From 400410fcd436d5e4310bfa779f0309c5fae5b2c2 Mon Sep 17 00:00:00 2001
From: Dan Goodliffe <dan@randomdan.homeip.net>
Date: Sat, 16 Jan 2021 18:09:15 +0000
Subject: Initial commit

Stripped back and formatted from https://github.com/BennyQBD/ModernOpenGLTutorial/
---
 shader.cpp | 118 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 118 insertions(+)
 create mode 100644 shader.cpp

(limited to 'shader.cpp')

diff --git a/shader.cpp b/shader.cpp
new file mode 100644
index 0000000..21098bd
--- /dev/null
+++ b/shader.cpp
@@ -0,0 +1,118 @@
+#include "shader.h"
+#include <fstream>
+#include <iostream>
+
+Shader::Shader(const std::string & fileName)
+{
+	m_program = glCreateProgram();
+	m_shaders[0] = CreateShader(LoadShader(fileName + ".vs"), GL_VERTEX_SHADER);
+	m_shaders[1] = CreateShader(LoadShader(fileName + ".fs"), GL_FRAGMENT_SHADER);
+
+	for (unsigned int i = 0; i < NUM_SHADERS; i++)
+		glAttachShader(m_program, m_shaders[i]);
+
+	glBindAttribLocation(m_program, 0, "position");
+	glBindAttribLocation(m_program, 1, "texCoord");
+	glBindAttribLocation(m_program, 2, "normal");
+
+	glLinkProgram(m_program);
+	CheckShaderError(m_program, GL_LINK_STATUS, true, "Error linking shader program");
+
+	glValidateProgram(m_program);
+	CheckShaderError(m_program, GL_LINK_STATUS, true, "Invalid shader program");
+
+	m_uniforms[0] = glGetUniformLocation(m_program, "MVP");
+	m_uniforms[1] = glGetUniformLocation(m_program, "Normal");
+	m_uniforms[2] = glGetUniformLocation(m_program, "lightDirection");
+}
+
+Shader::~Shader()
+{
+	for (unsigned int i = 0; i < NUM_SHADERS; i++) {
+		glDetachShader(m_program, m_shaders[i]);
+		glDeleteShader(m_shaders[i]);
+	}
+
+	glDeleteProgram(m_program);
+}
+
+void
+Shader::Bind()
+{
+	glUseProgram(m_program);
+}
+
+void
+Shader::Update(const Transform & transform, const Camera & camera)
+{
+	glm::mat4 MVP = transform.GetMVP(camera);
+	glm::mat4 Normal = transform.GetModel();
+
+	glUniformMatrix4fv(m_uniforms[0], 1, GL_FALSE, &MVP[0][0]);
+	glUniformMatrix4fv(m_uniforms[1], 1, GL_FALSE, &Normal[0][0]);
+	glUniform3f(m_uniforms[2], 0.0f, 0.0f, 1.0f);
+}
+
+std::string
+Shader::LoadShader(const std::string & fileName)
+{
+	std::ifstream file;
+	file.open((fileName).c_str());
+
+	std::string output;
+	std::string line;
+
+	if (file.is_open()) {
+		while (file.good()) {
+			getline(file, line);
+			output.append(line + "\n");
+		}
+	}
+	else {
+		std::cerr << "Unable to load shader: " << fileName << std::endl;
+	}
+
+	return output;
+}
+
+void
+Shader::CheckShaderError(GLuint shader, GLuint flag, bool isProgram, const std::string & errorMessage)
+{
+	GLint success = 0;
+	GLchar error[1024] = {0};
+
+	if (isProgram)
+		glGetProgramiv(shader, flag, &success);
+	else
+		glGetShaderiv(shader, flag, &success);
+
+	if (success == GL_FALSE) {
+		if (isProgram)
+			glGetProgramInfoLog(shader, sizeof(error), NULL, error);
+		else
+			glGetShaderInfoLog(shader, sizeof(error), NULL, error);
+
+		std::cerr << errorMessage << ": '" << error << "'" << std::endl;
+	}
+}
+
+GLuint
+Shader::CreateShader(const std::string & text, unsigned int type)
+{
+	GLuint shader = glCreateShader(type);
+
+	if (shader == 0)
+		std::cerr << "Error compiling shader type " << type << std::endl;
+
+	const GLchar * p[1];
+	p[0] = text.c_str();
+	GLint lengths[1];
+	lengths[0] = text.length();
+
+	glShaderSource(shader, 1, p, lengths);
+	glCompileShader(shader);
+
+	CheckShaderError(shader, GL_COMPILE_STATUS, false, "Error compiling shader!");
+
+	return shader;
+}
-- 
cgit v1.2.3