add uniform variable to shader

1 files changed, 13 insertions, 0 deletions

diff --git a/main.c b/main.c
index 09cf2fb..c4da904 100644
--- a/main.c
+++ b/main.c
@@ -1,6 +1,8 @@
 #include <stdlib.h>
 #include <GL/glew.h>
 #include <GLFW/glfw3.h>
+#include <sys/time.h>
+#include <time.h>
 
 #include "shader.h"
 #include "die.h"
@@ -63,10 +65,21 @@ int main(int argc, char** argv) {
 		frag_shader(visuals_frag, visuals_frag_size)
 	);
 
+	// prepare uniform variables
+	GLint u_time = glGetUniformLocation(shader, "time");
+	int time_start = time(NULL);
+
 	// main draw loop
 	while (!glfwWindowShouldClose(window)) {
 		glfwPollEvents();
 
+		// set `time` uniform
+		struct timeval t;
+		gettimeofday(&t, NULL);
+		t.tv_sec -= time_start;
+		float time = t.tv_sec + (t.tv_usec / 1e6);
+		glUniform1f(u_time, time);
+
 		glUseProgram(shader);
 		glDrawArrays(GL_TRIANGLES, 0, 3);