refactor opengl shader and add shader builder

framework/opengl_primitives/src/mm/opengl/shader_builder.cpp

@@ -0,0 +1,145 @@
+#include "./shader_builder.hpp"
+
+#ifdef MM_OPENGL_3_GLES
+	#include <GLES3/gl3.h>
+#else
+	#include <glad/glad.h>
+#endif
+
+#include <mm/services/filesystem.hpp>
+
+#include <mm/logger.hpp>
+#define LOG_CRIT(...)		__LOG_CRIT(	"OpenGL", __VA_ARGS__)
+#define LOG_ERROR(...)		__LOG_ERROR("OpenGL", __VA_ARGS__)
+#define LOG_WARN(...)		__LOG_WARN(	"OpenGL", __VA_ARGS__)
+#define LOG_INFO(...)		__LOG_INFO(	"OpenGL", __VA_ARGS__)
+#define LOG_DEBUG(...)		__LOG_DEBUG("OpenGL", __VA_ARGS__)
+#define LOG_TRACE(...)		__LOG_TRACE("OpenGL", __VA_ARGS__)
+
+namespace MM::OpenGL {
+
+ShaderBuilder::ShaderBuilder(void) {
+}
+
+ShaderBuilder::~ShaderBuilder(void) {
+	// after linking or in case of error, stages can be deleted
+	for (auto& stage : _stages) {
+		if (stage.id != 0) {
+			glDeleteShader(stage.id);
+		}
+	}
+}
+
+ShaderBuilder ShaderBuilder::start(void) {
+	return {};
+}
+
+std::shared_ptr<Shader> ShaderBuilder::finish(void) {
+	// check
+	for (auto& stage : _stages) {
+		if (stage.fail) {
+			// log error
+			return nullptr;
+		}
+	}
+
+	uint32_t program = glCreateProgram();
+
+	// attach
+	for (auto& stage : _stages) {
+		if (stage.id != 0) {
+			glAttachShader(program, stage.id);
+		}
+	}
+
+	// tf varying
+	if (!_tfs.empty()) {
+		std::vector<const char*> tmp_vars;
+
+		for (auto& tfv : _tfs) {
+			tmp_vars.push_back(tfv.var.c_str());
+		}
+
+		glTransformFeedbackVaryings(program, tmp_vars.size(), tmp_vars.data(), _tf_interleaved ? GL_INTERLEAVED_ATTRIBS : GL_SEPARATE_ATTRIBS);
+
+	}
+
+	glLinkProgram(program);
+
+	// diagnostics
+	GLint isLinked = 0;
+	glGetProgramiv(program, GL_LINK_STATUS, &isLinked);
+	if (isLinked == GL_FALSE) {
+		GLint maxLength = 0;
+		glGetProgramiv(program, GL_INFO_LOG_LENGTH, &maxLength);
+
+		// The maxLength includes the NULL character
+		std::vector<GLchar> infoLog(maxLength);
+		glGetProgramInfoLog(program, maxLength, &maxLength, infoLog.data());
+		LOG_ERROR("Linking Shader Programs: {}", infoLog.data());
+
+		// The program is useless now. So delete it.
+		glDeleteProgram(program);
+		return nullptr;
+	}
+
+	glValidateProgram(program);
+	GLint isValid = 0;
+	glGetProgramiv(program, GL_VALIDATE_STATUS, &isValid);
+	if (isValid == GL_FALSE) {
+		GLint maxLength = 0;
+		glGetProgramiv(program, GL_INFO_LOG_LENGTH, &maxLength);
+
+		// The maxLength includes the NULL character
+		std::vector<GLchar> infoLog(maxLength);
+		glGetProgramInfoLog(program, maxLength, &maxLength, infoLog.data());
+		LOG_ERROR("Validating Shader Programs: {}", infoLog.data());
+
+		// The program is useless now. So delete it.
+		glDeleteProgram(program);
+		return nullptr;
+
+	}
+
+	return std::shared_ptr<Shader>(new Shader(program));
+}
+
+ShaderBuilder& ShaderBuilder::addStageVertex(const std::string& shader_code) {
+	_stages[VERTEX].id = Shader::compile(GL_VERTEX_SHADER, shader_code);
+	if (_stages[VERTEX].id == 0) {
+		_stages[VERTEX].fail = true;
+	}
+
+	return *this;
+}
+
+ShaderBuilder& ShaderBuilder::addStageVertexF(MM::Engine& engine, const std::string& file_path) {
+	return addStageVertex(Shader::parse(engine, file_path));
+}
+
+ShaderBuilder& ShaderBuilder::addStageFragment(const std::string& shader_code) {
+	_stages[FRAGMENT].id = Shader::compile(GL_FRAGMENT_SHADER, shader_code);
+	if (_stages[FRAGMENT].id == 0) {
+		_stages[FRAGMENT].fail = true;
+	}
+
+	return *this;
+}
+
+ShaderBuilder& ShaderBuilder::addStageFragmentF(MM::Engine& engine, const std::string& file_path) {
+	return addStageFragment(Shader::parse(engine, file_path));
+}
+
+ShaderBuilder& ShaderBuilder::addTransformFeedbackVarying(const std::string& var_name) {
+	if (var_name.empty()) {
+		// log waring
+		return *this;
+	}
+
+	_tfs.push_back({var_name});
+
+	return *this;
+}
+
+} // MM::OpenGL
+