get rid of gb_math and create matrices from scratch

build.zig

@@ -140,8 +140,6 @@ fn addDeps(
     b: *std.build.Builder,
     step: *std.build.LibExeObjStep,
 ) !void {
-    step.addIncludeDir("src/");
-    step.addCSourceFile("src/gb_math.c", &.{});
     step.addIncludeDir("vendor/glad/include/");
     step.addCSourceFile("vendor/glad/src/gl.c", &.{});
 

src/Grid.zig

@@ -10,9 +10,9 @@ const font = @import("font/font.zig");
 const terminal = @import("terminal/main.zig");
 const Terminal = terminal.Terminal;
 const gl = @import("opengl.zig");
-const gb = @import("gb_math.zig");
 const trace = @import("tracy").trace;
 const Config = @import("config.zig").Config;
+const math = @import("math.zig");
 
 const log = std.log.scoped(.grid);
 
@@ -442,20 +442,20 @@ pub fn updateCells(self: *Grid, term: Terminal) !void {
 /// Set the screen size for rendering. This will update the projection
 /// used for the shader so that the scaling of the grid is correct.
 pub fn setScreenSize(self: *Grid, dim: ScreenSize) !void {
-    // Create a 2D orthographic projection matrix with the full width/height.
-    var projection: gb.gbMat4 = undefined;
-    gb.gb_mat4_ortho2d(
-        &projection,
-        0,
-        @intToFloat(f32, dim.width),
-        @intToFloat(f32, dim.height),
-        0,
-    );
-
     // Update the projection uniform within our shader
     const bind = try self.program.use();
     defer bind.unbind();
-    try self.program.setUniform("projection", projection);
+    try self.program.setUniform(
+        "projection",
+
+        // 2D orthographic projection with the full w/h
+        math.ortho2d(
+            0,
+            @intToFloat(f32, dim.width),
+            @intToFloat(f32, dim.height),
+            0,
+        ),
+    );
 
     // Recalculate the rows/columns.
     self.size.update(dim, self.cell_size);

src/gb_math.c

@@ -1,6 +0,0 @@
-// This file defines the implementation of gb_math and is compiled using clang.
-// gb_math.zig then imports gb_math.h without the implementation define set
-// so that it can just get the function prototypes.
-
-#define GB_MATH_IMPLEMENTATION
-#include "gb_math.h"

src/gb_math.zig

@@ -1,3 +0,0 @@
-pub usingnamespace @cImport({
-    @cInclude("gb_math.h");
-});

src/math.zig

@@ -0,0 +1,24 @@
+pub const F32x4 = @Vector(4, f32);
+
+/// Matrix type
+pub const Mat = [4]F32x4;
+
+/// Identity matrix
+pub fn identity() Mat {
+    return .{
+        .{ 1.0, 0.0, 0.0, 0.0 },
+        .{ 0.0, 1.0, 0.0, 0.0 },
+        .{ 0.0, 0.0, 1.0, 0.0 },
+        .{ 0.0, 0.0, 0.0, 1.0 },
+    };
+}
+
+pub fn ortho2d(left: f32, right: f32, bottom: f32, top: f32) Mat {
+    var mat = identity();
+    mat[0][0] = 2 / (right - left);
+    mat[1][1] = 2 / (top - bottom);
+    mat[2][2] = -1.0;
+    mat[3][0] = -(right + left) / (right - left);
+    mat[3][1] = -(top + bottom) / (top - bottom);
+    return mat;
+}

src/opengl/Program.zig

@@ -4,7 +4,6 @@ const std = @import("std");
 const assert = std.debug.assert;
 const log = std.log.scoped(.opengl);
 
-const gb = @import("../gb_math.zig");
 const c = @import("c.zig");
 const Shader = @import("Shader.zig");
 const errors = @import("errors.zig");
@@ -87,7 +86,7 @@ pub inline fn setUniform(p: Program, n: [:0]const u8, value: anytype) !void {
         @Vector(2, f32) => c.glUniform2f(loc, value[0], value[1]),
         @Vector(3, f32) => c.glUniform3f(loc, value[0], value[1], value[2]),
         @Vector(4, f32) => c.glUniform4f(loc, value[0], value[1], value[2], value[3]),
-        gb.gbMat4 => c.glUniformMatrix4fv(
+        [4]@Vector(4, f32) => c.glUniformMatrix4fv(
             loc,
             1,
             c.GL_FALSE,