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render text from our terminal!

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This commit is contained in:
Mitchell Hashimoto
2022-04-18 17:53:19 -07:00
parent 34cb9b2c27
commit 81d8ca5b9c
4 changed files with 130 additions and 12 deletions
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13
shaders/cell.f.glsl
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@ -1,8 +1,19 @@
#version 330 core
in vec2 glyph_tex_coords;
/// The background color for this cell.
flat in vec4 bg_color;
/// Font texture
uniform sampler2D text;
void main() {
gl_FragColor = bg_color;
int background = 0;
if (background == 1) {
gl_FragColor = bg_color;
} else {
float a = texture(text, glyph_tex_coords).r;
gl_FragColor = vec4(bg_color.rgb, bg_color.a*a);
}
}

50
shaders/cell.v.glsl
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@ -3,17 +3,31 @@
// The grid coordinates (x, y) where x < columns and y < rows
layout (location = 0) in vec2 grid_coord;
// Position of the glyph in the texture.
layout (location = 1) in vec2 glyph_pos;
// Width/height of the glyph
layout (location = 2) in vec2 glyph_size;
// Offset of the top-left corner of the glyph when rendered in a rect.
layout (location = 3) in vec2 glyph_offset;
// The background color for this cell in RGBA (0 to 1.0)
layout (location = 1) in vec4 bg_color_in;
layout (location = 4) in vec4 bg_color_in;
// The background color for this cell in RGBA (0 to 1.0)
flat out vec4 bg_color;
// The x/y coordinate for the glyph representing the font.
out vec2 glyph_tex_coords;
uniform sampler2D text;
uniform vec2 cell_size;
uniform mat4 projection;
void main() {
// Top-left cell coordinates converted to world space
// Example: (1,0) with a 30 wide cell is converted to (30,0)
vec2 cell_pos = cell_size * grid_coord;
// Turn the cell position into a vertex point depending on the
@ -21,11 +35,39 @@ void main() {
// for each corner of the cell. We can use gl_VertexID to determine
// which one we're looking at. Using this, we can use 1 or 0 to keep
// or discard the value for the vertex.
//
// 0 = top-right
// 1 = bot-right
// 2 = bot-left
// 3 = top-left
vec2 position;
position.x = (gl_VertexID == 0 || gl_VertexID == 1) ? 1. : 0.;
position.y = (gl_VertexID == 0 || gl_VertexID == 3) ? 0. : 1.;
cell_pos = cell_pos + cell_size * position;
gl_Position = projection * vec4(cell_pos, 1.0, 1.0);
bg_color = vec4(bg_color_in.rgb / 255.0, 1.0);
int background = 0;
if (background == 1) {
// Calculate the final position of our cell in world space.
// We have to add our cell size since our vertices are offset
// one cell up and to the left. (Do the math to verify yourself)
cell_pos = cell_pos + cell_size * position;
gl_Position = projection * vec4(cell_pos, 0.0, 1.0);
bg_color = vec4(bg_color_in.rgb / 255.0, 1.0);
} else {
// TODO: why?
vec2 glyph_offset_calc = glyph_offset;
glyph_offset_calc.y = cell_size.y - glyph_offset.y;
// Calculate the final position of the cell.
cell_pos = cell_pos + glyph_size * position + glyph_offset_calc;
gl_Position = projection * vec4(cell_pos, 0.0, 1.0);
// Calculate our texture coordinate
ivec2 text_size = textureSize(text, 0);
vec2 glyph_tex_size = glyph_size / text_size.xy;
glyph_tex_coords = glyph_pos + glyph_tex_size * position;
// This is used to color the font for now.
bg_color = vec4(bg_color_in.rgb / 255.0, 1.0);
}
}

1
src/FontAtlas.zig
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@ -191,6 +191,7 @@ fn f26dot6ToFloat(v: ftc.FT_F26Dot6) f32 {
fn codepoint(v: anytype) u32 {
// We need a UTF32 codepoint for freetype
return switch (@TypeOf(v)) {
u32 => v,
comptime_int, u8 => @intCast(u32, v),
[]const u8 => @intCast(u32, try std.unicode.utfDecode(v)),
else => @compileError("invalid codepoint type"),

78
src/Grid.zig
View File

@ -29,6 +29,10 @@ program: gl.Program,
vao: gl.VertexArray,
ebo: gl.Buffer,
vbo: gl.Buffer,
texture: gl.Texture,
/// The font atlas.
font_atlas: FontAtlas,
/// The raw structure that maps directly to the buffer sent to the vertex shader.
const GPUCell = struct {
@ -36,6 +40,18 @@ const GPUCell = struct {
grid_col: u16,
grid_row: u16,
/// vec2 glyph_pos
glyph_x: f32,
glyph_y: f32,
/// vec2 glyph_size
glyph_width: u32,
glyph_height: u32,
/// vec2 glyph_size
glyph_offset_x: i32,
glyph_offset_y: i32,
/// vec4 bg_color_in
bg_r: u8,
bg_g: u8,
@ -47,9 +63,9 @@ pub fn init(alloc: Allocator) !Grid {
// Initialize our font atlas. We will initially populate the
// font atlas with all the visible ASCII characters since they are common.
var atlas = try Atlas.init(alloc, 512);
defer atlas.deinit(alloc);
errdefer atlas.deinit(alloc);
var font = try FontAtlas.init(atlas);
defer font.deinit(alloc);
errdefer font.deinit(alloc);
try font.loadFaceFromMemory(face_ttf, 30);
// Load all visible ASCII characters and build our cell width based on
@ -117,11 +133,42 @@ pub fn init(alloc: Allocator) !Grid {
var offset: usize = 0;
try vbobind.attributeAdvanced(0, 2, gl.c.GL_UNSIGNED_SHORT, false, @sizeOf(GPUCell), offset);
offset += 2 * @sizeOf(u16);
try vbobind.attributeAdvanced(1, 4, gl.c.GL_UNSIGNED_BYTE, false, @sizeOf(GPUCell), offset);
try vbobind.attributeAdvanced(1, 2, gl.c.GL_FLOAT, false, @sizeOf(GPUCell), offset);
offset += 2 * @sizeOf(f32);
try vbobind.attributeAdvanced(2, 2, gl.c.GL_UNSIGNED_INT, false, @sizeOf(GPUCell), offset);
offset += 2 * @sizeOf(u32);
try vbobind.attributeAdvanced(3, 2, gl.c.GL_INT, false, @sizeOf(GPUCell), offset);
offset += 2 * @sizeOf(i32);
try vbobind.attributeAdvanced(4, 4, gl.c.GL_UNSIGNED_BYTE, false, @sizeOf(GPUCell), offset);
try vbobind.enableAttribArray(0);
try vbobind.enableAttribArray(1);
try vbobind.enableAttribArray(2);
try vbobind.enableAttribArray(3);
try vbobind.enableAttribArray(4);
try vbobind.attributeDivisor(0, 1);
try vbobind.attributeDivisor(1, 1);
try vbobind.attributeDivisor(2, 1);
try vbobind.attributeDivisor(3, 1);
try vbobind.attributeDivisor(4, 1);
// Build our texture
const tex = try gl.Texture.create();
errdefer tex.destroy();
const texbind = try tex.bind(.@"2D");
try texbind.parameter(.WrapS, gl.c.GL_CLAMP_TO_EDGE);
try texbind.parameter(.WrapT, gl.c.GL_CLAMP_TO_EDGE);
try texbind.parameter(.MinFilter, gl.c.GL_LINEAR);
try texbind.parameter(.MagFilter, gl.c.GL_LINEAR);
try texbind.image2D(
0,
.Red,
@intCast(c_int, atlas.size),
@intCast(c_int, atlas.size),
0,
.Red,
.UnsignedByte,
atlas.data.ptr,
);
return Grid{
.alloc = alloc,
@ -132,10 +179,15 @@ pub fn init(alloc: Allocator) !Grid {
.vao = vao,
.ebo = ebo,
.vbo = vbo,
.texture = tex,
.font_atlas = font,
};
}
pub fn deinit(self: *Grid) void {
self.font_atlas.atlas.deinit(self.alloc);
self.font_atlas.deinit(self.alloc);
self.texture.destroy();
self.vbo.destroy();
self.ebo.destroy();
self.vao.destroy();
@ -179,14 +231,21 @@ pub fn updateCells(self: *Grid, term: Terminal) !void {
for (term.screen.items) |line, y| {
for (line.items) |cell, x| {
_ = cell;
// Get our glyph
const glyph = try self.font_atlas.addGlyph(self.alloc, cell.char);
self.cells.appendAssumeCapacity(.{
.grid_col = @intCast(u16, x),
.grid_row = @intCast(u16, y),
.bg_r = @intCast(u8, @mod(x * y, 255)),
.bg_g = @intCast(u8, @mod(x, 255)),
.bg_b = @intCast(u8, 255 - @mod(x, 255)),
.glyph_x = glyph.s0,
.glyph_y = glyph.t0,
.glyph_width = glyph.width,
.glyph_height = glyph.height,
.glyph_offset_x = glyph.offset_x,
.glyph_offset_y = glyph.offset_y,
.bg_r = 0xFF,
.bg_g = 0xA5,
.bg_b = 0,
.bg_a = 255,
});
}
@ -237,6 +296,11 @@ pub fn render(self: Grid) !void {
defer binding.unbind();
try binding.setData(self.cells.items, .StaticDraw);
// Bind our texture
try gl.Texture.active(gl.c.GL_TEXTURE0);
var texbind = try self.texture.bind(.@"2D");
defer texbind.unbind();
try gl.drawElementsInstanced(
gl.c.GL_TRIANGLES,
6,