charcoal/charcoal-builtin/TextPipeline.h

#pragma once

#include <string>
#include <unordered_map>
#include <list>
#include <glm/glm.hpp>

#include <charcoal/Font.h>
#include <charcoal/TextureFactory.h>

#include "MeshGenerator.h"

#include "GLUtil.h"
#include "BuiltinPipeline.h"
#include "WithCamera.h"
#include "TextTypes.h"
#include "TextBatch.h"

namespace charcoal
{
	namespace builtin
	{
		namespace text
		{
			class Pipeline : private builtin::Pipeline<ShaderProgram, Batch>, public WithCamera
			{
			public:
				Pipeline(
					Font& font
				)
					: m_font(font)
				{
					std::string prepared_text = " abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ`1234567890-=[]\\;',./~!@#$%^&*()_+{}|:\"<>?";
					for (char c : prepared_text)
					{
						std::string s(1, c);
						const charcoal::image_loader::ImageRGBA& image = m_font.get_text_image(s);
						m_renderables.emplace_back(
							meshgenerator::gen_rect_pt<Vertex, Index>(DrawMode::DRAW_TRIANGLES, (float)image.width, (float)image.height),
							TextureFactory::gen_image_texture(image),
							TextureFactory::gen_sampler(Sampler::Wrap::CLAMP_TO_EDGE, Sampler::Wrap::CLAMP_TO_EDGE, Sampler::MagFilter::LINEAR, Sampler::MinFilter::NEAREST),
							DrawMode::DRAW_TRIANGLES
						);
						m_text_batches.emplace_back(&m_renderables.back());
						add_batch(&m_text_batches.back());
						m_text_to_index[s] = (unsigned int)(m_batches.size() - 1);
						m_text_to_width[s] = image.width;
					}
				}

				void init_text()
				{
					for (Batch& batch : m_text_batches)
					{
						batch.init();
					}
				}

				void render()
				{
					builtin::Pipeline<ShaderProgram, Batch>::render();
				}

				void reset_text()
				{
					for (Batch& batch : m_text_batches)
					{
						batch.reset_rendered();
					}
				}

				// Position specified as center of left most character.
				// TODO: May want to change this to be specifyable by different than center
				// and maybe do top/bottom/other stuff
				void add_text(const vec3& position, const std::string& text)
				{
					// For now, always do aa per-char calculation.
					// TODO for future would be to cache the commonly used words for faster word
					// rendering.
					vec3 p = position;
					for (char c : text)
					{
						std::string s(1, c);
						m_batches[m_text_to_index[s]]->add_rendered(charcoal::Poseable(p));
						p.x += m_text_to_width[s];
					}
				}

				void prerender_text()
				{
					for (Batch& batch : m_text_batches)
					{
						batch.prerender();
					}
				}

				void prepare_opengl() override
				{
					glEnable(GL_DEPTH_TEST);
					glDepthFunc(GL_LESS);
					glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
					glEnable(GL_BLEND);
				}

				void prepare_uniforms() override
				{
					glutil::uniform_matrix(0, get_camera()->get_world_to_view_matrix());
				}

			private:
				Font& m_font;
				std::unordered_map<std::string, unsigned int> m_text_to_index;
				std::unordered_map<std::string, unsigned int> m_text_to_width;
				std::list<Renderable> m_renderables;
				std::list<Batch> m_text_batches;
			};
		}
	}
}