Meshes (The Chickadee Game Toolkit)

From 0e699be281c8dea53e589e08a5831837e0eae7ea Mon Sep 17 00:00:00 2001 From: David Thompson Date: Thu, 7 Oct 2021 20:17:50 -0400 Subject: Updates for Chickadee 0.8.0 and Guile-SDL2 0.7.0. --- manuals/chickadee/Meshes.html | 413 ++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 413 insertions(+) create mode 100644 manuals/chickadee/Meshes.html (limited to 'manuals/chickadee/Meshes.html') diff --git a/manuals/chickadee/Meshes.html b/manuals/chickadee/Meshes.html new file mode 100644 index 0000000..2cd159e --- /dev/null +++ b/manuals/chickadee/Meshes.html @@ -0,0 +1,413 @@ + + + + + + +Meshes (The Chickadee Game Toolkit) + + + + + + + + + + + + + + + + + + + + +

5.3.11 Meshes

+ +

The (chickadee graphics mesh) modules provides procedures for +programmatically creating 3D objects (to load 3D models from a file on +disk, see Meshes.) +

5.3.11.1 Materials

+ +

Before we talk about meshes themselves, let’s discuss “materials.” +Materials control the appearance of 3D objects. Whether an object +appears like a rough rock, a smooth and shiny metal, etc. depends on +the material that is applied to it. Different types of materials use +different lighting models. Chickadee supports two lighting models: +The classic Blinn-Phong model and a more modern physically based +rendering (PBR) model. +

All materials share some common data: +

Procedure: material? obj: Return #t if obj is a material. +

+ +

Procedure: material-name material: Return the name of material. +

+ +

Procedure: material-shader material: Return the shader of material. +

+ +

Procedure: material-blend-mode material: Return the blend mode of material. +

+ +

Procedure: material-polygon-mode material: Return the polygon mode of material. +

+ +

Procedure: material-cull-face-mode material: Return the cull face mode of material. +

+ +

Procedure: material-depth-test material: Return the depth test of material. +

+ +

Procedure: material-stencil-test material: Return the stencil test of material. +

+ +

Procedure: material-multisample? material: Return #t if material uses multisampling. +

+ +

Materials support 5 textures. What each texture is used for depends +on the lighting model. +

Procedure: material-texture-0 material: Return the first texture of material. +

+ +

Procedure: material-texture-1 material: Return the second texture of material. +

+ +

Procedure: material-texture-2 material: Return the third texture of material. +

+ +

Procedure: material-texture-3 material: Return the fourth texture of material. +

+ +

Procedure: material-texture-4 material: Return the fifth texture of material. +

+ +

For all data that is specific to the lighting model, materials have a +“properties” field. +

Procedure: material-properties material: Return the lighting model specific properties of material. +

+ +

5.3.11.2 Blinn-Phong Materials

+ +

The (chickadee graphics phong) module has the Blinn-Phong +lighting model: +

Procedure: make-phong-material [#:name "anonymous"] [#:blend-mode] [#:polygon-mode] [#:cull-face-mode] [#:depth-test] [#:stencil-test] [#:multisample? #f] [#:ambient-factor (vec3 1 1 1)] [#:diffuse-factor (vec3 1 1 1)] [#:specular-factor (vec3 1 1 1)] [#:shininess 32] [#:ambient-texture] [#:diffuse-texture] [#:specular-texture] [#:normal-texture]: +
Return a new Blinn-Phong material. +

+ +

Procedure: make-phong-properties [#:ambient] [#:diffuse] [#:specular] [#:shininess]: +
Return a new Blinn-Phong properties object. +

+ +

Procedure: phong-properties? obj: Return #t if obj is a Blinn-Phong properties object. +

+ +

Procedure: phong-properties-ambient properties: Return the ambient factor of properties. +

+ +

Procedure: phong-properties-diffuse properties: Return the diffuse factor of properties. +

+ +

Procedure: phong-properties-specular properties: Return the specular factor of properties. +

+ +

Procedure: phong-properties-shininess properties: Return the shininess factor of properties. +

+ +

5.3.11.3 PBR Materials

+ +

The (chickadee graphics pbr) module has the PBR lighting model: +

Procedure: make-pbr-material [#:name "anonymous"] [#:blend-mode] [#:polygon-mode] [#:cull-face-mode] [#:depth-test] [#:stencil-test] [#:multisample? #f] [#:base-color-factor (vec3 1 1 1)] [#:base-color-texcoord 0] [#:metallic-factor 1.0] [#:roughness-factor 1.0] [#:metallic-roughness-texcoord 0] [#:normal-texcoord 0] [#:occlusion-texcoord 0] [#:emissive-factor (vec3 1 1 1)] [#:emissive-texcoord 0] [#:alpha-mode opaque] [#:alpha-cutoff 0.5] [#:base-color-texture] [#:metallic-roughness-texture] [#:normal-texture] [#:occlusion-texture] [#:emissive-texture]: +
Return a new PBR material. +

+ +

Procedure: make-pbr-properties [#:base-color-factor] [#:base-color-texcoord] [#:metallic-factor] [#:roughness-factor] [#:metallic-roughness-texcoord] [#:normal-texcoord] [#:occlusion-texcoord] [#:emissive-factor] [#:emissive-texcoord] [#:alpha-mode] [#:alpha-cutoff]: +
Return a new PBR properties object. +

+ +

Procedure: pbr-properties? obj: Return #t if obj is a PBR properties object. +

+ +

Procedure: pbr-properties-base-color-factor properties: Return the base color factor of properties. +

+ +

Procedure: pbr-properties-base-color-texcoord properties: Return the base color texture coordinate attribute index of +properties. +

+ +

Procedure: pbr-properties-metallic-factor properties: Return the metallic factor of properties. +

+ +

Procedure: pbr-properties-roughness properties: Return the roughness factor of properties. +

+ +

Procedure: pbr-properties-metallic-roughness-texcoord properties: Return the metallic-roughness texture coordinate attribute index of +properties. +

+ +

Procedure: pbr-properties-normal-texcoord properties: Return the normal texture coordinate attribute index of +properties. +

+ +

Procedure: pbr-properties-occlusion-texcoord properties: Return the ambient occlusion texture coordinate attribute index of +properties. +

+ +

Procedure: pbr-properties-emissive-factor properties: Return the emissive factor of properties. +

+ +

Procedure: pbr-properties-emissive-texcoord properties: Return the emissive texture coordinate attribute index of +properties. +

+ +

Procedure: pbr-properties-alpha-mode properties: Return the alpha mode of properties. +

+ +

Procedure: pbr-properties-alpha-cutoff properties: Return the alpha cutoff threshold of properties. +

+ +

5.3.11.4 Primitives and Meshes

+ +

A mesh is a collection of “primitives,” so we should discuss those +next. A primitive contains vertex data and a material. +

Procedure: make-primitive name vertex-array material: Return a new primitive named name that renders +vertex-array (see Buffers) using material. +

+ +

Procedure: primitive? obj: Return #t if obj is a primitive. +

+ +

Procedure: primitive-name primitive: Return the name of primitive. +

+ +

Procedure: primitive-vertex-array primitive: Return the vertex array of primitive. +

+ +

Procedure: primitive-material primitive: Return the material of primitive. +

+ +

Okay, now we can talk about meshes, which are just a glorified list of +primitive objects. +

Procedure: make-mesh name primitives: Return a new mesh named name that is composed of the list +primitives. +

+ +

Procedure: mesh? obj: Return #t if obj is a mesh. +

+ +

Procedure: mesh-name mesh: Return the name of mesh. +

+ +

Procedure: mesh-primitives mesh: Return the list of primitives for mesh. +

+ +

The mesh module also conveniently provides procedures to build several +basic 3D shapes. +

Procedure: make-plane length width material: Return a new mesh that forms a flat plane on the XZ axis that is +width units long along the X axis and length units long +along the Z axis. +

+ +

Procedure: make-tesselated-plane length width resolution material

Return a new mesh that forms a tesselated plane on the XZ axis that is +width units long along the X axis and length units long +along the Z axis. +

A regular plane is a single rectangle, but a tesselated plane is +subdivided into many smaller rectangles by resolution. This +allows for transforming the vertices in a shader to achieve effects +such as waves in water or mountainous terrain. +

+ +

Procedure: make-cube size material: Return a new mesh that forms a cube that is size units big. +

+ +

Procedure: make-sphere radius material [#:quality 2]: Return a new mesh that forms a sphere that has a radius of +radius units. Since 3D models are composed of triangles, the +quality of a sphere is entirely dependent upon how many triangles are +used to appromixate the shape. The higher the value of quality, +the better the appromixation, but the more time it will take to +generate and the more expensive it will be to draw. The number of +triangles in the resulting sphere increases exponentially with each +increment to quality. +

+ +

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