third_party/angle/util/geometry_utils.cpp

   1 //
   2 // Copyright (c) 2014 The ANGLE Project Authors. All rights reserved.
   3 // Use of this source code is governed by a BSD-style license that can be
   4 // found in the LICENSE file.
   5 //
   6 // geometry_utils:
   7 //   Helper library for generating certain sets of geometry.
   8 //
   9
  10 #include "geometry_utils.h"
  11
  12 #define _USE_MATH_DEFINES
  13 #include <math.h>
  14
  15 using namespace angle;
  16
  17 SphereGeometry::SphereGeometry()
  18 {
  19 }
  20
  21 SphereGeometry::~SphereGeometry()
  22 {
  23 }
  24
  25 CubeGeometry::CubeGeometry()
  26 {
  27 }
  28
  29 CubeGeometry::~CubeGeometry()
  30 {
  31 }
  32
  33 void CreateSphereGeometry(size_t sliceCount, float radius, SphereGeometry *result)
  34 {
  35     size_t parellelCount = sliceCount / 2;
  36     size_t vertexCount   = (parellelCount + 1) * (sliceCount + 1);
  37     size_t indexCount    = parellelCount * sliceCount * 6;
  38     float angleStep      = static_cast<float>(2.0f * M_PI) / sliceCount;
  39
  40     result->positions.resize(vertexCount);
  41     result->normals.resize(vertexCount);
  42     for (size_t i = 0; i < parellelCount + 1; i++)
  43     {
  44         for (size_t j = 0; j < sliceCount + 1; j++)
  45         {
  46             Vector3 direction(sinf(angleStep * i) * sinf(angleStep * j), cosf(angleStep * i),
  47                               sinf(angleStep * i) * cosf(angleStep * j));
  48
  49             size_t vertexIdx             = i * (sliceCount + 1) + j;
  50             result->positions[vertexIdx] = direction * radius;
  51             result->normals[vertexIdx]   = direction;
  52         }
  53     }
  54
  55     result->indices.clear();
  56     result->indices.reserve(indexCount);
  57     for (size_t i = 0; i < parellelCount; i++)
  58     {
  59         for (size_t j = 0; j < sliceCount; j++)
  60         {
  61             result->indices.push_back(static_cast<unsigned short>(i * (sliceCount + 1) + j));
  62             result->indices.push_back(static_cast<unsigned short>((i + 1) * (sliceCount + 1) + j));
  63             result->indices.push_back(
  64                 static_cast<unsigned short>((i + 1) * (sliceCount + 1) + (j + 1)));
  65
  66             result->indices.push_back(static_cast<unsigned short>(i * (sliceCount + 1) + j));
  67             result->indices.push_back(
  68                 static_cast<unsigned short>((i + 1) * (sliceCount + 1) + (j + 1)));
  69             result->indices.push_back(static_cast<unsigned short>(i * (sliceCount + 1) + (j + 1)));
  70         }
  71     }
  72 }
  73
  74 void GenerateCubeGeometry(float radius, CubeGeometry *result)
  75 {
  76     result->positions.resize(24);
  77     result->positions[0]  = Vector3(-radius, -radius, -radius);
  78     result->positions[1]  = Vector3(-radius, -radius, radius);
  79     result->positions[2]  = Vector3(radius, -radius, radius);
  80     result->positions[3]  = Vector3(radius, -radius, -radius);
  81     result->positions[4]  = Vector3(-radius, radius, -radius);
  82     result->positions[5]  = Vector3(-radius, radius, radius);
  83     result->positions[6]  = Vector3(radius, radius, radius);
  84     result->positions[7]  = Vector3(radius, radius, -radius);
  85     result->positions[8]  = Vector3(-radius, -radius, -radius);
  86     result->positions[9]  = Vector3(-radius, radius, -radius);
  87     result->positions[10] = Vector3(radius, radius, -radius);
  88     result->positions[11] = Vector3(radius, -radius, -radius);
  89     result->positions[12] = Vector3(-radius, -radius, radius);
  90     result->positions[13] = Vector3(-radius, radius, radius);
  91     result->positions[14] = Vector3(radius, radius, radius);
  92     result->positions[15] = Vector3(radius, -radius, radius);
  93     result->positions[16] = Vector3(-radius, -radius, -radius);
  94     result->positions[17] = Vector3(-radius, -radius, radius);
  95     result->positions[18] = Vector3(-radius, radius, radius);
  96     result->positions[19] = Vector3(-radius, radius, -radius);
  97     result->positions[20] = Vector3(radius, -radius, -radius);
  98     result->positions[21] = Vector3(radius, -radius, radius);
  99     result->positions[22] = Vector3(radius, radius, radius);
 100     result->positions[23] = Vector3(radius, radius, -radius);
 101
 102     result->normals.resize(24);
 103     result->normals[0]  = Vector3(0.0f, -1.0f, 0.0f);
 104     result->normals[1]  = Vector3(0.0f, -1.0f, 0.0f);
 105     result->normals[2]  = Vector3(0.0f, -1.0f, 0.0f);
 106     result->normals[3]  = Vector3(0.0f, -1.0f, 0.0f);
 107     result->normals[4]  = Vector3(0.0f, 1.0f, 0.0f);
 108     result->normals[5]  = Vector3(0.0f, 1.0f, 0.0f);
 109     result->normals[6]  = Vector3(0.0f, 1.0f, 0.0f);
 110     result->normals[7]  = Vector3(0.0f, 1.0f, 0.0f);
 111     result->normals[8]  = Vector3(0.0f, 0.0f, -1.0f);
 112     result->normals[9]  = Vector3(0.0f, 0.0f, -1.0f);
 113     result->normals[10] = Vector3(0.0f, 0.0f, -1.0f);
 114     result->normals[11] = Vector3(0.0f, 0.0f, -1.0f);
 115     result->normals[12] = Vector3(0.0f, 0.0f, 1.0f);
 116     result->normals[13] = Vector3(0.0f, 0.0f, 1.0f);
 117     result->normals[14] = Vector3(0.0f, 0.0f, 1.0f);
 118     result->normals[15] = Vector3(0.0f, 0.0f, 1.0f);
 119     result->normals[16] = Vector3(-1.0f, 0.0f, 0.0f);
 120     result->normals[17] = Vector3(-1.0f, 0.0f, 0.0f);
 121     result->normals[18] = Vector3(-1.0f, 0.0f, 0.0f);
 122     result->normals[19] = Vector3(-1.0f, 0.0f, 0.0f);
 123     result->normals[20] = Vector3(1.0f, 0.0f, 0.0f);
 124     result->normals[21] = Vector3(1.0f, 0.0f, 0.0f);
 125     result->normals[22] = Vector3(1.0f, 0.0f, 0.0f);
 126     result->normals[23] = Vector3(1.0f, 0.0f, 0.0f);
 127
 128     result->texcoords.resize(24);
 129     result->texcoords[0]  = Vector2(0.0f, 0.0f);
 130     result->texcoords[1]  = Vector2(0.0f, 1.0f);
 131     result->texcoords[2]  = Vector2(1.0f, 1.0f);
 132     result->texcoords[3]  = Vector2(1.0f, 0.0f);
 133     result->texcoords[4]  = Vector2(1.0f, 0.0f);
 134     result->texcoords[5]  = Vector2(1.0f, 1.0f);
 135     result->texcoords[6]  = Vector2(0.0f, 1.0f);
 136     result->texcoords[7]  = Vector2(0.0f, 0.0f);
 137     result->texcoords[8]  = Vector2(0.0f, 0.0f);
 138     result->texcoords[9]  = Vector2(0.0f, 1.0f);
 139     result->texcoords[10] = Vector2(1.0f, 1.0f);
 140     result->texcoords[11] = Vector2(1.0f, 0.0f);
 141     result->texcoords[12] = Vector2(0.0f, 0.0f);
 142     result->texcoords[13] = Vector2(0.0f, 1.0f);
 143     result->texcoords[14] = Vector2(1.0f, 1.0f);
 144     result->texcoords[15] = Vector2(1.0f, 0.0f);
 145     result->texcoords[16] = Vector2(0.0f, 0.0f);
 146     result->texcoords[17] = Vector2(0.0f, 1.0f);
 147     result->texcoords[18] = Vector2(1.0f, 1.0f);
 148     result->texcoords[19] = Vector2(1.0f, 0.0f);
 149     result->texcoords[20] = Vector2(0.0f, 0.0f);
 150     result->texcoords[21] = Vector2(0.0f, 1.0f);
 151     result->texcoords[22] = Vector2(1.0f, 1.0f);
 152     result->texcoords[23] = Vector2(1.0f, 0.0f);
 153
 154     result->indices.resize(36);
 155     result->indices[0]  = 0;
 156     result->indices[1]  = 2;
 157     result->indices[2]  = 1;
 158     result->indices[3]  = 0;
 159     result->indices[4]  = 3;
 160     result->indices[5]  = 2;
 161     result->indices[6]  = 4;
 162     result->indices[7]  = 5;
 163     result->indices[8]  = 6;
 164     result->indices[9]  = 4;
 165     result->indices[10] = 6;
 166     result->indices[11] = 7;
 167     result->indices[12] = 8;
 168     result->indices[13] = 9;
 169     result->indices[14] = 10;
 170     result->indices[15] = 8;
 171     result->indices[16] = 10;
 172     result->indices[17] = 11;
 173     result->indices[18] = 12;
 174     result->indices[19] = 15;
 175     result->indices[20] = 14;
 176     result->indices[21] = 12;
 177     result->indices[22] = 14;
 178     result->indices[23] = 13;
 179     result->indices[24] = 16;
 180     result->indices[25] = 17;
 181     result->indices[26] = 18;
 182     result->indices[27] = 16;
 183     result->indices[28] = 18;
 184     result->indices[29] = 19;
 185     result->indices[30] = 20;
 186     result->indices[31] = 23;
 187     result->indices[32] = 22;
 188     result->indices[33] = 20;
 189     result->indices[34] = 22;
 190     result->indices[35] = 21;
 191 }