275 lines
6.6 KiB
Rust
275 lines
6.6 KiB
Rust
use std::{
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convert::TryInto,
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ffi::{
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CString,
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c_void,
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},
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time::Duration,
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};
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use anyhow::{
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anyhow,
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Context,
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};
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use glam::{
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Mat4,
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Vec3,
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};
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use sdl2::{
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event::Event,
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keyboard::{Keycode, Scancode},
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};
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use tracing::instrument;
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use opengl_rust::{
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glezz,
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gpu_buffers,
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shader,
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timestep::TimeStep,
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};
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struct GameState {
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logic_frames: u64,
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}
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struct GraphicsContext {
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window: sdl2::video::Window,
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gl_ctx: sdl2::video::GLContext,
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vertex_buffer: gpu_buffers::VertexBuffer,
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index_buffer: gpu_buffers::IndexBuffer,
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shader_program: shader::ShaderProgram,
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shader_locations: ShaderLocations,
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}
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struct ShaderLocations {
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attr_pos: u32,
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attr_normal: u32,
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attr_color: u32,
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uni_mvp: i32,
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}
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impl ShaderLocations {
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pub fn new (shader_program: &shader::ShaderProgram) -> anyhow::Result <Self>
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{
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let attr = |name: &str| shader_program.get_attribute_location (&CString::new (name.as_bytes ())?).try_into ().context ("Attribute location negative");
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let uni = |name: &str| shader_program.get_uniform_location (&CString::new (name.as_bytes ())?).try_into ().context ("Uniform location bad");
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Ok (Self {
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attr_pos: attr ("attr_pos")?,
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attr_normal: attr ("attr_normal")?,
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attr_color: attr ("attr_color")?,
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uni_mvp: uni ("uni_mvp")?,
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})
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}
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}
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#[instrument (level = "trace", skip (ctx, state))]
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fn draw_graphics (ctx: &GraphicsContext, state: &GameState)
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{
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let shader_locs = &ctx.shader_locations;
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let attr_pos = shader_locs.attr_pos;
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let attr_normal = shader_locs.attr_normal;
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let attr_color = shader_locs.attr_color;
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let uni_mvp = shader_locs.uni_mvp;
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ctx.window.gl_make_current (&ctx.gl_ctx).unwrap ();
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glezz::enable (gl::DEPTH_TEST);
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glezz::clear_color (0.392f32, 0.710f32, 0.965f32, 1.0f32);
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glezz::clear (gl::COLOR_BUFFER_BIT | gl::DEPTH_BUFFER_BIT | gl::STENCIL_BUFFER_BIT);
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let screen_size = (960.0, 540.0);
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let proj_mat = Mat4::perspective_rh_gl (30.0f32.to_radians (), screen_size.0 / screen_size.1, 0.125, 200.0);
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let spin_period = 360 * 4;
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let view_mat = proj_mat *
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Mat4::from_translation (Vec3::from ((0.0, 0.0, -80.0))) *
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Mat4::from_rotation_x (-60.0 * 3.14159 / 180.0) *
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Mat4::from_rotation_z ((state.logic_frames % spin_period) as f32 * 3.1415926535 * 2.0 / spin_period as f32) *
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Mat4::from_translation (Vec3::from ((-32.0, -32.0, -5.0)));
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let mvp = view_mat;
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glezz::uniform_matrix_4fv (uni_mvp, &mvp);
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ctx.shader_program.use_program ();
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glezz::enable_vertex_attrib_array (Some (attr_pos));
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glezz::enable_vertex_attrib_array (Some (attr_color));
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glezz::enable_vertex_attrib_array (Some (attr_normal));
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ctx.vertex_buffer.bind ();
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ctx.index_buffer.bind ();
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unsafe {
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let num_quads = 64 * 64;
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let stride = 4 * 9;
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gl::VertexAttribPointer (attr_pos, 3, gl::FLOAT, 0, stride, 0 as *const u8 as *const c_void);
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gl::VertexAttribPointer (attr_normal, 3, gl::FLOAT, 0, stride, (4 * 3) as *const u8 as *const c_void);
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gl::VertexAttribPointer (attr_color, 3, gl::FLOAT, 0, stride, (4 * 6) as *const u8 as *const c_void);
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gl::DrawRangeElements (gl::TRIANGLES, 0, num_quads * 4, num_quads as i32 * 6, gl::UNSIGNED_INT, 0 as *const u8 as *const c_void);
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}
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ctx.window.gl_swap_window ();
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}
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fn main () -> anyhow::Result <()> {
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tracing_subscriber::fmt::fmt ()
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.with_env_filter (tracing_subscriber::EnvFilter::from_default_env())
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.with_span_events (tracing_subscriber::fmt::format::FmtSpan::CLOSE)
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.init ();
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let sdl_context = sdl2::init ().map_err (|e| anyhow! ("Can't init SDL: {}", e))?;
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let video_subsystem = sdl_context.video ().map_err (|e| anyhow! ("Can't get SDL video subsystem: {}", e))?;
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let window = video_subsystem.window ("Heightmap terrain demo", 960, 540)
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.position_centered ()
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.opengl ()
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.build ()
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?;
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gl::load_with (|s| {
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video_subsystem.gl_get_proc_address (s) as *const _
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});
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assert! (gl::ClearColor::is_loaded ());
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let gl_ctx = window.gl_create_context ().map_err (|e| anyhow! ("Can't create OpenGL context: {}", e))?;
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window.gl_make_current (&gl_ctx).map_err (|e| anyhow! ("Can't make OpenGL context current: {}", e))?;
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let mut time_step = TimeStep::new (60, 1000);
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let mut graphics_frames = 0;
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let controller_subsystem = sdl_context.game_controller ().unwrap ();
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let controller = controller_subsystem.open (0).ok ();
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let mut event_pump = sdl_context.event_pump ().unwrap ();
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let shader_program = shader::shader_from_files ("shaders/terrain-vert.glsl", "shaders/terrain-frag.glsl");
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let shader_locations = ShaderLocations::new (&shader_program)?;
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let mut vertexes = vec![];
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let mut indexes = vec![];
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let mut start_index = 0;
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let bump_at = |bump_x, bump_y, x, y| {
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let x = x - bump_x;
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let y = y - bump_y;
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let d = x * x + y * y;
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f32::max (0.0, 5.0 - d * 0.125)
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};
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let height_fn = |(x, y)| {
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bump_at (32.0, 32.0, x, y) +
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bump_at (64.0, 32.0, x, y) +
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bump_at (32.0, 48.0, x, y)
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};
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for y in 0..64 {
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for x in 0..64 {
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let (r, g, b) = if (x + y) % 2 == 0 {
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(0.4, 0.4, 0.4)
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}
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else {
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(0.5, 0.5, 0.5)
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};
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let x = x as f32;
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let y = y as f32;
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let i = start_index;
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let xys = [
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(x + 0.0, y + 0.0),
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(x + 1.0, y + 0.0),
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(x + 1.0, y + 1.0),
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(x + 0.0, y + 1.0),
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];
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let zs = [
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height_fn (xys [0]),
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height_fn (xys [1]),
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height_fn (xys [2]),
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height_fn (xys [3]),
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];
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let slope_x = (zs [1] + zs [2]) - (zs [0] + zs [3]);
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let slope_y = (zs [2] + zs [3]) - (zs [0] + zs [1]);
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let tangent_x = Vec3::from ((1.0, 0.0, slope_x));
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let tangent_y = Vec3::from ((0.0, 1.0, slope_y));
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let normal = Vec3::cross (tangent_x, tangent_y)
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.normalize ();
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let (nx, ny, nz) = normal.into ();
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for ((x, y), z) in xys.iter ().zip (&zs) {
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vertexes.extend (&[
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*x, *y, *z,
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nx, ny, nz,
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r, g, b,
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])
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}
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indexes.extend (&[
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i + 0, i + 1, i + 2,
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i + 0, i + 2, i + 3,
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]);
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start_index += 4;
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}
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}
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let vertex_buffer = gpu_buffers::VertexBuffer::from_slice (&vertexes);
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let index_buffer = gpu_buffers::IndexBuffer::from_slice_u32 (&indexes);
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let graphics_ctx = GraphicsContext {
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window,
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gl_ctx,
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vertex_buffer,
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index_buffer,
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shader_program,
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shader_locations,
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};
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let mut game_state = GameState {
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logic_frames: 0,
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};
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'running: loop {
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let frames_to_do = time_step.step ();
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let _mouse = event_pump.mouse_state ();
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for event in event_pump.poll_iter() {
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match event {
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Event::Quit {..} |
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Event::KeyDown { keycode: Some (Keycode::Escape), .. } => {
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break 'running
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},
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_ => (),
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}
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}
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for _ in 0..frames_to_do {
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game_state.logic_frames += 1;
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}
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draw_graphics (&graphics_ctx, &game_state);
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graphics_frames += 1;
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std::thread::sleep (Duration::from_millis (15));
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}
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Ok (())
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}
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