Draw lines with no geometry shader

[einarf]

No description provided.

[Copilot]

Pull Request Overview

This PR replaces the geometry-shader–based line rendering with an instanced vertex-shader approach, removing the unbuffered geometry shader and updating the draw calls and context setup accordingly.

• Remove unbuffered_geo.glsl and shift quad construction into the vertex shader
• Update draw_line/draw_lines to use instanced rendering instead of gl.LINES
• Adjust Context to configure a dummy quad buffer and instance position buffer

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

File	Description
resources/system/shaders/shapes/line/unbuffered_vs.glsl	New instanced vertex shader generates quads by gl_VertexID
resources/system/shaders/shapes/line/unbuffered_geo.glsl	Removed old geometry shader
draw/line.py	Switched geometry.render calls to use instances
context.py	Dropped geometry shader, added dummy quad & instance buffers

Comments suppressed due to low confidence (2)

resources/system/shaders/shapes/line/unbuffered_vs.glsl:10

• The attribute 'in_vert' is declared but not actually used after moving quad logic into the shader via gl_VertexID. Consider removing it and the corresponding dummy buffer setup to simplify the pipeline.

in vec2 in_vert;

resources/system/shaders/shapes/line/unbuffered_vs.glsl:24

• [nitpick] Using the literal '4' for the quad vertex count is a magic number. Define a constant like 'const int QUAD_VERT_COUNT = 4;' for clarity and easier updates.

    vec2 positions[4] = vec2[4](