Difference between revisions of "3D Fundamentals Tutorial 2"

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* The <code>Mat3</code> 3D Matrix class [https://youtu.be/HV1ZGyiY5C8?t=5m57s 5:57]
 
* The <code>Mat3</code> 3D Matrix class [https://youtu.be/HV1ZGyiY5C8?t=5m57s 5:57]
 
* Choosing a coordinate system [https://youtu.be/HV1ZGyiY5C8?t=7m37s 7:37]
 
* Choosing a coordinate system [https://youtu.be/HV1ZGyiY5C8?t=7m37s 7:37]
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:* We choose a Left Handed coordinate system
 
:* We choose a Left Handed coordinate system
 
:* And start with defining World Space (=object space for now) and Screen Space
 
:* And start with defining World Space (=object space for now) and Screen Space
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* Setting up a World Space (we'll all it Pube Space) [https://youtu.be/HV1ZGyiY5C8?t=10m08s 10:08]
 
* Setting up a World Space (we'll all it Pube Space) [https://youtu.be/HV1ZGyiY5C8?t=10m08s 10:08]
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:* We set the Origin (0,0,0) of world space in the middle of the screen
 
:* We set the Origin (0,0,0) of world space in the middle of the screen
 
::- This makes for better (easier) scaling
 
::- This makes for better (easier) scaling
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::- Note: Direct 3D and OpenGL use NDC
 
::- Note: Direct 3D and OpenGL use NDC
 
:* We will use the Pre-Clip 3D space definition: z=1.0 indicates half cube depth
 
:* We will use the Pre-Clip 3D space definition: z=1.0 indicates half cube depth
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* Transforming vertices from Pube Space to Screen Space [https://youtu.be/HV1ZGyiY5C8?t=14m01s 14:01]
 
* Transforming vertices from Pube Space to Screen Space [https://youtu.be/HV1ZGyiY5C8?t=14m01s 14:01]
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:* Introducing the <code>PubeScreenTransformer</code> class
 
:* Introducing the <code>PubeScreenTransformer</code> class
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* Testing: drawing a cube [https://youtu.be/HV1ZGyiY5C8?t=17m07s 17:07]
 
* Testing: drawing a cube [https://youtu.be/HV1ZGyiY5C8?t=17m07s 17:07]
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:* <code>Cube</code> class created as a data structure to hold the vertices
 
:* <code>Cube</code> class created as a data structure to hold the vertices
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* Representing lines: vertex container + vetor of indices [https://youtu.be/HV1ZGyiY5C8?t=18m34s 18:34]
 
* Representing lines: vertex container + vetor of indices [https://youtu.be/HV1ZGyiY5C8?t=18m34s 18:34]
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:* This strategy avoids having to transform vertices multiple times
 
:* This strategy avoids having to transform vertices multiple times
 
:* Same concept as IndexBuffer used in Direct3D to draw primitives [https://youtu.be/HV1ZGyiY5C8?t=20m40s 20:40]
 
:* Same concept as IndexBuffer used in Direct3D to draw primitives [https://youtu.be/HV1ZGyiY5C8?t=20m40s 20:40]
 
:* Make the <code>Cube</code> class return a <code>IndexedLineList</code> struct
 
:* Make the <code>Cube</code> class return a <code>IndexedLineList</code> struct
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* Code for drawing: transform the vertices and iterate through the index buffer [https://youtu.be/HV1ZGyiY5C8?t=21m50s 21:50]
 
* Code for drawing: transform the vertices and iterate through the index buffer [https://youtu.be/HV1ZGyiY5C8?t=21m50s 21:50]
 
* Limitations observed: not square and not 3D. Why? [https://youtu.be/HV1ZGyiY5C8?t=23m22s 23:22]
 
* Limitations observed: not square and not 3D. Why? [https://youtu.be/HV1ZGyiY5C8?t=23m22s 23:22]
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:* Screen size is not square, we'll use a quick fix for now
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:* We still lack 3D visual cues because we don't account for the z-component yet (we're still in Orthographic Projection)
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* ...
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Revision as of 06:10, 24 April 2020

In this video we lay the groundwork needed to represent and transform positions and 3D space, we define the relationship between our 3D space and the screen coordinates, and we setup a data structure to hold our test cube geometry.

Video

The tutorial video is on YouTube here.


  • Fix an error in Mat2.h (vector * Matrix multiplication) 0:16
  • Introducing 3D space 1:57
  • Implementing the Vec3 class 3:19
  • Inherits from Vec2 (z-component added)
  • Overload all operators for 3D
  • Advantage of inheritence here: enables passing Vec3s into functions that accept Vecc2& references
  • Calculating the length of a 3D vector (i.e., in R3) 4:57
  • The Mat3 3D Matrix class 5:57
  • Choosing a coordinate system 7:37
  • We choose a Left Handed coordinate system
  • And start with defining World Space (=object space for now) and Screen Space
  • Setting up a World Space (we'll all it Pube Space) 10:08
  • We set the Origin (0,0,0) of world space in the middle of the screen
- This makes for better (easier) scaling
  • We will use NDC (Normalized Device Coordinates)
- Meaning: we don't use pixel values, but normalized values relative to screen size
- (e.g. x=1.0 means far right end of screen, x=-1.0 for far left end of screen
- Main advantage: become independent from screen size
- Note: Direct 3D and OpenGL use NDC
  • We will use the Pre-Clip 3D space definition: z=1.0 indicates half cube depth
  • Transforming vertices from Pube Space to Screen Space 14:01
  • Introducing the PubeScreenTransformer class
  • Testing: drawing a cube 17:07
  • Cube class created as a data structure to hold the vertices
  • Representing lines: vertex container + vetor of indices 18:34
  • This strategy avoids having to transform vertices multiple times
  • Same concept as IndexBuffer used in Direct3D to draw primitives 20:40
  • Make the Cube class return a IndexedLineList struct
  • Code for drawing: transform the vertices and iterate through the index buffer 21:50
  • Limitations observed: not square and not 3D. Why? 23:22
  • Screen size is not square, we'll use a quick fix for now
  • We still lack 3D visual cues because we don't account for the z-component yet (we're still in Orthographic Projection)

Downloads

The GitHub repository for the tutorial code is here.


See also

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