feat: hello triangle compiling shader

Engine/engine/constants.hpp

@@ -1,4 +1,5 @@
 #ifndef CONSTANTS_HPP
+#include <GLFW/glfw3.h>
 #include <iostream>
 #include <string_view>
 
@@ -8,6 +9,26 @@ namespace constants
     inline const char* MAIN_WINDOW_NAME { "Match" }; 
     inline constexpr int MAIN_WINDOW_WIDTH { 800 };
     inline constexpr int MAIN_WINDOW_HEIGHT { 600 };
+    inline constexpr struct  { 
+        GLfloat red = 1.0f;
+        GLfloat green = 0.0f;
+        GLfloat blue = 0.0f;
+        GLfloat alpha = 1.0f;
+    } RED;
+
+        inline constexpr struct  { 
+        GLfloat red = 1.0f;
+        GLfloat green = 1.0f;
+        GLfloat blue = 1.0f;
+        GLfloat alpha = 1.0f;
+    } WHITE;
+
+    inline constexpr struct  { 
+        GLfloat red = 0.2f;
+        GLfloat green = 0.3f;
+        GLfloat blue = 0.3f;
+        GLfloat alpha = 1.0f;
+    } LEARN_OPEN_GL_COLOR;
 
 }
 

Engine/engine/match.cpp

@@ -3,8 +3,6 @@
 #include <glad/glad.h>
 #include <GLFW/glfw3.h>
 
-#include <glad/glad.h>
-#include <GLFW/glfw3.h>
 #include <iostream>
 
 #include <random> // I am using standart library RNG because I am lazy and wanted to create quick code snippet
@@ -83,18 +81,43 @@ void processInput(GLFWwindow *window)
         glfwSetWindowShouldClose(window, true);
 }
 
-const float padaczkaSimulator()
+void drawTriangle()
 {
-    // Seed our Mersenne Twister using the
-	std::mt19937 mt{ static_cast<unsigned int>(
-		std::chrono::steady_clock::now().time_since_epoch().count()
-		) };
+    // we specify three vertices
+    // each of them with position in 3d space
+    // x y z
+    const float triangleVertices[] = {
+        -0.5f, -0.5f, 0.0f,
+        0.5f, -0.5f, 0.0f,
+        0.0f,  0.5f, 0.0f
+    };
 
-	// Create a reusable random number generator that generates uniform numbers between 1 and 6
-	std::uniform_int_distribution ten{ 1, 10 }; // for C++14, use std::uniform_int_distribution<> die6{ 1, 6 };
+    // stores vertices in gpu memory
+    unsigned int vertexBufferObject;
+    // this is open gl object so we refer it by its ID generated here and stored in vertexBufferObject variable
+    glGenBuffers(1, &vertexBufferObject);
+    
+    // buffer type of vertex buffer object is GL_ARRAY_BUFFER
+    glBindBuffer(GL_ARRAY_BUFFER, vertexBufferObject);
+    // now whenever we change GL_ARRAY_BUFFER we change bound buffer vertexBufferObject
+
+    /* we copy vertex data into buffer memory
+    GL_STREAM_DRAW: the data is set only once and used by the GPU at most a few times.
+    GL_STATIC_DRAW: the data is set only once and used many times.
+    GL_DYNAMIC_DRAW: the data is changed a lot and used many times.
+    */
+    glBufferData(GL_ARRAY_BUFFER, sizeof(triangleVertices), triangleVertices, GL_STATIC_DRAW);
+
+    // we write vertex shader 
+    // version of glsl (since ogl 3.3 same as ogl so we pick 330)
+    // in this shader we just forward input data to shader output
+    const char *vertexShaderSource = "#version 330 core\n"
+    "layout (location = 0) in vec3 aPos;\n"
+    "void main()\n"
+    "{\n"
+    "   gl_Position = vec4(aPos.x, aPos.y, aPos.z, 1.0);\n"
+    "}\0";
 
-    const float MT_FLOAT = static_cast<float> (ten(mt) % 10);
-    return MT_FLOAT / 10;
 }
 
 void renderLoop(GLFWwindow* window)
@@ -104,13 +127,10 @@ void renderLoop(GLFWwindow* window)
     {
         // input
         processInput(window);
-
-        const float FIRST_COLOR = padaczkaSimulator(); 
-        const float SECOND_COLOR = padaczkaSimulator(); 
-        const float THIRD_COLOR = padaczkaSimulator(); 
-        const float FOUR_COLOR = padaczkaSimulator(); 
-
-        glClearColor( FIRST_COLOR, SECOND_COLOR, THIRD_COLOR, FOUR_COLOR);
+        // We specify the color to clear the screen with
+        // RGB and alpha value
+        glClearColor( constants::LEARN_OPEN_GL_COLOR.red, constants::LEARN_OPEN_GL_COLOR.green, constants::LEARN_OPEN_GL_COLOR.blue, constants::LEARN_OPEN_GL_COLOR.alpha);
+        // There is GL_COLOR_BUFFER_BIT, GL_DEPTH_BUFFER_BIT and GL_STENCIL_BUFFER_BIT
         glClear(GL_COLOR_BUFFER_BIT);