A small question about Engine.createMultipleRenderTarget

SilverBullet · March 18, 2019, 6:56am

When generating depth texture, why we activate the texture unit 0 instead of the next one behind the previous textures?

BabylonJS/Babylon.js/blob/6709a1a4e8bf39f9fff786ee87fcfe2919539380/src/Engines/engine.ts#L5309


    texture._generateStencilBuffer = generateStencilBuffer;

    texture._attachments = attachments;



    this._internalTexturesCache.push(texture);

}



if (generateDepthTexture && this._caps.depthTextureExtension) {

    // Depth texture

    var depthTexture = new InternalTexture(this, InternalTexture.DATASOURCE_MULTIRENDERTARGET);



    gl.activeTexture(gl.TEXTURE0);

    gl.bindTexture(gl.TEXTURE_2D, depthTexture._webGLTexture);

    gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, gl.NEAREST);

    gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, gl.NEAREST);

    gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE);

    gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE);

    gl.texImage2D(

        gl.TEXTURE_2D,

        0,

        this.webGLVersion < 2 ? gl.DEPTH_COMPONENT : gl.DEPTH_COMPONENT16,

        width,

github.com

BabylonJS/Babylon.js/blob/6709a1a4e8bf39f9fff786ee87fcfe2919539380/src/Engines/engine.ts#L5268


    type = Engine.TEXTURETYPE_UNSIGNED_INT;

    Logger.Warn("Float textures are not supported. Render target forced to TEXTURETYPE_UNSIGNED_BYTE type");

}



var texture = new InternalTexture(this, InternalTexture.DATASOURCE_MULTIRENDERTARGET);

var attachment = (<any>gl)[this.webGLVersion > 1 ? "COLOR_ATTACHMENT" + i : "COLOR_ATTACHMENT" + i + "_WEBGL"];



textures.push(texture);

attachments.push(attachment);



gl.activeTexture((<any>gl)["TEXTURE" + i]);

gl.bindTexture(gl.TEXTURE_2D, texture._webGLTexture);



gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MAG_FILTER, filters.mag);

gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_MIN_FILTER, filters.min);

gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_S, gl.CLAMP_TO_EDGE);

gl.texParameteri(gl.TEXTURE_2D, gl.TEXTURE_WRAP_T, gl.CLAMP_TO_EDGE);



gl.texImage2D(gl.TEXTURE_2D, 0, this._getRGBABufferInternalSizedFormat(type), width, height, 0, gl.RGBA, this._getWebGLTextureType(type), null);



gl.framebufferTexture2D(gl.DRAW_FRAMEBUFFER, attachment, gl.TEXTURE_2D, texture._webGLTexture, 0);

Thanks a lot

Deltakosh · March 18, 2019, 5:09pm

Well there is no good reason. We could as well have always activated 0 for each texture as they are unbound when ready

Both ways are acceptable

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A small question about Engine.createMultipleRenderTarget

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