init

engine/include/hd2d/Terrain.h

@@ -0,0 +1,61 @@
+#pragma once
+#include "hd2d/GL.h"
+#include "hd2d/Texture.h"
+
+#include <array>
+#include <cstdint>
+#include <glm/glm.hpp>
+#include <vector>
+
+namespace hd2d {
+
+// How a material id maps onto layers of the terrain texture array.
+struct TerrainMaterial {
+    int topFirst = 0, topCount = 1;        // layers picked per tile for top faces
+    int accentFirst = 0, accentCount = 0;  // occasional variation layers
+    float accentChance = 0.0f;             // probability a tile uses an accent layer
+    int sideFirst = 0, sideCount = 1;      // layers for cliff faces below this tile
+    int lipLayer = -1;                     // layer for an overhang strip atop cliff faces (-1 = none)
+};
+
+// Tile-based diorama terrain: every tile has an integer height level and a
+// material. Top faces are drawn with organically jittered material borders
+// at pixel granularity; height differences produce textured cliff faces.
+class Terrain {
+public:
+    static constexpr int kMaxMaterials = 8;
+
+    void init(int width, int depth, float levelHeight = 0.5f);
+    int width() const { return w_; }
+    int depth() const { return d_; }
+    float levelHeight() const { return levelHeight_; }
+
+    bool inBounds(int x, int z) const { return x >= 0 && z >= 0 && x < w_ && z < d_; }
+    int level(int x, int z) const;
+    uint8_t material(int x, int z) const;
+    void setLevel(int x, int z, int level);
+    void setMaterial(int x, int z, uint8_t mat);
+    float heightAt(float x, float z) const;  // top surface height of tile under (x, z)
+
+    // Cliff faces at the map border extend down to this level (diorama base).
+    int baseLevel = -6;
+    std::array<TerrainMaterial, kMaxMaterials> materials{};
+
+    // (Re)builds GPU mesh + material map after edits.
+    void build();
+    void draw() const;
+    void bindMaterialMap(GLuint unit) const { glBindTextureUnit(unit, matTex_); }
+
+    TextureArray textures;  // pixel-art material layers, all same size
+
+private:
+    int w_ = 0, d_ = 0;
+    float levelHeight_ = 0.5f;
+    std::vector<int> levels_;
+    std::vector<uint8_t> mats_;
+
+    GLuint vao_ = 0, vbo_ = 0, ibo_ = 0, matTex_ = 0;
+    GLsizei indexCount_ = 0;
+};
+
+}  // namespace hd2d