kc3-lang/angle/samples/torus_lighting/torus.h

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• Hash : d1da88ee
  Author :
  Date : 2021-04-28T14:23:48
  

  samples: Add TorusLighting sample.
  
  Add a vertex buffer example for GLES1 and 2.
  
  Bug: angleproject:5751
  Change-Id: If039451ff85dfffd8915497e9aaaab6e4ff71181
  Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2859827
  Commit-Queue: Cody Northrop <cnorthrop@google.com>
  Reviewed-by: Cody Northrop <cnorthrop@google.com>
  Reviewed-by: Jamie Madill <jmadill@chromium.org>
  

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• samples/torus_lighting/torus.h

• //
  // Copyright 2021 The ANGLE Project Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style license that can be
  // found in the LICENSE file.
  //
  
  // Based on CubeMapActivity.java from The Android Open Source Project ApiDemos
  // https://android.googlesource.com/platform/development/+/refs/heads/master/samples/ApiDemos/src/com/example/android/apis/graphics/CubeMapActivity.java
  
  #ifndef SAMPLE_TORUS_LIGHTING_H_
  #define SAMPLE_TORUS_LIGHTING_H_
  
  #include <cmath>
  
  const float kPi      = 3.1415926535897f;
  const GLushort kSize = 60;
  
  void GenerateTorus(GLuint *vertexBuffer, GLuint *indexBuffer, GLsizei *indexCount)
  {
      std::vector<GLushort> indices;
      for (GLushort y = 0; y < kSize; y++)
      {
          for (GLushort x = 0; x < kSize; x++)
          {
              GLushort a = y * (kSize + 1) + x;
              GLushort b = y * (kSize + 1) + x + 1;
              GLushort c = (y + 1) * (kSize + 1) + x;
              GLushort d = (y + 1) * (kSize + 1) + x + 1;
  
              indices.push_back(a);
              indices.push_back(c);
              indices.push_back(b);
  
              indices.push_back(b);
              indices.push_back(c);
              indices.push_back(d);
          }
      }
      *indexCount = static_cast<GLsizei>(indices.size());
  
      std::vector<GLfloat> vertices;
      for (uint32_t j = 0; j <= kSize; j++)
      {
          float angleV = kPi * 2 * j / kSize;
          float cosV   = cosf(angleV);
          float sinV   = sinf(angleV);
          for (uint32_t i = 0; i <= kSize; i++)
          {
              float angleU = kPi * 2 * i / kSize;
              float cosU   = cosf(angleU);
              float sinU   = sinf(angleU);
              float d      = 3.0f + 0.75f * cosU;
  
              float x = d * cosV;
              float y = d * (-sinV);
              float z = 0.75f * sinU;
  
              vertices.push_back(x);
              vertices.push_back(y);
              vertices.push_back(z);
  
              float nx = cosV * cosU;
              float ny = -sinV * cosU;
              float nz = sinU;
  
              float length = sqrtf(nx * nx + ny * ny + nz * nz);
              nx /= length;
              ny /= length;
              nz /= length;
  
              vertices.push_back(nx);
              vertices.push_back(ny);
              vertices.push_back(nz);
          }
      }
  
      glGenBuffers(1, vertexBuffer);
      glBindBuffer(GL_ARRAY_BUFFER, *vertexBuffer);
      glBufferData(GL_ARRAY_BUFFER, vertices.size() * sizeof(GLfloat), vertices.data(),
                   GL_STATIC_DRAW);
  
      glGenBuffers(1, indexBuffer);
      glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, *indexBuffer);
      glBufferData(GL_ELEMENT_ARRAY_BUFFER, indices.size() * sizeof(GLushort), indices.data(),
                   GL_STATIC_DRAW);
  }
  
  #endif  // SAMPLE_TORUS_LIGHTING_H_
  

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