Use proper UV in cubemap downsampler raster

This removes bias in cubemap downsampling shader that resulted in the bottom of cubemaps being over represented

(cherry picked from commit fb77021559c42d5512f12baa07dcf94c47b7ab15)

1 files changed, 101 insertions, 103 deletions

diff --git a/servers/rendering/renderer_rd/shaders/effects/cubemap_downsampler_raster.glsl b/servers/rendering/renderer_rd/shaders/effects/cubemap_downsampler_raster.glsl
index 0828ffd921..b8c64d09f4 100644
--- a/servers/rendering/renderer_rd/shaders/effects/cubemap_downsampler_raster.glsl
+++ b/servers/rendering/renderer_rd/shaders/effects/cubemap_downsampler_raster.glsl
@@ -55,109 +55,107 @@ void main() {
 	// Converted from compute shader which uses absolute coordinates.
 	// Could possibly simplify this
 	float face_size = float(params.face_size);
+	float inv_face_size = 1.0 / face_size;
+	vec2 id = floor(uv_interp);
 
-	if (uv_interp.x < face_size && uv_interp.y < face_size) {
-		float inv_face_size = 1.0 / face_size;
-
-		float u0 = (uv_interp.x * 2.0 + 1.0 - 0.75) * inv_face_size - 1.0;
-		float u1 = (uv_interp.x * 2.0 + 1.0 + 0.75) * inv_face_size - 1.0;
-
-		float v0 = (uv_interp.y * 2.0 + 1.0 - 0.75) * -inv_face_size + 1.0;
-		float v1 = (uv_interp.y * 2.0 + 1.0 + 0.75) * -inv_face_size + 1.0;
-
-		float weights[4];
-		weights[0] = calcWeight(u0, v0);
-		weights[1] = calcWeight(u1, v0);
-		weights[2] = calcWeight(u0, v1);
-		weights[3] = calcWeight(u1, v1);
-
-		const float wsum = 0.5 / (weights[0] + weights[1] + weights[2] + weights[3]);
-		for (int i = 0; i < 4; i++) {
-			weights[i] = weights[i] * wsum + .125;
-		}
-
-		vec3 dir;
-		vec4 color;
-		switch (params.face_id) {
-			case 0:
-				get_dir_0(dir, u0, v0);
-				color = textureLod(source_cubemap, normalize(dir), 0.0) * weights[0];
-
-				get_dir_0(dir, u1, v0);
-				color += textureLod(source_cubemap, normalize(dir), 0.0) * weights[1];
-
-				get_dir_0(dir, u0, v1);
-				color += textureLod(source_cubemap, normalize(dir), 0.0) * weights[2];
-
-				get_dir_0(dir, u1, v1);
-				color += textureLod(source_cubemap, normalize(dir), 0.0) * weights[3];
-				break;
-			case 1:
-				get_dir_1(dir, u0, v0);
-				color = textureLod(source_cubemap, normalize(dir), 0.0) * weights[0];
-
-				get_dir_1(dir, u1, v0);
-				color += textureLod(source_cubemap, normalize(dir), 0.0) * weights[1];
-
-				get_dir_1(dir, u0, v1);
-				color += textureLod(source_cubemap, normalize(dir), 0.0) * weights[2];
-
-				get_dir_1(dir, u1, v1);
-				color += textureLod(source_cubemap, normalize(dir), 0.0) * weights[3];
-				break;
-			case 2:
-				get_dir_2(dir, u0, v0);
-				color = textureLod(source_cubemap, normalize(dir), 0.0) * weights[0];
-
-				get_dir_2(dir, u1, v0);
-				color += textureLod(source_cubemap, normalize(dir), 0.0) * weights[1];
-
-				get_dir_2(dir, u0, v1);
-				color += textureLod(source_cubemap, normalize(dir), 0.0) * weights[2];
-
-				get_dir_2(dir, u1, v1);
-				color += textureLod(source_cubemap, normalize(dir), 0.0) * weights[3];
-				break;
-			case 3:
-				get_dir_3(dir, u0, v0);
-				color = textureLod(source_cubemap, normalize(dir), 0.0) * weights[0];
-
-				get_dir_3(dir, u1, v0);
-				color += textureLod(source_cubemap, normalize(dir), 0.0) * weights[1];
-
-				get_dir_3(dir, u0, v1);
-				color += textureLod(source_cubemap, normalize(dir), 0.0) * weights[2];
-
-				get_dir_3(dir, u1, v1);
-				color += textureLod(source_cubemap, normalize(dir), 0.0) * weights[3];
-				break;
-			case 4:
-				get_dir_4(dir, u0, v0);
-				color = textureLod(source_cubemap, normalize(dir), 0.0) * weights[0];
-
-				get_dir_4(dir, u1, v0);
-				color += textureLod(source_cubemap, normalize(dir), 0.0) * weights[1];
-
-				get_dir_4(dir, u0, v1);
-				color += textureLod(source_cubemap, normalize(dir), 0.0) * weights[2];
-
-				get_dir_4(dir, u1, v1);
-				color += textureLod(source_cubemap, normalize(dir), 0.0) * weights[3];
-				break;
-			default:
-				get_dir_5(dir, u0, v0);
-				color = textureLod(source_cubemap, normalize(dir), 0.0) * weights[0];
-
-				get_dir_5(dir, u1, v0);
-				color += textureLod(source_cubemap, normalize(dir), 0.0) * weights[1];
-
-				get_dir_5(dir, u0, v1);
-				color += textureLod(source_cubemap, normalize(dir), 0.0) * weights[2];
-
-				get_dir_5(dir, u1, v1);
-				color += textureLod(source_cubemap, normalize(dir), 0.0) * weights[3];
-				break;
-		}
-		frag_color = color;
+	float u1 = (id.x * 2.0 + 1.0 + 0.75) * inv_face_size - 1.0;
+	float u0 = (id.x * 2.0 + 1.0 - 0.75) * inv_face_size - 1.0;
+
+	float v0 = (id.y * 2.0 + 1.0 - 0.75) * -inv_face_size + 1.0;
+	float v1 = (id.y * 2.0 + 1.0 + 0.75) * -inv_face_size + 1.0;
+
+	float weights[4];
+	weights[0] = calcWeight(u0, v0);
+	weights[1] = calcWeight(u1, v0);
+	weights[2] = calcWeight(u0, v1);
+	weights[3] = calcWeight(u1, v1);
+
+	const float wsum = 0.5 / (weights[0] + weights[1] + weights[2] + weights[3]);
+	for (int i = 0; i < 4; i++) {
+		weights[i] = weights[i] * wsum + .125;
+	}
+
+	vec3 dir;
+	vec4 color;
+	switch (params.face_id) {
+		case 0:
+			get_dir_0(dir, u0, v0);
+			color = textureLod(source_cubemap, normalize(dir), 0.0) * weights[0];
+
+			get_dir_0(dir, u1, v0);
+			color += textureLod(source_cubemap, normalize(dir), 0.0) * weights[1];
+
+			get_dir_0(dir, u0, v1);
+			color += textureLod(source_cubemap, normalize(dir), 0.0) * weights[2];
+
+			get_dir_0(dir, u1, v1);
+			color += textureLod(source_cubemap, normalize(dir), 0.0) * weights[3];
+			break;
+		case 1:
+			get_dir_1(dir, u0, v0);
+			color = textureLod(source_cubemap, normalize(dir), 0.0) * weights[0];
+
+			get_dir_1(dir, u1, v0);
+			color += textureLod(source_cubemap, normalize(dir), 0.0) * weights[1];
+
+			get_dir_1(dir, u0, v1);
+			color += textureLod(source_cubemap, normalize(dir), 0.0) * weights[2];
+
+			get_dir_1(dir, u1, v1);
+			color += textureLod(source_cubemap, normalize(dir), 0.0) * weights[3];
+			break;
+		case 2:
+			get_dir_2(dir, u0, v0);
+			color = textureLod(source_cubemap, normalize(dir), 0.0) * weights[0];
+
+			get_dir_2(dir, u1, v0);
+			color += textureLod(source_cubemap, normalize(dir), 0.0) * weights[1];
+
+			get_dir_2(dir, u0, v1);
+			color += textureLod(source_cubemap, normalize(dir), 0.0) * weights[2];
+
+			get_dir_2(dir, u1, v1);
+			color += textureLod(source_cubemap, normalize(dir), 0.0) * weights[3];
+			break;
+		case 3:
+			get_dir_3(dir, u0, v0);
+			color = textureLod(source_cubemap, normalize(dir), 0.0) * weights[0];
+
+			get_dir_3(dir, u1, v0);
+			color += textureLod(source_cubemap, normalize(dir), 0.0) * weights[1];
+
+			get_dir_3(dir, u0, v1);
+			color += textureLod(source_cubemap, normalize(dir), 0.0) * weights[2];
+
+			get_dir_3(dir, u1, v1);
+			color += textureLod(source_cubemap, normalize(dir), 0.0) * weights[3];
+			break;
+		case 4:
+			get_dir_4(dir, u0, v0);
+			color = textureLod(source_cubemap, normalize(dir), 0.0) * weights[0];
+
+			get_dir_4(dir, u1, v0);
+			color += textureLod(source_cubemap, normalize(dir), 0.0) * weights[1];
+
+			get_dir_4(dir, u0, v1);
+			color += textureLod(source_cubemap, normalize(dir), 0.0) * weights[2];
+
+			get_dir_4(dir, u1, v1);
+			color += textureLod(source_cubemap, normalize(dir), 0.0) * weights[3];
+			break;
+		default:
+			get_dir_5(dir, u0, v0);
+			color = textureLod(source_cubemap, normalize(dir), 0.0) * weights[0];
+
+			get_dir_5(dir, u1, v0);
+			color += textureLod(source_cubemap, normalize(dir), 0.0) * weights[1];
+
+			get_dir_5(dir, u0, v1);
+			color += textureLod(source_cubemap, normalize(dir), 0.0) * weights[2];
+
+			get_dir_5(dir, u1, v1);
+			color += textureLod(source_cubemap, normalize(dir), 0.0) * weights[3];
+			break;
 	}
+	frag_color = color;
 }