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#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <GL/glew.h>
#include <GLFW/glfw3.h>
#include "main.h"
const char *vertexShaderSource = \
"#version 330 core\n"
"layout (location = 0) in vec3 aPos;\n"
"void main()\n"
"{\n"
" gl_Position = vec4(aPos.x, aPos.y, aPos.z, 1.0);\n"
"}\0";
const char *fragmentShaderSource = \
"#version 330 core\n"
"out vec4 FragColor;\n"
"void main()\n"
"{\n"
" FragColor = vec4(1.0f, 0.5f, 0.2f, 1.0f);\n"
"}\0";
float vertices[] = {
-0.5f, -0.5f, 0.0f,
0.5f, -0.5f, 0.0f,
0.0f, 0.5f, 0.0f
};
//static void sysError(const char *msg);
static void userError(const char *msg, const char *detail);
static void glfw_size_callback(GLFWwindow *window, int width, int height);
static void processInput(GLFWwindow *window, struct Background *c);
static void checkGLSuccess(unsigned int compiledShader, unsigned int shaderStep);
void
userError(const char *msg, const char *detail)
{
fprintf(stderr, "%s: %s\n", msg, detail);
exit(1);
}
static void
glfw_size_callback(GLFWwindow *window, int width, int height)
{
glViewport(0, 0, width, height);
}
static void
processInput(GLFWwindow *window, struct Background *c)
{
if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS
|| glfwGetKey(window, GLFW_KEY_Q) == GLFW_PRESS) {
glfwSetWindowShouldClose(window, 1);
} else if (glfwGetKey(window, GLFW_KEY_R) == GLFW_PRESS
&& glfwGetKey(window, GLFW_KEY_LEFT_SHIFT) == GLFW_PRESS
&& c->R >= 0.0) {
c->R -= 0.1;
} else if (glfwGetKey(window, GLFW_KEY_R) == GLFW_PRESS && c->R <= 1.0) {
c->R += 0.1;
}
}
void
checkGLSuccess(unsigned int shaderBinary, unsigned int shaderStep)
{
int success;
char infoLog[512];
switch (shaderStep) {
case 0:
glGetShaderiv(shaderBinary, GL_COMPILE_STATUS, &success);
if (!success) {
glGetShaderInfoLog(shaderBinary, 512, NULL, infoLog);
userError("glCompileShader() ERROR", infoLog);
}
break;
case 1:
glGetProgramiv(shaderBinary, GL_LINK_STATUS, &success);
if (!success) {
glGetProgramInfoLog(shaderBinary, 512, NULL, infoLog);
userError("glLinkProgram() ERROR", infoLog);
}
break;
default:
break;
}
}
int main()
{
GLFWwindow *window;
const char *glfwErrno;
if (!glfwInit()) {
glfwGetError(&glfwErrno);
glfwTerminate();
userError("glfwInit() Error", glfwErrno);
}
window = glfwCreateWindow(640, 480, "Mverse", NULL, NULL);
if (!window) {
glfwTerminate();
userError("glfwCreateWindow() failed", "Can't create window");
}
glfwSetFramebufferSizeCallback(window, glfw_size_callback);
glfwMakeContextCurrent(window);
GLubyte glewErrno = glewInit();
if (glewErrno != GLEW_OK) {
glfwTerminate();
userError("glewInit() failed", (const char *)glewGetErrorString(glewErrno));
}
struct Background colors = {.R = 0.0, .G = 0.0, .B = 0.0, .A = 0.0};
unsigned int VBO, VAO;
glGenVertexArrays(1, &VAO);
glBindVertexArray(VAO);
glGenBuffers(1, &VBO);
glBindBuffer(GL_ARRAY_BUFFER, VBO);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void *)0);
glEnableVertexAttribArray(0);
unsigned int vertexShader, fragmentShader, shaderProgram;
vertexShader = glCreateShader(GL_VERTEX_SHADER);
glShaderSource(vertexShader, 1, &vertexShaderSource, NULL);
glCompileShader(vertexShader);
checkGLSuccess(vertexShader, 0);
printf("Vertex Compiled\n");
fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
glShaderSource(fragmentShader, 1, &fragmentShaderSource, NULL);
glCompileShader(fragmentShader);
checkGLSuccess(fragmentShader, 0);
printf("Fragment Compiled\n");
shaderProgram = glCreateProgram();
glAttachShader(shaderProgram, vertexShader);
glAttachShader(shaderProgram, fragmentShader);
glLinkProgram(shaderProgram);
checkGLSuccess(shaderProgram, 1);
glDeleteShader(vertexShader);
glDeleteShader(fragmentShader);
while (!glfwWindowShouldClose(window)) {
processInput(window, &colors);
glClearColor(colors.R, colors.G, colors.B, colors.A);
glClear(GL_COLOR_BUFFER_BIT);
glUseProgram(shaderProgram);
glBindVertexArray(VAO);
glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
glDrawArrays(GL_TRIANGLES, 0, 3);
glfwSwapBuffers(window);
glfwPollEvents();
}
glfwTerminate();
return 0;
}
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