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(window.webpackJsonp=window.webpackJsonp||[]).push([[16],{210:function(t,s,a){t.exports=a.p+"assets/img/forest.5c5cf3ad.png"},260:function(t,s,a){"use strict";a.r(s);var n=a(10),e=Object(n.a)({},(function(){var t=this,s=t.$createElement,n=t._self._c||s;return n("ContentSlotsDistributor",{attrs:{"slot-key":t.$parent.slotKey}},[n("h1",{attrs:{id:"instancing"}},[n("a",{staticClass:"header-anchor",attrs:{href:"#instancing"}},[t._v("#")]),t._v(" Instancing")]),t._v(" "),n("p",[t._v("Our scene right now is very simple: we have one object centered at (0,0,0). What if we wanted more objects? This is were instancing comes in.")]),t._v(" "),n("p",[t._v("Instancing allows us to draw the same object multiple times with different properties (position, orientation, size, color, etc.). There are multiple ways of doing instancing. One way would be to modify the uniform buffer to include these properties and then update it before we draw each instance of our object.")]),t._v(" "),n("p",[t._v("We don't want to use this method for performance reasons. Updating the uniform buffer for each instance would require multiple buffer copies each frame. On top of that, our method to update the uniform buffer currently requires use to create a new buffer to store the updated data. That's a lot of time wasted between draw calls.")]),t._v(" "),n("p",[t._v("If we look at the parameters for the "),n("code",[t._v("draw_indexed")]),t._v(" function "),n("a",{attrs:{href:"https://docs.rs/wgpu/0.5.2/wgpu/struct.RenderPass.html#method.draw_indexed",target:"_blank",rel:"noopener noreferrer"}},[t._v("in the wgpu docs"),n("OutboundLink")],1),t._v(", we can see a solution to our problem.")]),t._v(" "),n("div",{staticClass:"language-rust extra-class"},[n("pre",{pre:!0,attrs:{class:"language-rust"}},[n("code",[n("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("pub")]),t._v(" "),n("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("fn")]),t._v(" "),n("span",{pre:!0,attrs:{class:"token function-definition function"}},[t._v("draw_indexed")]),n("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v("(")]),t._v("\n "),n("span",{pre:!0,attrs:{class:"token operator"}},[t._v("&")]),n("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("mut")]),t._v(" "),n("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("self")]),n("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n indices"),n("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(":")]),t._v(" "),n("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Range")]),n("span",{pre:!0,attrs:{class:"token operator"}},[t._v("<")]),n("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("u32")]),n("span",{pre:!0,attrs:{class:"token operator"}},[t._v(">")]),n("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n base_vertex"),n("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(":")]),t._v(" "),n("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("i32")]),n("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(",")]),t._v("\n instances"),n("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(":")]),t._v(" "),n("span",{pre:!0,attrs:{class:"token class-name"}},[t._v("Range")]),n("span",{pre:!0,attrs:{class:"token operator"}},[t._v("<")]),n("span",{pre:!0,attrs:{class:"token keyword"}},[t._v("u32")]),n("span",{pre:!0,attrs:{class:"token operator"}},[t._v(">")]),t._v(" "),n("span",{pre:!0,attrs:{class:"token comment"}},[t._v("// <-- This right here")]),t._v("\n"),n("span",{pre:!0,attrs:{class:"token punctuation"}},[t._v(")")]),t._v("\n")])])]),n("p",[t._v("The "),n("code",[t._v("instances")]),t._v(" parameter takes a "),n("code",[t._v("Range<u32>")]),t._v(". 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We'll use some constants to simplify things. 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