OpenGL - Bringing the 3D World into the Android
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The document provides an overview of OpenGL, a hardware-accelerated graphics API used for rendering 2D and 3D graphics across multiple platforms. It discusses OpenGL ES, which is tailored for Android, as well as WebGL for rendering graphics in web browsers, along with a basic introduction to 3D models, shaders, and lighting in graphics programming. Additionally, it highlights the role of vertex and fragment shaders in manipulating vertex data and calculating pixel colors.
OpenGL - Bringing the 3D World into the Android
- 3. First - few Examples Few Examples from the WebGL World: • Trigger Rally • Jellyfish Simulation • Train Demo • Mammoth
- 4. What is OpenGL? • Hardware-accelerated 3D graphics • API for rendering 2D and 3D • Cross-language • Multi-platform • Part of the Khronos Group • Royalty-free • Client-based rendering • Immediate mode rendering
- 5. Android Support • Android uses OpenGL ES • OpenGL ES 1.0 and 1.1 • Android 1.0 and higher • OpenGL ES 2.0 • Android 2.2 (API level 8) and higher • OpenGL ES 3.0 • Android 4.3 (API level 18) and higher may support • Requires device manufacturer support
- 6. WebGL for Android • Android also supports OpenGL for the Web • WebGL is the OpenGL ES JavaScript APIS • Browser Support: • FireFox for Mobile 4 • Chrome for Android 25 • Opera Mobile 12
- 7. 3D Models • Defined using meshes • Mesh composed of triangles • Triangles are 3 vertices • Vertices are x, y, z triples • No surface properties • No color • No Mateial
- 9. 3D Models • Can be written in Notepad • In practice we use 3D creation tools • Blender • Clara.io • Maya • Cinema4D • Unity • 3ds Max
- 10. Create a vertex array Create Simple Model
- 12. Create an index array Create Simple Model
- 13. OpenGL Pipeline Vertex Buffer Attributes Vertex Shader Fragmant (Pixel) Shader Frame Buffer Uniforms Varyings Coordinates, Colors, Normals
- 16. Vertex Shader • Invoked per each vertex • Shader Input: • Per vertex – Attributes • Globally for all vertices – Uniforms • Manipulate vertex position: • Scale • Rotate • Translate • Can send data to fragmant shader - Varying
- 17. Vertex Affine Transform • Rotation: • Scaling: • Translation:
- 18. Cameras, Perspective, Viewports • Camera position and orientation • Model – View matrix • Field of view (FOV) • Perspective matrix • Viewport • 2D projection of 3D scene
- 21. Vertices vs Fragments • More fragments than vertices
- 23. Vertices vs Fragments • More fragments than vertices • Vertex shader varying are interpolated
- 24. Textures What if we want to display this image On this surface?
- 25. Textures And get the following result?
- 26. Textures • Display image on the surface • Use texture mapping • Apply real time effects
- 27. Demo Textured Cube - Image
- 28. Demo Textured Cube – Two Textures
- 29. Lights and materials • Lightning model use physical principles • Final Color • Lights • Normals • Material
- 31. Picking • Create offscreen framebuffer • Label objects with unique colors • Off-screen – on screen render • Read Pixel Data
- 32. Summary • OpenGL – hardware accelerated 3D graphics • Vertex Shader - manipulates per-vertex data • Fragment Shader - calculates color of individual pixels • Textures display images on the surface of geometries
- 33. Questions?
Editor's Notes
- #5: Multi Platform - Linux, MacOS X, and Windows Cross-language – c++, C# and Java to Python and Lua