matrixcr · April 17, 2022 04:00 · Mar 10, 2015 · Mar 10, 2015 · Mar 10, 2015 · Mar 10, 2015
diff --git a/Usage.cpp b/Usage.cpp
@@ -0,0 +1,24 @@
+void initializeGL()
+{
+	// Load shaders, link program for drawing sphere
+	m_sphereProgramID = LoadShaders("shader/sphereShader.vert", "shader/sphereShader.frag");
+	GLuint vertexPosition_modelspaceID = glGetAttribLocation(m_sphereProgramID, "vertexPosition_modelspace");
+
+	// load OpenGL resources needed by the sphere
+	// pass the vertex position id to it
+	sphere.init(vertexPosition_modelspaceID);
+}
+
+void paintGL() {
+	// use corresponding shader program, and set the transformation matrices
+	glUseProgram(m_sphereProgramID);
+	GLuint projMatrixID = glGetUniformLocation(m_sphereProgramID, "projMatrix");
+	GLuint mvMatrixID = glGetUniformLocation(m_sphereProgramID, "mvMatrix");
+	glUniformMatrix4fv(projMatrixID, 1, GL_FALSE, glm::value_ptr(m_projMatrix));
+	glUniformMatrix4fv(mvMatrixID, 1, GL_FALSE, glm::value_ptr(m_mvMatrix));
+	sphere.draw();
+}
+
+void cleanUp() {
+	sphere.cleanup();
+}
diff --git a/sphereShader.frag b/sphereShader.frag
@@ -0,0 +1,7 @@
+#version 120
+
+
+void main(){
+	// Output color = color of the texture at the specified UV
+	gl_FragColor = vec4 (1.0, 0.0, 0.0, 1.0);
+}
diff --git a/sphereShader.vert b/sphereShader.vert
@@ -0,0 +1,14 @@
+#version 120
+// Input vertex data, different for all executions of this shader.
+attribute vec3 vertexPosition_modelspace;
+
+// Output data ; will be interpolated for each fragment.
+varying vec2 UV;
+
+uniform mat4 projMatrix;
+uniform mat4 mvMatrix;
+
+void main()
+{
+	gl_Position = projMatrix * mvMatrix * vec4(vertexPosition_modelspace, 1);
+}
diff --git a/Sphere.cpp b/Sphere.cpp
@@ -0,0 +1,114 @@
+#include "sphere.h"
+
+#include <vector>
+#include <iostream>
+#include <glm/gtc/matrix_inverse.hpp>
+#include <glm/gtc/type_ptr.hpp>
+#include <glm/gtx/string_cast.hpp>
+
+Sphere::Sphere()
+{
+    isInited = false;
+    m_vao = 0;
+    m_vboVertex = 0;
+    m_vboIndex = 0;
+
+    lats = 40;
+    longs = 40;
+}
+
+Sphere::~Sphere()
+{
+
+}
+
+void Sphere::init(GLuint vertexPositionID)
+{
+    int i, j;
+    std::vector<GLfloat> vertices;
+    std::vector<GLuint> indices;
+    int indicator = 0;
+    for(i = 0; i <= lats; i++) {
+        double lat0 = glm::pi<double>() * (-0.5 + (double) (i - 1) / lats);
+       double z0  = sin(lat0);
+       double zr0 =  cos(lat0);
+
+       double lat1 = glm::pi<double>() * (-0.5 + (double) i / lats);
+       double z1 = sin(lat1);
+       double zr1 = cos(lat1);
+
+       for(j = 0; j <= longs; j++) {
+           double lng = 2 * glm::pi<double>() * (double) (j - 1) / longs;
+           double x = cos(lng);
+           double y = sin(lng);
+
+           vertices.push_back(x * zr0);
+           vertices.push_back(y * zr0);
+           vertices.push_back(z0);
+           indices.push_back(indicator);
+           indicator++;
+
+           vertices.push_back(x * zr1);
+           vertices.push_back(y * zr1);
+           vertices.push_back(z1);
+           indices.push_back(indicator);
+           indicator++;
+       }
+       indices.push_back(GL_PRIMITIVE_RESTART_FIXED_INDEX);
+   }
+
+    // 创建并绑定环境
+    glGenVertexArrays(1, &m_vao);
+    glBindVertexArray(m_vao);
+
+    glGenBuffers(1, &m_vboVertex);
+    glBindBuffer(GL_ARRAY_BUFFER, m_vboVertex);
+    glBufferData(GL_ARRAY_BUFFER, vertices.size() * sizeof(GLfloat), &vertices[0], GL_STATIC_DRAW);
+
+    glVertexAttribPointer(vertexPositionID, 3, GL_FLOAT, GL_FALSE, 0, NULL);
+    glEnableVertexAttribArray (vertexPositionID);
+
+    glGenBuffers(1, &m_vboIndex);
+    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, m_vboIndex);
+    glBufferData(GL_ELEMENT_ARRAY_BUFFER, indices.size() * sizeof(GLuint), &indices[0], GL_STATIC_DRAW);
+
+    numsToDraw = indices.size();
+
+    isInited = true;
+}
+
+void Sphere::cleanup()
+{
+    if (!isInited) {
+        return;
+    }
+    if(m_vboVertex) {
+        glDeleteBuffers(1, &m_vboVertex);
+    }
+    if(m_vboIndex) {
+        glDeleteBuffers(1, &m_vboIndex);
+    }
+    if (m_vao) {
+        glDeleteVertexArrays(1, &m_vao);
+    }
+
+    isInited = false;
+    m_vao = 0;
+    m_vboVertex = 0;
+    m_vboIndex = 0;
+}
+
+void Sphere::draw()
+{
+    if (!isInited) {
+        std::cout << "please call init() before draw()" << std::endl;
+    }
+
+    // draw sphere
+    glBindVertexArray(m_vao);
+    glEnable(GL_PRIMITIVE_RESTART);
+    glPrimitiveRestartIndex(GL_PRIMITIVE_RESTART_FIXED_INDEX);
+    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, m_vboIndex);
+    glDrawElements(GL_QUAD_STRIP, numsToDraw, GL_UNSIGNED_INT, NULL);
+}
+
diff --git a/Sphere.h b/Sphere.h
@@ -0,0 +1,22 @@
+#ifndef SPHERE_H
+#define SPHERE_H
+
+#include <GL/glew.h>
+
+class Sphere
+{
+public:
+    Sphere();
+    ~Sphere();
+    void init(GLuint vertexPositionID);
+    void cleanup();
+    void draw();
+
+private:
+    int lats, longs;
+    bool isInited;
+    GLuint m_vao, m_vboVertex, m_vboIndex;
+    int numsToDraw;
+};
+
+#endif // SPHERE_H
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