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2f058bd053
This moves some logic that was previously being done per-character into the vertex shader. At this time, we've traded CPU computation for additional gl::Uniform2f calls. This is only a marginal improvement. However, this patch positions the renderer well for instanced drawing, and that will be a huge performance win.
41 lines
1 KiB
GLSL
41 lines
1 KiB
GLSL
#version 330 core
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layout (location = 0) in vec2 position;
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out vec2 TexCoords;
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// Terminal properties
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uniform vec2 termDim;
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uniform vec2 cellDim;
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uniform vec2 cellSep;
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// Cell properties
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uniform vec2 gridCoords;
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// glyph properties
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uniform vec2 glyphScale;
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uniform vec2 glyphOffset;
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// uv mapping
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uniform vec2 uvScale;
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uniform vec2 uvOffset;
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// Orthographic projection
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uniform mat4 projection;
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void main()
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{
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// Position of cell from top-left
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vec2 cellPosition = (cellDim + cellSep) * gridCoords;
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// Invert Y since framebuffer origin is bottom-left
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cellPosition.y = termDim.y - cellPosition.y - cellDim.y;
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// Glyphs are offset within their cell; account for y-flip
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vec2 cellOffset = vec2(glyphOffset.x, glyphOffset.y - glyphScale.y);
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// position coordinates are normalized on [0, 1]
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vec2 finalPosition = glyphScale * position + cellPosition + cellOffset;
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gl_Position = projection * vec4(finalPosition.xy, 0.0, 1.0);
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TexCoords = vec2(position.x, 1 - position.y) * uvScale + uvOffset;
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}
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