fixes

source/opengl/data/point_cloud_data.cpp

@@ -0,0 +1,99 @@
+#include "opengl/data/point_cloud_data.hpp"
+
+#include "opengl/type_utils.hpp"
+#include "opengl/error.hpp"
+
+#include <algorithm>
+#include "GL/glew.h"
+
+std::error_code zgl::point_cloud_data::build_from(
+		std::span<const std::uint8_t> point_buffer,
+		std::span<const GLenum> component_types,
+		std::span<const GLint> component_lengths,
+		GLsizei stride,
+		point_cloud_data& data
+) {
+	if (not std::ranges::all_of(component_types, type_utils::is_valid_type))
+	{
+		return std::make_error_code(std::errc::invalid_argument);
+	}
+
+	const auto points_byte_count = point_buffer.size() * sizeof(std::uint8_t);
+	if (points_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;
+	};
+
+	ztu::u32 vao_id;
+	glGenVertexArrays(1, &vao_id);
+	if (check_error()) return error;
+
+	glBindVertexArray(vao_id);
+	if (check_error()) return error;
+
+	ztu::u32 vertex_buffer_id;
+	glGenBuffers(1, &vertex_buffer_id);
+	if (check_error()) return error;
+
+	glBindBuffer(GL_ARRAY_BUFFER, vertex_buffer_id);
+	if (check_error()) return error;
+
+	glBufferData(
+		GL_ARRAY_BUFFER,
+		static_cast<GLsizeiptr>(points_byte_count),
+		point_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)
+		);
+		if (check_error()) return error;
+		glEnableVertexAttribArray(i);
+		if (check_error()) return error;
+
+		offset += length * byte_count;
+	}
+
+	glBindBuffer(GL_ARRAY_BUFFER, 0);
+	if (check_error()) return error;
+	glBindVertexArray(0);
+	if (check_error()) return error;
+
+	data = point_cloud_data(
+		vertex_buffer_id,
+		vao_id,
+		point_buffer.size()
+	);
+
+	return {};
+}