Draw a texture at the correct scale

2024-11-23 05:49:57 +00:00 · 2020-08-01 17:06:20 -04:00 · 2020-08-01 17:06:20 -04:00 · 043153acf0
commit 043153acf0
parent 7bd11fe72f
4 changed files with 233 additions and 16 deletions
--- a/Cargo.lock
+++ b/Cargo.lock
@ -42,6 +42,27 @@ dependencies = [
 "log",
 ]

+[[package]]
+name = "approx"
+version = "0.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f0e60b75072ecd4168020818c0107f2857bb6c4e64252d8d3983f6263b40a5c3"
+dependencies = [
+ "num-traits",
+]
+
+[[package]]
+name = "autocfg"
+version = "0.1.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1d49d90015b3c36167a20fe2810c5cd875ad504b39cff3d4eae7977e6b7c1cb2"
+
+[[package]]
+name = "autocfg"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f8aac770f1885fd7e387acedd76065302551364496e46b3dd00860b2f8359b9d"
+
 [[package]]
 name = "backtrace"
 version = "0.3.50"
@ -56,6 +77,12 @@ dependencies = [
 "rustc-demangle",
 ]

+[[package]]
+name = "bitflags"
+version = "1.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cf1de2fe8c75bc145a2f577add951f8134889b4795d47466a54a5c846d691693"
+
 [[package]]
 name = "bytes"
 version = "0.5.6"
@ -74,6 +101,26 @@ version = "0.1.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "4785bdd1c96b2a846b2bd7cc02e86b6b3dbf14e7e53446c4f54c92a361040822"

+[[package]]
+name = "cgmath"
+version = "0.17.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "283944cdecc44bf0b8dd010ec9af888d3b4f142844fdbe026c20ef68148d6fe7"
+dependencies = [
+ "approx",
+ "num-traits",
+ "rand",
+]
+
+[[package]]
+name = "cloudabi"
+version = "0.0.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ddfc5b9aa5d4507acaf872de71051dfd0e309860e88966e1051e462a077aac4f"
+dependencies = [
+ "bitflags",
+]
+
 [[package]]
 name = "combine"
 version = "4.2.1"
@ -104,6 +151,12 @@ dependencies = [
 "version_check",
 ]

+[[package]]
+name = "fuchsia-cprng"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "a06f77d526c1a601b7c4cdd98f54b5eaabffc14d5f2f0296febdc7f357c6d3ba"
+
 [[package]]
 name = "gimli"
 version = "0.22.0"
@ -183,12 +236,136 @@ dependencies = [
 "adler",
 ]

+[[package]]
+name = "num-traits"
+version = "0.2.12"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ac267bcc07f48ee5f8935ab0d24f316fb722d7a1292e2913f0cc196b29ffd611"
+dependencies = [
+ "autocfg 1.0.0",
+]
+
 [[package]]
 name = "object"
 version = "0.20.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1ab52be62400ca80aa00285d25253d7f7c437b7375c4de678f5405d3afe82ca5"

+[[package]]
+name = "rand"
+version = "0.6.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "6d71dacdc3c88c1fde3885a3be3fbab9f35724e6ce99467f7d9c5026132184ca"
+dependencies = [
+ "autocfg 0.1.7",
+ "libc",
+ "rand_chacha",
+ "rand_core 0.4.2",
+ "rand_hc",
+ "rand_isaac",
+ "rand_jitter",
+ "rand_os",
+ "rand_pcg",
+ "rand_xorshift",
+ "winapi",
+]
+
+[[package]]
+name = "rand_chacha"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "556d3a1ca6600bfcbab7c7c91ccb085ac7fbbcd70e008a98742e7847f4f7bcef"
+dependencies = [
+ "autocfg 0.1.7",
+ "rand_core 0.3.1",
+]
+
+[[package]]
+name = "rand_core"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7a6fdeb83b075e8266dcc8762c22776f6877a63111121f5f8c7411e5be7eed4b"
+dependencies = [
+ "rand_core 0.4.2",
+]
+
+[[package]]
+name = "rand_core"
+version = "0.4.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9c33a3c44ca05fa6f1807d8e6743f3824e8509beca625669633be0acbdf509dc"
+
+[[package]]
+name = "rand_hc"
+version = "0.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7b40677c7be09ae76218dc623efbf7b18e34bced3f38883af07bb75630a21bc4"
+dependencies = [
+ "rand_core 0.3.1",
+]
+
+[[package]]
+name = "rand_isaac"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "ded997c9d5f13925be2a6fd7e66bf1872597f759fd9dd93513dd7e92e5a5ee08"
+dependencies = [
+ "rand_core 0.3.1",
+]
+
+[[package]]
+name = "rand_jitter"
+version = "0.1.4"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1166d5c91dc97b88d1decc3285bb0a99ed84b05cfd0bc2341bdf2d43fc41e39b"
+dependencies = [
+ "libc",
+ "rand_core 0.4.2",
+ "winapi",
+]
+
+[[package]]
+name = "rand_os"
+version = "0.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "7b75f676a1e053fc562eafbb47838d67c84801e38fc1ba459e8f180deabd5071"
+dependencies = [
+ "cloudabi",
+ "fuchsia-cprng",
+ "libc",
+ "rand_core 0.4.2",
+ "rdrand",
+ "winapi",
+]
+
+[[package]]
+name = "rand_pcg"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "abf9b09b01790cfe0364f52bf32995ea3c39f4d2dd011eac241d2914146d0b44"
+dependencies = [
+ "autocfg 0.1.7",
+ "rand_core 0.4.2",
+]
+
+[[package]]
+name = "rand_xorshift"
+version = "0.1.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cbf7e9e623549b0e21f6e97cf8ecf247c1a8fd2e8a992ae265314300b2455d5c"
+dependencies = [
+ "rand_core 0.3.1",
+]
+
+[[package]]
+name = "rdrand"
+version = "0.4.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "678054eb77286b51581ba43620cc911abf02758c91f93f479767aed0f90458b2"
+dependencies = [
+ "rand_core 0.3.1",
+]
+
 [[package]]
 name = "regex"
 version = "1.3.9"
@ -242,6 +419,7 @@ name = "vvb"
 version = "0.1.0"
 dependencies = [
 "android_logger",
+ "cgmath",
 "gl_generator",
 "jni",
 "log",
--- a/Cargo.toml
+++ b/Cargo.toml
@ -7,6 +7,7 @@ build = "build.rs"

 [dependencies]
 android_logger = "0.9.0"
+cgmath = "0.17.0"
 jni = "0.17.0"
 log = "0.4.11"

--- a/src/renderer/gl_bindings.rs
+++ b/src/renderer/gl_bindings.rs
@ -1,7 +1,7 @@
 // This is the output of build.rs, but with Generator::Global instead of Generator::Static.
 // It's copied here so windows builds and autocomplete can work.

-#![cfg(target_os == "windows")]
+#![cfg(target_os = "windows")]

 mod __gl_imports {
    pub use std::mem;
--- a/src/renderer/mod.rs
+++ b/src/renderer/mod.rs
@ -14,10 +14,11 @@ mod gl {

 use gl::types::{GLboolean,GLshort,GLuint,GLint,GLsizei,GLchar,GLvoid,GLfloat,GLenum};
 use std::ffi::{CStr,CString};
-// use log::{debug};
+use cgmath::{self,Matrix4,SquareMatrix,vec4};
+use log::{debug};

 const GL_TRUE: GLboolean = 1;
-// const GL_FALSE: GLboolean = 0;
+const GL_FALSE: GLboolean = 0;

 macro_rules! c_string {
    ($string:expr) => {
@ -49,9 +50,10 @@ impl<T> AsVoidptr for [T] {
 const VERTEX_SHADER: &str = "\
 attribute vec4 a_Pos;
 attribute vec2 a_TexCoord;
+uniform mat4 u_MV;
 varying vec2 v_TexCoord;
 void main() {
-    gl_Position = a_Pos;
+    gl_Position = u_MV * a_Pos;
    v_TexCoord = a_TexCoord;
 }
 ";
@ -59,18 +61,24 @@ void main() {
 const FRAGMENT_SHADER: &str = "\
 precision mediump float;
 varying vec2 v_TexCoord;
-uniform sampler2D s_Texture;
+uniform sampler2D u_Texture;
 void main() {
-    gl_FragColor = texture2D(s_Texture, v_TexCoord);
+    gl_FragColor = texture2D(u_Texture, v_TexCoord);
 }
 ";

+const VB_WIDTH: i32 = 384;
+const VB_HEIGHT: i32 = 224;
+const TEXTURE_WIDTH: GLfloat = (VB_WIDTH * 2) as GLfloat;
+const TEXTURE_HEIGHT: GLfloat = VB_HEIGHT as GLfloat;
+
 const POS_VERTICES: [GLfloat; 8] = [
    -0.5, 0.5,
    -0.5, -0.5,
    0.5, -0.5,
    0.5, 0.5
 ];
+
 const TEX_VERTICES: [GLfloat; 8] = [
    0.0, 0.0,
    0.0, 1.0,
@ -83,16 +91,16 @@ const SQUARE_INDICES: [GLshort; 6] = [0, 1, 2, 0, 2, 3];
 const VERTEX_SIZE: GLsizei = 2;
 const VERTEX_STRIDE: GLsizei = 0;

-const VB_WIDTH: i32 = 384;
-const VB_HEIGHT: i32 = 224;
-const TEXTURE_SIZE: usize = (VB_WIDTH * VB_HEIGHT * 2 * 3) as usize;
+const TEXTURE_SIZE: usize = (TEXTURE_WIDTH * TEXTURE_HEIGHT) as usize * 3;

 pub struct Renderer {
    program_id: GLuint,
    position_location: GLuint,
    tex_coord_location: GLuint,
+    modelview_location : GLint,
    texture_location: GLint,
-    texture_id: GLuint
+    texture_id: GLuint,
+    modelview: Vec<GLfloat>
 }

 unsafe fn make_shader(type_: GLenum, source: &str) -> Result<GLuint, String> {
@ -149,7 +157,7 @@ fn load_texture() -> Result<Vec<u8>, String> {
    for r in (0..TEXTURE_SIZE).step_by(3) {
        let i = r / 3;
        let checker_x = (i / 16) % 2;
-        let checker_y = 1 - ((i / 224) / 16) % 2;
+        let checker_y = 1 - ((i / TEXTURE_WIDTH as usize) / 16) % 2;
        if checker_x != checker_y {
            texture_data[r] = 0xff;
        }
@ -166,7 +174,7 @@ fn create_texture() -> Result<GLuint, String> {
        });
        check_error("generate a texture")?;
        gl::BindTexture(gl::TEXTURE_2D, texture_id);
-        gl::TexImage2D(gl::TEXTURE_2D, 0, gl::RGB as GLint, VB_WIDTH, VB_HEIGHT, 0, gl::RGB, gl::UNSIGNED_BYTE, texture_data.as_voidptr());
+        gl::TexImage2D(gl::TEXTURE_2D, 0, gl::RGB as GLint, TEXTURE_WIDTH as GLsizei, TEXTURE_HEIGHT as GLsizei, 0, gl::RGB, gl::UNSIGNED_BYTE, texture_data.as_voidptr());
        check_error("load a texture")?;

        gl::TexParameteri(gl::TEXTURE_2D, gl::TEXTURE_MIN_FILTER, gl::NEAREST as GLint);
@ -175,6 +183,15 @@ fn create_texture() -> Result<GLuint, String> {
    }
 }

+fn as_vec<S: Clone>(mat: cgmath::Matrix4<S>) -> Vec<S> {
+    let mut res = Vec::with_capacity(16);
+    let rows: [[S;4];4] = mat.into();
+    for row in rows.iter() {
+        res.extend_from_slice(row);
+    }
+    res
+}
+
 impl Renderer {

    pub fn new() -> Result<Renderer, String> {
@ -197,7 +214,8 @@ impl Renderer {

            let position_location = gl::GetAttribLocation(program_id, c_string!("a_Pos")?.as_ptr()) as GLuint;
            let tex_coord_location = gl::GetAttribLocation(program_id, c_string!("a_TexCoord")?.as_ptr()) as GLuint;
-            let texture_location= gl::GetUniformLocation(program_id, c_string!("s_Texture")?.as_ptr());
+            let modelview_location = gl::GetUniformLocation(program_id, c_string!("u_MV")?.as_ptr());
+            let texture_location= gl::GetUniformLocation(program_id, c_string!("u_Texture")?.as_ptr());

            let texture_id = create_texture()?;

@ -208,18 +226,36 @@ impl Renderer {
                program_id,
                position_location,
                tex_coord_location,
+                modelview_location,
                texture_location,
-                texture_id
+                texture_id,
+                modelview: as_vec(Matrix4::identity())
            }
        };

        Ok(state)
    }

-    pub fn on_surface_changed(&mut self, width: i32, height: i32) {
+    pub fn on_surface_changed(&mut self, screen_width: i32, screen_height: i32) {
        unsafe {
-            gl::Viewport(0, 0, width, height);
+            gl::Viewport(0, 0, screen_width, screen_height);
        }
+        let hsw = screen_width as GLfloat / 2.0;
+        let hsh = screen_height as GLfloat / 2.0;
+        let htw = TEXTURE_WIDTH / 2.0;
+        let hth = TEXTURE_HEIGHT / 2.0;
+
+        let projection = cgmath::ortho(-hsw, hsw, -hsh, hsh, -100.0, 100.0);
+
+        // The texture should take up as much of the screen as possible
+        let scale_to_fit = (hsw / htw).min(hsh / hth);
+
+        let vm = projection * Matrix4::from_nonuniform_scale(TEXTURE_WIDTH * scale_to_fit, TEXTURE_HEIGHT * scale_to_fit, 0.0);
+
+        let bottom_left = vm * vec4(-htw, -hth, 0.0, 1.0);
+        let top_right = vm * vec4(htw, hth, 0.0, 1.0);
+        debug!("Screen stretches from from {:?} to {:?}", bottom_left, top_right);
+        self.modelview = as_vec(vm);
    }

    pub fn on_draw_frame(&self) -> Result<(), String> {
@ -240,6 +276,8 @@ impl Renderer {
            gl::EnableVertexAttribArray(self.position_location);
            gl::EnableVertexAttribArray(self.tex_coord_location);

+            gl::UniformMatrix4fv(self.modelview_location, 1, GL_FALSE, self.modelview.as_ptr());
+
            gl::ActiveTexture(gl::TEXTURE0);
            gl::BindTexture(gl::TEXTURE_2D, self.texture_id);