From f6da8751bf7a64f3a325b1bf8264d2ca99624360 Mon Sep 17 00:00:00 2001
From: Michal Idziorek <m.i@gmx.at>
Date: Sun, 4 Sep 2022 14:15:53 +0200
Subject: shader

---
 src/Shader.h | 122 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 122 insertions(+)
 create mode 100644 src/Shader.h

(limited to 'src/Shader.h')

diff --git a/src/Shader.h b/src/Shader.h
new file mode 100644
index 0000000..1a8b484
--- /dev/null
+++ b/src/Shader.h
@@ -0,0 +1,122 @@
+#ifndef SHADER_H
+#define SHADER_H
+
+#include <glad/glad.h>
+
+#include <string>
+#include <fstream>
+#include <sstream>
+#include <iostream>
+
+class Shader
+{
+public:
+    unsigned int ID;
+    // constructor generates the shader on the fly
+    // ------------------------------------------------------------------------
+    Shader(const char* vertexPath, const char* fragmentPath)
+    {
+        // 1. retrieve the vertex/fragment source code from filePath
+        std::string vertexCode;
+        std::string fragmentCode;
+        std::ifstream vShaderFile;
+        std::ifstream fShaderFile;
+        // ensure ifstream objects can throw exceptions:
+        vShaderFile.exceptions (std::ifstream::failbit | std::ifstream::badbit);
+        fShaderFile.exceptions (std::ifstream::failbit | std::ifstream::badbit);
+        try 
+        {
+            // open files
+            vShaderFile.open(vertexPath);
+            fShaderFile.open(fragmentPath);
+            std::stringstream vShaderStream, fShaderStream;
+            // read file's buffer contents into streams
+            vShaderStream << vShaderFile.rdbuf();
+            fShaderStream << fShaderFile.rdbuf();
+            // close file handlers
+            vShaderFile.close();
+            fShaderFile.close();
+            // convert stream into string
+            vertexCode   = vShaderStream.str();
+            fragmentCode = fShaderStream.str();
+        }
+        catch (std::ifstream::failure& e)
+        {
+            std::cout << "ERROR::SHADER::FILE_NOT_SUCCESFULLY_READ: " << e.what() << std::endl;
+        }
+        const char* vShaderCode = vertexCode.c_str();
+        const char * fShaderCode = fragmentCode.c_str();
+        // 2. compile shaders
+        unsigned int vertex, fragment;
+        // vertex shader
+        vertex = glCreateShader(GL_VERTEX_SHADER);
+        glShaderSource(vertex, 1, &vShaderCode, NULL);
+        glCompileShader(vertex);
+        checkCompileErrors(vertex, "VERTEX");
+        // fragment Shader
+        fragment = glCreateShader(GL_FRAGMENT_SHADER);
+        glShaderSource(fragment, 1, &fShaderCode, NULL);
+        glCompileShader(fragment);
+        checkCompileErrors(fragment, "FRAGMENT");
+        // shader Program
+        ID = glCreateProgram();
+        glAttachShader(ID, vertex);
+        glAttachShader(ID, fragment);
+        glLinkProgram(ID);
+        checkCompileErrors(ID, "PROGRAM");
+        // delete the shaders as they're linked into our program now and no longer necessary
+        glDeleteShader(vertex);
+        glDeleteShader(fragment);
+    }
+    // activate the shader
+    // ------------------------------------------------------------------------
+    void use() 
+    { 
+        glUseProgram(ID); 
+    }
+    // utility uniform functions
+    // ------------------------------------------------------------------------
+    void setBool(const std::string &name, bool value) const
+    {         
+        glUniform1i(glGetUniformLocation(ID, name.c_str()), (int)value); 
+    }
+    // ------------------------------------------------------------------------
+    void setInt(const std::string &name, int value) const
+    { 
+        glUniform1i(glGetUniformLocation(ID, name.c_str()), value); 
+    }
+    // ------------------------------------------------------------------------
+    void setFloat(const std::string &name, float value) const
+    { 
+        glUniform1f(glGetUniformLocation(ID, name.c_str()), value); 
+    }
+
+private:
+    // utility function for checking shader compilation/linking errors.
+    // ------------------------------------------------------------------------
+    void checkCompileErrors(unsigned int shader, std::string type)
+    {
+        int success;
+        char infoLog[1024];
+        if (type != "PROGRAM")
+        {
+            glGetShaderiv(shader, GL_COMPILE_STATUS, &success);
+            if (!success)
+            {
+                glGetShaderInfoLog(shader, 1024, NULL, infoLog);
+                std::cout << "ERROR::SHADER_COMPILATION_ERROR of type: " << type << "\n" << infoLog << "\n -- --------------------------------------------------- -- " << std::endl;
+            }
+        }
+        else
+        {
+            glGetProgramiv(shader, GL_LINK_STATUS, &success);
+            if (!success)
+            {
+                glGetProgramInfoLog(shader, 1024, NULL, infoLog);
+                std::cout << "ERROR::PROGRAM_LINKING_ERROR of type: " << type << "\n" << infoLog << "\n -- --------------------------------------------------- -- " << std::endl;
+            }
+        }
+    }
+};
+
+#endif
-- 
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