OpenGL练习
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#include <GL/glew.h>
#include <GLFW/glfw3.h>
#include <iostream>
#include <string>
#include <fstream>
using namespace std;
void printShaderLog(GLuint shader) {
int len = 0;
int chWrittn = 0;
char *log;
glGetShaderiv(shader, GL_INFO_LOG_LENGTH, &len);
if (len > 0) {
log = (char *) malloc(len);
glGetShaderInfoLog(shader, len, &chWrittn, log);
cout << "Shader Info Log: " << log << endl;
free(log);
}
}
void printProgramLog(int prog) {
int len = 0;
int chWrittn = 0;
char *log;
glGetProgramiv(prog, GL_INFO_LOG_LENGTH, &len);
if (len > 0) {
log = (char *) malloc(len);
glGetProgramInfoLog(prog, len, &chWrittn, log);
cout << "Program Info Log: " << log << endl;
free(log);
}
}
bool checkOpenGLError() {
bool foundError = false;
int glErr = glGetError();
while (glErr != GL_NO_ERROR) {
cout << "glError : " << glErr << endl;
foundError = true;
glErr = glGetError();
}
return foundError;
}
string readShaderSource(const char *filePath) {
string content;
ifstream fileStream(filePath, ios::in);
string line = "";
while (!fileStream.eof()) {
getline(fileStream, line);
content.append(line + "\n");
}
fileStream.close();
return content;
}
using namespace std;
#define numVAOs 1
GLuint renderingProgram;
GLuint vao[numVAOs];
float x = 0.0f;
float inc = 0.01f;
GLuint createShaderProgram() {
const char *vshaderSource = readShaderSource("../tri.vert").c_str();
// const char *vshaderSource = "#version 430 \n"
// "\n"
// "void main(void)\n"
// "{\n"
// " if (gl_VertexID == 0) gl_Position = vec4( 0.25, -0.25, 0.0, 1.0);\n"
// "else if (gl_VertexID == 1) gl_Position = vec4(-0.25, -0.25, 0.0, 1.0);\n"
// " else gl_Position = vec4( 0.25, 0.25, 0.0, 1.0);}";
// cout<<vshaderSource;
const char *fshaderSource = readShaderSource("../firstvert.vert").c_str();
// cout<<fshaderSource;
GLuint vShader = glCreateShader(GL_VERTEX_SHADER);
GLuint fShader = glCreateShader(GL_FRAGMENT_SHADER);
glShaderSource(vShader, 1, &vshaderSource, NULL);
glShaderSource(fShader, 1, &fshaderSource, NULL);
printShaderLog(vShader);
printShaderLog(fShader);
glCompileShader(fShader);
glCompileShader(vShader);
cout<<"on vShader";
printShaderLog(vShader);
cout<<"on fShader";
printShaderLog(fShader);
GLuint vfProgram = glCreateProgram();
glAttachShader(vfProgram, vShader);
glAttachShader(vfProgram, fShader);
glLinkProgram(vfProgram);
return vfProgram;
}
void init(GLFWwindow *window) {
renderingProgram = createShaderProgram();
glGenVertexArrays(numVAOs, vao);
glBindVertexArray(vao[0]);
}
void display(GLFWwindow *window, double currentTime) {
glClear(GL_DEPTH_BUFFER_BIT);
glClearColor(0, 0, 0, 1);
glClear(GL_COLOR_BUFFER_BIT);
glUseProgram(renderingProgram);
// printProgramLog(renderingProgram);
// glPointSize(3);
// x += inc;
// if (x > 1.0f) inc = -0.01f;
// if (x < -1.0f) inc = 0.01f;
// cout << x << endl;;
// GLuint offsetLoc = glGetUniformLocation(renderingProgram, "offset");
// glProgramUniform1f(renderingProgram, offsetLoc, x);
glDrawArrays(GL_TRIANGLES, 0, 3);
}
int main(void) {
if (!glfwInit()) { exit(EXIT_FAILURE); }
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 4);
glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
GLFWwindow *window = glfwCreateWindow(600, 600, "GLAPP0", NULL, NULL);
glfwMakeContextCurrent(window);
if (glewInit() != GLEW_OK) {
exit(EXIT_FAILURE);
}
glfwSwapInterval(1);
init(window);
checkOpenGLError();
while (!glfwWindowShouldClose(window)) {
display(window, glfwGetTime());
glfwSwapBuffers(window);
glfwPollEvents();
}
glfwDestroyWindow(window);
glfwTerminate();
exit(EXIT_SUCCESS);
}