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//------------------------------------------------------------------------------
// offscreen.zig
//
// Render to an offscreen rendertarget texture, and use this texture
// for rendering to the display.
//------------------------------------------------------------------------------
const sokol = @import("sokol");
const slog = sokol.log;
const sg = sokol.gfx;
const sapp = sokol.app;
const sglue = sokol.glue;
const imgui = sokol.imgui;
const appimgui = sokol.appimgui;
const vec3 = @import("math.zig").Vec3;
const mat4 = @import("math.zig").Mat4;
const shd = @import("shaders/main.glsl.zig");
const state = struct {
const display = struct {
var pass_action: sg.PassAction = .{};
var pip: sg.Pipeline = .{};
var bind: sg.Bindings = .{};
};
};
export fn init() void {
sg.setup(.{
.environment = sglue.environment(),
.logger = .{ .func = slog.func },
});
imgui.setup(.{});
appimgui.setup();
// default pass action: clear to blue-ish
state.display.pass_action.colors[0] = .{
.load_action = .CLEAR,
.clear_value = .{ .r = 0.25, .g = 0.45, .b = 0.65, .a = 1.0 },
};
const vbuf = sg.makeBuffer(.{});
state.display.bind.vertex_buffers[0] = vbuf;
// shader and pipeline object for the default render pass
state.display.pip = sg.makePipeline(.{
.shader = sg.makeShader(shd.offscreenShaderDesc(sg.queryBackend())),
.layout = init: {
var l = sg.VertexLayoutState{};
l.attrs[shd.ATTR_offscreen_position] = .{};
break :init l;
},
.index_type = .UINT16,
.cull_mode = .BACK,
.depth = .{
.compare = .LESS_EQUAL,
.write_enabled = true,
},
});
}
export fn event(ev: [*c]const sapp.Event) void {
appimgui.trackEvent(ev.*);
}
export fn frame() void {
// const dt: f32 = @floatCast(sapp.frameDuration() * 60);
// const aspect = sapp.widthf() / sapp.heightf();
sg.beginPass(.{ .action = state.display.pass_action, .swapchain = sglue.swapchain() });
sg.applyPipeline(state.display.pip);
sg.applyBindings(state.display.bind);
sg.draw(0, 3, 1);
sg.endPass();
sg.commit();
}
export fn cleanup() void {
appimgui.shutdown();
imgui.shutdown();
sg.shutdown();
}
pub fn main() void {
sapp.run(.{
.init_cb = init,
.frame_cb = frame,
.event_cb = event,
.cleanup_cb = cleanup,
.sample_count = 4,
.width = 800,
.height = 600,
.icon = .{ .sokol_default = true },
.window_title = "offscreen.zig",
.logger = .{ .func = slog.func },
});
}
fn computeVsParams(rx: f32, ry: f32, aspect: f32, eye_dist: f32) shd.VsParams {
const proj = mat4.persp(45, aspect, 0.01, 10);
const view = mat4.lookat(.{ .x = 0, .y = 0, .z = eye_dist }, vec3.zero(), vec3.up());
const view_proj = mat4.mul(proj, view);
const rxm = mat4.rotate(rx, .{ .x = 1, .y = 0, .z = 0 });
const rym = mat4.rotate(ry, .{ .x = 0, .y = 1, .z = 0 });
const model = mat4.mul(rxm, rym);
return shd.VsParams{ .mvp = mat4.mul(view_proj, model) };
}
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