The most ugly way to render a grid known to mankind

main.c

@@ -101,16 +101,26 @@ int main()
 
 
     hexgrid_t grid;
-    grid.rows = 1;
+    grid.rows = 3;
-    grid.columns = 1;
+    grid.columns = 3;
     grid.hexes = calloc(1, sizeof(hex_t) * grid.rows * grid.columns);
 
-    for (size_t i = 0; i < grid.rows * grid.columns; ++i)
+    float scale = 1.0f / 5.0f;
+
+    for (size_t i = 0; i < grid.rows; ++i)
     {
-        grid.hexes[i].position.x = 0.0f;
+        for (size_t j = 0; j < grid.columns; ++j)
-        grid.hexes[i].position.y = 0.0f;
+        {
-        grid.hexes[i].position.z = 0.0f;
+            float offset = 0.0f;
-        grid.hexes[i].position.w = 1.0f;
+            if (j % 2)
+                offset = sint(1.0f/6);
+
+            grid.hexes[i*grid.columns+j].position.x = (0.0f + j*(1 + cost(1.0f/6)));
+            grid.hexes[i*grid.columns+j].position.y = (0.0f + i*(sint(1.0f/6))*2.0f) + offset;
+            grid.hexes[i*grid.columns+j].position.z = 0.0f;
+            grid.hexes[i*grid.columns+j].position.w = 1.0f;
+            fprintf(stdout, "Position of hex %ld %ld is %f %f\n", i, j, grid.hexes[i*grid.columns+j].position.x, grid.hexes[i*grid.columns+j].position.y);
+        }
     }
 
     // Get OpenGL objects
@@ -119,27 +129,31 @@ int main()
 
     for (uint64_t i = 0; i < grid.columns * grid.rows; ++i)
     {
-        vertices[i*21] = grid.hexes[i].position.x;
+        vertices[i*21] = grid.hexes[i].position.x * scale;
-        vertices[i*21+1] = grid.hexes[i].position.y;
+        vertices[i*21+1] = grid.hexes[i].position.y * scale;
         vertices[i*21+2] = grid.hexes[i].position.z;
 
         for (int j = 1; j < 7; ++j)
         {
-            vertices[i*21+j*3] = grid.hexes[i].position.x + cost((j-1)/6.0f);
+            vertices[i*21+j*3] = (grid.hexes[i].position.x + cost((j-1)/6.0f)) * scale;
-            vertices[i*21+j*3+1] = grid.hexes[i].position.y + sint((j-1)/6.0f);
+            vertices[i*21+j*3+1] = (grid.hexes[i].position.y + sint((j-1)/6.0f)) * scale;
             vertices[i*21+j*3+2] = grid.hexes[i].position.z;
         }
     }
 
-    unsigned int indices[] =
+    size_t nindices = grid.columns * grid.rows * 3 * 6;
+    unsigned int *indices = calloc(nindices, sizeof(unsigned int));
+
+
+    for (size_t i = 0; i < grid.columns*grid.rows; ++i)
     {
-        0,1,2,
+        indices[i*6*3] = 0 + i*7; indices[i*6*3+1] = 1 + i*7; indices[i*6*3+2] = 2 + i*7;
-        0,2,3,
+        indices[i*6*3+3] = 0 + i*7; indices[i*6*3+4] = 2 + i*7; indices[i*6*3+5] = 3 + i*7;
-        0,3,4,
+        indices[i*6*3+6] = 0 + i*7; indices[i*6*3+7] = 3 + i*7; indices[i*6*3+8] = 4 + i*7;
-        0,4,5,
+        indices[i*6*3+9] = 0 + i*7; indices[i*6*3+10] = 4 + i*7; indices[i*6*3+11] = 5 + i*7;
-        0,5,6,
+        indices[i*6*3+12] = 0 + i*7; indices[i*6*3+13] = 5 + i*7; indices[i*6*3+14] = 6 + i*7;
-        0,6,1
+        indices[i*6*3+15] = 0 + i*7; indices[i*6*3+16] = 6 + i*7; indices[i*6*3+17] = 1 + i*7;
-    };
+    }
 
     glGenVertexArrays(1, &vao);
     glGenBuffers(1,&vbo);
@@ -150,7 +164,7 @@ int main()
     glBufferData(GL_ARRAY_BUFFER, 7*3*grid.rows*grid.columns*sizeof(float), vertices, GL_STATIC_DRAW);
 
     glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ebo);
-    glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);
+    glBufferData(GL_ELEMENT_ARRAY_BUFFER, nindices * sizeof(unsigned int), indices, GL_STATIC_DRAW);
 
     glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3*sizeof(float), (void*)0);
     glEnableVertexAttribArray(0);
@@ -170,7 +184,7 @@ int main()
         glUseProgram(shader_program);
         glBindVertexArray(vao);
         glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
-        glDrawElements(GL_TRIANGLES, 3*6, GL_UNSIGNED_INT, 0);
+        glDrawElements(GL_TRIANGLES, 3*6*grid.rows*grid.columns, GL_UNSIGNED_INT, 0);
 
         glfwPollEvents();
         glfwSwapBuffers(window);