Fastest way to draw sprites in opengles 2.0 on android

Question

So Im trying to figure out how to draw a single textured quad many times. My issue is that since these are create and deleted and every one of them has a unique position and rot

Answer 1

I think you're after a particle system. A similar question is here: Drawing many textured particles quickly in OpenGL ES 1.1.

Using point sprites is quite cheap, but you have to do extra work in the fragment shader and I'm not sure if GLES2 supports gl_PointSize if you need different sized particles. gl_PointSize Corresponding to World Space Size

My go-to particle system is storing positions in a double buffered texture, then draw using a single draw call and a static array of quads. This is related but I'll describe it a bit more here...

1. Create a texture (floating point if you can, but this may limit the supported devices). Each pixel holds the particle position and maybe rotation information.
2. [EDITED] If you need to animate the particles you want to change the values in the texture each frame. To make it fast, get the GPU to do it in a shader. Using an FBO, draw a fullscreen polygon and update the values in the fragment shader. The problem is you can't read and write to the same texture (or shouldn't). The common approach is to double buffer the texture by creating a second one to render to while you read from the first, then ping-pong between them.
3. Create a VBO for drawing triangles. The positions are all the same, filling a -1 to 1 quad. However make texture coordinates for each quad address the correct pixel in the above texture.

4. Draw the VBO, binding your positions texture. In the vertex shader, read the position given the vertex texture coordinate. Scale the -1 to 1 vertex positions to the right size, apply the position and any rotation. Use the original -1 to 1 position as the texture coordinate to pass to the fragment shader to add any regular colour textures.

   If you ever have a GLSL version with gl_Vertex, I quite like generating these coordinates in the vertex shader, saving storing unnecessarily trivial data just to draw simple objects. This for example.

5. To spawn particles, use glTexSubImage2D and write a block of particles into the position texture. You may need a few textures if you start storing more particle attributes.