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