Removed flipY from REGL renderer's texture load function, to increase similarity between renderer implementations and rule out a sampling discrepancy

js/regl/utils.js

@@ -59,7 +59,6 @@ const loadImage = (regl, url) => {
 					data,
 					mag: "linear",
 					min: "linear",
-					flipY: true,
 				});
 			}
 		})(),

shaders/glsl/rainPass.frag.glsl

@@ -102,13 +102,13 @@ vec3 getBrightness(vec4 raindrop, vec4 effect, float quadDepth, vec2 uv) {
 vec2 getSymbolUV(float index) {
 	float symbolX = modI(index, glyphTextureGridSize.x);
 	float symbolY = (index - symbolX) / glyphTextureGridSize.x;
-	symbolY = glyphTextureGridSize.y - symbolY - 1.;
 	return vec2(symbolX, symbolY);
 }
 
 vec2 getSymbol(vec2 uv, float index) {
 	// resolve UV to cropped position of glyph in MSDF texture
 	uv = fract(uv * vec2(numColumns, numRows));
+	uv.y = 1.0 - uv.y; // y-flip
 	uv -= 0.5;
 	uv *= clamp(1. - glyphEdgeCrop, 0., 1.);
 	uv += 0.5;

shaders/wgsl/rainPass.wgsl

@@ -493,7 +493,7 @@ fn getSymbolUV(symbol : i32) -> vec2<f32> {
 fn getSymbol(cellUV : vec2<f32>, index : i32) -> vec2<f32> {
 	// resolve UV to cropped position of glyph in MSDF texture
 	var uv = fract(cellUV * config.gridSize);
-	uv.y = 1.0 - uv.y; // WebGL -> WebGPU y-flip
+	uv.y = 1.0 - uv.y; // y-flip
 	uv -= 0.5;
 	uv *= clamp(1.0 - config.glyphEdgeCrop, 0.0, 1.0);
 	uv += 0.5;