Implement Sampler.grad method for HXSL

[Yanrishatum]

Adds support for GLSL textureGrad / HLSL SampleGrad methods as Sampler.grad().
Requested by CLYDE from Discord.

Sample shader (ported from this ShaderToy shader):

class HxslGradTest extends hxsl.Shader {

	static var SRC = {
		
		@borrow(h3d.shader.Base2d) var texture: Sampler2D;

		@global var time: Float;
		var calculatedUV: Vec2;
		var pixelColor: Vec4;

		function fragment() {
			var blur = pow(.0625 - cos(calculatedUV.x * 20.0 + time) * .0625, 2.);
			var grad = vec2(blur, blur);
			pixelColor =
				texture.grad(calculatedUV + .5 * vec2( blur, blur), grad, grad) * .25 +
				texture.grad(calculatedUV + .5 * vec2( blur,-blur), grad, grad) * .25 +
				texture.grad(calculatedUV + .5 * vec2(-blur, blur), grad, grad) * .25 +
				texture.grad(calculatedUV + .5 * vec2(-blur,-blur), grad, grad) * .25;
		}
	}

}

[onehundredfeet]

Do all platforms support this instruction? Are there any versions of GL or DX that don't?

[Yanrishatum]

Yes, all platforms properly support this method. GL method is supported by GLSL/HLSL versions Heaps targets as well as WebGL.

[ncannasse]

please note that we're using GLSL semantics, so while we can do tex.grad(...) , the toplevel function should be named textureGrad(...) and not "grad".

[Yanrishatum]

It's not a top-level function thought? It follows same approach as all sampler methods - sampler.method(), i.e. texture() -> sampler.get(), texelFetch -> sampler.fetch(), textureSize -> sampler.size() and consequently textureGrad -> sampler.grad()
If we to follow GLSL semantics, we also should remake get, size and fetch methods.

[ncannasse]

You can use both object access and toplevel functions in HXSL, so you simply need to rename your Global to TextureGrad Le jeu. 16 mars 2023 à 02:36, Pavel Alexandrov ***@***.***> a écrit :

…

It's not a top-level function thought? It follows same approach as all sampler methods - sampler.method(), i.e. texture() -> sampler.get(), texelFetch -> sampler.fetch(), textureSize -> sampler.size() and consequently textureGrad -> sampler.grad() If we to follow GLSL semantics, we also should remake get, size and fetch methods. — Reply to this email directly, view it on GitHub <#1127 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAHZXQEDFVAW3Y5RNG2RSMTW4JVCVANCNFSM6AAAAAAUSICDYU> . You are receiving this because you commented.Message ID: ***@***.***>