From 16b94e7221ee3b779caff6acb1aae5d6c8145768 Mon Sep 17 00:00:00 2001
From: Donovan Hutchence <slimbuck7@gmail.com>
Date: Mon, 6 Jun 2022 15:23:41 +0200
Subject: [PATCH] IE shader compile fix (#4298)

---
 src/graphics/program-lib/chunks/common/frag/reproject.js | 6 +-----
 src/graphics/reproject-texture.js                        | 1 +
 2 files changed, 2 insertions(+), 5 deletions(-)

diff --git a/src/graphics/program-lib/chunks/common/frag/reproject.js b/src/graphics/program-lib/chunks/common/frag/reproject.js
index 89d11f1e0a3..abb1e393fb1 100644
--- a/src/graphics/program-lib/chunks/common/frag/reproject.js
+++ b/src/graphics/program-lib/chunks/common/frag/reproject.js
@@ -9,6 +9,7 @@ export default /* glsl */`
 //
 // When filtering:
 // NUM_SAMPLES - number of samples
+// NUM_SAMPLES_SQRT - sqrt of number of samples
 //
 // SUPPORTS_TEXLOD - whether supports texlod is supported
 
@@ -273,11 +274,6 @@ vec4 reproject() {
         vec2 sph = toSpherical(TARGET_FUNC());
         vec2 sphu = dFdx(sph);
         vec2 sphv = dFdy(sph);
-
-        // TODO: check this declaration works on old devices.
-        // might need to be placed globally or be made a #define
-        const float NUM_SAMPLES_SQRT = sqrt(float(NUM_SAMPLES));
-
         vec3 result = vec3(0.0);
         for (float u = 0.0; u < NUM_SAMPLES_SQRT; ++u) {
             for (float v = 0.0; v < NUM_SAMPLES_SQRT; ++v) {
diff --git a/src/graphics/reproject-texture.js b/src/graphics/reproject-texture.js
index 1df4aaead4f..501c7768876 100644
--- a/src/graphics/reproject-texture.js
+++ b/src/graphics/reproject-texture.js
@@ -467,6 +467,7 @@ function reprojectTexture(source, target, options = {}) {
             `#define SOURCE_FUNC ${sourceFunc}\n` +
             `#define TARGET_FUNC ${targetFunc}\n` +
             `#define NUM_SAMPLES ${numSamples}\n` +
+            `#define NUM_SAMPLES_SQRT ${Math.round(Math.sqrt(numSamples)).toFixed(1)}\n` +
             (device.extTextureLod ? `#define SUPPORTS_TEXLOD\n` : '');
 
         let extensions = '';