webgl2.0 how I can get all uniforms except uniformBuffer item

Question

when I write uniformBuffer in shader like this.

uniform Material {
    uniform vec4 u_DiffuseColor;
    uniform vec4 u_TilingOffset;
    uniform vec3 u_MaterialSpecular;
    uniform float u_AlphaTestValue;
    uniform float u_Shininess;
};

gl.getProgramParameter(program, gl.ACTIVE_UNIFORMS) and gl.getActiveUniform(program, i) still contaion uniformBuffer item( for example u_DiffuseColor,it's redundant!), the only one thing I found is gl.getUniformLocation(program, uniName) will return null.

is there another better way i can get uniforms not include uniformBuffer item,because the i should dispose them with two different way.

How can I find a list of all the uniforms in OpenGL es 2.0 vertex shader pro Maybe this is not best way when have uniformBuffer block in shader with opengles3.0

thank you for your reply. it is webgl2.0. I fixed the question — gl3336563163com, Mar 30 '20 at 16:28

score 2 · Answer 1 · answered Mar 30 '20 at 15:35

Given some list of active uniform indices, you can query the value of a property for each item in that list with getActiveUniforms. Among the queryable properties is UNIFORM_BLOCK_INDEX, which is the index of the uniform block the uniform is a member of. If it's not a member of any block, the value will be -1.

So basically, you build a list of all the uniform indices (0 to ACTIVE_UNIFORMS - 1), query their block index, and then query the properties only for the indices whose block index is -1.

Alternatively, you could query, for each active block (0 to ACTIVE_UNIFORM_BLOCKS - 1), the list of uniform indices that are a member of that block with getActiveUniformBlockParameter, passing UNIFORM_BLOCK_ACTIVE_UNIFORM_INDICES as the property to be queried. Any uniform index not in one of these lists is therefore not a member of a block.

gman · Answer 2 · 2020-03-31T02:50:40.400

You can get all uniforms and which blocks they are in by calling gl.getActiveUniform and gl.getActiveUniforms. gl.getProgramParameter(program, gl.ACTIVE_UNIFORMS) returns the number of uniforms. You then create an array of indices to pass to gl.getActiveUniforms and pass it gl.UNIFORM_BLOCK_INDEX. -1 = not in a block.

const vs = `#version 300 es

// NOTE: We need to mark these as mediump to match
// the fragment shader (or of course we could mark
// the fragment shader's uniform block to highp)
//
layout(std140) uniform u_testBlock
{
    mediump vec4 foo;
    mediump vec3 bar;
};

void main() {
  gl_Position = foo;
}
`;
const fs = `#version 300 es
precision mediump float;

layout(std140) uniform u_testBlock
{
    vec4 foo;
    vec3 bar;
};

uniform vec2 blat;

out vec4 theColor;

void main() {
  theColor = vec4(bar + vec3(blat, 0), 1);
}
`;

function main() {
  const gl = document.createElement("canvas").getContext("webgl2");
  if (!gl) {
    return alert("ERROR: need WebGL 2 support");
  }
  const program = twgl.createProgram(gl, [vs, fs]);


  const numUniforms = gl.getProgramParameter(program, gl.ACTIVE_UNIFORMS);
  const indices = [...Array(numUniforms).keys()];
  const blockIndices = gl.getActiveUniforms(program, indices, gl.UNIFORM_BLOCK_INDEX);
    const offsets = gl.getActiveUniforms(program, indices, gl.UNIFORM_OFFSET);

  for (let ii = 0; ii < numUniforms; ++ii) {
    const uniformInfo = gl.getActiveUniform(program, ii);
    if (isBuiltIn(uniformInfo)) {
        continue;
    }
    const {name, type, size} = uniformInfo;
    const blockIndex = blockIndices[ii];
    const offset = offsets[ii];
    console.log(
       name, size, glEnumToString(gl, type),
       blockIndex, offset);
  }
}

function isBuiltIn(info) {
  const name = info.name;
  return name.startsWith("gl_") || name.startsWith("webgl_");
}

function glEnumToString(gl, value) {
  const keys = [];
  for (const key in gl) {
    if (gl[key] === value) {
      keys.push(key);
    }
  }
  return keys.length ? keys.join(' | ') : `0x${value.toString(16)}`;
}

main();

<script src="https://twgljs.org/dist/4.x/twgl.min.js"></script>

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Thank you very much! it's really help me! – gl3336563163com Mar 31 '20 at 07:36 — gl3336563163com, Mar 31 '20 at 07:36

webgl2.0 how I can get all uniforms except uniformBuffer item

2 Answers2