fixes

source/opengl/data/mesh_data.cpp

@@ -0,0 +1,119 @@
+#include "opengl/data/mesh_data.hpp"
+
+#include "opengl/type_utils.hpp"
+#include "opengl/error.hpp"
+
+#include "GL/glew.h"
+#include <algorithm>
+#include "util/logger.hpp" // TODO remove
+
+
+std::error_code zgl::mesh_data::build_from(
+	const std::span<const ztu::u8> vertex_buffer,
+	const std::span<const GLenum> component_types,
+	const std::span<const GLint> component_lengths,
+	const GLsizei stride,
+	const std::span<const ztu::u32> index_buffer,
+	const ztu::u32 material_id,
+	const components::mesh_vertex::flags components,
+	mesh_data& data
+) {
+	if (not std::ranges::all_of(component_types, type_utils::is_valid_type))
+	{
+		ztu::logger::debug("not all types valid.");
+		return std::make_error_code(std::errc::invalid_argument);
+	}
+
+	const auto vertices_byte_count = vertex_buffer.size() * sizeof(std::uint8_t);
+	if (vertices_byte_count > std::numeric_limits<GLsizeiptr>::max())
+	{
+		return std::make_error_code(std::errc::value_too_large);
+	}
+
+	const auto indices_byte_count = index_buffer.size() * sizeof(ztu::u32);
+	if (indices_byte_count > std::numeric_limits<GLsizeiptr>::max())
+	{
+		return std::make_error_code(std::errc::value_too_large);
+	}
+
+	auto error = std::error_code{};
+
+	auto check_error = [&error, ec = static_cast<GLenum>(GL_NO_ERROR)]() mutable -> const std::error_code&
+	{
+		ec = glGetError();
+		if (ec != GL_NO_ERROR)
+		{
+			error = make_error_code(ec);
+		}
+		return error;
+	};
+
+	GLuint vao_id;
+	glGenVertexArrays(1, &vao_id);
+	glBindVertexArray(vao_id);
+	if (check_error()) return error;
+
+	ztu::logger::debug("Created mesh vao: % valid: %", vao_id, (bool)glIsVertexArray(vao_id));
+
+	GLuint vertex_buffer_id;
+	glGenBuffers(1, &vertex_buffer_id);
+	glBindBuffer(GL_ARRAY_BUFFER, vertex_buffer_id);
+	glBufferData(
+		GL_ARRAY_BUFFER,
+		static_cast<GLsizeiptr>(vertices_byte_count),
+		vertex_buffer.data(),
+		GL_STATIC_DRAW
+	);
+	if (check_error()) return error;
+
+	GLuint index_buffer_id;
+	glGenBuffers(1, &index_buffer_id);
+	glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, index_buffer_id);
+	glBufferData(
+		GL_ELEMENT_ARRAY_BUFFER,
+		static_cast<GLsizeiptr>(indices_byte_count),
+		index_buffer.data(),
+		GL_STATIC_DRAW
+	);
+	if (check_error()) return error;
+
+	glBindBuffer(GL_ARRAY_BUFFER, vertex_buffer_id);
+	if (check_error()) return error;
+
+	auto offset = GLsizei{ 0 };
+
+	for (std::size_t i{}; i != component_types.size(); ++i)
+	{
+		const auto type = component_types[i];
+		const auto length = component_lengths[i];
+		const auto byte_count = type_utils::size_of(type);
+
+		glVertexAttribPointer(
+			i,
+			length,
+			type,
+			GL_FALSE,
+			stride,
+			reinterpret_cast<GLvoid*>(offset)
+		);
+
+		glEnableVertexAttribArray(i);
+		if (check_error()) return error;
+
+		offset += length * byte_count;
+	}
+
+	glBindBuffer(GL_ARRAY_BUFFER, 0);
+	glBindVertexArray(0);
+
+	data = mesh_data(
+		vertex_buffer_id,
+		index_buffer_id,
+		vao_id,
+		material_id,
+		components,
+		index_buffer.size()
+	);
+
+	return {};
+}