usg/src/Renderer.zig

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const sdl = @import("sdl2");
const gl = @import("zgl");
const Self = @This();
window: sdl.Window,
context: sdl.gl.Context,
color_loc: u32,
buffer: gl.Buffer,
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color: [4]f32,
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pub fn init() !Self {
try sdl.init(.{ .video = true, .audio = true, .events = true });
// Set OpenGL version
try sdl.gl.setAttribute(.{ .context_major_version = 3 });
try sdl.gl.setAttribute(.{ .context_minor_version = 3 });
const window = try sdl.createWindow(
"USG",
.{ .centered = {} },
.{ .centered = {} },
1280,
720,
.{ .opengl = true, .shown = true }
);
const ctx = try sdl.gl.createContext(window);
var color_loc: u32 = undefined;
const program = gl.Program.create();
{
const vs = gl.Shader.create(.vertex);
defer vs.delete();
vs.source(1, &.{@embedFile("shaders/vector.vs")});
vs.compile();
const fs = gl.Shader.create(.fragment);
defer fs.delete();
fs.source(1, &.{@embedFile("shaders/fragment.fs")});
fs.compile();
program.attach(vs);
defer program.detach(vs);
program.attach(fs);
defer program.detach(fs);
program.link();
color_loc = program.uniformLocation("color").?;
}
program.use();
var vertex_array = gl.VertexArray.gen();
vertex_array.bind();
const buf = gl.Buffer.gen();
buf.bind(.array_buffer);
gl.clearColor(0.91, 0.97, 1.00, 1.00);
return Self{
.window = window,
.context = ctx,
.color_loc = color_loc,
.buffer = buf,
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.color = .{0,0,0,0}
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};
}
pub fn render(self: Self) void {
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sdl.gl.swapWindow(self.window);
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gl.clear(.{ .color = true });
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}
pub fn deinit(self: Self) void {
sdl.quit();
self.window.destroy();
sdl.gl.deleteContext(self.context);
}
pub fn setColor(self: *Self, r: u8, g: u32, b: u32, a: u32) void {
self.*.color = .{
@intToFloat(f32, r)/255.0,
@intToFloat(f32, g)/255.0,
@intToFloat(f32, b)/255.0,
@intToFloat(f32, a)/255.0,
};
}
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pub fn drawRectangle(self: *Self, x: u32, y: u32, w: u32, h: u32) void {
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gl.enableVertexAttribArray(0);
gl.vertexAttribPointer(0, 3, .float, false, 0, 0);
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const vertex_buffer = [_]f32{
-1.0, -1.0, 0.0,
-1.0, 1.0, 0.0,
0.0, 1.0, 0.0,
1.0, 1.0, 0.0,
0.0, -1.0, 0.0,
1.0, -1.0, 0.0,
};
self.buffer.data(f32, &vertex_buffer, .static_draw);
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gl.uniform4fv(self.color_loc, &.{ self.color });
gl.drawArrays(.triangles, 0, 3);
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gl.drawArrays(.triangles, 3, 3);
gl.disableVertexAttribArray(0);
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_ = self;
_ = x;
_ = y;
_ = w;
_ = h;
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}