From ae2f086637691e62f58921caf3db2f23bbcada00 Mon Sep 17 00:00:00 2001
From: dengqn <434500374@qq.com>
Date: Thu, 31 Jul 2025 15:31:52 +0800
Subject: [PATCH] 2.Output an Image

---
 .gitignore             |  1 +
 Cargo.lock             |  7 +++++++
 Cargo.toml             |  6 ++++++
 src/image.rs           | 36 ++++++++++++++++++++++++++++++++++++
 src/main.rs            | 10 ++++++++++
 src/write_file_util.rs | 12 ++++++++++++
 6 files changed, 72 insertions(+)
 create mode 100644 .gitignore
 create mode 100644 Cargo.lock
 create mode 100644 Cargo.toml
 create mode 100644 src/image.rs
 create mode 100644 src/main.rs
 create mode 100644 src/write_file_util.rs

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..ea8c4bf
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+/target
diff --git a/Cargo.lock b/Cargo.lock
new file mode 100644
index 0000000..285b107
--- /dev/null
+++ b/Cargo.lock
@@ -0,0 +1,7 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 4
+
+[[package]]
+name = "ray-trace-w1"
+version = "0.1.0"
diff --git a/Cargo.toml b/Cargo.toml
new file mode 100644
index 0000000..8ab0327
--- /dev/null
+++ b/Cargo.toml
@@ -0,0 +1,6 @@
+[package]
+name = "ray-trace-w1"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
diff --git a/src/image.rs b/src/image.rs
new file mode 100644
index 0000000..0017c1e
--- /dev/null
+++ b/src/image.rs
@@ -0,0 +1,36 @@
+/*
+* -------width(i)-------
+* |
+* |
+* height(j)
+* |
+* |
+* ----------------------
+* 
+* ppm p3 format:
+* 
+* P3
+* 
+* [width] [height]
+* [max color]
+* R1 G1 B1
+* R2 G2 B2
+* R3 G3 B3
+* ...xN
+*/
+pub fn gen_gradient_ppm_p3(width: i32, height: i32) -> String {
+    let mut img_content = format!("P3\n{} {}\n255\n", width, height);
+
+    for j in 0..height {
+        for i in 0..width {
+            let r = 256.0 * (i as f32 / (width-1) as f32);
+            let g = 256.0 * (j as f32 / (height-1) as f32);
+            let b = 256.0 * ((i+j) as f32 / (width + height - 2) as f32);
+
+            img_content.push_str(format!("{} {} {}", r as u8, g as u8, b as u8).as_str());
+            img_content.push('\n');
+        }
+    }
+
+    img_content
+}
\ No newline at end of file
diff --git a/src/main.rs b/src/main.rs
new file mode 100644
index 0000000..efcc1ad
--- /dev/null
+++ b/src/main.rs
@@ -0,0 +1,10 @@
+use write_file_util::{write_image};
+use image::{gen_gradient_ppm_p3};
+
+mod image;
+mod write_file_util;
+
+fn main() {
+    let ppm_content = gen_gradient_ppm_p3(400, 225);
+    write_image(ppm_content, "./target/test.ppm".to_string())
+}
diff --git a/src/write_file_util.rs b/src/write_file_util.rs
new file mode 100644
index 0000000..ceca186
--- /dev/null
+++ b/src/write_file_util.rs
@@ -0,0 +1,12 @@
+use std::{fs::File, io::{BufWriter, Write}};
+
+pub fn write_image(content: String, file_path: String) {
+    if let Ok(file) = File::create(file_path) {
+        let mut writer = BufWriter::new(file);
+        if let Err(e) = writer.write(content.as_bytes()) {
+            println!("写出失败：{:#}", e)
+        }
+    } else {
+        println!("PPM保存失败")
+    }
+}
\ No newline at end of file