From 12d38a0114657cc468e93f7eb0f97b2b1ac8f924 Mon Sep 17 00:00:00 2001
From: Dan Goodliffe <dan@randomdan.homeip.net>
Date: Sun, 24 Jan 2021 13:16:05 +0000
Subject: Big tidy up of shader wrapper

---
 gfx/gl/shader.cpp | 59 ++++++++++++++++++++-----------------------------------
 1 file changed, 21 insertions(+), 38 deletions(-)

(limited to 'gfx/gl/shader.cpp')

diff --git a/gfx/gl/shader.cpp b/gfx/gl/shader.cpp
index 33fdf61..e59d431 100644
--- a/gfx/gl/shader.cpp
+++ b/gfx/gl/shader.cpp
@@ -1,20 +1,16 @@
 #include "shader.h"
 #include "transform.h"
+#include <array>
 #include <gfx/gl/shaders/fs-basicShader.h>
 #include <gfx/gl/shaders/vs-basicShader.h>
 #include <glm/glm.hpp>
 #include <stdexcept>
+#include <string>
 
-Shader::Shader(const std::string &) :
-	m_program {glCreateProgram()}, m_shaders {CreateShader(
-													  (GLchar *)(basicShader_vs), basicShader_vs_len, GL_VERTEX_SHADER),
-										   CreateShader(
-												   (GLchar *)basicShader_fs, basicShader_fs_len, GL_FRAGMENT_SHADER)},
-	m_uniforms {}
+Shader::Shader() : mvp_uniform {}, normal_uniform {}, lightDir_uniform {}
 {
-	for (auto m_shader : m_shaders) {
-		glAttachShader(m_program, m_shader);
-	}
+	glAttachShader(m_program, Source {{basicShader_vs, basicShader_vs_len}, GL_VERTEX_SHADER}.id);
+	glAttachShader(m_program, Source {{basicShader_fs, basicShader_fs_len}, GL_FRAGMENT_SHADER}.id);
 
 	glBindAttribLocation(m_program, 0, "position");
 	glBindAttribLocation(m_program, 1, "texCoord");
@@ -26,18 +22,9 @@ Shader::Shader(const std::string &) :
 	glValidateProgram(m_program);
 	CheckShaderError(m_program, GL_VALIDATE_STATUS, true, "Invalid shader program");
 
-	m_uniforms = {glGetUniformLocation(m_program, "MVP"), glGetUniformLocation(m_program, "Normal"),
-			glGetUniformLocation(m_program, "lightDirection")};
-}
-
-Shader::~Shader()
-{
-	for (auto m_shader : m_shaders) {
-		glDetachShader(m_program, m_shader);
-		glDeleteShader(m_shader);
-	}
-
-	glDeleteProgram(m_program);
+	mvp_uniform = glGetUniformLocation(m_program, "MVP");
+	normal_uniform = glGetUniformLocation(m_program, "Normal");
+	lightDir_uniform = glGetUniformLocation(m_program, "lightDirection");
 }
 
 void
@@ -52,13 +39,13 @@ Shader::Update(const Transform & transform, const Camera & camera) const
 	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);
+	glUniformMatrix4fv(mvp_uniform, 1, GL_FALSE, &MVP[0][0]);
+	glUniformMatrix4fv(normal_uniform, 1, GL_FALSE, &Normal[0][0]);
+	glUniform3f(lightDir_uniform, 0.0F, 0.0F, 1.0F);
 }
 
 void
-Shader::CheckShaderError(GLuint shader, GLuint flag, bool isProgram, const std::string & errorMessage)
+Shader::CheckShaderError(GLuint shader, GLuint flag, bool isProgram, std::string_view errorMessage)
 {
 	GLint success = 0;
 	std::array<GLchar, 1024> error {};
@@ -78,23 +65,19 @@ Shader::CheckShaderError(GLuint shader, GLuint flag, bool isProgram, const std::
 			glGetShaderInfoLog(shader, error.size(), nullptr, error.data());
 		}
 
-		throw std::runtime_error {errorMessage + ": '" + std::string {error.data(), error.size()} + "'"};
+		throw std::runtime_error {std::string {errorMessage} + ": '" + std::string {error.data(), error.size()} + "'"};
 	}
 }
 
-GLuint
-Shader::CreateShader(const GLchar * text, GLint len, unsigned int type)
+Shader::Source::Source(const std::basic_string_view<unsigned char> text, GLuint type) :
+	Source {(const GLchar *)(text.data()), (GLint)(text.length()), type}
 {
-	GLuint shader = glCreateShader(type);
-
-	if (shader == 0) {
-		throw std::runtime_error {"Error compiling shader type " + std::to_string(type)};
-	}
-
-	glShaderSource(shader, 1, &text, &len);
-	glCompileShader(shader);
+}
 
-	CheckShaderError(shader, GL_COMPILE_STATUS, false, "Error compiling shader!");
+Shader::Source::Source(const GLchar * text, GLint len, unsigned int type) : id {type}
+{
+	glShaderSource(id, 1, &text, &len);
+	glCompileShader(id);
 
-	return shader;
+	CheckShaderError(id, GL_COMPILE_STATUS, false, "Error compiling shader!");
 }
-- 
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