Add canvas that renders opengl texture

This commit is contained in:
2024-05-05 17:40:39 -04:00
parent cca8173be4
commit ac1b70f1b1
4 changed files with 342 additions and 28 deletions

271
src/app/waterfall.rs Normal file
View File

@@ -0,0 +1,271 @@
use eframe::glow;
use glow::HasContext as _;
use log;
use std::mem::{size_of, transmute};
const SIZE_OF_F32: i32 = size_of::<f32>() as i32;
unsafe fn check_for_gl_errors(gl: &glow::Context, msg: &str) {
while let Some(err) = match gl.get_error() {
glow::NO_ERROR => None,
err => Some(err),
} {
log::error!("Waterfall {}: GL ERROR {} ({:#X})", msg, err, err);
}
}
pub struct Waterfall {
program: glow::Program,
texture: glow::Texture,
vao: glow::VertexArray,
vbo: glow::Buffer,
ebo: glow::Buffer,
offset: usize,
}
impl Waterfall {
pub fn destroy(&self, gl: &glow::Context) {
unsafe {
gl.delete_program(self.program);
gl.delete_texture(self.texture);
gl.delete_vertex_array(self.vao);
gl.delete_buffer(self.vbo);
gl.delete_buffer(self.ebo);
check_for_gl_errors(&gl, "APP CLOSE");
}
}
pub fn paint(&mut self, gl: &glow::Context, _angle: f32) {
use glow::HasContext as _;
self.offset = (self.offset + 1) % 300;
let mut new_data: [u8; 300] = [0; 300];
for (i, data) in new_data.iter_mut().enumerate() {
*data = if self.offset == i { 255 } else { 0 };
}
unsafe {
//Clear screen
//gl.clear_color(0.0, 0.0, 0.0, 1.0);
//gl.clear(glow::COLOR_BUFFER_BIT | glow::DEPTH_BUFFER_BIT);
// Bind our texture
gl.bind_texture(glow::TEXTURE_2D, Some(self.texture));
// Use our shader program
gl.use_program(Some(self.program));
// Bind our vertex array object
gl.bind_vertex_array(Some(self.vao));
// Draw the elements
gl.draw_elements(glow::TRIANGLES, 6, glow::UNSIGNED_INT, 0);
/*
check_for_gl_error!(&gl, "sub_image");
gl.use_program(Some(self.program));
check_for_gl_error!(&gl, "use program");
gl.active_texture(glow::TEXTURE0);
gl.bind_texture(glow::TEXTURE_2D, Some(self.texture));
check_for_gl_error!(&gl, "bind texture");
gl.uniform_1_f32(
gl.get_uniform_location(self.program, "u_angle").as_ref(),
angle,
);
check_for_gl_error!(&gl, "set uniform 1 f32");
gl.bind_vertex_array(Some(self.vao));
check_for_gl_error!(&gl, "bind vertex array");
gl.draw_arrays(glow::TRIANGLES, 0, 6);
*/
check_for_gl_errors(&gl, "APP PAINT");
}
}
/*pub fn paint(&mut self, gl: &glow::Context) {
unsafe {
gl.bind_texture(glow::TEXTURE_2D, Some(self.texture));
gl.use_program(Some(self.program));
gl.bind_vertex_array(Some(self.vao));
gl.draw_elements(glow::TRIANGLES, 6, glow::UNSIGNED_BYTE, 0);
}
}*/
pub fn new(gl: &glow::Context, width: usize, height: usize) -> Self {
let vertices: [f32; 32] = [
// positions // colors // texture coords
1.0, 1.0, 0.0, /**/ 1.0, 0.0, 0.0, /**/ 1.0, 1.0, // top right
1.0, -1.0, 0.0, /**/ 0.0, 1.0, 0.0, /**/ 1.0, 0.0, // bottom right
-1.0, -1.0, 0.0, /**/ 0.0, 0.0, 1.0, /**/ 0.0, 0.0, // bottom left
-1.0, 1.0, 0.0, /**/ 1.0, 1.0, 0.0, /**/ 0.0, 1.0, // top left
];
let indices: [i32; 6] = [
0, 1, 3, // First triangle
1, 2, 3,
];
let shader_version: &str = if cfg!(target_arch = "wasm32") {
"#version 300 es"
} else {
"#version 330"
};
// Generate something to put into the texture Buffer
let mut buffer = vec![0; width * height];
// Add some stripes to the texture
for (i, val) in buffer.iter_mut().enumerate() {
*val = if i % 50 < 25 { 255 } else { 0 };
//*val = 255;
}
unsafe {
let vao = gl
.create_vertex_array()
.expect("Could not create vertex array");
let vbo = gl.create_buffer().expect("Could not create vertex buffer");
let ebo = gl.create_buffer().expect("Could not create element buffer");
gl.bind_vertex_array(Some(vao));
gl.bind_buffer(glow::ARRAY_BUFFER, Some(vbo));
gl.buffer_data_u8_slice(
glow::ARRAY_BUFFER,
&transmute::<[f32; 32], [u8; 128]>(vertices),
glow::STATIC_DRAW,
);
gl.bind_buffer(glow::ELEMENT_ARRAY_BUFFER, Some(ebo));
gl.buffer_data_u8_slice(
glow::ELEMENT_ARRAY_BUFFER,
&transmute::<[i32; 6], [u8; 24]>(indices),
glow::STATIC_DRAW,
);
// Position attribute
gl.vertex_attrib_pointer_f32(0, 3, glow::FLOAT, false, 8 * SIZE_OF_F32, 0);
gl.enable_vertex_attrib_array(0);
// Color attribute
gl.vertex_attrib_pointer_f32(
1,
3,
glow::FLOAT,
false,
8 * SIZE_OF_F32,
3 * SIZE_OF_F32,
);
gl.enable_vertex_attrib_array(1);
// Position attribute
gl.vertex_attrib_pointer_f32(
2,
2,
glow::FLOAT,
false,
8 * SIZE_OF_F32,
6 * SIZE_OF_F32,
);
gl.enable_vertex_attrib_array(2);
// Texture
let texture = gl.create_texture().expect("Could not create texture");
gl.bind_texture(glow::TEXTURE_2D, Some(texture));
gl.tex_parameter_i32(
glow::TEXTURE_2D,
glow::TEXTURE_MIN_FILTER,
glow::NEAREST as i32,
);
gl.tex_parameter_i32(
glow::TEXTURE_2D,
glow::TEXTURE_MAG_FILTER,
glow::NEAREST as i32,
);
//gl.tex_storage_2d(glow::TEXTURE_2D, 1, glow::R8, 300, 300);
gl.tex_image_2d(
glow::TEXTURE_2D,
0,
glow::RED as i32,
width as i32,
height as i32,
0,
glow::RED,
glow::UNSIGNED_BYTE,
Some(&buffer),
);
let program = gl.create_program().expect("Cannot create program");
let (vertex_shader_source, fragment_shader_source) = (
r#"
layout (location = 0) in vec3 aPos;
layout (location = 1) in vec3 aColor;
layout (location = 2) in vec3 aTexCoord;
out vec3 ourColor;
out vec2 TexCoord;
void main()
{
gl_Position = vec4(aPos, 1.0);
ourColor = aColor;
TexCoord = vec2(aTexCoord.x, aTexCoord.y);
}
"#,
r#"
out vec4 FragColor;
in vec3 ourColor;
in vec2 TexCoord;
// texture sampler
uniform sampler2D texture1;
void main()
{
FragColor = texture(texture1, TexCoord);
}
"#,
);
let shader_sources = [
(glow::VERTEX_SHADER, vertex_shader_source),
(glow::FRAGMENT_SHADER, fragment_shader_source),
];
let shaders: Vec<_> = shader_sources
.iter()
.map(|(shader_type, shader_source)| {
let shader = gl
.create_shader(*shader_type)
.expect("Cannot create shader");
gl.shader_source(shader, &format!("{shader_version}\n{shader_source}"));
gl.compile_shader(shader);
assert!(
gl.get_shader_compile_status(shader),
"Failed to compile {shader_type}: {}",
gl.get_shader_info_log(shader)
);
gl.attach_shader(program, shader);
shader
})
.collect();
gl.link_program(program);
assert!(
gl.get_program_link_status(program),
"{}",
gl.get_program_info_log(program)
);
for shader in shaders {
gl.detach_shader(program, shader);
gl.delete_shader(shader);
}
check_for_gl_errors(&gl, "APP INIT");
Self {
program,
texture,
vao,
vbo,
ebo,
offset: 0_usize,
}
}
}
}