From 74a2cf310f4891e17157b508edb0ea982b03619e Mon Sep 17 00:00:00 2001
From: Dan Goodliffe <dan@randomdan.homeip.net>
Date: Sun, 31 Jan 2021 14:02:13 +0000
Subject: Create terrain as collection of meshes

---
 game/terrain.cpp | 44 ++++++--------------------------------------
 game/terrain.h   | 11 +++--------
 2 files changed, 9 insertions(+), 46 deletions(-)

diff --git a/game/terrain.cpp b/game/terrain.cpp
index 092374c..3167972 100644
--- a/game/terrain.cpp
+++ b/game/terrain.cpp
@@ -1,19 +1,18 @@
 #include "terrain.h"
 #include "gfx/models/texture.h"
-#include <array>
+#include <GL/glew.h>
 #include <cache.h>
 #include <cmath>
-#include <cstddef>
 #include <gfx/gl/shader.h>
 #include <gfx/gl/transform.h>
 #include <gfx/image.h>
+#include <gfx/models/mesh.h>
 #include <gfx/models/vertex.hpp>
 #include <glm/glm.hpp>
 #include <random>
 #include <stb_image.h>
 
-Terrain::Terrain() :
-	m_vertexArrayObject {}, m_vertexArrayBuffers {}, texture {Texture::cachedTexture.get("terrain.png")}
+Terrain::Terrain() : texture {Texture::cachedTexture.get("terrain.png")}
 {
 	constexpr auto size {241}; // Vertices
 	constexpr auto offset {(size - 1) / 2};
@@ -64,8 +63,7 @@ Terrain::Terrain() :
 	finish(size, size, resolution);
 }
 
-Terrain::Terrain(const std::string & fileName) :
-	m_vertexArrayObject {}, m_vertexArrayBuffers {}, texture {Texture::cachedTexture.get("terrain.png")}
+Terrain::Terrain(const std::string & fileName) : texture {Texture::cachedTexture.get("terrain.png")}
 {
 	constexpr auto resolution {100};
 
@@ -131,27 +129,7 @@ Terrain::finish(unsigned int width, unsigned int height, unsigned int resolution
 	indices.push_back(verticesCount + 2);
 	indices.push_back(verticesCount + 3);
 
-	glGenVertexArrays(1, &m_vertexArrayObject);
-	glBindVertexArray(m_vertexArrayObject);
-
-	glGenBuffers(2, m_vertexArrayBuffers.data());
-
-	glBindBuffer(GL_ARRAY_BUFFER, m_vertexArrayBuffers[0]);
-	glBufferData(GL_ARRAY_BUFFER, sizeof(Vertex) * vertices.size(), vertices.data(), GL_STATIC_DRAW);
-
-	glEnableVertexAttribArray(0);
-	glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), (void *)offsetof(Vertex, pos));
-
-	glEnableVertexAttribArray(1);
-	glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex), (void *)offsetof(Vertex, texCoord));
-
-	glEnableVertexAttribArray(2);
-	glVertexAttribPointer(2, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), (void *)offsetof(Vertex, normal));
-
-	glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, m_vertexArrayBuffers[1]);
-	glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices[0]) * indices.size(), indices.data(), GL_STATIC_DRAW);
-
-	glBindVertexArray(0);
+	meshes.create<Mesh>(vertices, indices);
 }
 
 Vertex &
@@ -160,12 +138,6 @@ Terrain::v(unsigned int width, unsigned int x, unsigned int z)
 	return vertices[x + (z * width)];
 }
 
-Terrain::~Terrain()
-{
-	glDeleteBuffers(NUM_BUFFERS, m_vertexArrayBuffers.data());
-	glDeleteVertexArrays(1, &m_vertexArrayObject);
-}
-
 static const Transform identity {};
 static const auto identityModel {identity.GetModel()};
 
@@ -174,9 +146,5 @@ Terrain::render(const Shader & shader) const
 {
 	shader.setModel(identityModel);
 	texture->Bind();
-	glBindVertexArray(m_vertexArrayObject);
-
-	glDrawElementsBaseVertex(GL_TRIANGLES, indices.size(), GL_UNSIGNED_INT, nullptr, 0);
-
-	glBindVertexArray(0);
+	meshes.apply(&Mesh::Draw);
 }
diff --git a/game/terrain.h b/game/terrain.h
index 64c4f96..81ee128 100644
--- a/game/terrain.h
+++ b/game/terrain.h
@@ -1,13 +1,12 @@
 #ifndef TERRAIN_H
 #define TERRAIN_H
 
+#include "collection.hpp"
 #include "worldobject.h"
-#include <GL/glew.h>
-#include <array>
+#include <gfx/models/mesh.h>
 #include <gfx/models/vertex.hpp>
 #include <gfx/renderable.h>
 #include <memory>
-#include <special_members.hpp>
 #include <string>
 #include <vector>
 
@@ -18,9 +17,6 @@ class Terrain : public WorldObject, public Renderable {
 public:
 	Terrain();
 	explicit Terrain(const std::string &);
-	~Terrain() override;
-	NO_COPY(Terrain);
-	NO_MOVE(Terrain);
 
 	void render(const Shader & shader) const override;
 
@@ -33,8 +29,7 @@ private:
 
 	Vertex & v(unsigned int width, unsigned int x, unsigned int z);
 
-	GLuint m_vertexArrayObject;
-	std::array<GLuint, NUM_BUFFERS> m_vertexArrayBuffers;
+	Collection<Mesh, false> meshes;
 	std::vector<Vertex> vertices;
 	std::vector<unsigned int> indices;
 	std::shared_ptr<Texture> texture;
-- 
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