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GSoC 2019 Dev Log
Contents
[hide] LibreCAD 3 OpenGL Rendering - GSoC 2019
FINAL PR : click here ---> :OpenGL Rendering Implemented
LAST GSOC COMMIT ---> :4b43e5f
WORKING REPOSITORY ---> :Working Repo
MY GITHUB ---> :MyGitHub
There are a lot of commits made, these are the ones with major milestones
Viewport System :a589542
Coordinate System :f0b2787
Context-Management :8af6bcc
Matrix transformations :da330e5
Paper-Background :5c28e68
Caching-Mechanism :4a402df
Basic GL_Entity :dec9c97
Gradient Entity:fd9c35f
Gradient_Shader: b75f17f
Shader's Book: 6b44b40
Thicklines with mitter joints: c680b7e
Line-Patterns :7a8d468
Transparency :16d4d31
Font_Book :665a3a3
Text Entity :35d318d
Text-Rendering :b13289d
Bezier Curves :15af822
Arcs :470c15c
Ellipse :4b43e5f
PROJECT TIMELINE
Community Bonding Period (May 6th - May 27th)
> During Community Bonding Period i continued doing more research work for the LibreCAD OpenGL rendering project.
> Linked a partial implemented OpenGL painter with the LibreCAD 3 which uses BufferObjects for rendering
> Implemented basic facilities like pan, zoom
> I started with finding the connections of rendering functions of drawables,drawentities etc.
> Implement and connect the drawables like grid,cursor, origin pointer etc.
> Found connection of tempentities , drawentities
> Tried and check ways of Text Rendering with OpenGL painter( basic ttf type / MSDF type )
> Found place for the caching the saved entities.
> Implemented few more functions in opengl painter (analogous to Cairo) which does Matrix/Vector/Coordinate manipulations(manually with GLM)
> Deciding the basic complete layout of OpenGL painter and found possible ways of complete implementation : https://github.com/sckorpio/LibreCAD_3
> I created blog for the development log on LibreCAD blog : https://blog.librecad.org/tag/google-summer-of-code-gsoc-2019/
TODO:
> Finalize and implement basic gl_entity class which could hold all type of possible entities and render them
> Create a gl_pack class which could hold a number of gl_entities to cache and render complex entities (like dimensions)
> Decide which text rendering should be used (basic ttf or MSDF or both..)
> little research work left on gradient rendering and line patterns and continuing work to complete the painter implementation
Coding Period Phase 1
Week 1
May 27th
> I started with reviewing the partially implemented opengl painter and used only one painter instance with each viewer (which was earlier 3 instances for background,foreground and document using cairo)
> making the painter instance creation more robust starting from UI
May 28th
> Started with testing the drawables rendering with opengl painter , drawables doest require caching
> Connect the signal(drawevent) and slot(grid's draw() code) , Tested the grid drawing calls with the opengl painter
TODO: Debug later -- the zooming out of grid misses some lines
May 29th
> Connect the lccursor with drawevent signal , Tested the cursor drawing calls with the opengl painter
May 30th
> Connected the tempentities with the signal, Now the entities (during drawing/editing process) can also be rendered
> Connected the dragpoints with the signal, Now the entities can be edited using dragpoints
> Checked the editing options correct working like- translate, rotate, scale , copy etc
May 31st
> Found some errors in cursor during high zoom, debugging the lccursor
> Trying to get the perfect viewport with error free pan and zoom so that later the new entities can be seen while testing
June 1st
> Separated the translate,rotate,scale matrix from the model,view,projection matrix in Renderer
> Fixed the clipping of grid while zooming out also speed up the cursor at high zoom.
June 2nd
> Implemented the reset_transformation function
> Now the zoom is perfect working , zooming into the cursor with stability
> In Cairo all matrix are 3*3 so manually implemented all with 4*4 matrices in OpenGL Renderer Class
Week 2
June 3rd
> Found need of Isolated Transformations
> Need of context saving and restoring which stores the transformation matrices, linewidth, color etc
June 4th
> Created a structure which can save the context attributes like glm::mat , linewidth , color
> Created Stack Implementation for the saving and restoring of context
> Implemented the painters save() and restore() methods, now isolated transformations working correctly
June 5th
> Joined the lcvdimensions with the render calls, dimensions all working fine now
> Temporary Implemented the rendering of empty quads in place of text , just to check the saving and restoring of context. Working fine
June 6th
> Implemented the Rotation Matrix manipulation methods
> The Text Quads are now getting rendered with correct angle, working OK
> Now the basic operations of OpenGL painter are functioning correct ( without caching mechanism )
June 7th
> Starting with Caching mechanism
> Reviewing all draw() codes once again to design and finalize the gl_entity class
June 8th
> Found some possible errors which can clash with opengl painter
> Fix those draw codes to work correctly with painter
June 9th
> BREAK
Week 3
June 10th
> Found possible issue with multiple matrix transformations, Need to remember the transformations after caching
> Redesigned the painter matrix manipulations with single CTM and MVP
> Shifting the model matrix to caching painter
June 11th
> Understanding the kernel and storage part of librecad
> Found the Signal and slot connections of events between the document and documentcanvas
June 12th
> Found error with the remove entity signal emitting code ( of paperviewer )
> Fixed some function in storage manager to solve the issue , now entities are rendering OK in paperviewer tab also
June 13th
> Found the duplication of entities storing in entity container of document canvas
> Tried to make a new cached container with key = id of entity
June 14th
> Found some issue with the draw code of paperbackground
> Fixed the missing stroke() call , now the paper background is rendering correct ( Temporary as a white rectangle )
June 15th
> Reviewed all draw() codes and planned the structure of caching , things which are constant and which are variable
> Updated the gl_entity class to hold attributes need in caching
June 16th
> BREAK
Week 4
June 17th
> Discussed the different ways of caching with mentors and decided to implement a particular
> Started with making a separate class named caching painter which will only cache things without any rendering
June 18th
> Started making other classes like Cacher, gl_pack etc which will work in caching
> Added few more functions in main painter and documentcanvas for making caching more abstracted
June 19th
> Continuing working on these classes
June 20th
> Almost completed with the gl_entity, gl_pack, cacher , cacherpainter classes
> Now able to run the draw() codes through caching painter
> Able to cache the gl_packs and implemented the required query functions regarding caching
June 21st
> Ran Caching with basic entities lines , circle , arc etc and with dimensions ( leaving text) all working OK
> Fixed caching issues , all caching working OK
> Found some signal issues in PAPER viewer while MODEL viewer is all OK
June 22nd
> BREAK
June 23rd
> Fixed the entity storage issue and signals
> Changed the entityDrawItem map in document canvas with key as entity's ID
> Cleaned the Code till now
Week 5
June 24th
> Started with updating the gl_entity to hold the attributes of text rendering
> Making some temporary functions to render direct quads
June 25th
> Merged the old commits from the original repo
> Resolved the issues during compiling and finally updating and cleaning the repo till worked done now
> Submitted the first evaluation form
June 26th
> Got the Feedback on the caching mechanism implemented
> Discussed with mentor how to separate the classes for different types
June 27th
> Started with separating the draw() code from renderer to entity class
> Redesigning the structure of classes to work accordingly
June 28th
> Tried Compiling more than one shader working OK
> One Shader for the basic shape drawing the second one for rendering the gradients
June 29th
> Discussed more with Mentor to make the entities more abstracted and robust
> Avoiding the conditional statements and now implementing the draw logic of different entity in their respective classes
June 30th
> First time successfully separated the draw code , working OK
> Now working on making a Base class of entity which others will implement
Coding Period Phase 2
Week 6
July 1st
> Completed the Gradient rendering ( Gradient Entity , functions etc )
> Implemented the Linear_Gradient calculation function using vector geometry math
> Finally got the correct gradient background and paper background result all working OK
July 2nd
> Found out some issues with the coordinate system
> Solved the issue , Finally the coordinate system is corrected , rendering correct , gradient correct , DXF files opening correctly
July 3rd
> Started learning about the shader based linepattern, dashes
July 4th
> Searched some articles on how to render linepattern and dashes
> Learning how to design the fragment shader to render dashes
July 5th
> Implemented few simple linepattern ( consist of dash and gap only ) roughly in seperate codes
> Debugging how the LC3 stores the line pattern in vector
July 6th
> BREAK
July 7th
> Discussion with mentor on how to implement the linepattern based on the research work done yet
> Got a bug reported by mentor , discussing with him and trying to debug.
Week 7
July 8th
> Still finding Some concrete method for line pattern which is optimal and feasible ( It should have less CPU computations and support caching also )
> Trying Some GLSL Shaders to get results
July 9th
> Found out a mathematical way by which CPU computation is required only once , trying to implement this method with GLSL
> First Time successfully rendered correct line patterns , Now this looks integrable with LC3 and could support caching also
July 10th
> Working on GLSL shaders to render more line patterns
July 11th
> Trying to save the line pattern data as an array of ratios representing dash and gap
> The pattern with even elements is to repeated directly while the one with odd elements gets flipped every time.
July 12th
> made new GLSL Shaders to render thick , continous , seamless dashed lines with miter at edges
> Tessellate line with 2 triangles using Geometry Shader and then rendering or discarding fragments according to dash/gap in fragment shader
> Now have basic , gradient , thickline , dashed thickline etc as new shaders
> Next is to start with revamping code which can send data in correct format accordingly to shader type
July 13th
> made new commit , tried to solve the gradient background issue
> Gradient Repo seems working all ok, Current repo work fine on different machines too
July 14th
> BREAK
Week 8
July 15th
> Finding ways to integrate the thick line and line pattern shaders with codebase
July 16th
> finalize the shaders to be used with librecad opengl module for linepatterns
> Reviewing how much and where the changes would be required for integrating the shaders
July 17th
> Got reported by mentor about the OpenGL Debugger with Qt
> Found a number of gl calls which are depreciated and replaced then with latest compatible calls
> Still there is the issue of gradient background freeing memory
July 18th
> On AMD GPUs the repo works perfect , now checking on NVIDIA GPU
> Got the bug on NVIDIA systems, trying to seperate glDelete*** calls from destructors of CPU side objects
> Fixed the bug and got it reviewed by the mentor, Finally its done!!!
July 19th
> Back to work on Dash-Gap and linepatterns
> Add uniform arrays in shader files to pass variable dash-gap data
> Updated shader class to access the dash-gap uniforms
July 20th
> Raw testing the dash pattern shader with capped joints lines , working Ok
July 21st
> Also checked the Mitter Joints line / linepattern shader
> Discussing with mentor regarding the selection , integration of which type(CAP or MITTER) to be used
Week 9
July 22nd
> Also trying to find ways to integrate the MITTER joints thicklines/linepattern shaders
> Getting more complicated with GL_LINE_ADJACENCY , need to change functions to manipulate index data in Renderer class
July 23rd
> Making algorithms which can support jumping of pen also
> Multiple shapes within one VBO and which could still support GL_LINE_STRIP_ADJACENCY
July 24th
> Created a algorithm which can fulfill all the need and which is performance and memory efficient
> Coding it roughly in separate codes and testing, working OK
July 25th
> Now time is to Integrate this method and revamp the codebase of LC3
> Finally revamped the Code!!!
> Now it can support jumping pen , thick lines, linepatterns all working OK
July 26th
> Now working on shader class so that it can support geometry shader , parse it and compile it ( if present )
July 27th
> Updated Shader class
> Now its parsing and compiling Shader files having geometry shader also
July 28th
> Working on how and when to render Thicklines
> Making/Updating Functions to apply entity properties and pick the correct shader required
> Joined the thickline shader to work
> Finally rendered Thicklines having MITTER joints, all working OK
Coding Period Phase 3
Week 10
July 29th
> Now Starting with modifying codebase to render dash patterns
> Modified vertex data to store length of path
> Added new attributes in shape_entity to have properties of dashed patterns
July 30th
> Added new shader to render dashed/thick lines
> Rough testing the shader and clearing errors.
July 31st
> Finally Rendered dashed lines with fixed dash pattern right now
> Reported the mentor about implementation and asking feedback
> Now working on passing variable dash pattern data to shader via Renderer
August 1st
> Working on variable dashed lines pattern ( create from UI )
> Joined the dashed data coming from kernel to shaders via document canvas and renderer
> Finally finished rendering line patterns
August 2nd
> Working on transparency
> Enabled transparency and fixed the vertex data during fill
> transparency working OK
> fixed a minor segmentation fault because of a garbage value of uninitialized dash_size variable on launch of LC3
August 3rd
> Reported mentor about the work finished regarding linepatterns
> Got Feedback correct!!! All working Ok
August 4th
> Finding way to make the thick lines render with magnified or non magnified width while zooming keeping the same codebase
> Changed the draw() code of shape entity to support the magnified width property
Week 11
August 5th
> Started work on Text Rendering module
> Preparing the layout of different classes need to abstract text rendering property
August 6th
> Implemented Text_entity Class to support rendering and caching Text rendering
> Made a Writer class to use the Freetype Library and built and cache the character glyphs textures
August 7th
> Making changes in codebase to support Texture rendering
> Finding errors while using Freetype library with Qt
> Updated and Merged the Main Librecad_3 repo in the current repo
August 8th
> UNABLE TO WORK DUE TO ACADEMIC PURPOSE :(
August 9th
> UNABLE TO WORK DUE TO ACADEMIC PURPOSE :(
August 10th
> Again started with making new Gl_Font and Writer classes
> This Time making it more abstracted so that it can support multiple fonts in the same document
August 11th
> Finally integrated the Freetype Library correctly in lc3
> Implemented GL_font Class and tried rendering some text directly, Working Correct
Week 12
August 12th
> Working on Font_Book to cache multiple GL_Font objects ( discarding Writer class the text render method made itself in GL_Font )
> Created a Default Font to be used when a specific font is missing
> Implemented Font_Book , working OK
August 13th
> Started Working on Text_Entity
> Joined the Text_Entity with the GL_Font and Font_Book
> Tested rendering Font with Cursor , Dimensions and Entities with their model matrix, Working OK
August 14th
> Now Started Joining the outermost calls of painter to the Renderer/Cacher for Text Rendering
> Finished abstracting Text Rendering Calls , Checked text rendering with Cursor and Dimensions etc
> Finally Finished Text Rendering, Working all OK
August 15th
> Debugging for the Bezier curves , Quadratic , cubic curves
> Got Feedback from mentor regarding Text Rendering
> Writing blog for GSoC Phase 2 experience
August 16th
> Implementing Bezier curves
> Solving some issues related to vertex data
August 17th
> Finished Bezier curves , quadratic and cubic
> Starting implementing Ellipse
August 18th
> Found some issue with editing/rotating ellipse from UI , reported to mentor [ TODO: solve later ]
> Trying to implement ellipse using matrix transformation and arc method, but it is disturbing CTM and line patterns
> Implemented Ellipse using Parametric Equation after converting the angle limits to eccentric angles
> Finally Ellipse Implemented , Rendering all OK
Week 13
August 19th
> Working on cmake to create cpp file which will save the absolute paths of RESOURCES during compilation
> Accesing RESOURCES(SHADER and FONT) paths from that file and generate the resources at runtime
> Now No need to put shaders/font files absolute paths manually, All Working OK
August 20th
> Cleaning Code and syntax
> Got feedback from mentor to slightly change the approach of Settings to save Resources absolute path at compilation
August 21st
> Implemented the resources path settings using ModuleSettings
> Cleaned codebase according to LC3 syntax rules
> Removed the unused/dead codes
> Removed all the Debug calls
> Finally cleaned the code and testing , waiting for mentor's feedback
August 22nd
> Found some little issues in rendering module
> Implemented Extended character rendering
> Implemented Text Extends
> Fixed Arc rendering , made it perfect
> Finally Fixed all issues , Now rendering module has no issue
August 23rd
> Got Feedback from mentor regarding cleaning code
> Reset Unnecessarily Changed Files
> Changed folder names from UPPERCASE to lowercases
August 24th
> Trying to get build successfully on Travis CI , ( getting issues with QOpenglWidget)
> Discussing with mentor about the issue, we are still trying to fix it
> Got update from mentor with travis updated , Made progress build successful , but unittest failing
> Fixed some code in rendering module , Now Travis build and unittest all sucessful
> Now Working on CodeFactor issues , Fixed all codefactor issues
> All Checks passed for merging
August 25th
> Testing rendering and finding any issue
> Fixed a minor issue with ellipse , now rendering is perfect according to rendering tests
> Editing Dev-Log , adding important links to major commits
Week 14
August 26th
> Writing the final report for gsoc evaluation
> Finished the Final Evaluation submission
> Received feedback from mentor to use some superclass to remove some code duplication
August 27th
> Removed code duplication from renderer and cacher using new superclass manager
> Removed code duplication from render and cacher opengl painters using new class openglpainter
August 28th
> Removed unnecessary font files
> Set OpenGL major and minor versions
> Finding and creating issues on lc3 main repo
August 29th
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August 30th
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August 31th
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September 1st
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