Implemented chunk* allocate_chunk

src/inc/chunk.hpp

@@ -23,3 +23,105 @@ struct chunk
 
 	bool modified;
 };
+
+// Create a chunk* from a subset of a world.
+
+chunk* allocate_chunk
+(
+	world* input,
+
+	unsigned int x,
+	unsigned int y,
+	unsigned int z,
+
+	unsigned int x_res,
+	unsigned int y_res,
+	unsigned int z_res
+)
+{
+	// Allocate memory to hold the enclosed region's vertex array.
+
+	float* target = (float*)malloc(x_res * y_res * z_res * 6 * 2 * 3 * 7 * sizeof(float));
+
+	if (!target)
+	{
+		std::cout << "Could not allocate enough memory for a new chunk." << std::endl;
+
+		exit(14);
+	}
+
+	// Generate the enclosed region's vertex array.
+
+	unsigned int target_size_in_floats;
+
+	world_subset_to_mesh(input, x, y, z, x_res, y_res, z_res, target, target_size_in_floats);
+
+	// Create the chunk*.
+
+	chunk* the_chunk = new chunk();
+
+	the_chunk->x = x;
+	the_chunk->y = y;
+	the_chunk->z = z;
+
+	the_chunk->x_res = x_res;
+	the_chunk->y_res = y_res;
+	the_chunk->z_res = z_res;
+
+	the_chunk->target_size_in_floats = target_size_in_floats;
+
+	{
+		// Generate a target_vao and a target_vbo to reference the vertex data
+		// of the enclosed region after it is uploaded to the GPU.
+
+		GLuint target_vao;
+		GLuint target_vbo;
+
+		glGenVertexArrays(1, &target_vao);
+
+		glGenBuffers(1, &target_vbo);
+
+		// Bind the target_vao and the target_vbo to the current state.
+
+		glBindVertexArray(target_vao);
+
+		glBindBuffer(GL_ARRAY_BUFFER, target_vbo);
+
+		// Upload the target vertex data to the GPU.
+
+		glBufferData(GL_ARRAY_BUFFER, target_size_in_floats * sizeof(float), target, GL_STATIC_DRAW);
+
+		// Free the enclosed region's vertex data from the CPU.
+
+		free(target);
+
+		// Enable the default vertex attributes.
+
+		glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 7 * sizeof(float), (void*)(0 * sizeof(float)));
+
+		glEnableVertexAttribArray(0);
+
+		glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 7 * sizeof(float), (void*)(3 * sizeof(float)));
+
+		glEnableVertexAttribArray(1);
+
+		glVertexAttribPointer(2, 1, GL_FLOAT, GL_FALSE, 7 * sizeof(float), (void*)(6 * sizeof(float)));
+
+		glEnableVertexAttribArray(2);
+
+		// Unbind the target_vao and the target_vbo from the current state.
+
+		glBindVertexArray(0);
+
+		glBindBuffer(GL_ARRAY_BUFFER, 0);
+
+		// Store the target_vao and the target_vbo in the_chunk.
+
+		the_chunk->target_vao = target_vao;
+		the_chunk->target_vbo = target_vbo;
+	}
+
+	// Return the_chunk.
+
+	return the_chunk;
+}