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alacritty/res/text.v.glsl
Christian Duerr f37dd5c5bc
Draw visual bell as big quad over everything
A method `render_rect` has been added that allows drawing a rectangle
over anything in the terminal. This is used by the visual bell to draw a
big rectangle over everything.

To achieve this a new shader has been added. Shaders are now kept around
until the program is dropped. Then whenever a rectangle draw call is
issued, the shader is swapped from the default shader to the rectangle
drawing shader.

After the shader has been swapped and the rectangle has been drawn,
uniforms (like projection) and blending function are reset to make sure
the rendering can be continued on the default shader.

All current instances of visual_bell in the rendering have been removed,
it is now all done exclusively through the rectangle rendering function.

Currently the shaders are swapped every time `render_rect` is called, so
when rendering multiple rectangles (potentially for underline /
strikethrough) there would be a loads of shader swaps that could be
potentially very expensive.

So before using `render_rect` for a different application, the shader
swap should be removed from the `render_rect` method.
As long as the visual bell's alpha value is 0, this has no effect on
performance because no rectangle is rendered.
2018-02-16 22:41:55 +01:00

78 lines
2.3 KiB
GLSL

// Copyright 2016 Joe Wilm, The Alacritty Project Contributors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#version 330 core
layout (location = 0) in vec2 position;
// Cell properties
layout (location = 1) in vec2 gridCoords;
// glyph properties
layout (location = 2) in vec4 glyph;
// uv mapping
layout (location = 3) in vec4 uv;
// text fg color
layout (location = 4) in vec3 textColor;
// Background color
layout (location = 5) in vec4 backgroundColor;
out vec2 TexCoords;
out vec3 fg;
out vec4 bg;
// Terminal properties
uniform vec2 termDim;
uniform vec2 cellDim;
uniform int backgroundPass;
// Orthographic projection
uniform mat4 projection;
flat out int background;
void main()
{
vec2 glyphOffset = glyph.xy;
vec2 glyphSize = glyph.zw;
vec2 uvOffset = uv.xy;
vec2 uvSize = uv.zw;
// Position of cell from top-left
vec2 cellPosition = (cellDim) * gridCoords;
// Invert Y since framebuffer origin is bottom-left
cellPosition.y = termDim.y - cellPosition.y - cellDim.y;
if (backgroundPass != 0) {
cellPosition.y = cellPosition.y;
vec2 finalPosition = cellDim * position + cellPosition;
gl_Position = projection * vec4(finalPosition.xy, 0.0, 1.0);
TexCoords = vec2(0, 0);
} else {
// Glyphs are offset within their cell; account for y-flip
vec2 cellOffset = vec2(glyphOffset.x, glyphOffset.y - glyphSize.y);
// position coordinates are normalized on [0, 1]
vec2 finalPosition = glyphSize * position + cellPosition + cellOffset;
gl_Position = projection * vec4(finalPosition.xy, 0.0, 1.0);
TexCoords = uvOffset + vec2(position.x, 1 - position.y) * uvSize;
}
background = backgroundPass;
bg = vec4(backgroundColor.rgb / 255.0, backgroundColor.a);
fg = textColor / vec3(255.0, 255.0, 255.0);
}