WebGL2 rendering to R32F texture

Question

I can't bind R32F texture to framebuffer, because such textures are not "color renderable by default" according to this source.

But then it says "those features are available as optional extensions".

How to I use those extensions? How do I get it working?

Answer 1

You try to enable the EXT_color_buffer_float extension

function main() {
  const gl = document.createElement("canvas").getContext("webgl2");
  const ext = gl.getExtension("EXT_color_buffer_float");
  if (!ext) {
    console.log("sorry, can't render to floating point textures");
    return;
  }

  const tex = gl.createTexture();
  gl.bindTexture(gl.TEXTURE_2D, tex);
  const level = 0;
  const internalFormat = gl.R32F;
  const width = 1;
  const height = 1;
  const border = 0;
  const format = gl.RED;
  const type = gl.FLOAT;
  gl.texImage2D(
    gl.TEXTURE_2D, level, internalFormat,
    width, height, border, format, type, null);

  const fb = gl.createFramebuffer();
  gl.bindFramebuffer(gl.FRAMEBUFFER, fb);
  gl.framebufferTexture2D(
    gl.FRAMEBUFFER, gl.COLOR_ATTACHMENT0,
    gl.TEXTURE_2D, tex, level);

  const status = gl.checkFramebufferStatus(gl.FRAMEBUFFER);
  console.log(`can ${status === gl.FRAMEBUFFER_COMPLETE ? "" : "NOT "}render to R32`);
}
main();