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#include <GL/glew.h>
#include <GLFW/glfw3.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <pthread.h>
static void error_callback(int error, const char* description) { fputs(description, stderr); }
static void key_callback(GLFWwindow* window, int key, int scancode, int action, int mods) {
if (key == GLFW_KEY_Q && action == GLFW_PRESS) glfwSetWindowShouldClose(window, GL_TRUE);
}
const char * readShader(char * path) {
fputs(path,stderr);
fputs("\n",stderr);
FILE *file = fopen(path, "r");
if (!file) {
fputs("Cannot read ",stderr);
fputs(path,stderr);
exit(EXIT_FAILURE);
}
char source[2000];
int res = fread(source,1,2000-1,file);
source[res] = 0;
fclose(file);
const char *c_str = source;
return c_str;
}
GLuint compileShader(const char * source, GLenum type) {
GLuint shader = glCreateShader(type);
glShaderSource(shader, 1, &source, NULL);
glCompileShader(shader);
int success;
glGetShaderiv(shader, GL_COMPILE_STATUS, &success);
if (!success) {
char infoLog[512];
glGetShaderInfoLog(shader, 512, NULL, infoLog);
fputs("Shader compilation failed:\n",stderr);
fputs(infoLog,stderr);
exit(EXIT_FAILURE);
}
else { return shader; }
}
GLuint linkShader(GLuint vertex, GLuint fragment) {
GLuint shaderProgram = glCreateProgram();
glAttachShader(shaderProgram, vertex);
glAttachShader(shaderProgram, fragment);
glLinkProgram(shaderProgram);
int success;
char infoLog[512];
glGetProgramiv(shaderProgram, GL_LINK_STATUS, &success);
if (!success) {
glGetProgramInfoLog(shaderProgram, 512, NULL, infoLog);
fputs("Shader linking failed:\n",stderr);
fputs(infoLog,stderr);
}
glDetachShader(shaderProgram, vertex);
glDetachShader(shaderProgram, fragment);
glDeleteShader(vertex);
glDeleteShader(fragment);
glUseProgram(shaderProgram);
return shaderProgram;
}
GLFWwindow* createWindow() {
glfwInit();
glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 4);
GLFWwindow* window = glfwCreateWindow(1920,1080, "", NULL, NULL);
glfwMakeContextCurrent(window);
//glfwSetKeyCallback(window, key_callback);
glfwSetErrorCallback(error_callback);
glewInit();
return window;
}
GLuint createShader() {
GLuint vertexShader = compileShader(readShader("shader.vert"), GL_VERTEX_SHADER);
GLuint fragmentShader = compileShader(readShader("shader.frag"),GL_FRAGMENT_SHADER);
GLuint shaderProgram = linkShader(vertexShader,fragmentShader);
unsigned int VAO;
glGenVertexArrays(1, &VAO);
glBindVertexArray(VAO);
return shaderProgram;
};
void uniform1f(GLuint * shader, char * var, float f) {
int v = glGetUniformLocation(*shader, var);
glUniform1f(v, f);
}
void uniform2f(GLuint shader, char * var, float f0, float f1) {
int v = glGetUniformLocation(shader, var);
glUniform2f(v,f0,f1);
}
float color = 0.9;
void *readStdin(void * s) {
GLuint *shader = s;
while (1) {
char * str;
size_t l = 80;
getline(&str,&l,stdin);
char * variable = strtok (str," ");
float value = atof(strtok (NULL,"\n"));
printf("%.1f\n",value);
color = value;
}
}
int main(void) {
GLFWwindow* window = createWindow();
GLuint shader = createShader();
uniform2f(shader, "resolution", 1920,1080);
pthread_t tid;
pthread_create(&tid, NULL, readStdin, &shader);
while (!glfwWindowShouldClose(window)) {
uniform1f(&shader, "time",glfwGetTime());
uniform1f(&shader, "color",color);
glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
glfwSwapBuffers(window);
//glfwPollEvents();
}
//pthread_join(tid, NULL);
//printf("After Thread\n");
glfwDestroyWindow(window);
glfwTerminate();
exit(EXIT_SUCCESS);
}
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