Added bounds checking for triangles.

src/gen.c

@@ -1,122 +1,44 @@
 #include "include/gen.h"
+#include "include/geom.h"
 
 #include <stdlib.h>
 #include <time.h>
 
-Vec2 asth[WORLD_SZ][WORLD_SZ] = {
-    {
-        (Vec2){.x = 1, .y = 2},
-        (Vec2){1, 2},
-        (Vec2){1, 2},
-        (Vec2){1, 2},
-        (Vec2){1, 2},
-        (Vec2){1, 2},
-        (Vec2){1, 2},
-        (Vec2){1, 2},
-    },
-    {
-        (Vec2){1, 2},
-        (Vec2){1, 2},
-        (Vec2){1, 2},
-        (Vec2){1, 2},
-        (Vec2){1, 2},
-        (Vec2){1, 2},
-        (Vec2){1, 2},
-        (Vec2){1, 2},
-    },
-    {
-        (Vec2){1, 2},
-        (Vec2){1, 2},
-        (Vec2){1, 2},
-        (Vec2){1, 2},
-        (Vec2){1, 2},
-        (Vec2){1, 2},
-        (Vec2){1, 2},
-        (Vec2){1, 2},
-    },
-    {
-        (Vec2){1, 2},
-        (Vec2){1, 2},
-        (Vec2){1, 2},
-        (Vec2){1, 2},
-        (Vec2){1, 2},
-        (Vec2){1, 2},
-        (Vec2){1, 2},
-        (Vec2){1, 2},
-    },
-    {
-        (Vec2){1, 2},
-        (Vec2){1, 2},
-        (Vec2){1, 2},
-        (Vec2){1, 2},
-        (Vec2){1, 2},
-        (Vec2){1, 2},
-        (Vec2){1, 2},
-        (Vec2){1, 2},
-    },
-    {
-        (Vec2){1, 2},
-        (Vec2){1, 2},
-        (Vec2){1, 2},
-        (Vec2){1, 2},
-        (Vec2){1, 2},
-        (Vec2){1, 2},
-        (Vec2){1, 2},
-        (Vec2){1, 2},
-    },
-    {
-        (Vec2){1, 2},
-        (Vec2){1, 2},
-        (Vec2){1, 2},
-        (Vec2){1, 2},
-        (Vec2){1, 2},
-        (Vec2){1, 2},
-        (Vec2){1, 2},
-        (Vec2){1, 2},
-    },
-    {
-        (Vec2){1, 2},
-        (Vec2){1, 2},
-        (Vec2){1, 2},
-        (Vec2){1, 2},
-        (Vec2){1, 2},
-        (Vec2){1, 2},
-        (Vec2){1, 2},
-        (Vec2){1, 2},
-    },
-};
+Vec2 asth[WORLD_SZ][WORLD_SZ];
 
 Plate lith[NPLATES];
 
 // Find the point for an index to the edge of the world.
 Pt world_edge_idx_to_pt(int idx) {
-    if (0 <= idx && idx < 8) {
+    if (0 <= idx && idx < WORLD_SZ) {
         return (Pt){idx, 0};
-    } else if (8 <= idx && idx < 16) {
-        return (Pt){7, idx - 8};
-    } else if (16 <= idx && idx < 24) {
-        return (Pt){idx - 16, 0};
-    } else if (24 <= idx && idx < 32) {
-        return (Pt){7, idx - 24};
+    } else if (WORLD_SZ <= idx && idx < 2 * WORLD_SZ) {
+        return (Pt){WORLD_SZ - 1, idx - WORLD_SZ};
+    } else if (2 * WORLD_SZ <= idx && idx < 3 * WORLD_SZ) {
+        return (Pt){idx - 2 * WORLD_SZ, 0};
+    } else if (3 * WORLD_SZ <= idx && idx < 4 * WORLD_SZ) {
+        return (Pt){WORLD_SZ - 1, idx - 3 * WORLD_SZ};
     } else {
         exit(122);
     }
 }
 
+void gen_asth() {
+    srand(time(NULL));
+
+    for (int i = 0; i < WORLD_SZ; i++) {
+        for (int j = 0; j < WORLD_SZ; j++) {
+            asth[i][j] = (Vec2){rand() % 7 - 3, rand() % 7 - 3};
+        }
+    }
+}
+
 void gen_lith() {
     srand(time(NULL));
 
-    Tri tri1 = {
-        (Pt){0, 0},
-        (Pt){0, 7},
-        (Pt){7, 0},
-    };
-    Tri tri2 = {
-        (Pt){7, 0},
-        (Pt){0, 7},
-        (Pt){7, 7},
-    };
+    Tri* tri1 = tri_init((Pt){0, 0}, (Pt){0, 7}, (Pt){7, 0});
+    Tri* tri2 = tri_init((Pt){7, 0}, (Pt){0, 7}, (Pt){7, 7});
 
-    lith[0] = (Plate){.tris = {tri1}};
-    lith[1] = (Plate){.tris = {tri2}};
+    lith[0] = (Plate){.col = BLUE, .ntris = 1, .tris = tri1};
+    lith[1] = (Plate){.col = GREEN, .ntris = 1, .tris = tri2};
 }

src/geom.c

@@ -0,0 +1,26 @@
+#include "include/geom.h"
+
+Tri* alltris[512];
+size_t allsize = 0;
+
+Tri* tri_init(Pt a, Pt b, Pt c) {
+    Tri* tri = malloc(sizeof(Tri));
+    *(alltris + allsize) = tri;
+    allsize++;
+    *tri = (Tri){a, b, c};
+    return tri;
+}
+
+bool tri_within(Pt pt, Tri* tri) {
+    double denom =
+        ((tri->b.y - tri->c.y) * (tri->a.x - tri->c.x) +
+         (tri->c.x - tri->b.x) * (tri->a.y - tri->c.y));
+    double a = ((tri->b.y - tri->c.y) * (pt.x - tri->c.x) +
+                (tri->c.x - tri->b.x) * (pt.y - tri->c.y)) /
+               denom;
+    double b = ((tri->c.y - tri->a.y) * (pt.x - tri->c.x) +
+                (tri->a.x - tri->c.x) * (pt.y - tri->c.y)) /
+               denom;
+    double c = 1 - a - b;
+    return 0 <= a && a <= 1 && 0 <= b && b <= 1 && 0 <= c && c <= 1;
+}

src/include/gen.h

@@ -5,7 +5,7 @@
 
 #include <stdint.h>
 
-#define WORLD_SZ 8
+#define WORLD_SZ 12
 #define NPLATES 2
 
 // A two dimensional vector.
@@ -19,6 +19,7 @@ extern Vec2 asth[WORLD_SZ][WORLD_SZ];
 // The lithosphere; contians a list of plates.
 extern Plate lith[NPLATES];
 
+void gen_asth(void);
 void gen_lith(void);
 
 #endif

src/include/geom.h

@@ -1,6 +1,10 @@
 #ifndef GEOM_H
 #define GEOM_H
 
+#include <stdlib.h>
+#include <stdbool.h>
+#include <raylib.h>
+
 // The maximum number of Tris in a Plate.
 #define NTRI 4
 
@@ -19,8 +23,19 @@ typedef struct {
     Pt c;
 } Tri;
 
+extern Tri* alltris[512];
+extern size_t allsize;
+
+Tri* tri_init(Pt a, Pt b, Pt c);
+void tri_destroy(Tri* tri);
+
+// Check if a point is within the triangle. Uses barycentric coordinate system.
+bool tri_within(Pt pt, Tri* tri);
+
 typedef struct {
-    Tri tris[NTRI];
+    Color col;
+    size_t ntris;
+    Tri* tris;
 } Plate;
 
 #endif

src/include/render.h

@@ -3,8 +3,8 @@
 
 #include "gen.h"
 
-#define SCREEN_WIDTH 800
-#define SCREEN_HEIGHT 800
+#define SCREEN_WIDTH (100 * WORLD_SZ)
+#define SCREEN_HEIGHT (100 * WORLD_SZ)
 #define CELL_SZ (SCREEN_WIDTH / WORLD_SZ)
 
 void render(void);

src/include/tect.h

@@ -0,0 +1,8 @@
+#ifndef TECT_H
+#define TECT_H
+
+#include "gen.h"
+
+Vec2* tect_asth_vals(Plate p);
+
+#endif

src/include/util.h

@@ -0,0 +1,9 @@
+#ifndef UTIL_H
+#define UTIL_H
+
+#define MAX(a, b) a ? a > b : b
+#define MAX3(a, b, c) MAX(a, MAX(b, c))
+#define MIN(a, b) a ? a < b : b
+#define MIN3(a, b, c) MIN(a, MIN(b, c))
+
+#endif

src/main.c

@@ -6,6 +6,7 @@
 #include <raylib.h>
 
 int main(int argc, char** argv) {
+    gen_asth();
     gen_lith();
     InitWindow(SCREEN_WIDTH, SCREEN_HEIGHT, "Terrin");
     SetTargetFPS(110);

src/render.c

@@ -1,5 +1,7 @@
 #include "include/render.h"
 #include "include/gen.h"
+#include "include/geom.h"
+#include "include/util.h"
 
 #include <raylib.h>
 #include <stdio.h>
@@ -18,27 +20,44 @@ Vector2 PointpToVector2(Pt* p) {
     return v;
 }
 
-void render() {
-    for (int i = 0; i < NPLATES; i++) {
-        Plate plate = lith[i];
-
+void draw_tri(Tri* tri) {
     DrawTriangleLines(
-            PointToVector2(plate.tris[0].a), PointToVector2(plate.tris[0].b),
-            PointToVector2(plate.tris[0].c), RED
-        );
-        printf(
-            ">>>>>>>>>>>>>>>>>>%i %i\n", plate.tris[0].a.x, plate.tris[0].a.y
+        PointToVector2(tri->a), PointToVector2(tri->b), PointToVector2(tri->c),
+        RED
     );
 }
 
+// bad.
+void draw_tri_inside(Tri* tri, Color col) {
+    // int maxx = MAX3(tri->a.x, tri->b.x, tri->c.x);
+    // int maxy = MAX3(tri->a.y, tri->b.y, tri->c.y);
+    // int minx = MIN3(tri->a.y, tri->b.y, tri->c.y);
+    // int miny = MIN3(tri->a.y, tri->b.y, tri->c.y);
+    for (int x = 0; x <= WORLD_SZ; x++) {
+        for (int y = 0; y < WORLD_SZ; y++) {
+            if (tri_within((Pt){x, y}, tri)) {
+                DrawCircleV(PointToVector2((Pt){x, y}), 4.f, col);
+            }
+        }
+    }
+}
+
+void render() {
     for (int x = 0; x < WORLD_SZ; x++) {
         for (int y = 0; y < WORLD_SZ; y++) {
             Vector2 v = PointToVector2((Pt){x, y});
             DrawCircleV(v, 4.f, WHITE);
             DrawLineV(
-                v, (Vector2){v.x + asth[x][y].x * 8, v.y + asth[x][y].y * 8},
+                v,
+                (Vector2){v.x + asth[x][y].x * WORLD_SZ,
+                          v.y + asth[x][y].y * WORLD_SZ},
                 WHITE
             );
         }
     }
+    for (int i = 0; i < NPLATES; i++) {
+        Plate plate = lith[i];
+        draw_tri(plate.tris);
+        draw_tri_inside(plate.tris, plate.col);
+    }
 }

src/tect.c

@@ -0,0 +1,9 @@
+#include "include/tect.h"
+#include "include/gen.h"
+#include "include/geom.h"
+
+Vec2* tect_asth_vals(Plate p) {
+    Vec2 buf[WORLD_SZ * WORLD_SZ];
+    for (int i = 0; i < p.ntris; i++) {}
+    return buf;
+}