AndroidKotlinLearnOpenGL

Building

This repo is set up to build using Android Studio 3.5 or greater. It is written in Kotlin. It is important to build the project before looking at the code closely in Android Studio. Both the Data Binding and the Navigator frameworks generate code that is called directly by the project. These calls will show as undefined before the project is built!!

Emulators and devices

When displaying in an emulator - enable the higher level of OpenGL ES.

GLESDynamicVersion = on

to ~/.android/advancedFeatures.ini

For more information on this emulator configuration see the MISC.md file.

Current Status

Exercises are operational through Instancing. Basic camera manipulation is included and is implemented only for movement in the x and z direction. The camera movement leverages the Quaternion implementation of Rajawali.

Architecture diagram

Sample Screenshot

Exercise Descriptions

The project implements the following exercises in descending complexity. The exercises are adapted for Android, OpenGL ES3+, and are implemented in Kotlin.

It also borrows from the camera.h located at:

https://learnopengl.com/code_viewer_gh.php?code=includes/learnopengl/camera.h

Renderer4103AdvancedAsteroidsInstanced

Tutorial URL: https://learnopengl.com/Advanced-OpenGL/Instancing

Code link URL: https://learnopengl.com/code_viewer_gh.php?code=src/4.advanced_opengl/10.3.asteroids_instanced/asteroids_instanced.cpp

Uses a Matrix4 instance array and the associated hacks to set up 4 vector4 attributes to import the Matrix4 into the shader. TODO: replace this ugly hack with a modern buffer if that works in the emulator and phone.

Renderer4102InstancingHacking

No tutorial for this - this was a variation on "Renderer4101InstancingQuads" to add an OBJ based rendering with an instanced based renderer and work through the shader mechanics.

This works for hacking the patches based on instance:

void main()
{
    fColor = aColor;
    float myfloat = float(gl_InstanceID+1);
    vec2 pos = aPos * myfloat;
    gl_Position = vec4(pos + aOffset, 0.0, 1.0);
}

Renderer480AdvancedGlslUBO

Tutorial URL: https://learnopengl.com/Advanced-OpenGL/Advanced-GLSL

Code link URL: https://learnopengl.com/code_viewer_gh.php?code=src/4.advanced_opengl/8.advanced_glsl_ubo/advanced_glsl_ubo.cpp

Use of simple Uniform Buffer Object - in this case to pass in the projection and view matrices to the common shader.

layout (std140) uniform Matrices
{
    mat4 projection;
    mat4 view;
};

Notes: code needs further cleanup as I left parts of the instancing project in the original for use in debugging. This should get stripped out at some point.

Renderer242LightingMapsPlusCubeObject

No tutorial for this. It is a variation on Renderer242LightingMapsSpecular and adds in an OBJ based cube to test integration of OBJ rendering into the scene.

Renderer242LightingMapsSpecular

Tutorial URL: https://learnopengl.com/Lighting/Lighting-maps

Code link URL: https://learnopengl.com/code_viewer_gh.php?code=src/2.lighting/4.2.lighting_maps_specular_map/lighting_maps_specular.cpp

Excellent tutorial on lighting combined with textures.

Renderer174Camera

Tutorial URL: https://learnopengl.com/Getting-started/Camera

Code link URL: https://learnopengl.com/code_viewer_gh.php?code=src/1.getting_started/7.4.camera_class/camera_class.cpp

Renderer163CoordinateSystems

Tutorial URL: https://learnopengl.com/Getting-started/Coordinate-Systems

Code link URL: https://learnopengl.com/code_viewer_gh.php?code=src/1.getting_started/6.3.coordinate_systems_multiple/coordinate_systems_multiple.cpp

Renderer121HelloTriangle

Tutorial URL: https://learnopengl.com/Getting-started/Hello-Triangle

Code link URL: https://learnopengl.com/code_viewer_gh.php?code=src/1.getting_started/2.1.hello_triangle/hello_triangle.cpp

The "hello world" basics in the learnopengl.com style. But adapted to Android and OpenGL ES and Kotlin instead of a PC and a GPU and C++.

GoogleSampleRenderer

Android OpenGL Triangle and Square sample

Tutorial URL: https://developer.android.com/training/graphics/opengl

This is the basic "Hello Opengl" introduction - just the basics. It is included for comparisons to code styling to the learnopengl methodology.

Project notes

Android Framework

The Android application framework is one Activity and multiple Fragments - one for each major section in the learnopengl "coursework". The framework also includes modern Android techniques - more can be learned about these techniques in the excellent Udacity course:

https://classroom.udacity.com/courses/ud9012

• Databinding
• ViewModel with LiveData controls

Imported content

The project does not use any supporting graphics libraries aside what is built into the Android Framework. The math support is provided by the Rajawali Math modules. The modules are converted to kotlin and are located in the java/org/rejawali3d subtree.

See also the Github repo:

https://github.com/Rajawali/Rajawali