What are gl.MAX_TEXTURE_SIZE and gl.MAX_RENDERBUFFER_SIZE exacly? - webgl

Question

I would like to display a graphic (map) in a canvas.
Now this error message appears for large displays:
WebGL warning: width/height: Requested size 8316x3141 was too large, but resize to 4158x1570 succeeded.
I found this code snippet on the website https://docs.developer.canva.com/apps/frontend-development/webgl.
// Ensure we can render images this size
const maxTextureSize = gl.getParameter(gl.MAX_TEXTURE_SIZE);
const maxRenderBufferSize = gl.getParameter(gl.MAX_RENDERBUFFER_SIZE);
const maxSize = Math.max(state.image.width, state.image.height);
if (maxSize > maxTextureSize || maxSize > maxRenderBufferSize) {
throw new Error("Failed to render image. The image is too large.");
}
But neither https://developer.mozilla.org/en-US/docs/Web/API/WebGL_API/WebGL_best_practices nor https://developer.mozilla.org/en-US/docs/Web/API/WebGLRenderingContext/getParameter explain to me exactly what the parameters gl.MAX_TEXTURE_SIZE and MAX_RENDERBUFFER_SIZE mean. I can't find any other documentation.
For me, the error already occurs when my image is much smaller.
Example
maxTextureSize = 16384
maxRenderBufferSize = 16384
mymaxSize = 8316
shows the warnung
WebGL warning: width/height: Requested size 8316x3141 was too large, but resize to 4158x1570 succeeded.
and does not render properly.

Answer 1

For 1D and 2D textures (and any texture types that use similar dimensionality, like cubemaps) the max size of either dimension is GL_MAX_TEXTURE_SIZE
Khronos OpenGL wiki
The same applies for MAX_RENDERBUFFER_SIZE except that it pertains to renderbuffers created via createRenderbuffer or implicitly by the canvas as a backbuffer.
There's been some GPU drivers that falsely report sizes that they're not able to support, are you by chance using some age-old integrated or mobile graphics solution?