From d493d60fe5f612822a1746074b0e59be3bcd7f5c Mon Sep 17 00:00:00 2001
From: sigonasr2 <sigonasr2@gmail.com>
Date: Wed, 25 Oct 2023 19:46:44 -0500
Subject: [PATCH] Consolidated all shader loading inside its own util.

---
 OpenGLTemplate/fragShader.glsl |  4 +-
 OpenGLTemplate/main.cpp        | 80 +++++++++-------------------------
 OpenGLTemplate/utils.h         | 58 ++++++++++++++++++++++--
 OpenGLTemplate/vertShader.glsl | 13 +++++-
 4 files changed, 89 insertions(+), 66 deletions(-)

diff --git a/OpenGLTemplate/fragShader.glsl b/OpenGLTemplate/fragShader.glsl
index c5a70ca..1da04d5 100644
--- a/OpenGLTemplate/fragShader.glsl
+++ b/OpenGLTemplate/fragShader.glsl
@@ -3,9 +3,9 @@ out vec4 color;
 void main(void)
 {
 	color=vec4(
-		(gl_FragCoord.x - 300) / 5.f,
+		(gl_FragCoord.x) / 600.f,
 		0.0,
-		5 - (gl_FragCoord.x - 300) / 5.f,
+		1-(gl_FragCoord.x) / 600.f,
 		1.0
 	);
 }
\ No newline at end of file
diff --git a/OpenGLTemplate/main.cpp b/OpenGLTemplate/main.cpp
index 70448bc..b28e99c 100644
--- a/OpenGLTemplate/main.cpp
+++ b/OpenGLTemplate/main.cpp
@@ -1,85 +1,45 @@
 #include <GL/glew.h>
 #include <GLFW/glfw3.h>
-#include <iostream>
 #include "utils.h"
-#include "ShaderError.h"
 
 #define numVAOs 1
 
 GLuint renderingProgram;
 GLuint vao[numVAOs];
 
-GLuint createShaderProgram(){
-    GLint vertCompiled;
-    GLint fragCompiled;
-    GLint linked;
-    // catch errors while compiling shaders
-
-    GLuint vShader=glCreateShader(GL_VERTEX_SHADER);
-    GLuint fShader=glCreateShader(GL_FRAGMENT_SHADER);
-
-    std::string vertShaderStr=utils::readShaderSource("vertShader.glsl");
-    std::string fragShaderStr=utils::readShaderSource("fragShader.glsl");
-
-    const char*vertShaderSrc=vertShaderStr.c_str();
-    const char*fragShaderSrc=fragShaderStr.c_str();
-
-    glShaderSource(vShader,1,&vertShaderSrc,NULL);
-    glShaderSource(fShader,1,&fragShaderSrc,NULL);
-
-    glCompileShader(vShader);
-    ErrorCheck::checkOpenGLError();
-    glGetShaderiv(vShader,GL_COMPILE_STATUS,&vertCompiled);
-    if(vertCompiled!=1){
-        std::cout<<"Vertex Compilation Failed!"<<std::endl;
-        ErrorCheck::printShaderLog(vShader);
-        throw;
-    }
-
-    glCompileShader(fShader);
-    ErrorCheck::checkOpenGLError();
-    glGetShaderiv(fShader,GL_COMPILE_STATUS,&fragCompiled);
-    if(fragCompiled!=1){
-        std::cout<<"Fragment Compilation Failed!"<<std::endl;
-        ErrorCheck::printShaderLog(fShader);
-        throw;
-    }
-
-    //catch errors while linking shaders
-
-    GLuint vfProgram=glCreateProgram();
-
-    glAttachShader(vfProgram,vShader);
-    glAttachShader(vfProgram,fShader);
-
-    glLinkProgram(vfProgram);
-    ErrorCheck::checkOpenGLError();
-    glGetProgramiv(vfProgram,GL_LINK_STATUS,&linked);
-    if(linked!=1){
-        std::cout<<"Linking Failed!"<<std::endl;
-        ErrorCheck::printProgramLog(vfProgram);
-    }
-
-    return vfProgram;
-}
-
 void init(GLFWwindow* window) {
-    renderingProgram=createShaderProgram();
+    renderingProgram=utils::createShaderProgram("vertShader.glsl","fragShader.glsl");
     glGenVertexArrays(numVAOs,vao);
     glBindVertexArray(vao[0]);
 }
 
+float x=0;
+float inc=0.01;
+double lastTime=0;
+
 void display(GLFWwindow* window, double currentTime) {
+    double elapsedTime=currentTime-lastTime;
+    lastTime=currentTime;
+
+    glClear(GL_DEPTH_BUFFER_BIT);
+    glClearColor(0,0,0.2,1);
+    glClear(GL_COLOR_BUFFER_BIT);
+
     glUseProgram(renderingProgram);
-    glPointSize(30);
-    glDrawArrays(GL_POINTS,0,1);
+    x+=inc;//*elapsedTime;
+    if(x>1||x<-1){inc*=-1;}
+
+    GLuint offsetLoc=glGetUniformLocation(renderingProgram,"offset");
+    glProgramUniform1f(renderingProgram,offsetLoc,x);
+
+    glDrawArrays(GL_TRIANGLES,0,3);
 }
 
 int main(void) {
     if (!glfwInit()) { exit(EXIT_FAILURE); }
     glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 4);
     glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
-    GLFWwindow* window = glfwCreateWindow(600, 600, "My First OpenGL Program!", NULL, NULL);
+    GLFWwindow* window = glfwCreateWindow(600, 600, "Hello Triangle!", NULL, NULL);
     glfwMakeContextCurrent(window);
     if (glewInit() != GLEW_OK) { exit(EXIT_FAILURE); }
     glfwSwapInterval(1);
diff --git a/OpenGLTemplate/utils.h b/OpenGLTemplate/utils.h
index b612af0..c87e4e8 100644
--- a/OpenGLTemplate/utils.h
+++ b/OpenGLTemplate/utils.h
@@ -2,9 +2,10 @@
 #include <string>
 #include <fstream>
 #include <GL/glew.h>
+#include "ShaderError.h"
 
-namespace utils{
-	inline std::string readShaderSource(const char *filePath){
+class utils{
+	inline static std::string readShaderSource(const char *filePath){
         std::string content;
         std::ifstream fileStream(filePath, std::ios::in);
         std::string line = "";
@@ -19,4 +20,55 @@ namespace utils{
         fileStream.close();
         return content;
     }
-}
\ No newline at end of file
+    inline static void CompileShader(GLuint shader,std::string type){
+        GLint compiled;
+        glCompileShader(shader);
+        ErrorCheck::checkOpenGLError();
+        glGetShaderiv(shader,GL_COMPILE_STATUS,&compiled);
+        if(compiled!=1){
+            std::cout<<type<<" Compilation Failed!"<<std::endl;
+            ErrorCheck::printShaderLog(shader);
+            throw;
+        }
+    }
+    inline static void CreateShader(GLuint type,std::string shaderName,const char*source,GLuint vfProgram){
+        if(source!=nullptr){
+            GLuint vShader=glCreateShader(type);
+            std::string shaderFile=readShaderSource(source);
+            const char*vertShaderSrc=shaderFile.c_str();
+            glShaderSource(vShader,1,&vertShaderSrc,NULL);
+            CompileShader(vShader,shaderName);
+            glAttachShader(vfProgram,vShader);
+        }
+    };
+public:
+    inline static GLuint createShaderProgram(const char*vertex,const char*fragment){
+        return createShaderProgram(vertex,nullptr,nullptr,nullptr,fragment);
+    }
+    inline static GLuint createShaderProgram(const char*vertex,const char*geometry,const char*fragment){
+        return createShaderProgram(vertex,nullptr,nullptr,geometry,fragment);
+    }
+    inline static GLuint createShaderProgram(const char*vertex,const char*tesselationCS,const char*tesselationES,const char*fragment){
+        return createShaderProgram(vertex,tesselationCS,tesselationES,nullptr,fragment);
+    }
+    inline static GLuint createShaderProgram(const char*vertex,const char*tesselationCS,const char*tesselationES,const char*geometry,const char*fragment){
+        
+        GLuint vfProgram=glCreateProgram();
+
+        CreateShader(GL_VERTEX_SHADER,"Vertex",vertex,vfProgram);
+        CreateShader(GL_FRAGMENT_SHADER,"Fragment",fragment,vfProgram);
+        CreateShader(GL_TESS_CONTROL_SHADER,"Tesselation Control",tesselationCS,vfProgram);
+        CreateShader(GL_TESS_EVALUATION_SHADER,"Tesselation Evaluation",tesselationES,vfProgram);
+        CreateShader(GL_GEOMETRY_SHADER,"Geometry",geometry,vfProgram);
+
+        GLint linked;
+        glLinkProgram(vfProgram);
+        ErrorCheck::checkOpenGLError();
+        glGetProgramiv(vfProgram,GL_LINK_STATUS,&linked);
+        if(linked!=1){
+            std::cout<<"Linking Failed!"<<std::endl;
+            ErrorCheck::printProgramLog(vfProgram);
+        }
+        return vfProgram;
+    }
+};
\ No newline at end of file
diff --git a/OpenGLTemplate/vertShader.glsl b/OpenGLTemplate/vertShader.glsl
index 789385e..6323541 100644
--- a/OpenGLTemplate/vertShader.glsl
+++ b/OpenGLTemplate/vertShader.glsl
@@ -1,5 +1,16 @@
 #version 430
+uniform float offset;
 void main(void)
 {
-	gl_Position=vec4(0.0,0.0,0.0,1.0);
+	switch(gl_VertexID){
+		case 0:{
+			gl_Position=vec4(-0.5+offset,-0.5,0.0,1.0);
+		}break;
+		case 1:{
+			gl_Position=vec4(0.5+offset,-0.5,0.0,1.0);
+		}break;
+		case 2:{
+			gl_Position=vec4(0.0+offset,0.25,0.0,1.0);
+		}break;
+	}
 }