From 56cf6098493af08145c987bae11d60c0503a99cb Mon Sep 17 00:00:00 2001
From: Nathan Chapman <nchapman@iworq.com>
Date: Wed, 2 Jul 2025 08:09:31 -0600
Subject: [PATCH] Add GLM and make the triangle move

---
 CMakeLists.txt |  4 +++-
 src/main.cpp   | 56 +++++++++++++++++++++++++++++++++++---------------
 2 files changed, 42 insertions(+), 18 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index b16cebd..1e46acf 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -5,6 +5,7 @@ set(CMAKE_CXX_STANDARD 17)
 
 find_package(OpenGL REQUIRED)
 find_package(GLEW REQUIRED)
+find_package(glm REQUIRED)
 find_package(glfw3 REQUIRED)
 
 add_executable(opengl_test src/main.cpp)
@@ -12,5 +13,6 @@ add_executable(opengl_test src/main.cpp)
 target_link_libraries(opengl_test
     OpenGL::GL
     GLEW::GLEW
+    glm::glm
     glfw
-)
\ No newline at end of file
+)
diff --git a/src/main.cpp b/src/main.cpp
index 5e6de88..88c0bca 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -2,28 +2,31 @@
 #include <string.h>
 #include <GL/glew.h>
 #include <GLFW/glfw3.h>
+#include <cmath>
 
 // Window dimensions
 const GLint WIDTH = 800, HEIGHT = 600;
 
 // Vertex Shader
-static const char *vertex_shader = "              \n\
-#version 330                                      \n\
-                                                  \n\
-layout (location = 0) in vec3 pos;                \n\
-                                                  \n\
-void main() {                                     \n\
-    gl_Position = vec4(pos.x, pos.y, pos.z, 1.0); \n\
+static const char *vertex_shader = "                                 \n\
+#version 330                                                         \n\
+                                                                     \n\
+layout (location = 0) in vec3 pos;                                   \n\
+                                                                     \n\
+uniform float x_move;                                                \n\
+                                                                     \n\
+void main() {                                                        \n\
+    gl_Position = vec4(pos.x + x_move, pos.y, pos.z, 1.0);           \n\
 }";
 
 // Fragment shader
-static const char *fragment_shader =  "           \n\
-#version 330                                      \n\
-                                                  \n\
-out vec4 color;                                   \n\
-                                                  \n\
-void main() {                                     \n\
-    color = vec4(1.0, 0.0, 0.0, 1.0);             \n\
+static const char *fragment_shader =  "                              \n\
+#version 330                                                         \n\
+                                                                     \n\
+out vec4 color;                                                      \n\
+                                                                     \n\
+void main() {                                                        \n\
+    color = vec4(1.0, 0.0, 0.0, 1.0);                                \n\
 }";
 
 bool add_shader(GLuint *program, const char *shader_code, GLenum shader_type) {
@@ -51,7 +54,7 @@ bool add_shader(GLuint *program, const char *shader_code, GLenum shader_type) {
     return true;
 }
 
-bool compile_shaders(GLuint *shader_program) {
+bool compile_shaders(GLuint *shader_program, GLuint *x_move) {
     *shader_program = glCreateProgram();
 
     if (!shader_program) {
@@ -83,6 +86,8 @@ bool compile_shaders(GLuint *shader_program) {
         return false;
     }
 
+    *x_move = glGetUniformLocation(*shader_program, "x_move");
+
     return true;
 }
 
@@ -109,7 +114,11 @@ void create_triangle(GLuint *VAO, GLuint *VBO) {
 }
 
 int main() {
-    GLuint VAO, VBO, shader_program;
+    GLuint VAO, VBO, shader_program, x_move;
+    bool direction = true;
+    float tri_offset = 0.0f;
+    float tri_max_offset = 0.7f;
+    float tri_increment = 0.005f;
 
     // Initialize GLFW
     glfwInitHint(GLFW_PLATFORM, GLFW_PLATFORM_WAYLAND);
@@ -168,18 +177,31 @@ int main() {
 
     // Create our triangle
     create_triangle(&VAO, &VBO);
-    compile_shaders(&shader_program);
+    compile_shaders(&shader_program, &x_move);
 
     // Loop until window is closed
     while (!glfwWindowShouldClose(window)) {
         // Get and handle user input events
         glfwPollEvents();
 
+        if (direction) {
+            tri_offset += tri_increment;
+        } else {
+            tri_offset -= tri_increment;
+        }
+
+        if (std::abs(tri_offset) >= tri_max_offset) {
+            direction = !direction;
+        }
+
         // Clear window
         glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
         glClear(GL_COLOR_BUFFER_BIT);
 
         glUseProgram(shader_program);
+
+        glUniform1f(x_move, tri_offset);
+        
         glBindVertexArray(VAO);
         glDrawArrays(GL_TRIANGLES, 0, 3);