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| author | David Thompson <dthompson2@worcester.edu> | 2021-10-07 20:17:50 -0400 |
|---|---|---|
| committer | David Thompson <dthompson2@worcester.edu> | 2021-10-07 20:17:50 -0400 |
| commit | 0e699be281c8dea53e589e08a5831837e0eae7ea (patch) | |
| tree | 4266aebec927b13ca56410be1901e3ee78dff49e /manuals/chickadee/Rendering-Engine.html | |
| parent | 38daa330f2194de5f39cd41b270c89d7b2e94427 (diff) | |
Updates for Chickadee 0.8.0 and Guile-SDL2 0.7.0.
Diffstat (limited to 'manuals/chickadee/Rendering-Engine.html')
| -rw-r--r-- | manuals/chickadee/Rendering-Engine.html | 140 |
1 files changed, 54 insertions, 86 deletions
diff --git a/manuals/chickadee/Rendering-Engine.html b/manuals/chickadee/Rendering-Engine.html index bdc2444..1c90022 100644 --- a/manuals/chickadee/Rendering-Engine.html +++ b/manuals/chickadee/Rendering-Engine.html @@ -1,6 +1,6 @@ <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> -<!-- Copyright (C) 2017-2020 David Thompson davet@gnu.org +<!-- Copyright (C) 2017-2021 David Thompson davet@gnu.org Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 @@ -32,8 +32,8 @@ http://www.texinfo.org/ (GNU Texinfo). <link href="Index.html" rel="index" title="Index"> <link href="index.html#SEC_Contents" rel="contents" title="Table of Contents"> <link href="Graphics.html" rel="up" title="Graphics"> -<link href="Buffers.html" rel="next" title="Buffers"> -<link href="Viewports.html" rel="prev" title="Viewports"> +<link href="Audio.html" rel="next" title="Audio"> +<link href="Render-Settings.html" rel="prev" title="Render Settings"> <style type="text/css"> <!-- a.summary-letter {text-decoration: none} @@ -82,27 +82,60 @@ ul.no-bullet {list-style: none} <body lang="en"> <span id="Rendering-Engine"></span><div class="header"> <p> -Next: <a href="Buffers.html" accesskey="n" rel="next">Buffers</a>, Previous: <a href="Viewports.html" accesskey="p" rel="prev">Viewports</a>, Up: <a href="Graphics.html" accesskey="u" rel="up">Graphics</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Index.html" title="Index" rel="index">Index</a>]</p> +Previous: <a href="Render-Settings.html" accesskey="p" rel="prev">Render Settings</a>, Up: <a href="Graphics.html" accesskey="u" rel="up">Graphics</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Index.html" title="Index" rel="index">Index</a>]</p> </div> <hr> -<span id="Rendering-Engine-1"></span><h4 class="subsection">2.3.13 Rendering Engine</h4> - -<p>Chickadee defines rendering using a metaphor familiar to Scheme -programmers: procedure application. A shader (see <a href="Shaders.html">Shaders</a>) is -like a procedure for the GPU to apply. Shaders are passed arguments: -A vertex array containing the geometry to render (see <a href="Buffers.html">Buffers</a>) and -zero or more keyword arguments that the shader understands. Similar -to how Scheme has <code>apply</code> for calling procedures, Chickadee -provides <code>shader-apply</code> for calling shaders. +<span id="Rendering-Engine-1"></span><h4 class="subsection">5.3.17 Rendering Engine</h4> + +<p>The <code>(chickadee graphics engine)</code> module provides a Scheme +abstraction to the state of the GPU driver. When the Chickadee game +loop launches, it takes care to initialize the engine. All draw calls +and state changes happen within the context of this engine. +</p> +<p>Performing a custom draw call could look something like this: </p> -<p>Additionally, there is some dynamic state that effects how -<code>shader-apply</code> will behave. Things like the current viewport, -framebuffer, and blend mode are stored as dynamic state because it -would be tedious to have to have to specify them each time -<code>shader-apply</code> is called. +<div class="example"> +<pre class="example">(with-graphics-state ((g:blend-mode blend:alpha) + (g:texture-0 my-texture)) + (shader-apply my-shader #:foo 1)) +</pre></div> + +<span id="Render-States"></span><h4 class="subsubsection">5.3.17.1 Render States</h4> + +<p>Render states represent individual state values on the GPU. For +example, the current shader. As a naming convention, Chickadee +prefixes variables containing render states with <code>g:</code>. Render +states can be manipulated using the <code>with-graphics-state</code> macro. +</p> +<dl> +<dt id="index-with_002dgraphics_002dstate">Syntax: <strong>with-graphics-state</strong> <em>((name value) …) body …</em></dt> +<dd><p>Evaluate <var>body</var> with render states defined by <var>name</var> changed +to <var>value</var>. The render states are restored to their previous +values afterwards. +</p></dd></dl> + +<p>One additional piece of state that the rendering engine has, that is +not part of the GPU state, is the current projection matrix: </p> -<p>The following procedures and syntax can be found in the -<code>(chickadee graphics)</code> module. +<dl> +<dt id="index-current_002dprojection">Procedure: <strong>current-projection</strong></dt> +<dd><p>Return the currently bound projection matrix (see <a href="Matrices.html">Matrices</a>). +</p></dd></dl> + +<dl> +<dt id="index-with_002dprojection">Syntax: <strong>with-projection</strong> <em>projection body …</em></dt> +<dd><p>Evaluate <var>body</var> with the current projection matrix bound to +<var>projection</var> (see <a href="Matrices.html">Matrices</a>). +</p></dd></dl> + +<span id="Rendering"></span><h4 class="subsubsection">5.3.17.2 Rendering</h4> + +<p>Chickadee likens a GPU draw call to a Scheme procedure call. A shader +(see <a href="Shaders.html">Shaders</a>) is like a procedure for the GPU to apply. Shaders +are passed arguments: The positional arguments are vertex array +attributes (see <a href="Buffers.html">Buffers</a>) and the keyword arguments correspond to +the shader’s uniform variables. Scheme uses <code>apply</code> to call a +procedure, so Chickadee uses <code>shader-apply</code> to call a shader. </p> <dl> <dt id="index-shader_002dapply">Syntax: <strong>shader-apply</strong> <em>shader vertex-array [#:uniform-key uniform-value …]</em></dt> @@ -131,75 +164,10 @@ particle effects described in <a href="Particles.html">Particles</a> use instanc vertices. </p></dd></dl> -<dl> -<dt id="index-current_002dviewport">Procedure: <strong>current-viewport</strong></dt> -<dd><p>Return the currently bound viewport (see <a href="Viewports.html">Viewports</a>). -</p></dd></dl> - -<dl> -<dt id="index-current_002dframebuffer">Procedure: <strong>current-framebuffer</strong></dt> -<dd><p>Return the currently bound framebuffer (see <a href="Framebuffers.html">Framebuffers</a>). -</p></dd></dl> - -<dl> -<dt id="index-current_002dblend_002dmode">Procedure: <strong>current-blend-mode</strong></dt> -<dd><p>Return the currently bound blend mode (see <a href="Blending.html">Blending</a>). -</p></dd></dl> - -<dl> -<dt id="index-current_002ddepth_002dtest">Procedure: <strong>current-depth-test</strong></dt> -<dd><p>Return <code>#t</code> if depth testing is currently enabled (see <a href="Blending.html">Blending</a>). -</p></dd></dl> - -<dl> -<dt id="index-current_002dtexture">Procedure: <strong>current-texture</strong></dt> -<dd><p>Return the currently bound texture (see <a href="Textures.html">Textures</a>). -</p></dd></dl> - -<dl> -<dt id="index-current_002dprojection">Procedure: <strong>current-projection</strong></dt> -<dd><p>Return the currently bound projection matrix (see <a href="Matrices.html">Matrices</a>). -</p></dd></dl> - -<dl> -<dt id="index-with_002dviewport">Syntax: <strong>with-viewport</strong> <em>viewport body …</em></dt> -<dd><p>Evaluate <var>body</var> with the current viewport bound to <var>viewport</var> (see <a href="Viewports.html">Viewports</a>). -</p></dd></dl> - -<dl> -<dt id="index-with_002dframebuffer">Syntax: <strong>with-framebuffer</strong> <em>framebuffer body …</em></dt> -<dd><p>Evaluate <var>body</var> with the current framebuffer bound to -<var>framebuffer</var> (see <a href="Framebuffers.html">Framebuffers</a>). -</p></dd></dl> - -<dl> -<dt id="index-with_002dblend_002dmode">Syntax: <strong>with-blend-mode</strong> <em>blend-mode body …</em></dt> -<dd><p>Evaluate <var>body</var> with the current blend mode bound to -<var>blend-mode</var> (see <a href="Blending.html">Blending</a>). -</p></dd></dl> - -<dl> -<dt id="index-with_002ddepth_002dtest">Syntax: <strong>with-depth-test</strong> <em>depth-test? body …</em></dt> -<dd><p>Evaluate <var>body</var> with the depth-test disabled if <var>depth-test?</var> -is <code>#f</code>, or enabled otherwise (see <a href="Blending.html">Blending</a>). -</p></dd></dl> - -<dl> -<dt id="index-with_002dtexture">Syntax: <strong>with-texture</strong> <em>texture body …</em></dt> -<dd><p>Evaluate <var>body</var> with the current texture bound to <var>texture</var> -(see <a href="Textures.html">Textures</a>). -</p></dd></dl> - -<dl> -<dt id="index-with_002dprojection">Syntax: <strong>with-projection</strong> <em>projection body …</em></dt> -<dd><p>Evaluate <var>body</var> with the current projection matrix bound to -<var>projection</var> (see <a href="Matrices.html">Matrices</a>). -</p></dd></dl> - <hr> <div class="header"> <p> -Next: <a href="Buffers.html" accesskey="n" rel="next">Buffers</a>, Previous: <a href="Viewports.html" accesskey="p" rel="prev">Viewports</a>, Up: <a href="Graphics.html" accesskey="u" rel="up">Graphics</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Index.html" title="Index" rel="index">Index</a>]</p> +Previous: <a href="Render-Settings.html" accesskey="p" rel="prev">Render Settings</a>, Up: <a href="Graphics.html" accesskey="u" rel="up">Graphics</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Index.html" title="Index" rel="index">Index</a>]</p> </div> |