From d79f49535e3563ae89d59b370a7d54e5212a2c43 Mon Sep 17 00:00:00 2001
From: k <markers711@gmail.com>
Date: Sun, 8 Dec 2024 02:05:17 -0500
Subject: [PATCH] hello rectangele

---
 headers/shapes.h | 18 ++++++++++++++++--
 src/main.cpp     | 12 ++++++++----
 2 files changed, 24 insertions(+), 6 deletions(-)

diff --git a/headers/shapes.h b/headers/shapes.h
index b8cc635..77b7c09 100644
--- a/headers/shapes.h
+++ b/headers/shapes.h
@@ -1,16 +1,30 @@
 float tri_vertices[] = {-0.5f, -0.5f, 0.0f, 0.5f, -0.5f, 0.0f, 0.0f, 0.5f, 0.0f};
 
+float sqr_vertices[] = {
+  0.5f,  0.5f, 0.0f,  /*top R*/
+  0.5f, -0.5f, 0.0f,  /*bottom R*/
+  -0.5f, -0.5f, 0.0f, /*bottom L*/
+  -0.5f,  0.5f, 0.0f/*top R*/
+};
+
+unsigned int sqr_indices[] = {
+  0, 1, 3,/*tl triangle*/
+  1, 2, 3 /*br triangle*/
+};
 
 const char *basicVertexShaderSource = "#version 330 core\n"
     "layout (location = 0) in vec3 aPos;\n"
+    "out vec3 color;\n"
     "void main()\n"
     "{\n"
+    "   color = aPos;"
     "   gl_Position = vec4(aPos.x, aPos.y, aPos.z, 1.0);\n"
     "}\0";
 
 const char *basicFragmentShaderSource = "#version 330 core\n"
-  "out vec4 FragColor;\n"
+  "out vec3 FragColor;\n"
+  "in vec3 color;"
   "void main()\n"
   "{\n"
-  "    FragColor = vec4(1.0f, 0.5f, 0.2f, 1.0f);\n"
+  "    FragColor = (color/2+.5)*1.5;\n"
   "}\n";
diff --git a/src/main.cpp b/src/main.cpp
index d1a4991..763d2b7 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -32,19 +32,22 @@ int main(void) {
   glViewport(0, 0, 800, 600);
   glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
 
-  unsigned int VBO,VAO;
+  unsigned int VBO,VAO,EBO;
   glGenVertexArrays(1, &VAO);
   glBindVertexArray(VAO);
 
   glGenBuffers(1, &VBO);
   glBindBuffer(GL_ARRAY_BUFFER, VBO);
 
-  glBufferData(GL_ARRAY_BUFFER, sizeof(tri_vertices), tri_vertices,
+  glBufferData(GL_ARRAY_BUFFER, sizeof(sqr_vertices), sqr_vertices,
                GL_STATIC_DRAW);
-
   glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void *)0);
   glEnableVertexAttribArray(0);
 
+  glGenBuffers(1, &EBO);
+  glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
+  glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(sqr_indices), sqr_indices, GL_STATIC_DRAW);
+
   unsigned int shaderProgram =
       shaderProgramCMPL(basicVertexShaderSource, basicFragmentShaderSource);
   glUseProgram(shaderProgram);
@@ -57,7 +60,8 @@ int main(void) {
 
     glUseProgram(shaderProgram);
     glBindVertexArray(VAO);
-    glDrawArrays(GL_TRIANGLES, 0, 3);
+
+    glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
     glfwSwapBuffers(window);
 
     glfwPollEvents();