add fps display

src/main.c

@@ -2,11 +2,15 @@
 #include <GLFW/glfw3.h>
 #include <stdio.h>
 #include <string.h>
+#include <time.h>
+#include <unistd.h>
 
 #include "shader.h"
 #include "log.h"
 #include "src/shader.h"
 
+#define STATUS_INTERVAL 0.5
+
 GLuint program;
 
 GLuint vertexArrayObject;
@@ -14,6 +18,27 @@ GLuint vertexArrayObject;
 GLuint initialWindowWidth = 800;
 GLuint initialWindowHeight = 600;
 
+int frameCount = 0;
+struct timespec last_time, current_time;
+
+void initialiseStatusDisplay() {
+	clock_gettime(CLOCK_MONOTONIC, &last_time);
+}
+
+void updateStatusDisplay() {
+	frameCount++;
+	clock_gettime(CLOCK_MONOTONIC, &current_time);
+	double elapsed = (current_time.tv_sec - last_time.tv_sec) +
+					 (current_time.tv_nsec - last_time.tv_nsec) / 1e9;
+	if (elapsed >= STATUS_INTERVAL) {
+		double fps = frameCount / elapsed;
+		frameCount = 0;
+		last_time = current_time;
+		printf("\rFPS: %.2f ", fps);
+		fflush(stdout);
+	}
+}
+
 void init(void) {
 	INFO("Compiling Shaders...");
 
@@ -55,12 +80,14 @@ void init(void) {
 		 0.5f, -0.5f,   1.0f, 1.0f, 0.0f
 	};
 
+	DEBUG("Creating vertext buffer");
 	GLuint vertexBuffer;
 	glGenBuffers(1, &vertexBuffer);
 	glBindBuffer(GL_ARRAY_BUFFER, vertexBuffer);
 	glBufferData(GL_ARRAY_BUFFER, sizeof(triangleVertices), triangleVertices, GL_STATIC_DRAW);
 	glBindBuffer(GL_ARRAY_BUFFER, 0);
 
+	DEBUG("Creating vertex array object");
 	// create vertex array object
 	glGenVertexArrays(1, &vertexArrayObject);
 	glBindVertexArray(vertexArrayObject);
@@ -86,9 +113,14 @@ void init(void) {
 
 	glClearColor(0.1f, 0.1f, 0.1f, 1.0f);
 	glViewport(0, 0, initialWindowWidth, initialWindowHeight);
+
+	initialiseStatusDisplay();
+
+	INFO("--- Initialisation done ---");
 }
 
 void draw(void) {
+	updateStatusDisplay();
 	glClear(GL_COLOR_BUFFER_BIT);
 	glUseProgram(program);