C math library

• use man sqrt to look up man page for sqrt function
• note use of #include <math.h> header
• note use of -lm link library

• distinction between compiling and linking

• e.g., #include <math.h> and -lm
• "interface" (.h) and "implementation" (.c)
• example of vec_sum function

• vec_sum
• vec_dot
• vec_len
• vec_scale
• vec_unit
• vec_print
• example Makefile

• vec_unit (argument aliasing example)
• vec_cross
• vec_project

• concept of generic linked list data structure
• typedef struct _link { ... } link_t; link node
• link_init
• typedef struct _list { ... } list_t; list header
• list_init
• list_empty

• print statements
• the gdb debugger
  • break <file:line_no>
  • print <variable_name>
  • run
  • where
  • next
  • step

• list_add (note how to set current pointer)
• list_fdel (delete first node)
• list_del (delete entire list)
• list_not_end
• list_reset
• "interface" (.h) and "implementation" (.c)
• example Makefile

• coordinate reference frame mapping (image to world coord's)
• linear interpolation
• the main double for loop

• ray definition (pos, dir) and parametric representation point_along_ray = pos + t * dir
• 3-step outline of ray tracing algorithm

Building the material_t library (cont'd)

• material_getbyname
• material_list_print
• material_print
• material_getambient (return ambient pixel)

• pix_sum
• pix_nonzero
• pix_print

• generic objects and specialized object instances (inheritance)
• generic and specialized object member functions (polymorphism)
• object_t and plane_t data types
• object_print and plane_print functions
• object_init and plane_init functions

• (fabs(a-b) < epsilon) instead of (a == b) if a and b are floating point

• "isa" relationship
• iterating through list of objects, calling obj->printer(obj,out)
• idea of virtual object and virtual method
• sphere_print()
• function pointers (polymorphic functions)
• typedef struct object_type { ... } object_t; structure
• typedef struct plane_type { ... } plane_t; structure
• contiguous memory
• plane_init()
• object_init()

• plane_t must contain object_t at top for pointer masquerading to work
• no void *priv; pointer is needed
• object_init() function signature changes

• (object_t *) and (plane_t *) pointers and type casting
• hits() virtual function (function pointer) (like object_print())
• plane_hits()
• sphere_hits()
• plane_init() again and setting of function pointers
• object_init() refresher

• ray-plane intersection
• what is pln->ndotq?
• plane equation
• plane_hits function

• using obj->hits() to find the closest intersected object via object_find_closest() (lab 5)

• Makefile
• model.h
• model.c

• matrix.h
• matrix.c
• mat_xpose() and vec_xform()
• mtx_t "class" (lab 6)
• vec_xform() bug

• camera_t
• camera.h
• camera.c
• calling camera_init() and camera_print()

Odds and ends

• argc, argv
• fopen, fclose

See also: Lab 5 redux: object_find_closest()

Assignment 2

Redoing object_last_hit to get rid of the check for last_hit

• remove object_t *last_hit from funciton arguments
• add vec_t hit and vec_t N to arguments
• need to rewrite hits() functions so they all accept and set hit and N

Basic ray caster

• writing a .ppm image
• converting image pixel coordinates to world coordinates
• calculating ray direction
• converting double pixel r,g,b values to unsigned char r,g,b values

• using drgb_t color as color accumulator
• calling object_find_closest()
• getting material ambient color
• scaling material ambient color, adding to drgb_t color color accumulator

• #import <Foundation/Foundation.h>
• #import <stdio.h>
• #import <vector.h>
• .h and .m files
• @interface and @implementation
• member function categories:
  • constructor
  • accessor/mutator
  • operator
  • friends

• int main()
• NSLog()
• NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
• [pool drain];
• [[v1 scale: 1./[v1 len]] write: stderr: "v1 scaled by 1/length is:"];
  is this a memory leak?

Assignment 3

Building a list library (lab 8)

• NSString
• a basic data_t object
• link_t and list_t interface and implementation
• example of init, add, empty

• pixels like vectors (both now objects)
• material now stores pointers to objects instead of double[3] arrays
• need for accessor/mutator functions
• material members "read themselves"
• material_t object
• material_getbyname search function

• similar to vec_t
• still using drgb_t although one could explore:
  • NSImage,
  • NSColor, and mabye
  • NSNumber

• base class, derived class relationships
• using NSString as index into materials list
  (eventually could use an associative array to store materials)
• virtual functions
• derived class : public object_t syntax
• getting base class (parent) to read/write itself
  (no need for *priv pointer)

Assignment 4

Objective-C and OpenMP

• writing an image (color bands) sequentially and in parallel
• timer_r class to time program execution
• #pragma calls for parallel execution on multi-core platforms
• NSImage
• NSBitmapImageRep
• NSData

• C
• linear algebra
• object-oriented principles
• writing functions, programs
• understanding (tracing) programs
• pointers, pointers to functions
• linked lists

• Objective-C file i/o
• find_closest() function
• getting model to "read itself" via [model: read: model_file];

• pass-by-reference arguments of vec_t *hit and vec_t *N
• asg 5 pre-dates lab 11, so complete asg 5 first
• model_t and camera_t objects

• take out image writing loop from within nested for loops
• run two set of nested for loops one after the other, the second set of for loops just writes image data to file (can use NSdata instead)
• can use timer_t to time first set of nested for loops

Midterm answers

Dr. D. out of town

Objective-C list_t (doubly-linked) and idea of a separate list iterator (lab 12)

• two problems with old, singly-linked list
• the doubly-linked list
• writing your own iterators

• ray/sphere intersection
• ray_trace call
• light_t object
• rendering equation: ambient and diffuse components (Lambert's Law)
• pixel_t clamp function

See also: Lab 11 redux: hits, find_closest

• rendering equation: specualr component (Phong model)
• recursive call to ray_trace function
• final color composite (linear interpolation)

Ray tracing extensions

• ray objectification
• vector reflect, refract functions
• ray transmission
• bounded planes
• depth of field
• shadow casting

• NSArray
• NSNumber (Assignment 4 redux with "temlatized" rgb_t object))
• NSMutableDictionary
• NSSet

• NSMutableData
• NSFileManager

Assignment 8

C++

• class
• iostream
• polymorphic (virtual) functions

• Makefile
• data.h
• data.cpp
• main.cpp
• listdata.txt

• containters
• iterators
• templates

Final exam review

• Makefiles
• C programming
• Objective-C programming
• Objective-C polymorphism
• Objective-C iterators
• Objective-C Foundation classes (NSNumber, NSArray, NSEnumerator)