Remove UV warning when setting textures with setUniform()

[aferriss]

Most appropriate sub-area of p5.js?

• Accessibility (Web Accessibility)
• Build tools and processes
• Color
• Core/Environment/Rendering
• Data
• DOM
• Events
• Friendly error system
• Image
• IO (Input/Output)
• Localization
• Math
• Unit Testing
• Typography
• Utilities
• WebGL
• Other (specify if possible)

Details about the bug:

If you are using the vertex function and supplying your own UV's, when using the setUniform() function to send a texture to a custom shader, a warning is triggered telling you: "You must first call texture() before using vertex() with image based u and v coordinates ".

Since we're supplying the texture with setUniform(), we shouldn't be showing this warning.

Actually, I think there is a case to be made to remove this warning entirely. It could be that the user is writing a procedural shader, and not using textures, in which case, the warning isn't necessary at all.

The warning seems to go away when using textureMode(NORMAL);

• p5.js version: 1.4
• Web browser and version: Chrome 96
• Operating System: Mac OSX
• Steps to reproduce this:

1. Load a custom shader that samples a texture
2. Send the texture to the shader
3. Draw some geometry with beginShape(), vertex() ....
4. Observe the warning.

Here's a small example showing the issue

[Yash621]

@aferriss can I work on this issue ?

[aferriss]

@Yash621 Of course, go right ahead!

[Gaurav-1306]

Can the admins suggest that if removing this line with close the issue.

p5.js/src/webgl/p5.RendererGL.Immediate.js

Lines 140 to 144 in 95b82ea

	) {
	// Only throw this warning if custom uv's have been provided
	console.warn(
	'You must first call texture() before using' +
	' vertex() with image based u and v coordinates'

Or I can write a if statement that can check if setUniform has been called and then no warning is issured.

[Qianqianye]

Thanks @Gaurav-1306. What do you think, @aferriss and @davepagurek?

[davepagurek]

I think that line is indeed the one causing the error! I think we still want it, so like you said, we'd add to the if statement condition so that it doesn't get logged in as many cases.

I think we don't even need to check if setUniform has been called, since some shaders will use the texture coordinates without needing a uniform. So maybe we can just check if there's any user shader at all? e.g. if any of these is not undefined?

p5.js/src/webgl/p5.RendererGL.js

Lines 540 to 542 in 95b82ea

	this.userFillShader = undefined;
	this.userStrokeShader = undefined;
	this.userPointShader = undefined;

[Gaurav-1306]

@davepagurek

  if (
    this.textureMode === constants.IMAGE &&
    !this.isProcessingVertices
  ) {
    if (this._tex !== null ) {
      if (this._tex.width > 0 && this._tex.height > 0 ) {
        u /= this._tex.width;
        v /= this._tex.height;
      }
    } else if (
      (this.userFillShader !== undefined ||
      this.userStrokeShader !== undefined ||
      this.userPointShader !== undefined)
    ) {
    // Do nothing if user-defined shaders are present
    } else if (
      this._tex === null &&
      arguments.length >= 4
    ) {
      // Only throw this warning if custom uv's have  been provided
      console.warn(
        'You must first call texture() before using' +
          ' vertex() with image based u and v coordinates'
      );
    }
  }

i came up with this implementation. do you think it is good to be merged?

i basically added a else if statement with the new conditions. i tested it using the lib/empty-example. it was showing no error.

[davepagurek]

I think that looks good!