Implement md2 model animation (VAT) #117 [DRAFT]

[demoth]

Implement efficient GPU based animation for md2 models

Should be smooth as butter and run natively on 144Hz

Some very early attempts with the shaders was already in main, thats why some classes are changed and not added

STATUS: Works flawlessly (Md2ShaderTest.kt)
TODO: switch the model viewer and the game onto the new implementation

This is a complex topic I understand, nevertheless I added people for review to try to start a discussion and raise question.

Pick any line and ask a question

[Copilot]

Pull Request Overview

This PR implements an efficient GPU-based animation system for md2 models by refactoring vertex data preparation, updating shader interfaces, and adjusting model loading routines. Key changes include:

• Renaming and refactoring of functions (e.g. toFloats → toVertexAttributes) to better express functionality.
• Modifications in model frame parsing (using Md2Frame.fromBuffer) and texture creation for vertex animations.
• Updates to shader code and resource handling in the model viewer and test cases.

Reviewed Changes

Copilot reviewed 11 out of 11 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
qcommon/src/test/kotlin/jake2/qcommon/filesystem/Md2ModelVertexDataTest.kt	Added thorough test data for verifying vertex re-indexing and attribute generation.
qcommon/src/test/kotlin/jake2/qcommon/filesystem/Md2ModelTest.kt	Updated test assertions to use the new toVertexAttributes API.
qcommon/src/main/kotlin/jake2/qcommon/filesystem/md2.kt	Replaced toFloats with toVertexAttributes and updated frame parsing logic via Md2Frame.fromBuffer.
cake/lwjgl3/src/main/kotlin/org/demoth/cake/lwjgl3/Md2ShaderTest.kt	Adjusted animation control, resource loading and input handling for model rendering.
cake/core/src/main/kotlin/org/demoth/cake/modelviewer/Md2Shader.kt	Introduced a new shader implementation for md2 vertex animations using VAT.
cake/core/src/main/kotlin/org/demoth/cake/modelviewer/Md2ModelLoader.kt	Added loadStaticMd2Model and refactored VAT texture creation and mesh building.
cake/core/src/main/kotlin/org/demoth/cake/modelviewer/CustomTextureData.kt	Updated Md2ShaderModel to reflect disposed texture handling.
cake/core/src/main/kotlin/org/demoth/cake/modelviewer/CakeModelViewer.kt	Temporarily commented out rendering call with a fixme note for further review.
cake/core/src/main/java/org/demoth/cake/stages/Game3dScreen.kt	Updated to use the static model loading approach.
assets/shaders/vat.glsl	Adjusted attribute usage to use a_vat_index instead of relying on gl_VertexID.
assets/shaders/md2-fragment.glsl	Removed the custom fragment shader in favor of default shader behavior.

Comments suppressed due to low confidence (2)

qcommon/src/main/kotlin/jake2/qcommon/filesystem/md2.kt:266

• [nitpick] The parameter name 'framePositions' in toVertexAttributes is inconsistent with similar methods which use 'points'. Consider renaming it to 'points' for clarity and consistency.

fun toVertexAttributes(framePositions: List<Md2Point>, returnTexCoords: Boolean = true): List<Float> {

cake/core/src/main/kotlin/org/demoth/cake/modelviewer/Md2ModelLoader.kt:74

• [nitpick] There is legacy commented-out code related to mesh building that is no longer used. Removing these comments could improve code readability and maintainability.

/* ... legacy meshBuilder code commented out ... */