1 files changed, 25 insertions, 8 deletions
diff --git a/src/main.c b/src/main.c
index 8c77270..77ed9d5 100644
--- a/src/main.c
+++ b/src/main.c
@@ -1,5 +1,6 @@
 #include <GL/glew.h>
 #include <GLFW/glfw3.h>
+#include <math.h>
 #include <stdio.h>
 #include <stdlib.h>
 
@@ -7,6 +8,11 @@ void on_resize(GLFWwindow *win, int width, int height) {
   glViewport(0, 0, width, height);
 }
 
+void get_max_attrib_count(int *attrib_count) {
+  glGetIntegerv(GL_MAX_VERTEX_ATTRIBS, attrib_count);
+  printf("Max vertex attribs %d\n", *attrib_count);
+}
+
 int main() {
   // Initialize GLFW
   if (!glfwInit()) {
@@ -25,7 +31,6 @@ int main() {
   }
 
   glfwSetFramebufferSizeCallback(window, (void *)on_resize);
-
   glfwMakeContextCurrent(window);
 
   // Initialize GLEW
@@ -35,6 +40,9 @@ int main() {
     return -1;
   }
 
+  int attrib_count;
+  get_max_attrib_count(&attrib_count);
+
   float vertices[] = {
       0.5f,  0.5f,  0.0f, // top right
       0.5f,  -0.5f, 0.0f, // bottom right
@@ -55,9 +63,11 @@ int main() {
   const char *vertex_shader_src =
       "#version 330 core\n"
       "layout (location = 0) in vec3 aPos;\n"
+      "out vec4 vertexColor;\n"
       "void main()\n"
       "{\n"
       "   gl_Position = vec4(aPos.x, aPos.y, aPos.z, 1.0);\n"
+      "   vertexColor = vec4(0.5, 0.0, 0.0, 1.0);\n"
       "}\0";
 
   unsigned int vertex_shader = glCreateShader(GL_VERTEX_SHADER);
@@ -73,13 +83,13 @@ int main() {
     printf("ERROR::SHADER::VERTEX::COMPILATION_FAILED\n%s\n", info_log);
   }
 
-  const char *fragment_shader_src =
-      "#version 330 core\n"
-      "out vec4 FragColor;\n"
-      "void main()\n"
-      "{\n"
-      " FragColor = vec4(1.0f, 0.5f, 0.2f, 1.0f);\n"
-      "}\0";
+  const char *fragment_shader_src = "#version 330 core\n"
+                                    "out vec4 FragColor;\n"
+                                    "uniform vec4 ourColor;\n"
+                                    "void main()\n"
+                                    "{\n"
+                                    " FragColor = ourColor;\n"
+                                    "}\0";
 
   unsigned int fragment_shader = glCreateShader(GL_FRAGMENT_SHADER);
   glShaderSource(fragment_shader, 1, &fragment_shader_src, NULL);
@@ -124,6 +134,13 @@ int main() {
     glClear(GL_COLOR_BUFFER_BIT);
 
     glUseProgram(shader_program);
+    float time_value = glfwGetTime();
+    float green_value = (sin(time_value) / 2.0f) + 0.5f;
+    int vertex_color_location =
+        glGetUniformLocation(shader_program, "ourColor");
+
+    glUniform4f(vertex_color_location, 0.0f, green_value, 0.0f, 1.0f);
+
     glBindVertexArray(VAO);
     glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
     glBindVertexArray(0);