From 8ceaec9517b075f3dcde1ac99755dac59657b280 Mon Sep 17 00:00:00 2001
From: Dzmitry Malyshau <kvark@fastmail.com>
Date: Fri, 20 Sep 2024 00:14:29 -0700
Subject: [PATCH] Fix viewport Y orientation

---
 blade-render/code/camera.inc.wgsl | 6 ++++--
 blade-render/code/post-proc.wgsl  | 2 +-
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/blade-render/code/camera.inc.wgsl b/blade-render/code/camera.inc.wgsl
index bffbbbd9..c7132373 100644
--- a/blade-render/code/camera.inc.wgsl
+++ b/blade-render/code/camera.inc.wgsl
@@ -6,11 +6,13 @@ struct CameraParams {
     target_size: vec2<u32>,
 }
 
+const VFLIP: vec2<f32> = vec2<f32>(1.0, -1.0);
+
 fn get_ray_direction(cp: CameraParams, pixel: vec2<i32>) -> vec3<f32> {
     let half_size = 0.5 * vec2<f32>(cp.target_size);
     let ndc = (vec2<f32>(pixel) + vec2<f32>(0.5) - half_size) / half_size;
     // Right-handed coordinate system with X=right, Y=up, and Z=towards the camera
-    let local_dir = vec3<f32>(ndc * tan(0.5 * cp.fov), -1.0);
+    let local_dir = vec3<f32>(VFLIP * ndc * tan(0.5 * cp.fov), -1.0);
     return normalize(qrot(cp.orientation, local_dir));
 }
 
@@ -21,7 +23,7 @@ fn get_projected_pixel_float(cp: CameraParams, point: vec3<f32>) -> vec2<f32> {
     }
     let ndc = local_dir.xy / (-local_dir.z * tan(0.5 * cp.fov));
     let half_size = 0.5 * vec2<f32>(cp.target_size);
-    return (ndc + vec2<f32>(1.0)) * half_size;
+    return (VFLIP * ndc + vec2<f32>(1.0)) * half_size;
 }
 
 fn get_projected_pixel(cp: CameraParams, point: vec3<f32>) -> vec2<i32> {
diff --git a/blade-render/code/post-proc.wgsl b/blade-render/code/post-proc.wgsl
index c0681446..dc708bb3 100644
--- a/blade-render/code/post-proc.wgsl
+++ b/blade-render/code/post-proc.wgsl
@@ -30,7 +30,7 @@ fn postfx_vs(@builtin(vertex_index) vi: u32) -> VertexOutput {
 
 @fragment
 fn postfx_fs(vo: VertexOutput) -> @location(0) vec4<f32> {
-    let tc = vec2<i32>(i32(vo.clip_pos.x), i32(vo.input_size.y) - i32(vo.clip_pos.y) - 1);
+    let tc = vec2<i32>(i32(vo.clip_pos.x), i32(vo.clip_pos.y));
     let illumunation = textureLoad(light_diffuse, tc, 0);
     if (debug_params.view_mode == DebugMode_Final) {
         let albedo = textureLoad(t_albedo, tc, 0).xyz;