color vertex

1 files changed, 20 insertions, 30 deletions

diff --git a/src/main.c b/src/main.c
index 77ed9d5..a125823 100644
--- a/src/main.c
+++ b/src/main.c
@@ -44,30 +44,27 @@ int main() {
   get_max_attrib_count(&attrib_count);
 
   float vertices[] = {
-      0.5f,  0.5f,  0.0f, // top right
-      0.5f,  -0.5f, 0.0f, // bottom right
-      -0.5f, -0.5f, 0.0f, // bottom left
-      -0.5f, 0.5f,  0.0f  // top left
-  };
-  unsigned int indices[] = {
-      0, 1, 3, // first triangle
-      1, 2, 3  // second triangle
+      // positions         // colors
+      0.5f,  -0.5f, 0.0f, 1.0f, 0.0f, 0.0f, // bottom right
+      -0.5f, -0.5f, 0.0f, 0.0f, 1.0f, 0.0f, // bottom left
+      0.0f,  0.5f,  0.0f, 0.0f, 0.0f, 1.0f  // top
   };
 
   unsigned int VBO;
   glGenBuffers(1, &VBO);
   glBindBuffer(GL_ARRAY_BUFFER, VBO);
-  glBufferData(GL_ARRAY_BUFFER, sizeof(float) * 6 * 3, vertices,
+  glBufferData(GL_ARRAY_BUFFER, sizeof(float) * 3 * 6, vertices,
                GL_STATIC_DRAW);
 
   const char *vertex_shader_src =
       "#version 330 core\n"
       "layout (location = 0) in vec3 aPos;\n"
-      "out vec4 vertexColor;\n"
+      "layout (location = 1) in vec3 aColor;\n"
+      "out vec3 ourColor;\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"
+      "   ourColor = aColor;\n"
       "}\0";
 
   unsigned int vertex_shader = glCreateShader(GL_VERTEX_SHADER);
@@ -85,10 +82,10 @@ int main() {
 
   const char *fragment_shader_src = "#version 330 core\n"
                                     "out vec4 FragColor;\n"
-                                    "uniform vec4 ourColor;\n"
+                                    "in vec3 ourColor;\n"
                                     "void main()\n"
                                     "{\n"
-                                    " FragColor = ourColor;\n"
+                                    " FragColor = vec4(ourColor, 1.0);\n"
                                     "}\0";
 
   unsigned int fragment_shader = glCreateShader(GL_FRAGMENT_SHADER);
@@ -119,36 +116,29 @@ int main() {
   glGenVertexArrays(1, &VAO);
   glBindVertexArray(VAO);
 
-  unsigned int EBO;
-  glGenBuffers(1, &EBO);
-  glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
-  glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(float) * 2 * 3, indices,
-               GL_STATIC_DRAW);
-
   glBindBuffer(GL_ARRAY_BUFFER, VBO);
-  glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void *)0);
+  glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void *)0);
   glEnableVertexAttribArray(0);
+  glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float),
+                        (void *)(3 * sizeof(float)));
+  glEnableVertexAttribArray(1);
 
+  glUseProgram(shader_program);
   while (!glfwWindowShouldClose(window)) {
     glClearColor(0.1f, 0.1f, 0.25f, 1.0f);
     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);
+    glDrawArrays(GL_TRIANGLES, 0, 3);
 
     glfwSwapBuffers(window);
     glfwPollEvents();
   }
 
+  glDeleteVertexArrays(1, &VAO);
+  glDeleteBuffers(1, &VBO);
+  glDeleteProgram(shader_program);
+
   glfwTerminate();
   return 0;
 }