Rendering Engine (The Chickadee Game Toolkit)

From 25c5eac5e6ca1035db1eddd7bea9ac78531da57e Mon Sep 17 00:00:00 2001 From: David Thompson Date: Thu, 28 Dec 2023 11:23:49 -0500 Subject: Delete manuals! Good riddance! These are hosted on files.dthompson.us now! --- manuals/chickadee/Rendering-Engine.html | 176 -------------------------------- 1 file changed, 176 deletions(-) delete mode 100644 manuals/chickadee/Rendering-Engine.html (limited to 'manuals/chickadee/Rendering-Engine.html') diff --git a/manuals/chickadee/Rendering-Engine.html b/manuals/chickadee/Rendering-Engine.html deleted file mode 100644 index 8f81fc6..0000000 --- a/manuals/chickadee/Rendering-Engine.html +++ /dev/null @@ -1,176 +0,0 @@ - - - - - - -Rendering Engine (The Chickadee Game Toolkit) - - - - - - - - - - - - - - - - - - - - -

5.3.17 Rendering Engine

- -

The (chickadee graphics engine) 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. -

Performing a custom draw call could look something like this: -

(with-graphics-state ((g:blend-mode blend:alpha)
-                      (g:texture-0 my-texture))
-  (shader-apply my-shader #:foo 1))
-

- -

5.3.17.1 Render States

- -

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 g:. Render -states can be manipulated using the with-graphics-state macro. -

Syntax: with-graphics-state ((name value) …) body …: Evaluate body with render states defined by name changed -to value. The render states are restored to their previous -values afterwards. -

- -

One additional piece of state that the rendering engine has, that is -not part of the GPU state, is the current projection matrix: -

Procedure: current-projection: Return the currently bound projection matrix (see Matrices). -

- -

Syntax: with-projection projection body …: Evaluate body with the current projection matrix bound to -projection (see Matrices). -

- -

5.3.17.2 Rendering

- -

Chickadee likens a GPU draw call to a Scheme procedure call. A shader -(see Shaders) is like a procedure for the GPU to apply. Shaders -are passed arguments: The positional arguments are vertex array -attributes (see Buffers) and the keyword arguments correspond to -the shader’s uniform variables. Scheme uses apply to call a -procedure, so Chickadee uses shader-apply to call a shader. -

Syntax: shader-apply shader vertex-array [#:uniform-key uniform-value …]

Syntax: shader-apply* shader vertex-array count [#:uniform-key uniform-value …]

Render vertex-array using shader with the uniform values -specified in the following keyword arguments. -

While shader-apply will draw every vertex in vertex-array, -shader-apply* will only draw count vertices. -

- -

Syntax: shader-apply/instanced shader vertex-array n [#:uniform-key uniform-value …]

Syntax: shader-apply/instanced shader vertex-array count n [#:uniform-key uniform-value …]

Render vertex-array n times using shader with the -uniform values specified in the following keyword arguments. -

Instanced rendering is very beneficial for rendering the same object -many times with only small differences for each one. For example, the -particle effects described in Particles use instanced rendering. -

While shader-apply/instanced will draw every vertex in -vertex-array, shader-apply* will only draw count -vertices. -

- -

- - - - - - -- cgit v1.2.3